Sample records for multiple crystal cavities

  1. Enhanced photodetection in graphene-integrated photonic crystal cavity

    SciTech Connect (OSTI)

    Shiue, Ren-Jye; Englund, Dirk, E-mail: englund@mit.edu [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Gan, Xuetao; Li, Luozhou; Yao, Xinwen [Department of Electrical Engineering, Columbia University, New York, New York 10027 (United States)] [Department of Electrical Engineering, Columbia University, New York, New York 10027 (United States); Gao, Yuanda; Hone, James [Department of Mechanical Engineering, Columbia University, New York, New York 10027 (United States)] [Department of Mechanical Engineering, Columbia University, New York, New York 10027 (United States); Szep, Attila; Walker, Dennis [Air Force Research Laboratory, Sensors Directorate, WPAFB, Dayton, Ohio 45433 (United States)] [Air Force Research Laboratory, Sensors Directorate, WPAFB, Dayton, Ohio 45433 (United States)

    2013-12-09T23:59:59.000Z

    We demonstrate the controlled enhancement of photoresponsivity in a graphene photodetector by coupling to slow light modes in a long photonic crystal linear defect cavity. Near the Brillouin zone (BZ) boundary, spectral coupling of multiple cavity modes results in broad-band photocurrent enhancement from 1530?nm to 1540?nm. Away from the BZ boundary, individual cavity resonances enhance the photocurrent eight-fold in narrow resonant peaks. Optimization of the photocurrent via critical coupling of the incident field with the graphene-cavity system is discussed. The enhanced photocurrent demonstrates the feasibility of a wavelength-scale graphene photodetector for efficient photodetection with high spectral selectivity and broadband response.

  2. General recipe for designing photonic crystal cavities

    E-Print Network [OSTI]

    Vuckovic, Jelena

    . Yariv and P. Yeh, Optical Waves in Crystals (Wiley and Sons, 2003). 13. A. Badolato, K. Hennessy, M and links 1. S. Johnson, S. Fan, A. Mekis, and J. Joannopoulos, "Multipole-cancellation mechanism for high. Vuckovi´c, M. Loncar, H. Mabuchi, and A. Scherer, "Design of photonic crystal microcavities for cavity QED

  3. Nanobeam photonic crystal cavity quantum dot laser

    E-Print Network [OSTI]

    Vuckovic, Jelena

    1. O. Painter, R. K. Lee, A. Scherer, A. Yariv, J. D. O'Brien, P. D. Dapkus, and I. Kim, "Two, J. Vuckovi´c, and A. Scherer, "Planar photonic crystal nanolasers (I): Porous cavity lasers," IEICE coupling factor," Phys. Rev. B 75, 195313 (2007). 9. S. Strauf, K. Hennessy, M. T. Rakher, Y.-S. Choi, A

  4. Enhanced photodetection in graphene-integrated photonic crystal cavity

    E-Print Network [OSTI]

    Shiue, Ren-Jye

    We demonstrate the controlled enhancement of photoresponsivity in a graphene photodetector by coupling to slow light modes in a long photonic crystal linear defect cavity. Near the Brillouin zone (BZ) boundary, spectral ...

  5. Nanobeam Photonic Crystal Cavity Light-Emitting Diodes

    E-Print Network [OSTI]

    Shambat, Gary; Petykiewicz, Jan; Mayer, Marie A; Sarmiento, Tomas; Harris, James; Haller, Eugene E; Vuckovic, Jelena

    2011-01-01T23:59:59.000Z

    We present results on electrically driven nanobeam photonic crystal cavities formed out of a lateral p-i-n junction in gallium arsenide. Despite their small conducting dimensions, nanobeams have robust electrical properties with high current densities possible at low drive powers. Much like their two-dimensional counterparts, the nanobeam cavities exhibit bright electroluminescence at room temperature from embedded 1,250 nm InAs quantum dots. A small room temperature differential gain is observed in the cavities with minor beam self-heating suggesting that lasing is possible. These results open the door for efficient electrical control of active nanobeam cavities for diverse nanophotonic applications.

  6. Design of photonic crystal microcavities for cavity QED

    E-Print Network [OSTI]

    Jelena Vuckovic; Marko Loncar; Hideo Mabuchi; Axel Scherer

    2002-08-15T23:59:59.000Z

    We discuss the optimization of optical microcavity designs based on 2D photonic crystals for the purpose of strong coupling between the cavity field and a single neutral atom trapped within a hole. We present numerical predictions for the quality factors and mode volumes of localized defect modes as a function of geometric parameters, and discuss some experimental challenges related to the coupling of a defect cavity to gas-phase atoms.

  7. Local tuning of photonic crystal cavities using chalcogenide glasses

    E-Print Network [OSTI]

    Andrei Faraon; Dirk Englund; Douglas Bulla; Barry Luther-Davies; Benjamin J. Eggleton; Nick Stoltz; Pierre Petroff; Jelena Vuckovic

    2007-11-09T23:59:59.000Z

    We demonstrate a method to locally change the refractive index in planar optical devices by photodarkening of a thin chalcogenide glass layer deposited on top of the device. The method is used to tune the resonance of GaAs-based photonic crystal cavities by up to 3 nm at 940 nm, with only 5% deterioration in cavity quality factor. The method has broad applications for postproduction tuning of photonic devices.

  8. Novel photonic crystal cavities and related structures.

    SciTech Connect (OSTI)

    Luk, Ting Shan

    2007-11-01T23:59:59.000Z

    The key accomplishment of this project is to achieve a much more in-depth understanding of the thermal emission physics of metallic photonic crystal through theoretical modeling and experimental measurements. An improved transfer matrix technique was developed to enable incorporation of complex dielectric function. Together with microscopic theory describing emitter radiative and non-radiative relaxation dynamics, a non-equilibrium thermal emission model is developed. Finally, experimental methodology was developed to measure absolute emissivity of photonic crystal at high temperatures with accuracy of +/-2%. Accurate emissivity measurements allow us to validate the procedure to treat the effect of the photonic crystal substrate.

  9. Design and analysis of photonic crystal coupled cavity arrays for quantum simulation

    E-Print Network [OSTI]

    Arka Majumdar; Armand Rundquist; Michal Bajcsy; Vaishno D. Dasika; Seth R. Bank; Jelena Vuckovic

    2012-09-14T23:59:59.000Z

    We performed an experimental study of coupled optical cavity arrays in a photonic crystal platform. We find that the coupling between the cavities is significantly larger than the fabrication-induced disorder in the cavity frequencies. Satisfying this condition is necessary for using such cavity arrays to generate strongly correlated photons, which has potential application to the quantum simulation of many-body systems.

  10. Collective cavity quantum electrodynamics with multiple atomic levels

    E-Print Network [OSTI]

    K. J. Arnold; M. P. Baden; M. D. Barrett

    2011-09-21T23:59:59.000Z

    We study the transmission spectra of ultracold rubidium atoms coupled to a high-finesse optical cavity. Under weak probing with pi-polarized light, the linear response of the system is that of a collective spin with multiple levels coupled to a single mode of the cavity. By varying the atom number, we change the collective coupling of the system. We observe the change in transmission spectra when going from a regime where the collective coupling is much smaller than the separation of the atomic levels to a regime where both are of comparable size. The observations are in good agreement with a reduced model we developed for our system.

  11. Quantum optics and cavity QED with quantum dots in photonic crystals

    E-Print Network [OSTI]

    Jelena Vuckovic

    2014-02-11T23:59:59.000Z

    This chapter will primarily focus on the studies of quantum optics with semiconductor, epitaxially grown quantum dots embedded in photonic crystal cavities. We will start by giving brief introductions into photonic crystals and quantum dots, then proceed with the introduction to cavity quantum electrodynamics (QED) effects, with a particular emphasis on the demonstration of these effects on the quantum dot-photonic crystal platform. Finally, we will focus on the applications of such cavity QED effects.

  12. SINGLE CRYSTAL NIOBIUM TUBES FOR PARTICLE COLLIDERS ACCELERATOR CAVITIES

    SciTech Connect (OSTI)

    MURPHY, JAMES E [University of Nevada, Reno] [University of Nevada, Reno

    2013-02-28T23:59:59.000Z

    The objective of this research project is to produce single crystal niobium (Nb) tubes for use as particle accelerator cavities for the Fermi laboratory’s International Linear Collider project. Single crystal Nb tubes may have superior performance compared to a polycrystalline tubes because the absence of grain boundaries may permit the use of higher accelerating voltages. In addition, Nb tubes that are subjected to the high temperature, high vacuum crystallization process are very pure and well annealed. Any impurity with a significantly higher vapor pressure than Nb should be decreased by the relatively long exposure at high temperature to the high vacuum environment. After application of the single crystal process, the surfaces of the Nb tubes are bright and shiny, and the tube resembles an electro polished Nb tube. For these reasons, there is interest in single crystal Nb tubes and in a process that will produce single crystal tubes. To convert a polycrystalline niobium tube into a single crystal, the tube is heated to within a few hundred ?C of the melting temperature of niobium, which is 2477 ?C. RF heating is used to rapidly heat the tube in a narrow zone and after reaching the operating temperature, the hot zone is slowly passed along the length of the tube. For crystallization tests with Nb tubes, the traverse rate was in the range of 1-10 cm per hour. All the crystallization tests in this study were performed in a water-cooled, stainless steel chamber under a vacuum of 5 x10-6 torr or better. In earliest tests of the single crystal growth process, the Nb tubes had an OD of 1.9 cm and a wall thickness of 0.15 mm. With these relatively small Nb tubes, the single crystal process was always successful in producing single crystal tubes. In these early tests, the operating temperature was normally maintained at 2200 ?C, and the traverse rate was 5 cm per hour. In the next test series, the Nb tube size was increased to 3.8 cm OD and the wall thickness was increased 0.18 mm and eventually to 0.21 mm. Again, with these larger tubes, single crystal tubes were usually produced by the crystallization process. The power supply was generally operated at full output during these tests, and the traverse rate was 5 cm per hour. In a few tests, the traverse rate was increased to 10 cm per hour, and at the faster traverse rate, single crystal growth was not achieved. In these tests with a faster traverse rate, it was thought that the tube was not heated to a high enough temperature to achieve single crystal growth. In the next series of tests, the tube OD was unchanged at 3.8 cm and the wall thickness was increased to 0.30 mm. The increased wall thickness made it difficult to reach an operating temperature above 2,000 ?C, and although the single crystal process caused a large increase in the crystal grains, no single crystal tubes were produced. It was assumed that the operating temperature in these tests was not high enough to achieve single crystal growth. In FY 2012, a larger power supply was purchased and installed. With the new power supply, temperatures above the melting point of Nb were easily obtained regardless of the tube thickness. A series of crystallization tests was initiated to determine if indeed the operating temperature of the previous tests was too low to achieve single crystal growth. For these tests, the Nb tube OD remained at 3.8 cm and the wall thickness was 0.30 mm. The first test had an operating temperature of 2,000 ?C. and the operating temperature was increased by 50 ?C increments for each successive test. The final test was very near the Nb melting temperature, and indeed, the Nb tube eventually melted in the center of the tube. These tests showed that higher temperatures did yield larger grain sizes if the traverse rate was held constant at 5 cm per hour, but no single crystal tubes were produced even at the highest operating temperature. In addition, slowing the traverse rate to as low as 1 cm per hour did not yield a single crystal tube regardless of operating temperature. At this time, it

  13. Off-resonant coupling between a single quantum dot and a nanobeam photonic crystal cavity

    E-Print Network [OSTI]

    Armand Rundquist; Arka Majumdar; Jelena Vuckovic

    2011-10-05T23:59:59.000Z

    We demonstrate off-resonant coupling between a single quantum dot and a nanobeam photonic crystal cavity, under resonant excitation of the quantum dot or the cavity. These results are consistent with previous descriptions of off-resonant coupling as an incoherent phonon-mediated process. The extension of this phenomenon to a nanobeam photonic crystal cavity presents interesting possibilities for coherent control of this interaction by tailoring the phonon density of states.

  14. Collective strong coupling between ion Coulomb crystals and an optical cavity field: Theory and experiment

    E-Print Network [OSTI]

    Albert, M.

    A detailed description and theoretical analysis of experiments achieving coherent coupling between an ion Coulomb crystal and an optical cavity field are presented. The various methods used to measure the coherent coupling ...

  15. Development of large Grain/Single Crystal Niobium Cavity Technology at Jefferson Lab

    SciTech Connect (OSTI)

    Peter Kneisel; J. Sekutowicz; T. Carneiro; G. Ciovati

    2006-10-31T23:59:59.000Z

    Approximately two years ago we started to develop high performance niobium accelerating cavities based on large grain or single crystal high purity niobium. We have fabricated and tested 15 single cell cavities of various shapes and frequencies between 1300 MHz and 2300 MHz using material from a total of 9 different very large grain niobium ingots from four niobium suppliers. The materials differed not only in grain sizes, but also in RRR ? value and in the amount of Ta contained in the material. In one ingot supplied by CBMM the central grain exceeded 7 inches in diameter and this was used to fabricate two 2.2 GHz cavities. A single crystal 1300 MHz mono-cell cavity was also produced at DESY by rolling out a single crystal to the size required for this cavity. It was sent to Jlab for surface treatment and testing. In addition, we have fabricated three 7-cell cavities: two of the Jlab high gradient (HG) shape and one of the ILC Low Loss shape. Two 9-cell TESLA shape cavities are presently in fabrication at Jlab and are close to completion.

  16. Coupled mode theory for photonic crystal cavity-waveguide interaction

    E-Print Network [OSTI]

    Vuckovic, Jelena

    nanocavity in a two-dimensional photonic crystal," Nature 425, 944­947 (2003) 16. A. Yariv. Optical in a two- dimensional photonic-crystal slab," App. Phys. Lett. 83, 407­409 (2003) 5. T. Asano et al. "A

  17. Photonic Crystal Cavities in Cubic (3C) Polytype Silicon Carbide Films

    E-Print Network [OSTI]

    Marina Radulaski; Thomas M. Babinec; Sonia Buckley; Armand Rundquist; J Provine; Kassem Alassaad; Gabriel Ferro; Jelena Vu?kovi?

    2013-11-30T23:59:59.000Z

    We present the design, fabrication, and characterization of high quality factor and small mode volume planar photonic crystal cavities from cubic (3C) thin films (thickness ~ 200 nm) of silicon carbide (SiC) grown epitaxially on a silicon substrate. We demonstrate cavity resonances across the telecommunications band, with wavelengths from 1,250 - 1,600 nm. Finally, we discuss possible applications in nonlinear optics, optical interconnects, and quantum information science.

  18. Deterministic coupling of a single nitrogen vacancy center to a photonic crystal cavity

    E-Print Network [OSTI]

    Dirk Englund; Brendan Shields; Kelley Rivoire; Fariba Hatami; Jelena Vuckovic; Hongkun Park; Mikhail D. Lukin

    2010-05-12T23:59:59.000Z

    We describe and experimentally demonstrate a technique for deterministic coupling between a photonic crystal (PC) nanocavity and single emitters. The technique is based on in-situ scanning of a PC cavity over a sample and allows the positioning of the cavity over a desired emitter with nanoscale resolution. The power of the technique, which we term a Scanning Cavity Microscope (SCM), is demonstrated by coupling the PC nanocavity to a single nitrogen vacancy (NV) center in diamond, an emitter system that provides optically accessible electron and nuclear spin qubits.

  19. A picogram and nanometer scale photonic crystal opto-mechanical cavity

    E-Print Network [OSTI]

    Eichenfield, M; Chan, J; Vahala, K J; Painter, O

    2008-01-01T23:59:59.000Z

    We describe the design, fabrication, and measurement of a cavity opto-mechanical system consisting of two nanobeams of silicon nitride in the near-field of each other, forming a so-called "zipper" cavity. A photonic crystal patterning is applied to the nanobeams to localize optical and mechanical energy to the same cubic-micron-scale volume. The picrogram-scale mass of the structure, along with the strong per-photon optical gradient force, results in a giant optical spring effect. In addition, a novel damping regime is explored in which the small heat capacity of the zipper cavity results in blue-detuned opto-mechanical damping.

  20. Coupling of PbS Quantum Dots to Photonic Crystal Cavities at Room Temperature

    E-Print Network [OSTI]

    Ilya Fushman; Dirk Englund; Jelena Vuckovic

    2005-05-14T23:59:59.000Z

    We demonstrate the coupling of PbS quantum dot emission to photonic crystal cavities at room temperature. The cavities are defined in 33% Al, AlGaAs membranes on top of oxidized AlAs. Quantum dots were dissolved in Poly-methyl-methacrylate (PMMA) and spun on top of the cavities. Quantum dot emission is shown to map out the structure resonances, and may prove to be viable sources for room temperature cavity coupled single photon generation for quantum information processing applications. These results also indicate that such commercially available quantum dots can be used for passive structure characterization. The deposition technique is versatile and allows layers with different dot densities and emission wavelengths to be re-deposited on the same chip.

  1. Linewidth narrowing and Purcell enhancement in photonic crystal cavities

    E-Print Network [OSTI]

    Vuckovic, Jelena

    . Rev. 69, 681 (1946). 7. O. Painter, R. K. Lee, A. Scherer, A. Yariv, J. D. O'Brien, P.D. Dapkus, and I. References and links 1. L. Pavesi, "A review of the various approaches to a silicon laser," Proc. SPIE 4997. Loncar, T. Yoshie, A. Scherer, P. Gogna, and Y. Qiu, "Low-threshold photonic crystal laser," Appl. Phys

  2. Optical properties of photonic crystal heterostructure cavity lasers

    E-Print Network [OSTI]

    Choquette, Kent

    ; (230.5298) Photonic crystals. References and links 1. O. Painter, R. K. Lee, A. Scherer, A. Yariv, J. D," J. Opt. Soc. Am. B 22, 2581­2595 (2005). 11. F. Bordas, M. J. Steel, C. Seassal, and A. Rahamani

  3. Second harmonic generation in photonic crystal cavities in (111)-oriented GaAs

    SciTech Connect (OSTI)

    Buckley, Sonia, E-mail: bucklesm@stanford.edu; Radulaski, Marina; Vu?kovi?, Jelena [E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305 (United States)] [E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305 (United States); Biermann, Klaus [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)] [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)

    2013-11-18T23:59:59.000Z

    We demonstrate second harmonic generation at telecommunications wavelengths in photonic crystal cavities in (111)-oriented GaAs. We fabricate 30 photonic crystal structures in both (111)- and (100)-oriented GaAs and observe an increase in generated second harmonic power in the (111) orientation, with the mean power increased by a factor of 3, although there is a large scatter in the measured values. We discuss possible reasons for this increase, in particular, the reduced two photon absorption for transverse electric modes in (111) orientation, as well as a potential increase due to improved mode overlap.

  4. Dynamics of cavity fields with dissipative and amplifying couplings through multiple quantum two-state systems

    SciTech Connect (OSTI)

    Haeyrynen, Teppo; Oksanen, Jani; Tulkki, Jukka [Department of Biomedical Engineering and Computational Science, Aalto University School of Science and Technology, P. O. Box 12200, FI-00076 AALTO (Finland)

    2011-01-15T23:59:59.000Z

    We consider simultaneous dissipative and amplifying coupling of cavity fields to multiple two-state systems. We derive a master equation for optical field in a leaky cavity coupled to a reservoir through multiple two-state systems. In our previous works we have limited our study to systems where the reservoir either solely absorbs energy (detector setup) or adds energy (amplifying setup) to the cavity through a single two-state system. In this work we allow both interactions simultaneously and derive a reduced dynamic model for the optical field. We also generalize our model to cover the coupling of the field to several two state systems and discuss its connection to macroscopic interaction, e.g., in semiconductors. Our model includes four physical parameters: the field two-state system coupling {gamma}, the excitation and deexcitation couplings of the two-state system by the reservoir {lambda}{sub A} and {lambda}{sub D}, respectively, and the mirror losses of the cavity C. We solve the steady-state fields at different regimes of these physical parameters. Furthermore, we show that, depending on the parameters, our model can describe the operation of a detector, a light emitting diode, or a laser.

  5. Microwave power coupler for a superconducting multiple-cell cavity for accelerator application and its testing procedures

    SciTech Connect (OSTI)

    Li, Jianjian; /IIT, Chicago

    2008-12-01T23:59:59.000Z

    Superconducting cavity resonators offer the advantage of high field intensity for a given input power, making them an attractive contender for particle accelerator applications. Power coupling into a superconducting cavity employed in a particle accelerator requires unique provisions to maintain high vacuum and cryogenic temperature on the cavity side, while operating with ambient conditions on the source side. Components introduced to fulfill mechanical requirements must show negligible obstruction of the propagation of the microwave with absence of critical locations that may give rise to electron multipaction, leading to a multiple section design, instead of an aperture, a probe, or a loop structure as found in conventional cavities. A coaxial power coupler for a superconducting multiple-cell cavity at 3.9 GHz has been developed. The cavity is intended to be employed as an accelerator to provide enhanced electron beam quality in a free-electron laser in Hamburg (FLASH) user facility. The design of the coupler called for two windows to sustain high vacuum in the cavity and two bellows to accommodate mechanical dimensional changes resulting from cryogenics. Suppression of multipacting was accomplished by the choice of conductor dimensions and materials with low second yield coefficients. Prior to integration with the cavity, the coupler was tested for intrinsic properties in a back-to-back configuration and conditioned for high-power operation with increasing power input. Maximum incident power was measured to be 61 kW. When integrated with the superconducting cavity, a loaded quality factor of 9 x 10{sup 5} was measured by transient method. Coupler return loss and insertion loss were estimated to be around -21 dB and -0.2 dB, respectively.

  6. Quasiresonant Excitation of InP/InGaP Quantum Dots Using Second Harmonic Generated in a Photonic Crystal Cavity

    E-Print Network [OSTI]

    Buckley, Sonia; Hatami, Fariba; Vuckovic, Jelena

    2012-01-01T23:59:59.000Z

    Indistinguishable single photons are necessary for quantum information processing applications. Resonant or quasiresonant excitation of single quantum dots provides greater single photon indistinguishability than incoherent pumping, but is also more challenging experimentally. Here, we demonstrate high signal to noise quasiresonant excitation of InP/InGaP quantum dots. The excitation is provided via second harmonic generated from a telecommunications wavelength laser resonant with the fundamental mode of a photonic crystal cavity, fabricated at twice the quantum dot transition wavelength. The second harmonic is generated using the \\chi(2) nonlinearity of the InGaP material matrix.

  7. Quasiresonant Excitation of InP/InGaP Quantum Dots Using Second Harmonic Generated in a Photonic Crystal Cavity

    E-Print Network [OSTI]

    Sonia Buckley; Kelley Rivoire; Fariba Hatami; Jelena Vuckovic

    2012-10-03T23:59:59.000Z

    Indistinguishable single photons are necessary for quantum information processing applications. Resonant or quasiresonant excitation of single quantum dots provides greater single photon indistinguishability than incoherent pumping, but is also more challenging experimentally. Here, we demonstrate high signal to noise quasiresonant excitation of InP/InGaP quantum dots. The excitation is provided via second harmonic generated from a telecommunications wavelength laser resonant with the fundamental mode of a photonic crystal cavity, fabricated at twice the quantum dot transition wavelength. The second harmonic is generated using the \\chi(2) nonlinearity of the InGaP material matrix.

  8. Large optical cavity AlGaAs injection lasers with multiple active regions

    SciTech Connect (OSTI)

    Katz, J.; Bar-Chaim, N.; Margalit, S.; Yariv, A.

    1980-08-01T23:59:59.000Z

    A new type of AlGaAs injection laser is described. The structure consists of alternating p- and n-type layers of GaAs and Al/sub x/ Ga/sub 1-x/As . The electrical mode of operation of the device is that of a Shockley diode (SCR). Optically the device operates as a large optical cavity. Single transverse mode operation was observed with optical cavities larger than 4 ..mu..m.

  9. Nanobeam photonic crystal cavity light-emitting diodes Gary Shambat,1,a)

    E-Print Network [OSTI]

    Vuckovic, Jelena

    temperature differential gain is observed in the cavities with minor beam self-heating suggesting that lasing Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA 2 Materials 2011; accepted 26 July 2011; published online 16 August 2011) We present results on electrically driven

  10. A short working distance multiple crystal x-ray spectrometer

    SciTech Connect (OSTI)

    Dickinson, B.; Seidler, G. T.; Webb, Z. W.; Bradley, J. A.; Nagle, K. P. [Department of Physics, University of Washington, Seattle, Washington 98195 (United States); Heald, S. M. [Advanced Photon Source, Argonne National Laboratories, Argonne, Illinois 60439 (United States); Gordon, R. A. [Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Chou, I. M. [U.S. Geological Survey, Reston, Virginia 20192 (United States)

    2008-12-15T23:59:59.000Z

    For x-ray spot sizes of a few tens of microns or smaller, a millimeter-sized flat analyzer crystal placed {approx}1 cm from the sample will exhibit high energy resolution while subtending a collection solid angle comparable to that of a typical spherically bent crystal analyzer (SBCA) at much larger working distances. Based on this observation and a nonfocusing geometry for the analyzer optic, we have constructed and tested a short working distance (SWD) multicrystal x-ray spectrometer. This prototype instrument has a maximum effective collection solid angle of 0.14 sr, comparable to that of 17 SBCA at 1 m working distance. We find good agreement with prior work for measurements of the Mn K{beta} x-ray emission and resonant inelastic x-ray scattering for MnO, and also for measurements of the x-ray absorption near-edge structure for Dy metal using L{alpha}{sub 2} partial-fluorescence yield detection. We discuss future applications at third- and fourth-generation light sources. For concentrated samples, the extremely large collection angle of SWD spectrometers will permit collection of high-resolution x-ray emission spectra with a single pulse of the Linac Coherent Light Source. The range of applications of SWD spectrometers and traditional multi-SBCA instruments has some overlap, but also is significantly complementary.

  11. Paired modes of heterostructure cavities in photonic crystal waveguides with split

    E-Print Network [OSTI]

    . Painter, R. K. Lee, A. Scherer, A. Yariv, J. D. O'Brien, P. D. Dapkus, and I. Kim, "Two Sahand Mahmoodian,1, Andrey A. Sukhorukov,2 Sangwoo Ha,2 Andrei V. Lavrinenko,2,4 Christopher G. Poulton crystals. References and links 1. K. Nozaki, T. Tanabe, A. Shinya, S. Matsuo, T. Sato, H. Taniyama, and M

  12. High sensitivity and high Q-factor nanoslotted parallel quadrabeam photonic crystal cavity for real-time and label-free sensing

    SciTech Connect (OSTI)

    Yang, Daquan [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); State Key Laboratory of Information Photonics and Optical Communications, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Kita, Shota; Wang, Cheng; Lon?ar, Marko [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Liang, Feng; Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Tian, Huiping; Ji, Yuefeng [State Key Laboratory of Information Photonics and Optical Communications, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2014-08-11T23:59:59.000Z

    We experimentally demonstrate a label-free sensor based on nanoslotted parallel quadrabeam photonic crystal cavity (NPQC). The NPQC possesses both high sensitivity and high Q-factor. We achieved sensitivity (S) of 451?nm/refractive index unit and Q-factor >7000 in water at telecom wavelength range, featuring a sensor figure of merit >2000, an order of magnitude improvement over the previous photonic crystal sensors. In addition, we measured the streptavidin-biotin binding affinity and detected 10 ag/mL concentrated streptavidin in the phosphate buffered saline solution.

  13. Optical and mechanical design of a "zipper" photonic crystal optomechanical cavity

    E-Print Network [OSTI]

    Chan, Jasper; Camacho, Ryan; Painter, Oskar

    2008-01-01T23:59:59.000Z

    Design of a doubly-clamped beam structure capable of localizing mechanical and optical energy at the nanoscale is presented. The optical design is based upon photonic crystal concepts in which patterning of a nanoscale-cross-section beam can result in strong optical localization to an effective optical mode volume of 0.2 cubic wavelengths ((\\lambda_{c})^3). By placing two identical nanobeams within the near field of each other, strong optomechanical coupling can be realized for differential motion between the beams. Current designs for thin film silicon nitride beams at a wavelength of 1.5 microns indicate that such structures can simultaneously realize an optical Q-factor of 7x10^6, motional mass m~40 picograms, mechanical mode frequency ~170 MHz, and an optomechanical coupling factor (g_{OM}=d\\omega_{c}/dx = \\omega_{c}/L_{OM}) with effective length L_{OM} ~ \\lambda = 1.5 microns.

  14. The effect of photo-generated carriers on the spectral diffusion of a quantum dot coupled to a photonic crystal cavity

    E-Print Network [OSTI]

    Arka Majumdar; Erik D. Kim; Jelena Vuckovic

    2011-07-24T23:59:59.000Z

    We experimentally observe the effect of photo-generated carriers on the spectral diffusion of a quantum dot (QD) coupled to a photonic crystal (PC) cavity. In this system, spectral diffusion arises in part from charge fluctuations on the etched surfaces of the PC. We find that these fluctuations may be suppressed by photo-generated carriers, leading to a reduction of the measured QD linewidth by a factor of ~2 compared to the case where the photo-generated carriers are not present. This result demonstrates a possible means of countering the effects of spectral diffusion in QD-PC cavity systems and thus may be useful for quantum information applications where narrow QD linewidths are desired.

  15. Generation of Multiple Circular Walls on a Thin Film of Nematic Liquid Crystal by Laser Scanning

    E-Print Network [OSTI]

    M. Kojima; J. Yamamoto; K. Sadakane; K. Yoshikawa

    2008-03-02T23:59:59.000Z

    We found that multiple circular walls (MCW) can be generated on a thin film of a nematic liquid crystal through a spiral scanning of a focused IR laser. The ratios between radii of adjacent rings of MCW were almost constant. These constant ratios can be explained theoretically by minimization of the Frank elastic free energy of nematic medium. The director field on a MCW exhibits chiral symmetry-breaking although the elastic free energies of both chiral MCWs are degenerated, i.e., the director on a MCW can rotate clockwise or counterclockwise along the radial direction.

  16. Photoluminescence from In0.5Ga0.5As/GaP quantum dots coupled to photonic crystal cavities

    E-Print Network [OSTI]

    Kelley Rivoire; Sonia Buckley; Yuncheng Song; Minjoo Larry Lee; Jelena Vuckovic

    2012-01-05T23:59:59.000Z

    We demonstrate room temperature visible wavelength photoluminescence from In0.5Ga0.5As quantum dots embedded in a GaP membrane. Time-resolved above band photoluminescence measurements of quantum dot emission show a biexpontential decay with lifetimes of ~200 ps. We fabricate photonic crystal cavities which provide enhanced outcoupling of quantum dot emission, allowing the observation of narrow lines indicative of single quantum dot emission. This materials system is compatible with monolithic integration on Si, and is promising for high efficiency detection of single quantum dot emission as well as optoelectronic devices emitting at visible wavelengths.

  17. Generation and manipulation of nonclassical light using photonic crystals

    E-Print Network [OSTI]

    Jelena Vuckovic; Dirk Englund; David Fattal; Edo Waks; Yoshihisa Yamamoto

    2005-10-07T23:59:59.000Z

    Photonic crystal cavities can localize light into nanoscale volumes with high quality factors. This permits a strong interaction between light and matter, which is important for the construction of classical light sources with improved properties (e.g., low threshold lasers) and of nonclassical light sources (such as single and entangled photon sources) that are crucial pieces of hardware of quantum information processing systems. This article will review some of our recent experimental and theoretical results on the interaction between single quantum dots and photonic crystal cavity fields, and on the integration of multiple photonic crystal devices into functional circuits for quantum information processing.

  18. Final LDRD report : enhanced spontaneous emission rate in visible III-nitride LEDs using 3D photonic crystal cavities.

    SciTech Connect (OSTI)

    Fischer, Arthur Joseph; Subramania, Ganapathi S.; Coley, Anthony J.; Lee, Yun-Ju; Li, Qiming; Wang, George T.; Luk, Ting Shan; Koleske, Daniel David; Fullmer, Kristine Wanta

    2009-09-01T23:59:59.000Z

    The fundamental spontaneous emission rate for a photon source can be modified by placing the emitter inside a periodic dielectric structure allowing the emission to be dramatically enhanced or suppressed depending on the intended application. We have investigated the relatively unexplored realm of interaction between semiconductor emitters and three dimensional photonic crystals in the visible spectrum. Although this interaction has been investigated at longer wavelengths, very little work has been done in the visible spectrum. During the course of this LDRD, we have fabricated TiO{sub 2} logpile photonic crystal structures with the shortest wavelength band gap ever demonstrated. A variety of different emitters with emission between 365 nm and 700 nm were incorporated into photonic crystal structures. Time-integrated and time-resolved photoluminescence measurements were performed to measure changes to the spontaneous emission rate. Both enhanced and suppressed emission were demonstrated and attributed to changes to the photonic density of states.

  19. Thermoelectric material including a multiple transition metal-doped type I clathrate crystal structure

    DOE Patents [OSTI]

    Yang, Jihui (Lakeshore, CA); Shi, Xun (Troy, MI); Bai, Shengqiang (Shanghai, CN); Zhang, Wenqing (Shanghai, CN); Chen, Lidong (Shanghai, CN); Yang, Jiong (Shanghai, CN)

    2012-01-17T23:59:59.000Z

    A thermoelectric material includes a multiple transition metal-doped type I clathrate crystal structure having the formula A.sub.8TM.sub.y.sub.1.sup.1TM.sub.y.sub.2.sup.2 . . . TM.sub.y.sub.n.sup.nM.sub.zX.sub.46-y.sub.1.sub.-y.sub.2.sub.- . . . -y.sub.n.sub.-z. In the formula, A is selected from the group consisting of barium, strontium, and europium; X is selected from the group consisting of silicon, germanium, and tin; M is selected from the group consisting of aluminum, gallium, and indium; TM.sup.1, TM.sup.2, and TM.sup.n are independently selected from the group consisting of 3d, 4d, and 5d transition metals; and y.sub.1, y.sub.2, y.sub.n and Z are actual compositions of TM.sup.1, TM.sup.2, TM.sup.n, and M, respectively. The actual compositions are based upon nominal compositions derived from the following equation: z=8q.sub.A-|.DELTA.q.sub.1|y.sub.1-|.DELTA.q.sub.2|y.sub.2- . . . -|.DELTA.q.sub.n|y.sub.n, wherein q.sub.A is a charge state of A, and wherein .DELTA.q.sub.1, .DELTA.q.sub.2, .DELTA.q.sub.n are, respectively, the nominal charge state of the first, second, and n-th TM.

  20. High Cooperativity Cavity QED with Magnons at Microwave Frequencies

    E-Print Network [OSTI]

    Maxim Goryachev; Warrick G. Farr; Daniel L. Creedon; Yaohui Fan; Mikhail Kostylev; Michael E. Tobar

    2014-10-16T23:59:59.000Z

    Using a sub-millimetre sized YIG (Yttrium Iron Garnet) sphere mounted in a magnetic field-focusing cavity, we demonstrate an ultra-high cooperativity of $10^5$ between magnon and photon modes at millikelvin temperatures and microwave frequencies. The cavity is designed to act as a magnetic dipole by using a novel multiple-post approach, effectively focusing the cavity magnetic field within the YIG crystal with a filling factor of 3%. Coupling strength (normal-mode splitting) of 2 GHz, (equivalent to 76 cavity linewidths or $0.3$ Hz per spin), is achieved for a bright cavity mode that constitutes about 10% of the photon energy and shows that ultra-strong coupling is possible in spin systems at microwave frequencies. With straight forward optimisations we demonstrate that with that this system has the potential to reach cooperativities of $10^7$, corresponding to a normal mode splitting of 5.2 GHz and a coupling per spin approaching 1 Hz. We also observe a three-mode strong coupling regime between a dark cavity mode and a magnon mode doublet pair, where the photon-magnon and magnon-magnon couplings (normal-mode splittings) are 143 MHz and 12.5 MHz respectively, with HWHM bandwidth of about 0.5 MHz.

  1. Optical cavity furnace for semiconductor wafer processing

    DOE Patents [OSTI]

    Sopori, Bhushan L.

    2014-08-05T23:59:59.000Z

    An optical cavity furnace 10 having multiple optical energy sources 12 associated with an optical cavity 18 of the furnace. The multiple optical energy sources 12 may be lamps or other devices suitable for producing an appropriate level of optical energy. The optical cavity furnace 10 may also include one or more reflectors 14 and one or more walls 16 associated with the optical energy sources 12 such that the reflectors 14 and walls 16 define the optical cavity 18. The walls 16 may have any desired configuration or shape to enhance operation of the furnace as an optical cavity 18. The optical energy sources 12 may be positioned at any location with respect to the reflectors 14 and walls defining the optical cavity. The optical cavity furnace 10 may further include a semiconductor wafer transport system 22 for transporting one or more semiconductor wafers 20 through the optical cavity.

  2. Coherent excitation of a strongly coupled quantum dot - cavity system

    E-Print Network [OSTI]

    Dirk Englund; Arka Majumdar; Andrei Faraon; Mitsuru Toishi; Nick Stoltz; Pierre Petroff; Jelena Vuckovic

    2009-02-19T23:59:59.000Z

    We have studied the coherent excitation of a strongly coupled QD/photonic crystal cavity system. Time-resolved reflectivity measurements show the vacuum Rabi oscillation of the dot in the cavity. Next, we considered the resonant driving of a cavity-detuned dot, which efficiently populates the cavity mode. This cavity-controlled read-out channel allows high-resolution single quantum dot spectroscopy. Autocorrelation measurements on the cavity mode show antibunching and suggest the use of the resonantly driven QD/cavity system as an on-demand source of single photons with potentially near-unity indistinguishability.

  3. Linear and nonlinear capacitive coupling of electro-opto-mechanical photonic crystal cavities Alessandro Pitanti,1, 2 Johannes M. Fink,1 Amir H. Safavi-Naeini,1 Chan

    E-Print Network [OSTI]

    Painter, Oskar

    ] or pressure sensors [3]. Recently, MEMS have been proposed for energy harvesting applications [4], ultra be suitable for realizing efficient microwave-to-optical signal conversion. Microelectromechanical systems of coherent, quantum frequency translation be- tween an optical and microwave cavity which shares the same

  4. Design of Plasmon Cavities for Solid-State Cavity QED Applications

    E-Print Network [OSTI]

    Yiyang Gong; Jelena Vuckovic

    2006-11-25T23:59:59.000Z

    Research on photonic cavities with low mode volume and high quality factor garners much attention because of applications ranging from optoelectronics to cavity quantum electrodynamics (QED). We propose a cavity based on surface plasmon modes confined by metallic distributed Bragg reflectors. We analyze the structure with Finite Difference Time Domain simulations and obtain modes with quality factor 1000 (including losses from metals), reduced mode volume relative to photonic crystal cavities, Purcell enhancements of hundreds, and even the capability of enabling cavity QED strong coupling.

  5. Photon Storage Cavities

    E-Print Network [OSTI]

    Kim, K.-J.

    2008-01-01T23:59:59.000Z

    Sessler, "Analysis of Photon Storage Cavities for a Free-configuration of coupled storage cavity and PEL cavity. TheFig. 2. A ring resonator storage cavity coupled through a

  6. Bichromatic Driving of a Solid State Cavity QED System

    E-Print Network [OSTI]

    Alexander Papageorge; Arka Majumdar; Erik D. Kim; Jelena Vuckovic

    2011-08-27T23:59:59.000Z

    The bichromatic driving of a solid state cavity quantum electrodynamics system is used to probe cavity dressed state transitions and observe coherent interaction between the system and the light field. We theoretically demonstrate the higher order cavity-dressed states, supersplitting, and AC stark shift in a solid state system comprised of a quantum dot strongly coupled to a photonic crystal cavity for on- and far off-resonant cases. For the off-resonant case, phonons mediate off-resonant coupling between the quantum dot and the photonic resonator, a phenomenon unique to solid state cavity quantum electrodynamics.

  7. Linewidth broadening of a quantum dot coupled to an off-resonant cavity

    E-Print Network [OSTI]

    Arka Majumdar; Andrei Faraon; Erik Kim; Dirk Englund; Hyochul Kim; Pierre Petroff; Jelena Vuckovic

    2010-03-11T23:59:59.000Z

    We study the coupling between a photonic crystal cavity and an off-resonant quantum dot under resonant excitation of the cavity or the quantum dot. Linewidths of the quantum dot and the cavity as a function of the excitation laser power are measured. We show that the linewidth of the quantum dot, measured by observing the cavity emission, is significantly broadened compared to the theoretical estimate. This indicates additional incoherent coupling between the quantum dot and the cavity.

  8. Jefferson Lab Builds First Single Crystal Single Cell Accelerating...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Single Cell Cavity This single cell cavity was made from a single crystal of niobium. Made in the same shape as the low-loss design proposed as an improvement to the baseline for...

  9. WAFER TEST CAVITY -Linking Surface Microstructure to RF Performance: a ‘Short-­?Sample Test Facility’ for characterizing superconducting materials for SRF cavities.

    SciTech Connect (OSTI)

    Pogue, Nathaniel; Comeaux, Justin; McIntyre, Peter

    2014-05-30T23:59:59.000Z

    The Wafer Test cavity was designed to create a short sample test system to determine the properties of the superconducting materials and S?I?S hetero?structures. The project, funded by ARRA, was successful in accomplishing several goals to achieving a high gradient test system for SRF research and development. The project led to the design and construction of the two unique cavities that each severed unique purposes: the Wafer test Cavity and the Sapphire Test cavity. The Sapphire Cavity was constructed first to determine the properties of large single crystal sapphires in an SRF environment. The data obtained from the cavity greatly altered the design of the Wafer Cavity and provided the necessary information to ascertain the Wafer Test cavity’s performance.

  10. Enhanced optical power of GaN-based light-emitting diode with compound photonic crystals by multiple-exposure nanosphere-lens lithography

    SciTech Connect (OSTI)

    Zhang, Yonghui; Wei, Tongbo, E-mail: tbwei@semi.ac.cn; Xiong, Zhuo; Shang, Liang; Tian, Yingdong; Zhao, Yun; Zhou, Pengyu; Wang, Junxi; Li, Jinmin [Semiconductor Lighting Technology Research and Development Center, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2014-07-07T23:59:59.000Z

    The light-emitting diodes (LEDs) with single, twin, triple, and quadruple photonic crystals (PCs) on p-GaN are fabricated by multiple-exposure nanosphere-lens lithography (MENLL) process utilizing the focusing behavior of polystyrene spheres. Such a technique is easy and economical for use in fabricating compound nano-patterns. The optimized tilted angle is decided to be 26.6° through mathematic calculation to try to avoid the overlay of patterns. The results of scanning electron microscopy and simulations reveal that the pattern produced by MENLL is a combination of multiple ovals. Compared to planar-LED, the light output power of LEDs with single, twin, triple, and quadruple PCs is increased by 14.78%, 36.03%, 53.68%, and 44.85% under a drive current 350?mA, respectively. Furthermore, all PC-structures result in no degradation of the electrical properties. The stimulated results indicate that the highest light extraction efficiency of LED with the clover-shape triple PC is due to the largest scattering effect on propagation of light from GaN into air.

  11. Specimen illumination apparatus with optical cavity for dark field illumination

    DOE Patents [OSTI]

    Pinkel, Daniel (Walnut Creek, CA); Sudar, Damir (Walnut Creek, CA); Albertson, Donna (Lafayette, CA)

    1999-01-01T23:59:59.000Z

    An illumination apparatus with a specimen slide holder, an illumination source, an optical cavity producing multiple reflection of illumination light to a specimen comprising a first and a second reflective surface arranged to achieve multiple reflections of light to a specimen is provided. The apparatus can further include additional reflective surfaces to achieve the optical cavity, a slide for mounting the specimen, a coverslip which is a reflective component of the optical cavity, one or more prisms for directing light within the optical cavity, antifading solutions for improving the viewing properties of the specimen, an array of materials for analysis, fluorescent components, curved reflective surfaces as components of the optical cavity, specimen detection apparatus, optical detection equipment, computers for analysis of optical images, a plane polarizer, fiberoptics, light transmission apertures, microscopic components, lenses for viewing the specimen, and upper and lower mirrors above and below the specimen slide as components of the optical cavity. Methods of using the apparatus are also provided.

  12. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    SciTech Connect (OSTI)

    KRUGER AA; HRMA PR

    2009-10-08T23:59:59.000Z

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  13. Electromagnetic SCRF Cavity Tuner

    SciTech Connect (OSTI)

    Kashikhin, V.; Borissov, E.; Foster, G.W.; Makulski, A.; Pischalnikov, Y.; Khabiboulline, T.; /Fermilab

    2009-05-01T23:59:59.000Z

    A novel prototype of SCRF cavity tuner is being designed and tested at Fermilab. This is a superconducting C-type iron dominated magnet having a 10 mm gap, axial symmetry, and a 1 Tesla field. Inside the gap is mounted a superconducting coil capable of moving {+-} 1 mm and producing a longitudinal force up to {+-} 1.5 kN. The static force applied to the RF cavity flanges provides a long-term cavity geometry tuning to a nominal frequency. The same coil powered by fast AC current pulse delivers mechanical perturbation for fast cavity tuning. This fast mechanical perturbation could be used to compensate a dynamic RF cavity detuning caused by cavity Lorentz forces and microphonics. A special configuration of magnet system was designed and tested.

  14. Passivated niobium cavities

    DOE Patents [OSTI]

    Myneni, Ganapati Rao (Yorktown, VA); Hjorvarsson, Bjorgvin (Lagga Arby, SE); Ciovati, Gianluigi (Newport News, VA)

    2006-12-19T23:59:59.000Z

    A niobium cavity exhibiting high quality factors at high gradients is provided by treating a niobium cavity through a process comprising: 1) removing surface oxides by plasma etching or a similar process; 2) removing hydrogen or other gases absorbed in the bulk niobium by high temperature treatment of the cavity under ultra high vacuum to achieve hydrogen outgassing; and 3) assuring the long term chemical stability of the niobium cavity by applying a passivating layer of a superconducting material having a superconducting transition temperature higher than niobium thereby reducing losses from electron (cooper pair) scattering in the near surface region of the interior of the niobium cavity. According to a preferred embodiment, the passivating layer comprises niobium nitride (NbN) applied by reactive sputtering.

  15. Tuned optical cavity magnetometer

    DOE Patents [OSTI]

    Okandan, Murat (Edgewood, NM); Schwindt, Peter (Albuquerque, NM)

    2010-11-02T23:59:59.000Z

    An atomic magnetometer is disclosed which utilizes an optical cavity formed from a grating and a mirror, with a vapor cell containing an alkali metal vapor located inside the optical cavity. Lasers are used to magnetically polarize the alkali metal vapor and to probe the vapor and generate a diffracted laser beam which can be used to sense a magnetic field. Electrostatic actuators can be used in the magnetometer for positioning of the mirror, or for modulation thereof. Another optical cavity can also be formed from the mirror and a second grating for sensing, adjusting, or stabilizing the position of the mirror.

  16. Hydroforming of elliptical cavities

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Singer, W.; Singer, X.; Jelezov, I.; Kneisel, Peter

    2015-02-01T23:59:59.000Z

    Activities of the past several years in developing the technique of forming seamless (weldless) cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area and at the ends. Tube radii and axial displacements are computer controlled during the forming process in accordance with resultsmore »of finite element method simulations for necking and expansion using the experimentally obtained strain-stress relationship of tube material. In cooperation with industry different methods of niobium seamless tube production have been explored. The most appropriate and successful method is a combination of spinning or deep drawing with flow forming. Several single-cell niobium cavities of the 1.3 GHz TESLA shape were produced by hydroforming. They reached accelerating gradients Eacc up to 35 MV/m after buffered chemical polishing (BCP) and up to 42 MV/m after electropolishing (EP). More recent work concentrated on fabrication and testing of multicell and nine-cell cavities. Several seamless two- and three-cell units were explored. Accelerating gradients Eacc of 30–35 MV/m were measured after BCP and Eacc up to 40 MV/m were reached after EP. Nine-cell niobium cavities combining three three-cell units were completed at the company E. Zanon. These cavities reached accelerating gradients of Eacc = 30–35 MV/m. One cavity is successfully integrated in an XFEL cryomodule and is used in the operation of the FLASH linear accelerator at DESY. Additionally the fabrication of bimetallic single-cell and multicell NbCu cavities by hydroforming was successfully developed. Several NbCu clad single-cell and double-cell cavities of the TESLA shape have been fabricated. The clad seamless tubes were produced using hot bonding or explosive bonding and subsequent flow forming. The thicknesses of Nb and Cu layers in the tube wall are about 1 and 3 mm respectively. The rf performance of the best NbCu clad cavities is similar to that of bulk Nb cavities. The highest accelerating gradient achieved was 40 MV/m. The advantages and disadvantages of hydroformed cavities are discussed in this paper.« less

  17. Superconducting Radiofrequency (SRF) Accelerator Cavities

    ScienceCinema (OSTI)

    Reece, Charlie

    2014-05-22T23:59:59.000Z

    Charlie Reece, an accelerator technology scientist, explains how superconducting radiofrequency accelerator cavities work.

  18. Lateral coupled cavity semiconductor laser

    SciTech Connect (OSTI)

    Salzman, J.; Lang, R.J.; Yariv, A.

    1987-06-16T23:59:59.000Z

    This patent describes a monolithic lateral-coupled laser array comprised of at least two stripe laser cavities of different effective length in close parallel proximity to each other for coupling of radiation. The longer of the stripe laser cavities is cleaved to provide separate parts, and the parts are cleaved coupled to form one strip laser cavity lateral coupled to the shorter laser cavity. A separate stripe contact varies the relative currents supplied to each laser cavity, including the cleaved coupled cavities of the longer of the stripe laser cavities.

  19. Ring resonant cavities for spectroscopy

    DOE Patents [OSTI]

    Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

    1999-06-15T23:59:59.000Z

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

  20. Apparatus And Method For Producing Single Crystal Metallic Objects

    DOE Patents [OSTI]

    Huang, Shyh-Chin (Latham, NY); Gigliotti, Jr., Michael Francis X. (Scotia, NY); Rutkowski, Stephen Francis (Duanesburg, NY); Petterson, Roger John (Fultonville, NY); Svec, Paul Steven (Scotia, NY)

    2006-03-14T23:59:59.000Z

    A mold is provided for enabling casting of single crystal metallic articles including a part-defining cavity, a sorter passage positioned vertically beneath and in fluid communication with the part-defining cavity, and a seed cavity positioned vertically beneath and in fluid communication with the sorter passage. The sorter passage includes a shape suitable for encouraging a single crystal structure in solidifying molten metal. Additionally, a portion of the mold between the sorter passage and the part-defining cavity includes a notch for facilitating breakage of a cast article proximate the notch during thermal stress build-up, so as to prevent mold breakage or the inclusion of part defects.

  1. Cavity Quantum Electrodynamics with a Single Quantum Dot Coupled to a Photonic Molecule

    E-Print Network [OSTI]

    Arka Majumdar; Armand Rundquist; Michal Bajcsy; Jelena Vu?kovi?

    2012-01-30T23:59:59.000Z

    We demonstrate the effects of cavity quantum electrodynamics for a quantum dot coupled to a photonic molecule, consisting of a pair of coupled photonic crystal cavities. We show anti-crossing between the quantum dot and the two super-modes of the photonic molecule, signifying achievement of the strong coupling regime. From the anti-crossing data, we estimate the contributions of both mode-coupling and intrinsic detuning to the total detuning between the super-modes. Finally, we also show signatures of off-resonant cavity-cavity interaction in the photonic molecule.

  2. Video Toroid Cavity Imager

    DOE Patents [OSTI]

    Gerald, Rex E. II; Sanchez, Jairo; Rathke, Jerome W.

    2004-08-10T23:59:59.000Z

    A video toroid cavity imager for in situ measurement of electrochemical properties of an electrolytic material sample includes a cylindrical toroid cavity resonator containing the sample and employs NMR and video imaging for providing high-resolution spectral and visual information of molecular characteristics of the sample on a real-time basis. A large magnetic field is applied to the sample under controlled temperature and pressure conditions to simultaneously provide NMR spectroscopy and video imaging capabilities for investigating electrochemical transformations of materials or the evolution of long-range molecular aggregation during cooling of hydrocarbon melts. The video toroid cavity imager includes a miniature commercial video camera with an adjustable lens, a modified compression coin cell imager with a fiat circular principal detector element, and a sample mounted on a transparent circular glass disk, and provides NMR information as well as a video image of a sample, such as a polymer film, with micrometer resolution.

  3. A process for separation by semi-continuous counter-current crystallization

    E-Print Network [OSTI]

    Aumock, Nathan M. (Nathan Micheal)

    2011-01-01T23:59:59.000Z

    A process is proposed to perform separations via crystallization by using multiple tanks and constraining crystal growth to solid surfaces. Multiple tanks allow multiple recrystallizations to improve product purity and to ...

  4. Design of RF Conditioner Cavities

    E-Print Network [OSTI]

    Govil, R.

    2008-01-01T23:59:59.000Z

    For most designs, the power loss at the cavity surface atheld fixed, the frequency, power loss and a more systematicwhile the cavity power loss (normalized by a factor of four

  5. Experience with capture cavity II

    SciTech Connect (OSTI)

    Koeth, T.; /Fermilab /Rutgers U., Piscataway; Branlard, J.; Edwards, H.; Fliller, R.; Harms, E.; Hocker, A.; McGee, M.; Pischalnikov, Y.; Prieto, P.; Reid, J.; /Fermilab

    2007-06-01T23:59:59.000Z

    Valuable experience in operating and maintaining superconducting RF cavities in a horizontal test module has been gained with Capture Cavity II. We report on all facets of our experience to date.

  6. Electropolishing of niobium cavities

    E-Print Network [OSTI]

    Electropolishing of niobium cavities Lutz Lilje@desy.de DESY -MPY- R&D one single-cells Rissen 2002 #12;01.03.02Lutz Lilje DESY -FDET- Electropolishing of Niobium · EP Electrolyte (KEK / Siemens) · 90 -FDET- Niobium surfaces 50 µm 50 µm BCP EP #12;01.03.02Lutz Lilje DESY -FDET- Results from half-cell EP

  7. Large area photodetector based on microwave cavity perturbation techniques

    SciTech Connect (OSTI)

    Braggio, C., E-mail: caterina.braggio@unipd.it; Carugno, G.; Sirugudu, R. K. [Dip. di Fisica e Astronomia and INFN Sez. di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); Lombardi, A.; Ruoso, G. [INFN, Laboratori Nazionali di Legnaro, Viale dell'Università 2, I-35020 Legnaro (Italy)

    2014-07-28T23:59:59.000Z

    We present a preliminary study to develop a large area photodetector, based on a semiconductor crystal placed inside a superconducting resonant cavity. Laser pulses are detected through a variation of the cavity impedance, as a consequence of the conductivity change in the semiconductor. A novel method, whereby the designed photodetector is simulated by finite element analysis, makes it possible to perform pulse-height spectroscopy on the reflected microwave signals. We measure an energy sensitivity of 100 fJ in the average mode without the employment of low noise electronics and suggest possible ways to further reduce the single-shot detection threshold, based on the results of the described method.

  8. Channeling through Bent Crystals

    SciTech Connect (OSTI)

    Mack, Stephanie; /Ottawa U. /SLAC

    2012-09-07T23:59:59.000Z

    Bent crystals have demonstrated potential for use in beam collimation. A process called channeling is when accelerated particle beams are trapped by the nuclear potentials in the atomic planes within a crystal lattice. If the crystal is bent then the particles can follow the bending angle of the crystal. There are several different effects that are observed when particles travel through a bent crystal including dechanneling, volume capture, volume reflection and channeling. With a crystal placed at the edge of a particle beam, part of the fringe of the beam can be deflected away towards a detector or beam dump, thus helping collimate the beam. There is currently FORTRAN code by Igor Yazynin that has been used to model the passage of particles through a bent crystal. Using this code, the effects mentioned were explored for beam energy that would be seen at the Facility for Advanced Accelerator Experimental Tests (FACET) at a range of crystal orientations with respect to the incoming beam. After propagating 5 meters in vacuum space past the crystal the channeled particles were observed to separate from most of the beam with some noise due to dechanneled particles. Progressively smaller bending radii, with corresponding shorter crystal lengths, were compared and it was seen that multiple scattering decreases with the length of the crystal therefore allowing for cleaner detection of the channeled particles. The input beam was then modified and only a portion of the beam sent through the crystal. With the majority of the beam not affected by the crystal, most particles were not deflected and after propagation the channeled particles were seen to be deflected approximately 5mm. After a portion of the beam travels through the crystal, the entire beam was then sent through a quadrupole magnet, which increased the separation of the channeled particles from the remainder of the beam to a distance of around 20mm. A different code, which was developed at SLAC, was used to create an angular profile plot which was compared to what was produced by Yazynin's code for a beam with no multiple scattering. The results were comparable, with volume reflection and channeling effects observed and the range of crystal orientations at which volume reflection is seen was about 1 mrad in both simulations.

  9. Coupled-resonator vertical-cavity lasers with two active gain regions

    DOE Patents [OSTI]

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-05-20T23:59:59.000Z

    A new class of coupled-resonator vertical-cavity semiconductor lasers has been developed. These lasers have multiple resonant cavities containing regions of active laser media, resulting in a multi-terminal laser component with a wide range of novel properties.

  10. CAVITY CONTROL ALGORITHM

    SciTech Connect (OSTI)

    Tomasz Plawski, J. Hovater

    2010-09-01T23:59:59.000Z

    A digital low level radio frequency (RF) system typically incorporates either a heterodyne or direct sampling technique, followed by fast ADCs, then an FPGA, and finally a transmitting DAC. This universal platform opens up the possibilities for a variety of control algorithm implementations. The foremost concern for an RF control system is cavity field stability, and to meet the required quality of regulation, the chosen control system needs to have sufficient feedback gain. In this paper we will investigate the effectiveness of the regulation for three basic control system algorithms: I&Q (In-phase and Quadrature), Amplitude & Phase and digital SEL (Self Exciting Loop) along with the example of the Jefferson Lab 12 GeV cavity field control system.

  11. Rotational cavity optomechanics

    E-Print Network [OSTI]

    Bhattacharya, M

    2015-01-01T23:59:59.000Z

    We theoretically examine the optomechanical interaction between a rotating nanoparticle and an orbital angular momentum-carrying optical cavity mode. Specifically, we consider a dielectric nanosphere rotating uniformly in a ring-shaped optical potential inside a Fabry-Perot resonator. The motion of the particle is probed by a weak angular lattice, created by introducing two additional degenerate Laguerre-Gaussian cavity modes carrying equal and opposite orbital angular momenta. We demonstrate that the rotation frequency of the nanoparticle is imprinted on the probe optical mode, via the Doppler shift, and thus may be sensed experimentally using homodyne detection. We show analytically that the effect of the optical probe on the particle rotation vanishes in the regime of linear response, resulting in an accurate frequency measurement. We also numerically characterize the degradation of the measurement accuracy when the system is driven in the nonlinear regime. Our results are relevant to rotational Doppler ve...

  12. A compact chaotic laser device with a two-dimensional external cavity structure

    SciTech Connect (OSTI)

    Sunada, Satoshi, E-mail: sunada@se.kanazawa-u.ac.jp; Adachi, Masaaki [Faculty of Mechanical Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192 (Japan); Fukushima, Takehiro [Department of Information and Communication Engineering, Okayama Prefectural University, 111 Kuboki, Soja, Okayama 719-1197 (Japan); Shinohara, Susumu; Arai, Kenichi [NTT Communication Science Laboratories, NTT Corporation, 2-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237 (Japan); Harayama, Takahisa [NTT Communication Science Laboratories, NTT Corporation, 2-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237 (Japan); Department of Mechanical Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan)

    2014-06-16T23:59:59.000Z

    We propose a compact chaotic laser device, which consists of a semiconductor laser and a two-dimensional (2D) external cavity for delayed optical feedback. The overall size of the device is within 230??m?×?1?mm. A long time delay sufficient for chaos generation can be achieved with the small area by the multiple reflections at the 2D cavity boundary, and the feedback strength is controlled by the injection current to the external cavity. We experimentally demonstrate that a variety of output properties, including chaotic output, can be selectively generated by controlling the injection current to the external cavity.

  13. Plasmon resonant cavities in vertical nanowire arrays

    DOE Patents [OSTI]

    Bora, Mihail; Bond, Tiziana C.; Fasenfest, Benjamin J.; Behymer, Elaine M.

    2014-07-15T23:59:59.000Z

    Tunable plasmon resonant cavity arrays in paired parallel nanowire waveguides are presented. Resonances can be observed when the waveguide length is an odd multiple of quarter plasmon wavelengths, consistent with boundary conditions of node and antinode at the ends. Two nanowire waveguides can satisfy the dispersion relation of a planar metal-dielectric-metal waveguide of equivalent width equal to the square field average weighted gap. Confinement factors of over 10.sup.3 are possible due to plasmon focusing in the inter-wire space.

  14. Crystal Structures of Apo and Metal-Bound Forms of the UreE Protein from Helicobacter pylori: Role of Multiple Metal Binding Sites

    SciTech Connect (OSTI)

    Shi, Rong; Munger, Christine; Asinas, Abdalin; Benoit, Stephane L.; Miller, Erica; Matte, Allan; Maier, Robert J.; Cygler, Miroslaw (McGill); (Georgia); (Biotech Res.)

    2010-10-22T23:59:59.000Z

    The crystal structure of the urease maturation protein UreE from Helicobacter pylori has been determined in its apo form at 2.1 {angstrom} resolution, bound to Cu{sup 2+} at 2.7 {angstrom} resolution, and bound to Ni{sup 2+} at 3.1 {angstrom} resolution. Apo UreE forms dimers, while the metal-bound enzymes are arranged as tetramers that consist of a dimer of dimers associated around the metal ion through coordination by His102 residues from each subunit of the tetramer. Comparison of independent subunits from different crystal forms indicates changes in the relative arrangement of the N- and C-terminal domains in response to metal binding. The improved ability of engineered versions of UreE containing hexahistidine sequences at either the N-terminal or C-terminal end to provide Ni{sup 2+} for the final metal sink (urease) is eliminated in the H102A version. Therefore, the ability of the improved Ni{sup 2+}-binding versions to deliver more nickel is likely an effect of an increased local concentration of metal ions that can rapidly replenish transferred ions bound to His102.

  15. A Casimir cannot cavity fly

    E-Print Network [OSTI]

    Massimo Cerdonio; Carlo Rovelli

    2015-02-08T23:59:59.000Z

    The field inside a Casimir cavity has an effective negative mass, which acts as a buoyancy force in a gravitational field. Can this render the total mass of the cavity negative, making it "float" in the vacuum ? Recent theoretical arguments indicate that this is impossible. We provide support to this conclusion discussing a concrete simple model of cavity, with plane parallel metallic plates kept in mechanical equilibrium by a spring and placed in a weak gravitational field. We show that basic facts about the structure of matter imply that the total mass of the cavity is always positive. This has implications for the hypothetical relation between vacuum energy and cosmological constant.

  16. Cavity soliton billiards

    SciTech Connect (OSTI)

    Prati, F.; Lugiato, L. A. [CNISM and Dipartimento di Fisica e Matematica, Universita dell'Insubria, Via Valleggio 11, I-22100 Como (Italy); Tissoni, G. [Institut Non Lineaire de Nice, UMR 6618, Universite de Nice Sophia Antipolis,1361 Route des Lucioles, F-06560 Valbonne (France); Brambilla, M. [CNISM and Dipartimento Interateneo di Fisica, Universita e Politecnico di Bari, Via Amendola 173, I-70123 Bari (Italy)

    2011-11-15T23:59:59.000Z

    The motion of a self-propelled cavity soliton in a laser where the pump profile acts as a square billiard is investigated. In the long-term dynamics, only closed trajectories are possible, exhibiting nonspecular reflections with striking similarities to walking droplets in a vibrated liquid bath. Open orbits can be achieved either by introducing scattering defects in the pump profile or in the presence of more than two solitons, due to their interaction. Such dynamical properties can be exploited for applications such as a compact soliton-force microscope.

  17. Cavity Cooling with a Hot Cavity Vladan Vuletic

    E-Print Network [OSTI]

    Vuletic, Vladan

    Cavity Cooling with a Hot Cavity Vladan Vuleti´c 1 Introduction Whereas from a classical point extended electromagnetic modes. Conventional Doppler cooling [5], that makes use of the conservation, realize an atomic laser, or maybe build time machines? Doppler cooling relies on the anisotropic

  18. Microwave pulse compression from a storage cavity with laser-induced switching

    DOE Patents [OSTI]

    Bolton, Paul R. (Menlo Park, CA)

    1992-01-01T23:59:59.000Z

    A laser-induced switch and a multiple cavity configuration are disclosed for producing high power microwave pulses. The microwave pulses are well controlled in wavelength and timing, with a quick rise time and a variable shape and power of the pulse. In addition, a method of reducing pre-pulse leakage to a low level is disclosed. Microwave energy is directed coherently to one or more cavities that stores the energy in a single mode, represented as a standing wave pattern. In order to switch the stored microwave energy out of the main cavity and into the branch waveguide, a laser-actuated switch is provided for the cavity. The switch includes a laser, associated optics for delivering the beam into the main cavity, and a switching gas positioned at an antinode in the main cavity. When actuated, the switching gas ionizes, creating a plasma, which becomes reflective to the microwave energy, changing the resonance of the cavity, and as a result the stored microwave energy is abruptly switched out of the cavity. The laser may directly pre-ionize the switching gas, or it may pump an impurity in the switching gas to an energy level which switches when a pre-selected cavity field is attained. Timing of switching the cavities is controlled by varying the pathlength of the actuating laser beam. For example, the pathlengths may be adjusted to output a single pulse of high power, or a series of quick lower power pulses.

  19. Applications of cavity optomechanics

    SciTech Connect (OSTI)

    Metcalfe, Michael [Booz Allen Hamilton, 3811 Fairfax Drive, Arlington, Virginia 22203 (United States)

    2014-09-15T23:59:59.000Z

    Cavity-optomechanics” aims to study the quantum properties of mechanical systems. A common strategy implemented in order to achieve this goal couples a high finesse photonic cavity to a high quality factor mechanical resonator. Then, using feedback forces such as radiation pressure, one can cool the mechanical mode of interest into the quantum ground state and create non-classical states of mechanical motion. On the path towards achieving these goals, many near-term applications of this field have emerged. After briefly introducing optomechanical systems and describing the current state-of-the-art experimental results, this article summarizes some of the more exciting practical applications such as ultra-sensitive, high bandwidth accelerometers and force sensors, low phase noise x-band integrated microwave oscillators and optical signal processing such as optical delay-lines, wavelength converters, and tunable optical filters. In this rapidly evolving field, new applications are emerging at a fast pace, but this article concentrates on the aforementioned lab-based applications as these are the most promising avenues for near-term real-world applications. New basic science applications are also becoming apparent such as the generation of squeezed light, testing gravitational theories and for providing a link between disparate quantum systems.

  20. Toroid cavity/coil NMR multi-detector

    DOE Patents [OSTI]

    Gerald, II, Rex E. (Brookfield, IL); Meadows, Alexander D. (Indianapolis, IN); Gregar, Joseph S. (Naperville, IL); Rathke, Jerome W. (Homer Glen, IL)

    2007-09-18T23:59:59.000Z

    An analytical device for rapid, non-invasive nuclear magnetic resonance (NMR) spectroscopy of multiple samples using a single spectrometer is provided. A modified toroid cavity/coil detector (TCD), and methods for conducting the simultaneous acquisition of NMR data for multiple samples including a protocol for testing NMR multi-detectors are provided. One embodiment includes a plurality of LC resonant circuits including spatially separated toroid coil inductors, each toroid coil inductor enveloping its corresponding sample volume, and tuned to resonate at a predefined frequency using a variable capacitor. The toroid coil is formed into a loop, where both ends of the toroid coil are brought into coincidence. Another embodiment includes multiple micro Helmholtz coils arranged on a circular perimeter concentric with a central conductor of the toroid cavity.

  1. Quench studies of ILC cavities

    SciTech Connect (OSTI)

    Eremeev, Grigory; Geng, Rongli; Palczewski, Ari; Dai, Jin

    2011-07-01T23:59:59.000Z

    Quench limits accelerating gradient in SRF cavities to a gradient lower than theoretically expected for superconducting niobium. Identification of the quenching site with thermometry and OST, optical inspection, and replica of the culprit is an ongoing effort at Jefferson Lab aimed at better understanding of this limiting phenomenon. In this contribution we present our finding with several SRF cavities that were limited by quench.

  2. Cavity ring-down Spectroscopy

    E-Print Network [OSTI]

    Budker, Dmitry

    ? · Technical limitations: Laser noise, detector noise.. · Fundamental limitations: Shot-noise Lmin = s 2eB ´ P0 10-8 #12;How small of an absorption can we resolve? · Technical noise limits us to a few percent length L 2FL/ #12;Cavities in general · Cavity length L · FSR = c/2L · Mirrors have Losses: not perfect

  3. Crystallization during processing of nuclear waste glass

    SciTech Connect (OSTI)

    Hrma, Pavel R.

    2010-12-01T23:59:59.000Z

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glassmaking are reviewed.

  4. Reaching 10 ms single photon lifetimes for superconducting aluminum cavities

    E-Print Network [OSTI]

    M. Reagor; Hanhee Paik; G. Catelani; L. Sun; C. Axline; E. Holland; I. M. Pop; N. A. Masluk; T. Brecht; L. Frunzio; M. H. Devoret; L. I. Glazman; R. J. Schoelkopf

    2013-05-22T23:59:59.000Z

    Three-dimensional microwave cavities have recently been combined with superconducting qubits in the circuit quantum electrodynamics (cQED) architecture. These cavities should have less sensitivity to dielectric and conductor losses at surfaces and interfaces, which currently limit the performance of planar resonators. We expect that significantly (>10^3) higher quality factors and longer lifetimes should be achievable for 3D structures. Motivated by this principle, we have reached internal quality factors greater than 0.5x10^9 and intrinsic lifetimes of 0.01 seconds for multiple aluminum superconducting cavity resonators at single photon energies and millikelvin temperatures. These improvements could enable long lived quantum memories with submicrosecond access times when strongly coupled to superconducting qubits.

  5. Design of flexible ultrahigh-Q microcavities in diamond-based photonic crystal slabs

    E-Print Network [OSTI]

    Snjezana Tomljenovic-Hanic; Andrew D. Greentree; C. Martijn de Sterke; Steven Prawer

    2008-12-10T23:59:59.000Z

    We design extremely flexible ultrahigh-Q diamond-based double-heterostructure photonic crystal slab cavities by modifying the refractive index of the diamond. The refractive index changes needed for ultrahigh-Q cavities with $Q ~ 10^7$, are well within what can be achieved ($\\Delta n \\sim 0.02$). The cavity modes have relatively small volumes $Vflexible because the range of parameters, cavity length and the index changes, that enables an ultrahigh-Q is quite broad. Furthermore as the index modification is post-processed, an efficient technique to generate cavities around defect centres is achievable, improving prospects for defect-tolerant quantum architectures.

  6. Information dynamics in cavity QED

    E-Print Network [OSTI]

    Soklakov, A N; Soklakov, Andrei N.; Schack, Ruediger

    2003-01-01T23:59:59.000Z

    A common experimental setup in cavity quantum electrodynamics (QED) consists of a single two-level atom interacting with a single mode of the electromagnetic field inside an optical cavity. The cavity is externally driven and the output is continuously monitored via homodyne measurements. We derive formulas for the optimal rates at which these measurements provide information about (i) the quantum state of the system composed of atom and electromagnetic field, and (ii) the coupling strength between atom and field. We find that the two information rates are anticorrelated.

  7. Information dynamics in cavity QED

    E-Print Network [OSTI]

    Andrei N. Soklakov; Ruediger Schack

    2003-05-09T23:59:59.000Z

    A common experimental setup in cavity quantum electrodynamics (QED) consists of a single two-level atom interacting with a single mode of the electromagnetic field inside an optical cavity. The cavity is externally driven and the output is continuously monitored via homodyne measurements. We derive formulas for the optimal rates at which these measurements provide information about (i) the quantum state of the system composed of atom and electromagnetic field, and (ii) the coupling strength between atom and field. We find that the two information rates are anticorrelated.

  8. Microwave cavity search for paraphotons

    SciTech Connect (OSTI)

    Povey, Rhys; Hartnett, John; Tobar, Michael [School of Physics, University of Western Australia, 35 Stirling Hwy, Crawley 6009 WA (Australia)

    2010-06-15T23:59:59.000Z

    In this proceeding we report the first results of a microwave cavity search for hidden sector photons. Using a pair of isolated resonant cavities we look for 'light shining through a wall' from photon--hidden sector photon oscillations. Our prototype experiment consists of two cylindrical, copper cavities stacked axially inside a single vacuum chamber. At a hidden sector photon mass of 39.58 mueV we place an upper limit on the kinetic mixing parameter chi at 7.8x10{sup -6}. Whilst this result is inside already established limits our experiment has great scope for improvement.

  9. Experimental Investigations on Superconducting Niobium Cavities

    E-Print Network [OSTI]

    Experimental Investigations on Superconducting Niobium Cavities at Highest Radiofrequency Fields niobium cavities, electrolytic polishing was applied to 1.3 GHz single cell and nine-cell cavities . . . . . . . . . . . . . . . . . . . . 14 1.4.1 Cavity fabrication . . . . . . . . . . . . . . . . . . . . . 16 1.4.1.1 Niobium properties

  10. Crystal_Reporting_9_1 LSUNO_LSUSH

    E-Print Network [OSTI]

    , products and services. Oracle Corporation and its affiliates will not be responsible for any loss, costs........................................................................................3 Running Crystal Reports......................................................................................................13 Run a Single Report for Multiple Departments

  11. Large mode-volume, large beta, photonic crystal laser resonator

    SciTech Connect (OSTI)

    Dezfouli, Mohsen Kamandar; Dignam, Marc M. [Department of Physics, Engineering Physics and Astronomy, Queen’s University, Kingston, ON K7L 3N6 (Canada)

    2014-12-15T23:59:59.000Z

    We propose an optical resonator formed from the coupling of 13, L2 defects in a triangular-lattice photonic crystal slab. Using a tight-binding formalism, we optimized the coupled-defect cavity design to obtain a resonator with predicted single-mode operation, a mode volume five times that of an L2-cavity mode and a beta factor of 0.39. The results are confirmed using finite-difference time domain simulations. This resonator is very promising for use as a single mode photonic crystal vertical-cavity surface-emitting laser with high saturation output power compared to a laser consisting of one of the single-defect cavities.

  12. Review of a Spoke-Cavity Design Option for the RIA Driver Linac

    SciTech Connect (OSTI)

    Petr Ostroumov; Kenneth Shepard; Jean Delayen

    2005-05-16T23:59:59.000Z

    A design option for the 1.4 GV, multiple-charge-state driver linac required for the U. S. Rare Isotope Accelerator Project based on 345 MHz, 3-cell spoke-loaded cavities has been previously discussed [1]. This paper updates consideration of design options for the RIA driver, including recent results from numerically-modeling the multi-charge-state beam dynamics and also cold test results for prototype superconducting niobium 3-cell spoke-loaded cavities.

  13. Jefferson Lab Builds First Single Crystal Single Cell Accelerating Cavity |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12 Investigation PeerNOON...January 2015H8/0UpgradeJefferson

  14. The Cavity of Cygnus A

    E-Print Network [OSTI]

    A. S. Wilson; David A. Smith; A. J. Young

    2006-06-25T23:59:59.000Z

    In this paper, we focus on the limb-brightened, prolate spheroidal cavity of the radio galaxy Cygnus A, as revealed by the Chandra X-ray Observatory. We use the shock heated, thermal intracluster medium around the expanding cavity to infer the properties of the radio synchrotron-emitting gas inside the cavity. The gas along the N and S edges of the cavity is found to have an average temperature of 6.0 keV, which is hotter than the temperature (4.6 keV) of the adjacent intracluster gas. It is proposed that this hotter gas is intracluster gas shocked by the expanding cavity. The shock is thus inferred to be weak (Mach number 1.3, a value also inferred from the density jump at the cavity edge) and its velocity 1,460 km/s. The total kinetic power of the expansion is found to be 1.2 x 10^{46} erg/s, which is larger than both the total radio power and the power emitted by the entire intracluster medium in the 2 -- 10 keV band. It appears that most of the power of the jets in Cygnus A is currently going into heating the intracluster medium. From the derived pressure inside the cavity, there is no conclusive evidence for a component contributing pressure additional to the magnetic fields and relativistic particles responsible for the synchrotron radio emission. Further, the ratio of energy densities in positive to negative cosmic rays in Cygnus A is between 1 and 100 (the value in our Galaxy).

  15. Characterization of radiation pressure and thermal effects in a nanoscale optomechanical cavity

    E-Print Network [OSTI]

    Camacho, Ryan M; Eichenfield, Matt; Painter, Oskar

    2009-01-01T23:59:59.000Z

    Optical forces in guided-wave nanostructures have recently been proposed as an effective means of mechanically actuating and tuning optical components. In this work, we study the properties of a photonic crystal optomechanical cavity consisting of a pair of patterned silicon nitride nanobeams. Internal stresses in the stoichiometric silicon nitride thin-film are used to produce inter-beam slot-gaps ranging from 560 to 40nm. A general pump-probe measurement scheme is described which determines, self-consistently, the contributions of thermo-mechanical, thermo-optic, and radiation pressure effects. For devices with 40nm slot-gap, the optical gradient force is measured to be 134fN per cavity photon for the strongly coupled symmetric cavity supermode, producing a static cavity tuning greater than five times that of either the parasitic thermo-mechanical or thermo-optic effects.

  16. The ESS elliptical cavity cryomodules

    SciTech Connect (OSTI)

    Darve, Christine [ESS, 22100, Lund (Sweden); Bosland, Pierre; Devanz, Guillaume; Renard, Bertrand [CEA-Saclay, 91191 Gif-sur-Yvette (France); Olivier, Gilles; Thermeau, Jean-Pierre [CNRS/IN2P3, IPN Orsay (France)

    2014-01-29T23:59:59.000Z

    The European Spallation Source (ESS) is a multi-disciplinary research centre under design and construction in Lund, Sweden. This new facility is funded by a collaboration of 17 European countries and is expected to be up to 30 times brighter than today’s leading facilities and neutron sources. The ESS will enable new opportunities for researchers in the fields of life sciences, energy, environmental technology, cultural heritage and fundamental physics. A 5 MW long pulse proton accelerator is used to reach this goal. The pulsed length is 2.86 ms, the repetition frequency is 14 Hz (4 % duty cycle), and the beam current is 62.5 mA. The superconducting section of the Linac accelerates the beam from 80 MeV to 2.0 GeV. It is composed of one string of spoke cavity cryomodule and two strings of elliptical cavity cryomodules. These cryomodules contain four elliptical Niobium cavities operating at 2 K and at a frequency of 704.42 MHz. This paper introduces the thermo-mechanical design, the prototyping and the expected operation of the ESS elliptical cavity cryomodules. An Elliptical Cavity Cryomodule Technology Demonstrator (ECCTD) will be built and tested in order to validate the ESS series production.

  17. The ESS spoke cavity cryomodules

    SciTech Connect (OSTI)

    Bousson, Sebastien; Duthil, Patxi; Reynet, Denis; Thermeau, Jean-Pierre [CNRS/IN2P3, IPN Orsay (France); Darve, Christine; Elias, Nuno; Molloy, Steve [ESS, 22100, Lund (Sweden)

    2014-01-29T23:59:59.000Z

    The European Spallation Source (ESS) is a multi-disciplinary research centre under design and construction in Lund, Sweden. This new facility is funded by a collaboration of 17 European countries and is expected to be up to 30 times brighter than today’s leading facilities and neutron sources. The ESS will enable new opportunities for researchers in the fields of life sciences, energy, environmental technology, cultural heritage and fundamental physics. A 5 MW long pulse proton accelerator is used to reach this goal. The pulsed length is 2.86 ms, the repetition frequency is 14 Hz (4 % duty cycle), and the beam current is 62.5 mA. It is composed of one string of spoke cavity cryomodule and two strings of elliptical cavity cryomodules. This paper introduces the thermo-mechanical design and expected operation of the ESS spoke cavity cryomodules. These cryomodules contain two double spoke bulk Niobium cavities operating at 2 K and at a frequency of 352.21 MHz. The superconducting section of the Spoke Linac accelerates the beam from 90 MeV to 220 MeV. A Spoke Cavity Cryomodule Technology Demonstrator will be built and tested in order to validate the ESS series production.

  18. Foundations for quantitative microstructural models to track evolution of the metallurgical state during high purity Nb cavity fabrication

    SciTech Connect (OSTI)

    Bieler, Thomas R [Michigan State University; Wright, Neil T [Michigan State University; Compton, Chris C [Facility for Rare Isotope Beams

    2014-03-15T23:59:59.000Z

    The goal of the Materials Science SRF Cavity Group of Michigan State University and the National Superconducting Cyclotron has been (and continues to be) to understand quantitatively the effects of process history on functional properties. These relationships were assessed via studies on Nb samples and cavity parts, which had various combinations of forming processes, welding, heat treatments, and surface preparation. A primary focus was on large-grain cavity building strategies. Effects of processing operations and exposure to hydrogen on the thermal conductivity has been identified in single and bi-crystal samples, showing that the thermal conductivity can be altered by a factor of 5 depending on process history. Characterization of single crystal tensile samples show a strong effect of crystal orientation on deformation resistance and shape changes. Large grain half cells were examined to characterize defect content and surface damage effects, which provided quantitative information about the depth damage layers from forming.

  19. Phonon-mediated squeezing of the cavity field off-resonantly coupled with a coherently driven quantum dot

    SciTech Connect (OSTI)

    Zhu, Jia-pei [Department of Physics, Huazhong Normal University, Wuhan 430079 (China); College of Science, Honghe University, Mengzi 661100 (China); Huang, Hui; Li, Gao-xiang, E-mail: gaox@phy.ccnu.edu.cn [Department of Physics, Huazhong Normal University, Wuhan 430079 (China)

    2014-01-21T23:59:59.000Z

    We theoretically propose a scheme for the quadrature squeezing of the cavity field via dissipative processes. The effects of the electron-phonon interaction (EPI) on the squeezing are investigated, where the cavity is off-resonantly coupled with a coherently driven quantum dot (QD) which is allowed to interact with an acoustic-phonon reservoir. Under certain conditions, the participation of the phonon induced by both the EPI and the off-resonant coupling of the cavity with the QD enables some dissipative processes to occur resonantly in the dressed-state basis of the QD. The cavity-mode photons emitted or absorbed during the phonon-mediated dissipative processes are correlated, thus leading to the squeezing of the cavity field. A squeezed vacuum reservoir for the cavity field is built up due to the EPI plus the off-resonant coupling between the cavity and the QD. The numerical results obtained with an effective polaron master equation derived using second-order perturbation theory indicate that, in low temperature limit, the degree of squeezing is maximal but the increasing temperature of the phonon reservoir could hinder the squeezing and degrade the degree of the squeezing of the cavity field. In addition, the presence of the photonic crystal could enhance the quadrature squeezing of the cavity field.

  20. Electromagnetic Scattering by Multiple Cavities Embedded in the ...

    E-Print Network [OSTI]

    2014-08-30T23:59:59.000Z

    Nov 26, 2013 ... HS. : ? : which is a Hilbert space with the usual norm. Multiplying a test ..... k j j k j g. uT. uT u. S u u u. N. (27) for n j ,,1 ! . Therefore, we only ...

  1. Review of cavity optomechanical cooling

    E-Print Network [OSTI]

    Yong-Chun Liu; Yu-Wen Hu; Chee Wei Wong; Yun-Feng Xiao

    2014-11-14T23:59:59.000Z

    Quantum manipulation of macroscopic mechanical systems is of great interest in both fundamental physics and applications ranging from high-precision metrology to quantum information processing. A crucial goal is to cool the mechanical system to its quantum ground state. In this review, we focus on the cavity optomechanical cooling, which exploits the cavity enhanced interaction between optical field and mechanical motion to reduce the thermal noise. Recent remarkable theoretical and experimental efforts in this field have taken a major step forward in preparing the motional quantum ground state of mesoscopic mechanical systems. This review first describes the quantum theory of cavity optomechanical cooling, including quantum noise approach and covariance approach; then the up-to-date experimental progresses are introduced. Finally, new cooling approaches are discussed along the directions of cooling in the strong coupling regime and cooling beyond the resolved sideband limit.

  2. Holographic Graphene in a Cavity

    E-Print Network [OSTI]

    Nick Evans; Peter A. R. Jones

    2014-07-11T23:59:59.000Z

    The effective strength of EM interactions can be controlled by confining the fields to a cavity and these effects might be used to push graphene into a strongly coupled regime. We study the similar D3/probe D5 system on a compact space and discuss the gravity dual for a cavity between two mirrors. We show that the introduction of a conformal symmetry breaking length scale introduces a mass gap on a single D5 sheet. Bilayer configurations display exciton condensation between the sheets. There is a first order phase transition away from the exciton condensate if a strong enough magnetic field is applied. We finally map out the phase structure of these systems in a cavity with the presence of mirror reflections of the probes - a mass gap may form through exciton condensation with the mirror image.

  3. Cavity enhanced transport of excitons

    E-Print Network [OSTI]

    Johannes Schachenmayer; Claudiu Genes; Edoardo Tignone; Guido Pupillo

    2015-05-20T23:59:59.000Z

    We show that exciton-type transport in certain materials can be dramatically modified by their inclusion in an optical cavity: the modification of the electromagnetic vacuum mode structure introduced by the cavity leads to transport via delocalized polariton modes rather than through tunneling processes in the material itself. This can help overcome exponential suppression of transmission properties as a function of the system size in the case of disorder and other imperfections. We exemplify massive improvement of transmission for excitonic wave-packets through a cavity, as well as enhancement of steady-state exciton currents under incoherent pumping. These results may have implications for experiments of exciton transport in disordered organic materials. We propose that the basic phenomena can be observed in quantum simulators made of Rydberg atoms, cold molecules in optical lattices, as well as in experiments with trapped ions.

  4. Thermomechanical cavity-growth modeling

    SciTech Connect (OSTI)

    Glass, R.E.

    1982-01-01T23:59:59.000Z

    The results of recent field tests, laboratory studies, and modeling efforts in UCG have indicated that the thermal and mechanical properties of coal may be the controlling parameters in determining initial cavity shape. In examining this possibility, laboratory efforts have been directed at determining temperature and bedding plane dependent properties of coal. A thermomechanical model which uses these properties has indicated that the cavity shapes seen at both the Hanna and Hoe Creek test sites result from the temperature dependent properties of the coal such as the coefficients of thermal expansion and the elastic moduli. The model determines stress levels and uses a simple bedding plane dependent stress failure mechanism to determine cavity growth.

  5. Surface Topography of 'Hotspot' Regions from a Single Cell SRF Cavity

    SciTech Connect (OSTI)

    Xin Zhao, Gianluigi Ciovati, Charles Reece, Andy Wu

    2009-05-01T23:59:59.000Z

    Performance of SRF cavities are limited by non-linear localized effects. The variation of local material characters between "hot" and "cold" spots is thus of intense interest. Such locations were identified in a BCP-etched large-grain single-cell cavity and removed for examination by high resolution electron microscopy (SEM), electron-back scattering diffraction microscopy (EBSD), optical microscopy, and 3D profilometry. Pits with clearly discernable crystal facets were observed in both "hotspot" and "coldspot" specimens. The pits were found in-grain, at bi-crystal boundaries, and on tri-crystal junctions. They are interpreted as etch pits induced by surface crystal defects (e.g. dislocations). All "coldspots" examined had qualitatively low density of etching pits or very shallow tri-crystal boundary junction. EBSD revealed the crystal structure surrounding the pits via crystal phase orientation mapping, while 3D profilometry gave information on the depth and size of the pits. In addition, a survey of the samples by energy dispersive X-ray analysis (EDX) did not show any significant contamination of the samples surface.

  6. Study of Etching Pits in a Large-grain Single Cell Bulk Niobium Cavity

    SciTech Connect (OSTI)

    Zhao, Xin [William and Mary College; Ciovati, Gianluigi [JLAB; Reece, Charles E. [JLAB; Wu, Andy T. [JLAB

    2009-11-01T23:59:59.000Z

    Performance of SRF cavities are limited by non-linear localized effects. The variation of local material characters between "hot" and "cold" spots is thus of intense interest. Such locations were identified in a BCP-etched large-grain single-cell cavity and removed for examination by high resolution electron microscopy (SEM), electron-back scattering diffraction microscopy (EBSD), optical microscopy, and 3D profilometry. Pits with clearly discernable crystal facets were observed in both "hotspot" and "coldspot" specimens. The pits were found in-grain, at bi-crystal boundaries, and on tri-crystal junctions. They are interpreted as etch pits induced by surface crystal defects (e.g. dislocations). All "coldspots" examined had qualitatively low density of etching pits or very shallow tri-crystal boundary junction. EBSD revealed crystal structure surrounding the pits via crystal phase orientation mapping, while 3D profilometry gave information on the depth and size of the pits. In addition, a survey of the samples by energy dispersive X-ray analysis (EDX) did not show any significant contamination of the samples surface.

  7. PROGRESS ON LARGE GRAIN AND SINGLE GRAIN NIOBIUM: INGOTS AND SHEET AND REVIEW OF PROGRESS ON LARGE GRAIN AND SINGLE GRAIN NIOBIUM CAVITIES

    SciTech Connect (OSTI)

    Peter Kneisel

    2008-02-12T23:59:59.000Z

    Large grain and single crystal niobium has been proposed several years ago as an alternative material to poly-crystalline niobium for superconducting cavities, exhibiting potential advantages such as ¿stream-lined¿ procedures, reduced costs and better reproducibility in performance. Several major laboratories have investigated the use of large grain and single crystal material in the past years and the niobium producing industry has responded in providing ingot material with enlarged grain sizes. Besides a large number of single cell and multi-cell cavities from large grain niobium, several single crystal cavities have been fabricated and tested with good performances. This contribution will review the progress since the SRF workshop in 2005 in material processing and handling and in cavity performances.

  8. Synchronization in an Optomechanical Cavity

    E-Print Network [OSTI]

    Keren Shlomi; D. Yuvaraj; Ilya Baskin; Oren Suchoi; Roni Winik; Eyal Buks

    2014-10-01T23:59:59.000Z

    We study self-excited oscillations (SEO) in an on-fiber optomechanical cavity. Synchronization is observed when the optical power that is injected into the cavity is periodically modulated. A theoretical analysis based on the Fokker-Planck equation evaluates the expected phase space distribution (PSD) of the self-oscillating mechanical resonator. A tomography technique is employed for extracting PSD from the measured reflected optical power. Time-resolved state tomography measurements are performed to study phase diffusion and phase locking of the SEO. The detuning region inside which synchronization occurs is experimentally determined and the results are compared with the theoretical prediction.

  9. Cryogenic infrastructure for Fermilab's ILC vertical cavity test facility

    SciTech Connect (OSTI)

    Carcagno, R.; Ginsburg, C.; Huang, Y.; Norris, B.; Ozelis, J.; Peterson, T.; Poloubotko, V.; Rabehl, R.; Sylvester, C.; Wong, M.; /Fermilab

    2006-06-01T23:59:59.000Z

    Fermilab is building a Vertical Cavity Test Facility (VCTF) to provide for R&D and pre-production testing of bare 9-cell, 1.3-GHz superconducting RF (SRF) cavities for the International Linear Collider (ILC) program. This facility is located in the existing Industrial Building 1 (IB1) where the Magnet Test Facility (MTF) also resides. Helium and nitrogen cryogenics are shared between the VCTF and MTF including the existing 1500-W at 4.5-K helium refrigerator with vacuum pumping for super-fluid operation (125-W capacity at 2-K). The VCTF is being constructed in multiple phases. The first phase is scheduled for completion in mid 2007, and includes modifications to the IB1 cryogenic infrastructure to allow helium cooling to be directed to either the VCTF or MTF as scheduling demands require. At this stage, the VCTF consists of one Vertical Test Stand (VTS) cryostat for the testing of one cavity in a 2-K helium bath. Planning is underway to provide a total of three Vertical Test Stands at VCTF, each capable of accommodating two cavities. Cryogenic infrastructure improvements necessary to support these additional VCTF test stands include a dedicated ambient temperature vacuum pump, a new helium purification skid, and the addition of helium gas storage. This paper describes the system design and initial cryogenic operation results for the first VCTF phase, and outlines future cryogenic infrastructure upgrade plans for expanding to three Vertical Test Stands.

  10. Microstructural parameters from Multiple Whole Profile (MWP) or Convolutional Multiple Whole Profile

    E-Print Network [OSTI]

    Balzar, Davor

    Microstructural parameters from Multiple Whole Profile (MWP) or Convolutional Multiple Whole Profile (CMWP) computer programs 54th Annual Denver X-ray Conference Line Profile Analysis Workshop system, 2) hexagonal crystal system, 4) MWP (Multiple Whole Profile Fitting), 5) CMWP (Convolutional

  11. Electrically driven photonic crystal nanocavity devices

    E-Print Network [OSTI]

    Shambat, Gary; Petykiewicz, Jan; Mayer, Marie A; Majumdar, Arka; Sarmiento, Tomas; Harris, James; Haller, Eugene E; Vuckovic, Jelena

    2012-01-01T23:59:59.000Z

    Interest in photonic crystal nanocavities is fueled by advances in device performance, particularly in the development of low-threshold laser sources. Effective electrical control of high performance photonic crystal lasers has thus far remained elusive due to the complexities associated with current injection into cavities. A fabrication procedure for electrically pumping photonic crystal membrane devices using a lateral p-i-n junction has been developed and is described in this work. We have demonstrated electrically pumped lasing in our junctions with a threshold of 181 nA at 50K - the lowest threshold ever demonstrated in an electrically pumped laser. At room temperature we find that our devices behave as single-mode light-emitting diodes (LEDs), which when directly modulated, have an ultrafast electrical response up to 10 GHz corresponding to less than 1 fJ/bit energy operation - the lowest for any optical transmitter. In addition, we have demonstrated electrical pumping of photonic crystal nanobeam LEDs...

  12. Symmetry breaking in laser cavities

    E-Print Network [OSTI]

    Malomed, Boris A

    2015-01-01T23:59:59.000Z

    A brief introduction to the topic of spontaneous symmetry breaking (SSB) in conservative and dissipative nonlinear systems with an underlying double-well-potential structure is given. The reason is a discussion of a recent observation of the SSB a dual-core nanolaser cavity [5]. The effect is illustrated by means of a simple semi-analytically-tractable model (Fig. 1).

  13. Dynamics of Quantum Dot Photonic Crystal Lasers

    E-Print Network [OSTI]

    Bryan Ellis; Ilya Fushman; Dirk Englund; Bingyang Zhang; Yoshihisa Yamamoto; Jelena Vuckovic

    2007-03-07T23:59:59.000Z

    Quantum dot photonic crystal membrane lasers were fabricated and the large signal modulation characteristics were studied. We find that the modulation characteristics of quantum dot lasers can be significantly improved using cavities with large spontaneous emission coupling factor. Our experiments show, and simulations confirm, that the modulation rate is limited by the rate of carrier capture into the dots to around 30GHz in our present system.

  14. Electro-optic harmonic conversion to switch a laser beam out of a cavity

    DOE Patents [OSTI]

    Haas, Roger A. (Pleasanton, CA); Henesian, Mark A. (Livermore, CA)

    1987-01-01T23:59:59.000Z

    The invention is a switch to permit a laser beam to escape a laser cavity through the use of an externally applied electric field across a harmonic conversion crystal. Amplification takes place in the laser cavity, and then the laser beam is switched out by the laser light being harmonically converted with dichroic or polarization sensitive elements present to alter the optical path of the harmonically converted laser light. Modulation of the laser beam can also be accomplished by varying the external electric field.

  15. Semiconductor laser with multiple lasing wavelengths

    DOE Patents [OSTI]

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-07-29T23:59:59.000Z

    A new class of multi-terminal vertical-cavity semiconductor laser components has been developed. These multi-terminal laser components can be switched, either electrically or optically, between distinct lasing wavelengths, or can be made to lase simultaneously at multiple wavelengths.

  16. Status of the ILC Crab Cavity Development

    SciTech Connect (OSTI)

    Burt, G.; Dexter, A.; /Cockcroft Inst. Accel. Sci. Tech.; Beard, C.; Goudket, P.; McIntosh, P.; /Daresbury; Bellantoni, L.; /Fermilab; Grimm, T.; Li, Z.; Xiao, L.; /SLAC

    2011-10-20T23:59:59.000Z

    The International Linear Collider (ILC) will require two dipole cavities to 'crab' the electron and positron bunches prior to their collision. It is proposed to use two 9 cell SCRF dipole cavities operating at a frequency of 3.9 GHz, with a transverse gradient of 3.8MV/m in order to provide the required transverse kick. Extensive numerical modelling of this cavity and its couplers has been performed. Aluminium prototypes have been manufactured and tested to measure the RF properties of the cavity and couplers. In addition single cell niobium prototypes have been manufactured and tested in a vertical cryostat. The International Collider (ILC) [1] collides bunches of electrons and positrons at a crossing angle of 14 mrad. The angle between these bunches causes a loss in luminosity due to geometric effects [2]. The luminosity lost from this geometric effect can be recovered by rotating the bunches into alignment prior to collision. One possible method of rotating the bunches is to use a crab cavity [3]. A crab cavity is a transverse defecting cavity, where the phase of the cavity is such that the head and tail of the bunch receive equal and opposite kicks. As the bunches are only 500 nm wide in the horizontal plane, the cavity phase must be strictly controlled to avoid the bunch centre being deflected too much. In order to keep the phase stability within the required limits it is required that the cavity be superconducting to avoid thermal effects in both the cavity and its RF source. At the location of the crab cavity in the ILC there is only 23 cm separation between the centre of the cavity and the extraction line, hence the cavity must be small enough to fit in this space. This, along with the difficulty of making high frequency SRF components, set the frequency of the cavity to 3.9 GHz.

  17. Fano Resonance in GaAs 2D Photonic Crystal Nanocavities

    SciTech Connect (OSTI)

    Valentim, P. T.; Guimaraes, P.S. S. [Departamento de Fisica, Universidade Federal de Minas Gerais, Belo Horizonte (Brazil); Instituto Nacional de Ciencia e Tecnologia de Nanodispositivos Semicondutores - INCT-DISSE (Brazil); Luxmoore, I. J.; Szymanski, D.; Whittaker, D. M.; Fox, A. M.; Skolnick, M. S. [Department of Physics and Astronomy, University of Sheffield, Sheffield (United Kingdom); Vasco, J. P. [Instituto de Fisica, Universidad de Antioquia, Medellin (Colombia); Vinck-Posada, H. [Departamento de Fisica, Facultad de Ciencias, Universidad Nacional de Colombia, Bogota (Colombia)

    2011-12-23T23:59:59.000Z

    We report the results of polarization resolved reflectivity experiments in GaAs air-bridge photonic crystals with L3 cavities. We show that the fundamental L3 cavity mode changes, in a controlled way, from a Lorentzian symmetrical lineshape to an asymmetrical form when the linear polarization of the incident light is rotated in the plane of the crystal. The different lineshapes are well fitted by the Fano asymmetric equation, implying that a Fano resonance is present in the reflectivity. We use the scattering matrix method to model the Fano interference between a localized discrete state (the cavity fundamental mode) and a background of continuum states (the light reflected from the crystal slab in the vicinity of the cavity) with very good agreement with the experimental data.

  18. Vented Cavity Radiant Barrier Assembly And Method

    DOE Patents [OSTI]

    Dinwoodie, Thomas L. (Piedmont, CA); Jackaway, Adam D. (Berkeley, CA)

    2000-05-16T23:59:59.000Z

    A vented cavity radiant barrier assembly (2) includes a barrier (12), typically a PV module, having inner and outer surfaces (18, 22). A support assembly (14) is secured to the barrier and extends inwardly from the inner surface of the barrier to a building surface (14) creating a vented cavity (24) between the building surface and the barrier inner surface. A low emissivity element (20) is mounted at or between the building surface and the barrier inner surface. At least part of the cavity exit (30) is higher than the cavity entrance (28) to promote cooling air flow through the cavity.

  19. On-chip generation of indistinguishable photons using cavity quantum-electrodynamics

    E-Print Network [OSTI]

    Kai Müller; Armand Rundquist; Kevin A. Fischer; Tomas Sarmiento; Konstantinos G. Lagoudakis; Yousif A. Kelaita; Carlos Sánchez Muñoz; Elena del Valle; Fabrice P. Laussy; Jelena Vu?kovi?

    2014-08-25T23:59:59.000Z

    The on-chip generation of non-classical states of light is a key requirement for future optical quantum hardware. In solid-state cavity quantum electrodynamics (QED), such non-classical light can be generated from self-assembled quantum dots (QDs) strongly coupled to photonic crystal cavities. Their anharmonic strong light-matter interaction results in large optical nonlinearities at the single photon level, where the admission of a single photon into the cavity may enhance (photon-tunnelling) or diminish (photon-blockade) the probability for a second photon to enter the cavity. Here, we demonstrate that detuning the cavity and QD resonances enables the generation of high-fidelity non-classical light from strongly coupled systems. For specific detunings we show that not only the purity but also the probability of single photon generation increases significantly, making almost-perfect single photon generation by photon-blockade possible with current state-of-the-art samples. Finally, we show that photon-blockade under fully resonant excitation is a promising candidate for the generation of indistinguishable single photons due to a short cavity lifetime that suppresses phonon dephasing.

  20. Accurate Multipole Analysis for Leaky Microcavities in Two-dimensional Photonic Crystals

    E-Print Network [OSTI]

    Lu, Ya Yan

    1 Accurate Multipole Analysis for Leaky Microcavities in Two-dimensional Photonic Crystals Shaojie Li and Ya Yan Lu Abstract--A multipole method is presented to analyze leaky microcavities in finite expansions. Index Terms--Optical cavities, photonic crystals, numerical methods, multipole method. I

  1. Novel Geometries for the LHC Crab Cavity

    SciTech Connect (OSTI)

    B. Hall, G. Burt, J.D.A. Smith, R. Rimmer, H. Wang, J. Delayen, R. Calaga

    2009-05-01T23:59:59.000Z

    In 2017 the LHC is envisioned to increase its luminosity via an upgrade. This upgrade is likely to require a large crossing angle hence a crab cavity is required to align the bunches prior to collision. There are two possible schemes for crab cavity implementation, global and local. In a global crab cavity the crab cavity is far from the IP and the bunch rotates back and forward as it traverses around the accelerator in a closed orbit. For this scheme a two-cell elliptical squashed cavity at 800 MHz is preferred. To avoid any potential beam instabilities all the parasitic modes of the cavities must be damped strongly, however crab cavities have lower order and same order modes in addition to the usual higher order modes and hence a novel damping scheme must be used to provide sufficient damping of these modes. In the local scheme two crab cavities are placed at each side of the IP two start and stop rotation of the bunches. This would require crab cavities much smaller transversely than in the global scheme but the frequency cannot be increased any higher due to the long bunch length of the LHC beam. This will require a novel compact crab cavity design. A superconducting version of a two rod coaxial deflecting cavity as a suitable design is proposed in this paper.

  2. Unstable resonator cavity semiconductor lasers

    SciTech Connect (OSTI)

    Salzman, J.; Venkatesan, T.; Lang, R.; Mittelstein, M.; Yariv, A.

    1985-02-01T23:59:59.000Z

    GaAs heterostructure lasers with unstable resonator cavities were demonstrated for the first time with both curved mirrors fabricated by etching. Typical output powers of 0.35 W were observed in a stable, highly coherent lateral mode. The laser operated stably in a single longitudinal mode over a large range of injection currents. The external quantum efficiency was 70% of that of a similar laser with both mirror facets cleaved implying good output coupling of the energy from the entire region.

  3. Lateral coupled cavity semiconductor laser

    SciTech Connect (OSTI)

    Salzman, J.; Lang, R.; Yariv, A.

    1985-08-01T23:59:59.000Z

    We report the fabrication and operation of a lateral coupled cavity semiconductor laser that consists of two phase-locked parallel lasers of different lengths and with separate electrical contacts. Mode selectivity that results from the interaction between the two supermodes is investigated experimentally. Frequency selectivity and tunability are obtained by controlling the current to each laser separately. Highly stable single mode operation is also demonstrated.

  4. Coupled-cavity drift-tube linac

    DOE Patents [OSTI]

    Billen, J.H.

    1996-11-26T23:59:59.000Z

    A coupled-cavity drift-tube linac (CCDTL) combines features of the Alvarez drift-tube linac (DTL) and the {pi}-mode coupled-cavity linac (CCL). In one embodiment, each accelerating cavity is a two-cell, 0-mode DTL. The center-to-center distance between accelerating gaps is {beta}{lambda}, where {lambda} is the free-space wavelength of the resonant mode. Adjacent accelerating cavities have oppositely directed electric fields, alternating in phase by 180 degrees. The chain of cavities operates in a {pi}/2 structure mode so the coupling cavities are nominally unexcited. The CCDTL configuration provides an rf structure with high shunt impedance for intermediate velocity charged particles, i.e., particles with energies in the 20-200 MeV range. 5 figs.

  5. Ligand Migration and Cavities within Scapharca Dimeric HbI: Studies by Time-Resolved Crystallo- graphy, Xe Binding, and Computational Analysis

    SciTech Connect (OSTI)

    Knapp, James E.; Pahl, Reinhard; Cohen, Jordi; Nichols, Jeffry C.; Schulten, Klaus; Gibson, Quentin H.; Š rajer, Vukica; Royer, Jr., William E.; (UMASS MED); (UIUC); (UC_

    2009-12-01T23:59:59.000Z

    As in many other hemoglobins, no direct route for migration of ligands between solvent and active site is evident from crystal structures of Scapharca inaequivalvis dimeric HbI. Xenon (Xe) and organic halide binding experiments, along with computational analysis presented here, reveal protein cavities as potential ligand migration routes. Time-resolved crystallographic experiments show that photodissociated carbon monoxide (CO) docks within 5 ns at the distal pocket B site and at more remote Xe4 and Xe2 cavities. CO rebinding is not affected by the presence of dichloroethane within the major Xe4 protein cavity, demonstrating that this cavity is not on the major exit pathway. The crystal lattice has a substantial influence on ligand migration, suggesting that significant conformational rearrangements may be required for ligand exit. Taken together, these results are consistent with a distal histidine gate as one important ligand entry and exit route, despite its participation in the dimeric interface.

  6. Resonant-cavity antenna for plasma heating

    DOE Patents [OSTI]

    Perkins, Jr., Francis W. (Princeton, NJ); Chiu, Shiu-Chu (San Diego, CA); Parks, Paul (San Diego, CA); Rawls, John M. (Del Mar, CA)

    1987-01-01T23:59:59.000Z

    Disclosed is a resonant coil cavity wave launcher for energizing a plasma immersed in a magnetic field. Energization includes launching fast Alfven waves to excite ion cyclotron frequency resonances in the plasma. The cavity includes inductive and capacitive reactive members spaced no further than one-quarter wavelength from a first wall confinement chamber of the plasma. The cavity wave launcher is energized by connection to a waveguide or transmission line carrying forward power from a remote radio frequency energy source.

  7. Ultrafast photon-photon interaction in a strongly coupled quantum dot-cavity system

    E-Print Network [OSTI]

    Dirk Englund; Arka Majumdar; Michal Bajcsy; Andrei Faraon; Pierre Petroff; Jelena vuckovic

    2011-07-14T23:59:59.000Z

    We study dynamics of the interaction between two weak light beams mediated by a strongly coupled quantum dot-photonic crystal cavity system. First, we perform all optical switching of a weak continuous-wave signal with a pulsed control beam, and then perform switching between two pulsed beams (40ps pulses) at the single photon level. Our results show that the quantum dot-nanocavity system creates strong, controllable interactions at the single photon level.

  8. Probing the ladder of dressed states and nonclassical light generation in quantum dot-cavity QED

    E-Print Network [OSTI]

    Arka Majumdar; Michal Bajcsy; Jelena Vuckovic

    2011-10-21T23:59:59.000Z

    We investigate the photon induced tunneling phenomena in a photonic crystal cavity containing a strongly coupled quantum dot and describe how this tunneling can be used to generate photon states consisting mainly of a particular Fock state. Additionally, we study experimentally the photon-induced tunneling as a function of excitation laser power and frequency and show the signature of second rung of the Jaynes-Cummings Hamiltonian in the observed photon-statistics.

  9. Pressurized melt ejection into scaled reactor cavities

    SciTech Connect (OSTI)

    Tarbell, W.W.; Pilch, M.; Brockmann, J.E.; Ross, J.W.; Gilbert, D.W.

    1986-10-01T23:59:59.000Z

    This report describes four tests performed in the High-Pressure Melt Streaming Program (HIPS) using linear-scaled cavities of the Zion Nuclear Power Plant. These experiments were conducted to study the phenomena involved in high-pressure ejection of core debris into the cavity beneath the reactor pressure vessel. One-tenth and one-twentieth linear scale models of reactor cavities were constructed and instrumented. The first test used an apparatus constructed of alumina firebrick to minimize the potential interaction between the ejected melt and cavity material. The remaining three experiments used scaled representations of the Zion nuclear plant geometry, constructed of prototypic concrete composition.

  10. Low beta spoke cavity multipacting analysis

    E-Print Network [OSTI]

    Xu Bo; Li Han; Zhang Juan; Sha Peng; Wang Qunyao; Lin Haiying; Huang Hong; Dai Jianping; Sun Yi; Wang Guangwei; Pan Weimin

    2013-03-27T23:59:59.000Z

    The simulation and analysis for electron multipacting phenomenon in low {\\beta} spoke superconducting cavity in ADS proton accelerator are proposed. Using both CST and Track3P codes, the electron multipacting calculation for {\\beta} = 0.12 spoke superconducting cavity is implemented. The methods of multipacting calculation on both codes are studied and described. With the comparison between the calculation results and the cavity vertical test results, the accuracy and reliability of different code on calculating multipacting are analyzed. Multipacting calculation can help to understand the result of vertical test and also can help to do the optimation in cavity design.

  11. An Overfilled Cavity Problem for Maxwell's Equations

    E-Print Network [OSTI]

    2011-12-23T23:59:59.000Z

    target is of high importance in the aircraft or stealth design. Time-harmonic analysis of cavity-backed apertures with penetrable material filling the cav- ity interior ...

  12. JLab Supports International Linear Collider Cavity Development...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the Department of Energy's Jefferson Lab. The baseball connection involves a nine-cell niobium cavity developed by KEK accelerator scientists in Japan as one of several designs...

  13. Design and performance of a new induction furnace for heat treatment of superconducting radiofrequency niobium cavities

    SciTech Connect (OSTI)

    Dhakal, Pashupati; Ciovati, Gianluigi; Myneni, Ganapati Rao [Jefferson Lab, Newport News, Virginia 23606 (United States); Rigby, Wayne [Specialty Vacuum, Placitas, New Mexico 87043 (United States); Wallace, John [Casting Analysis Corporation, Weyers Cave, Virginia 24468 (United States)

    2012-06-15T23:59:59.000Z

    Superconducting radio frequency (SRF) cavities made of high purity niobium (Nb) are the building blocks of many modern particle accelerators. The fabrication process includes several cycles of chemical and heat treatment at low ({approx}120 Degree-Sign C) and high ({approx}800 Degree-Sign C) temperatures. In this contribution, we describe the design and performance of an ultra-high-vacuum furnace which uses an induction heating system to heat treat SRF cavities. Cavities are heated by radiation from the Nb susceptor. By using an all-niobium hot zone, contamination of the Nb cavity by foreign elements during heat treatment is minimized and allows avoiding subsequent chemical etching. The furnace was operated up to 1400 Degree-Sign C with a maximum pressure of {approx}1 Multiplication-Sign 10{sup -5} Torr and the maximum achievable temperature is estimated to be higher than 2000 Degree-Sign C. Initial results on the performance of a single cell 1.5 GHz cavity made of ingot Nb heat treated at 1200 Degree-Sign C using this new induction furnace and without subsequent chemical etching showed a reduction of the RF losses by a factor of {approx}2 compared to cavities made of fine-grain Nb which underwent standard chemical and heat treatments.

  14. Cavity quantum electro-optics

    E-Print Network [OSTI]

    Mankei Tsang

    2010-06-30T23:59:59.000Z

    The quantum dynamics of the coupling between a cavity optical field and a resonator microwave field via the electro-optic effect is studied. This coupling has the same form as the opto-mechanical coupling via radiation pressure, so all previously considered opto-mechanical effects can in principle be observed in electro-optic systems as well. In particular, I point out the possibilities of laser cooling of the microwave mode, entanglement between the optical mode and the microwave mode via electro-optic parametric amplification, and back-action-evading optical measurements of a microwave quadrature.

  15. Optomechanical Crystals

    E-Print Network [OSTI]

    Eichenfield, Matt; Camacho, Ryan M; Vahala, Kerry J; Painter, Oskar

    2009-01-01T23:59:59.000Z

    Structured, periodic optical materials can be used to form photonic crystals capable of dispersing, routing, and trapping light. A similar phenomena in periodic elastic structures can be used to manipulate mechanical vibrations. Here we present the design and experimental realization of strongly coupled optical and mechanical modes in a planar, periodic nanostructure on a silicon chip. 200-Terahertz photons are co-localized with mechanical modes of Gigahertz frequency and 100-femtogram mass. The effective coupling length, which describes the strength of the photon-phonon interaction, is as small as 2.9 microns, which, together with minute oscillator mass, allows all-optical actuation and transduction of nanomechanical motion with near quantum-limited sensitivity. Optomechanical crystals have many potential applications, from RF-over-optical communication to the study of quantum effects in mesoscopic mechanical systems.

  16. Breakthrough: Record-Setting Cavity

    ScienceCinema (OSTI)

    Ciovati, Gianluigi

    2014-05-21T23:59:59.000Z

    Gianluigi "Gigi" Ciovati, a superconducting radiofrequency scientist, discusses how scientists at the U.S. Department of Energy's Jefferson Lab in Newport News, VA, used ARRA funds to fabricate a niobium cavity for superconducting radiofrequency accelerators that has set a world record for energy efficiency. Jefferson Lab's scientists developed a new, super-hot treatment process that could soon make it possible to produce cavities more quickly and at less cost, benefitting research and healthcare around the world. Accelerators are critical to our efforts to study the structure of matter that builds our visible universe. They also are used to produce medical isotopes and particle beams for diagnosing and eradicating disease. And they offer the potential to power future nuclear power plants that produce little or no radioactive waste.around the world. Accelerators are critical to our efforts to study the structure of matter that builds our visible universe. They also are used to produce medical isotopes and particle beams for diagnosing and eradicating disease. And they offer the potential to power future nuclear power plants that produce little or no radioactive waste.

  17. RF study and simulations of a C-band Barrel Open Cavity (BOC) pulse compressor

    E-Print Network [OSTI]

    Shu, Guan; He, Xiang

    2014-01-01T23:59:59.000Z

    This paper focuses on the RF study of a C-band(5712MHz) BOC pulse compressor. The operating principle of BOC is presented and the technical specifications are determined. The main components of BOC such as the cavity, the matching waveguide, the coupling slots and the tuning rings were numerically simulated by 3-D codes software HFSS and CST Microwave Studio(MWS). The "whispering gallery" mode TM6,1,1 with an unload Q of 100000 was chosen to oscillate in the cavity. An energy multiplication factor of 1.99 and a peak power gain of 6.34 were achieved theoretically.

  18. BRF Crystal_Reporting_9_1 Version Date: February 2014

    E-Print Network [OSTI]

    . Oracle Corporation and its affiliates will not be responsible for any loss, costs, or damages incurred........................................................................................1 Running Crystal Reports ...............................................................................................................................9 Run a Single Report for Multiple Departments

  19. Ultrafast Optical Switching Using Photonic Molecules in Photonic Crystal Waveguides

    E-Print Network [OSTI]

    Zhao, Yanhui; Qiu, Kangsheng; Gao, Yunan; Xu, Xiulai

    2015-01-01T23:59:59.000Z

    We study the coupling between photonic molecules and waveguides in photonic crystal slab structures using finite-difference time-domain method and coupled mode theory. In a photonic molecule with two cavities, the coupling of cavity modes results in two super-modes with symmetric and anti-symmetric field distributions. When two super-modes are excited simultaneously, the energy of electric field oscillates between the two cavities. To excite and probe the energy oscillation, we integrate photonic molecule with two photonic crystal waveguides. In coupled structure, we find that the quality factors of two super-modes might be different because of different field distributions of super-modes. After optimizing the radii of air holes between two cavities of photonic molecule, nearly equal quality factors of two super-modes are achieved, and coupling strengths between the waveguide modes and two super-modes are almost the same. In this case, complete energy oscillations between two cavities can be obtained with a p...

  20. The Multi-Cavity Free-Electron Laser

    E-Print Network [OSTI]

    Krishnagopal, S.

    2008-01-01T23:59:59.000Z

    The Multi-Cavity Free-Electron Laser S. Krishnagopal, G.414 The Multi-Cavity Free-Electron Laser S. Krishnagopal, G.of Multi-Cavity Free-Electron Lasers Parameters A(,um) '

  1. Quantum Properties of Cavity Cerenkov Radiation

    E-Print Network [OSTI]

    Gao, J; Gao, Ju; Shen, Fang

    2005-01-01T23:59:59.000Z

    Cerenkov radiation from cavities have been analyzed by quantum electrodynamic theory. Analytical expressions of some basic radiation properties including Einstein's $A$ and $B$ coefficients are derived and shown to be directly modified by the cavities. Coherent and incoherent radiations are analyzed with the aim of generating THz radiation from the devices.

  2. Cavity-QED-based quantum phase gate

    E-Print Network [OSTI]

    Zubairy, M. Suhail; Kim, M.; Scully, Marlan O.

    2003-01-01T23:59:59.000Z

    We describe a quantum phase gate in which the two qubits are represented by the photons in the two modes of the cavity field. The gate is implemented by passing a three-level atom in a cascade configuration through the cavity. The upper levels...

  3. Large grain cavities from pure niobium ingot

    DOE Patents [OSTI]

    Myneni, Ganapati Rao (Yorktown, VA); Kneisel, Peter (Williamsburg, VA); Cameiro, Tadeu (McMurray, PA)

    2012-03-06T23:59:59.000Z

    Niobium cavities are fabricated by the drawing and ironing of as cast niobium ingot slices rather than from cold rolled niobium sheet. This method results in the production of niobium cavities having a minimum of grain boundaries at a significantly reduced cost as compared to the production of such structures from cold rolled sheet.

  4. Reentrant Klystron Cavity as an Electromechanical Transducer

    E-Print Network [OSTI]

    12245-670, SP, Brazil Abstract. The resonance properties of reentrant cavities with circularly stored energy the strongest field is desired [1]. Also relying on intense fields to increase the energy by FAPESP, SP, Brazil. Fig.1. Reentrant cavity schematic showing electric field lines On condition

  5. Nanophotonic coherent light-matter interfaces based on rare-earth-doped crystals

    E-Print Network [OSTI]

    Zhong, Tian; Miyazono, Evan; Faraon, Andrei

    2015-01-01T23:59:59.000Z

    Quantum light-matter interfaces (QLMIs) connecting stationary qubits to photons will enable optical networks for quantum communications, precise global time keeping, photon switching, and studies of fundamental physics. Rare-earth-ion (REI) doped crystals are state-of-the-art materials for optical quantum memories and quantum transducers between optical photons, microwave photons and spin waves. Here we demonstrate coupling of an ensemble of neodymium REIs to photonic nano-cavities fabricated in the yttrium orthosilicate host crystal. Cavity quantum electrodynamics effects including Purcell enhancement (F=42) and dipole-induced transparency are observed on the highly coherent 4I9/2-4F3/2 optical transition. Fluctuations in the cavity transmission due to statistical fine structure of the atomic density are measured, indicating operation at the quantum level. Coherent optical control of cavity-coupled REIs is performed via photon echoes. Long optical coherence times (T2~100 microseconds) and small inhomogeneous...

  6. Performance of 3-cell Seamless Niobium cavities

    SciTech Connect (OSTI)

    Kneisel, Peter K. [JLAB; Ciovati, Gianluigi [JLBA; Jelezov, I. [DESY, Hamburg; Singer, W. [DESY, Hamburg; Singer, X. [DESY, Hamburg

    2009-11-01T23:59:59.000Z

    In the last several months we have surface treated and cryogenically tested three TESLA-type 3-cell cavities, which had been manufactured at DESY as seamless assemblies by hydroforming. The cavities were completed at JLab with beam tube/flange assemblies. All three cavities performed very well after they had been post-purified with titanium at 1250C for 3 hrs. The cavities, two of which consisted of an end cell and 2 center cells and one was a center cell assembly, achieved gradients of Eacc = 32 MV/m, 34 MV/m and 35 MV/m without quenches. The performance was limited by the appearance of the “Q-drop” in the absence of field emission. This contribution reports about the various measurements undertaken with these cavities.

  7. Analysis of Direct and Inverse Cavity Scattering Prob- lems

    E-Print Network [OSTI]

    2011-02-15T23:59:59.000Z

    cavity are perfect electric conductors, and the open cavity is filled with a .... assume Re? ? ?0 > 0, ? > 0 accounting for a loss medium and excludes the possible ...

  8. abdominal cavity: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Florian Marquardt 2013-03-04 6 radiofrequency cavity CERN Preprints Summary: The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned...

  9. Frequency mixing crystal

    DOE Patents [OSTI]

    Ebbers, Christopher A. (Livermore, CA); Davis, Laura E. (Manteca, CA); Webb, Mark (Salida, CA)

    1992-01-01T23:59:59.000Z

    In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmoic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X.sub.2 Y(NO.sub.3).sub.5 .multidot.2 nZ.sub.2 o wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.

  10. Dependence of the residual surface resistance of superconducting radio frequency cavities on the cooling dynamics around T{sub c}

    SciTech Connect (OSTI)

    Romanenko, A., E-mail: aroman@fnal.gov; Grassellino, A., E-mail: annag@fnal.gov; Melnychuk, O.; Sergatskov, D. A. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)

    2014-05-14T23:59:59.000Z

    We report a strong effect of the cooling dynamics through T{sub c} on the amount of trapped external magnetic flux in superconducting niobium cavities. The effect is similar for fine grain and single crystal niobium and all surface treatments including electropolishing with and without 120?°C baking and nitrogen doping. Direct magnetic field measurements on the cavity walls show that the effect stems from changes in the flux trapping efficiency: slow cooling leads to almost complete flux trapping and higher residual resistance, while fast cooling leads to the much more efficient flux expulsion and lower residual resistance.

  11. Human Glucocorticoid-Induced TNF Receptor Ligand Regulates its Signaling Activity Through Multiple Oligomerization States

    SciTech Connect (OSTI)

    Zhou,Z.; Dong, X.; Berezov, A.; Zhang, G.; Li, Y.; Zhang, H.; Murali, R.; Li, B.; Greene, M.

    2008-01-01T23:59:59.000Z

    Ligation between glucocorticoid-induced tumor necrosis factor receptor (GITR) and its ligand (GITRL) provides an undefined signal that renders CD4+CD25- effector T cells resistant to the inhibitory effects of CD4+CD25+ regulatory T cells. To understand the structural basis of GITRL function, we have expressed and purified the extracellular domain of human GITR ligand in Escherichia coli. Chromotography and cross-linking studies indicate that human GITRL (hGITRL) exists as dimers and trimers in solution and also can form a supercluster. To gain insight into the nature of GITRL oligomerization, we determined the crystallographic structures of hGITRL, which revealed a loosely associated open trimer with a deep cavity at the molecular center and a flexible C-terminal tail bent for trimerization. Moreover, a tetramer of trimers (i.e., supercluster) has also been observed in the crystal, consistent with the cross-linking analysis. Deletion of the C-terminal distal three residues disrupts the loosely assembled trimer and favors the formation of a dimer that has compromised receptor binding and signaling activity. Collectively, our studies identify multiple oligomeric species of hGITRL that possess distinct kinetics of ERK activation. The studies address the functional implications and structural models for a process by which hGITRL utilizes multiple oligomerization states to regulate GITR-mediated signaling during T cell costimulation.

  12. Numerical modeling of vertical cavity semiconductor lasers

    SciTech Connect (OSTI)

    Chow, W.W.; Hadley, G.R.

    1996-08-01T23:59:59.000Z

    A vertical cavity surface emitting laser (VCSEL) is a diode laser whose optical cavity is formed by growing or depositing DBR mirror stacks that sandwich an active gain region. The resulting short cavity supports lasing into a single longitudinal mode normal to the wafer, making these devices ideal for a multitude of applications, ranging from high-speed communication to high-power sources (from 2D arrays). This report describes the development of a numerical VCSEL model, whose goal is to both further their understanding of these complex devices and provide a tool for accurate design and data analysis.

  13. Monochromator Crystal Glitch Library

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    SSRL's Monochromator Crystal Glitch Library allows users to view glitch spectra online, list specific crystal orientations, and download PDF files of the glitch spectra. (Specialized Interface)

  14. Design approach for the development of a cryomodule for compact crab cavities for Hi-Lumi LHC

    SciTech Connect (OSTI)

    Pattalwar, Shrikant; Goudket, Philippe; McIntosh, Peter; Wheelhouse, Alan [Accelerator Science and Technology Centre, STFC Daresbury Laboratory, Warrington WA44AD, UK and Cockcroft Institute, STFC Daresbury Laboratory, Warrington, WA44AD (United Kingdom); Jones, Thomas; Templeton, Niklas [Technology Group, STFC Daresbury Laboratory, Warrington, WA44A (United Kingdom); Burt, Graeme; Hall, Ben [University of Lancaster, Lancaster, UK and Cockcroft Institute, STFC Daresbury Laboratory, Warrington, WA44AD (United Kingdom); Wright, Loren [University of Lancaster, Lancaster, UK and TE-MSC-C, CERN, Geneva (Switzerland); Peterson, Tom [Technical Division, Fermilab, P.O. Box 500, Batavia, IL 60510 (United States)

    2014-01-29T23:59:59.000Z

    A prototype Superconducting RF (SRF) cryomodule, comprising multiple compact crab cavities is foreseen to realise a local crab crossing scheme for the “Hi-Lumi LHC”, a project launched by CERN to increase the luminosity performance of LHC. A cryomodule with two cavities will be initially installed and tested on the SPS drive accelerator at CERN to evaluate performance with high-intensity proton beams. A series of boundary conditions influence the design of the cryomodule prototype, arising from; the complexity of the cavity design, the requirement for multiple RF couplers, the close proximity to the second LHC beam pipe and the tight space constraints in the SPS and LHC tunnels. As a result, the design of the helium vessel and the cryomodule has become extremely challenging. This paper assesses some of the critical cryogenic and engineering design requirements and describes an optimised cryomodule solution for the evaluation tests on SPS.

  15. e-Cooling High Cavity & Cryomodule Systems, Inc.

    E-Print Network [OSTI]

    Beta Cavity & Cryomodule Final Design Review Cryomodule Design Brookhaven National Laboratory July 22;e-Cooling High Cavity & Cryomodule Advanced Energy Systems, Inc. Slide 7 of 24 Cavity Cold Model) 40.0 85.0 Wall Thickness (mm) 4 mm 3 mm Cavity Configuration Freq. Cells Tuner Load (400 kHz) Tuning

  16. Compound parabolic concentrator with cavity for tubular absorbers

    DOE Patents [OSTI]

    Winston, Roland (5217C S. University Ave., Chicago, IL 60615)

    1983-01-01T23:59:59.000Z

    A compond parabolic concentrator with a V-shaped cavity is provided in which an optical receiver is emplaced. The cavity redirects all energy entering between the receiver and the cavity structure onto the receiver, if the optical receiver is emplaced a distance from the cavity not greater than 0.27 r (where r is the radius of the receiver).

  17. Resonant-cavity enhanced thermal emission

    E-Print Network [OSTI]

    Celanovic, Ivan

    In this paper we present a vertical-cavity enhanced resonant thermal emitter—a highly directional, narrow-band, tunable, partially coherent thermal source. This device enhances thermal emittance of a metallic or any other ...

  18. Degreasing and cleaning superconducting RF Niobium cavities

    SciTech Connect (OSTI)

    Rauchmiller, Michael; Kellett, Ron; /Fermilab

    2011-09-01T23:59:59.000Z

    The purpose and scope of this report is to detail the steps necessary for degreasing and cleaning of superconducting RF Niobium cavities in the A0 clean room. It lists the required equipment and the cleaning procedure.

  19. Atom interferometry in an optical cavity

    E-Print Network [OSTI]

    Paul Hamilton; Matt Jaffe; Justin M. Brown; Lothar Maisenbacher; Brian Estey; Holger Müller

    2014-09-25T23:59:59.000Z

    We propose and demonstrate a new scheme for atom interferometry, using light pulses inside an optical cavity as matter wave beamsplitters. The cavity provides power enhancement, spatial filtering, and a precise beam geometry, enabling new techniques such as low power beamsplitters ($modest power, or new self-aligned interferometer geometries utilizing the transverse modes of the optical cavity. As a first demonstration, we obtain Ramsey-Raman fringes with $>75\\%$ contrast and measure the acceleration due to gravity, $\\mathit{g}$, to $60 \\mathrm{\\mu \\mathit{g} / \\sqrt{Hz}}$ resolution in a Mach-Zehnder geometry. We use $>10^7$ cesium atoms in the compact mode volume ($600 \\mathrm{\\mu m}$ $1/e^2$ waist) of the cavity and show trapping of atoms in higher transverse modes. This work paves the way toward compact, high sensitivity, multi-axis interferometry.

  20. Constant field gradient planar coupled cavity structure

    DOE Patents [OSTI]

    Kang, Y.W.; Kustom, R.L.

    1999-07-27T23:59:59.000Z

    A cavity structure is disclosed having at least two opposing planar housing members spaced apart to accommodate the passage of a particle beam through the structure between the members. Each of the housing members have a plurality of serially aligned hollows defined therein, and also passages, formed in the members, which interconnect serially adjacent hollows to provide communication between the hollows. The opposing planar housing members are spaced and aligned such that the hollows in one member cooperate with corresponding hollows in the other member to form a plurality of resonant cavities aligned along the particle beam within the cavity structure. To facilitate the obtaining of a constant field gradient within the cavity structure, the passages are configured so as to be incrementally narrower in the direction of travel of the particle beam. In addition, the spacing distance between the opposing housing members is configured to be incrementally smaller in the direction of travel of the beam. 16 figs.

  1. Deflecting light into resonant cavities for spectroscopy

    DOE Patents [OSTI]

    Zare, R.N.; Martin, J.; Paldus, B.A.

    1998-09-29T23:59:59.000Z

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available. 5 figs.

  2. Thermodynamic cycle in a cavity optomechanical system

    E-Print Network [OSTI]

    Hou Ian

    2014-02-16T23:59:59.000Z

    A cavity optomechanical system is initiated by a radiation pressure of a cavity field onto a mirror element acting as a quantum resonator. This radiation pressure can control the thermodynamic character of the mirror to some extent, such as cooling its effective temperature. Here we show that by properly engineering the spectral density of a thermal heat bath that interacts with a quantum system, the evolution of the quantum system can be effectively turned on and off. Inside a cavity optomechanical system, when the heat bath is realized by a multi-mode oscillator modeling of the mirror, this on-off effect translates to infusion or extraction of heat energy in and out of the cavity field, facilitating a four-stroke thermodynamic cycle.

  3. Resonance control in SRF cavities at FNAL

    SciTech Connect (OSTI)

    Schappert, W.; Pischalnikov, Y.; /Fermilab; Scorrano, M.; /INFN, Pisa

    2011-03-01T23:59:59.000Z

    The Lorentz force can dynamically detune pulsed Superconducting RF cavities. Considerable additional RF power can be required to maintain the accelerating gradient if no effort is made to compensate for this detuning. Compensation systems using piezo actuators have been used successfully at DESY and elsewhere to control Lorentz Force Detuning (LFD). Recently, Fermilab has developed an adaptive compensation system for cavities in the Horizontal Test Stand, in the SRF Accelerator Test Facility, and for the proposed Project X.

  4. Exploration of very high gradient cavities

    SciTech Connect (OSTI)

    Grigory Eremeev

    2011-07-01T23:59:59.000Z

    Several of the 9-cell ILC cavities processed at Jlab within ongoing ILC R&D program have shown interesting behavior at high fields, such as mode mixing and sudden field emission turn-on during quench. Equipped with thermometry and oscillating superleak transducer (OST) system for quench detection, we couple our RF measurements with local dissipation measurements. In this contribution we report on our findings with high gradient SRF cavities.

  5. JLab SRF Cavity Fabrication Errors, Consequences and Lessons Learned

    SciTech Connect (OSTI)

    Frank Marhauser

    2011-09-01T23:59:59.000Z

    Today, elliptical superconducting RF (SRF) cavities are preferably made from deep-drawn niobium sheets as pursued at Jefferson Laboratory (JLab). The fabrication of a cavity incorporates various cavity cell machining, trimming and electron beam welding (EBW) steps as well as surface chemistry that add to forming errors creating geometrical deviations of the cavity shape from its design. An analysis of in-house built cavities over the last years revealed significant errors in cavity production. Past fabrication flaws are described and lessons learned applied successfully to the most recent in-house series production of multi-cell cavities.

  6. "Fine grain Nb tube for SRF cavities"

    SciTech Connect (OSTI)

    Robert E. Barber

    2012-07-08T23:59:59.000Z

    Superconducting radio frequency (SRF) cavities used in charged particle linear accelerators, are currently fabricated by deep drawing niobium sheets and welding the drawn dishes together. The Nb sheet has a non-uniform microstructure, which leads to unpredictable cavity shape and surface roughness, and inconsistent "spring-back" during forming. In addition, weld zones cause hot spots during cavity operation. These factors limit linear accelerator performance and increase cavity manufacturing cost. Equal channel angular extrusion (ECAE) can be used to refine and homogenize the microstructure of Nb tube for subsequent hydroforming into SRF cavities. Careful selection of deformation and heat treatment conditions during the processing steps can give a uniform and consistent microstructure in the tube, leading to improved deformability and lower manufacturing costs. Favorable microstructures were achieved in short test samples of RRR Nb tube, which may be particularly suitable for hydroforming into SRF cavity strings. The approach demonstrated could be applicable to microstructure engineering of other tube materials including tantalum, titanium, and zirconium.

  7. Optimization of three-dimensional micropost microcavities for cavity quantum electrodynamics

    E-Print Network [OSTI]

    Jelena Vuckovic; Matthew Pelton; Axel Scherer; Yoshihisa Yamamoto

    2002-08-21T23:59:59.000Z

    This article presents a detailed analysis, based on the first-principles finite-difference time-domain method, of the resonant frequency, quality factor (Q), mode volume (V), and radiation pattern of the fundamental (HE11) mode in a three-dimensional distributed-Bragg-reflector (DBR) micropost microcavity. By treating this structure as a one-dimensional cylindrical photonic crystal containing a single defect, we are able to push the limits of Q/V beyond those achievable by standard micropost designs, based on the simple rules established for planar DBR microcavities. We show that some of the rules that work well for designing large-diameter microposts (e.g., high-refractive index contrast) fail to provide high-quality cavities with small diameters. By tuning the thicknesses of mirror layers and the spacer, the number of mirror pairs, the refractive indices of high and low refractive index regions, and the cavity diameter, we are able to achieve Q as high as 10^4, together with a mode volume of 1.6 cubic wavelengths of light in the high-refractive-index material. The combination of high Q and small V makes these structures promising candidates for the observation of such cavity quantum electrodynamics phenomena as strong coupling between a quantum dot and the cavity field, and single-quantum-dot lasing.

  8. Process of making cryogenically cooled high thermal performance crystal optics

    DOE Patents [OSTI]

    Kuzay, T.M.

    1992-06-23T23:59:59.000Z

    A method is disclosed for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N[sub 2] is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation. 7 figs.

  9. Process of making cryogenically cooled high thermal performance crystal optics

    DOE Patents [OSTI]

    Kuzay, Tuncer M. (Naperville, IL)

    1992-01-01T23:59:59.000Z

    A method for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N.sub.2 is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation.

  10. Mixed crystal organic scintillators

    DOE Patents [OSTI]

    Zaitseva, Natalia P; Carman, M Leslie; Glenn, Andrew M; Hamel, Sebastien; Hatarik, Robert; Payne, Stephen A; Stoeffl, Wolfgang

    2014-09-16T23:59:59.000Z

    A mixed organic crystal according to one embodiment includes a single mixed crystal having two compounds with different bandgap energies, the organic crystal having a physical property of exhibiting a signal response signature for neutrons from a radioactive source, wherein the signal response signature does not include a significantly-delayed luminescence characteristic of neutrons interacting with the organic crystal relative to a luminescence characteristic of gamma rays interacting with the organic crystal. According to one embodiment, an organic crystal includes bibenzyl and stilbene or a stilbene derivative, the organic crystal having a physical property of exhibiting a signal response signature for neutrons from a radioactive source.

  11. Control of the electromagnetic environment of a quantum emitter by shaping the vacuum field in a coupled-cavity system

    E-Print Network [OSTI]

    Robert Johne; Ron Schutjens; Sartoon Fattah poor; Chao-Yuan Jin; Andrea Fiore

    2015-03-20T23:59:59.000Z

    We propose a scheme for the ultrafast control of the emitter-field coupling rate in cavity quantum electrodynamics. This is achieved by the control of the vacuum field seen by the emitter through a modulation of the optical modes in a coupled-cavity structure. The scheme allows the on/off switching of the coupling rate without perturbing the emitter and without introducing frequency chirps on the emitted photons. It can be used to control the shape of single-photon pulses for high-fidelity quantum state transfer, to control Rabi oscillations and as a gain-modulation method in lasers. We discuss two possible experimental implementations based on photonic crystal cavities and on microwave circuits.

  12. Crystal structure refinement with SHELXL

    SciTech Connect (OSTI)

    Sheldrick, George M., E-mail: gsheldr@shelx.uni-ac.gwdg.de [Department of Structural Chemistry, Georg-August Universität Göttingen, Tammannstraße 4, Göttingen 37077 (Germany)

    2015-01-01T23:59:59.000Z

    New features added to the refinement program SHELXL since 2008 are described and explained. The improvements in the crystal structure refinement program SHELXL have been closely coupled with the development and increasing importance of the CIF (Crystallographic Information Framework) format for validating and archiving crystal structures. An important simplification is that now only one file in CIF format (for convenience, referred to simply as ‘a CIF’) containing embedded reflection data and SHELXL instructions is needed for a complete structure archive; the program SHREDCIF can be used to extract the .hkl and .ins files required for further refinement with SHELXL. Recent developments in SHELXL facilitate refinement against neutron diffraction data, the treatment of H atoms, the determination of absolute structure, the input of partial structure factors and the refinement of twinned and disordered structures. SHELXL is available free to academics for the Windows, Linux and Mac OS X operating systems, and is particularly suitable for multiple-core processors.

  13. Local Quantum Dot Tuning on Photonic Crystal Chips

    E-Print Network [OSTI]

    Andrei Faraon; Dirk Englund; Ilya Fushman; Nick Stoltz; Pierre Petroff; Jelena Vuckovic

    2007-03-28T23:59:59.000Z

    Quantum networks based on InGaAs quantum dots embedded in photonic crystal devices rely on QDs being in resonance with each other and with the cavities they are embedded in. We developed a new technique based on temperature tuning to spectrally align different quantum dots located on the same chip. The technique allows for up to 1.8nm reversible on-chip quantum dot tuning.

  14. Pressure cryocooling protein crystals

    DOE Patents [OSTI]

    Kim, Chae Un (Ithaca, NY); Gruner, Sol M. (Ithaca, NY)

    2011-10-04T23:59:59.000Z

    Preparation of cryocooled protein crystal is provided by use of helium pressurizing and cryocooling to obtain cryocooled protein crystal allowing collection of high resolution data and by heavier noble gas (krypton or xenon) binding followed by helium pressurizing and cryocooling to obtain cryocooled protein crystal for collection of high resolution data and SAD phasing simultaneously. The helium pressurizing is carried out on crystal coated to prevent dehydration or on crystal grown in aqueous solution in a capillary.

  15. RF BREAKDOWN STUDIES USING PRESSURIZED CAVITIES

    SciTech Connect (OSTI)

    Johnson, Rolland

    2014-09-21T23:59:59.000Z

    Many present and future particle accelerators are limited by the maximum electric gradient and peak surface fields that can be realized in RF cavities. Despite considerable effort, a comprehensive theory of RF breakdown has not been achieved and mitigation techniques to improve practical maximum accelerating gradients have had only limited success. Part of the problem is that RF breakdown in an evacuated cavity involves a complex mixture of effects, which include the geometry, metallurgy, and surface preparation of the accelerating structures and the make-up and pressure of the residual gas in which plasmas form. Studies showed that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas, as needed for muon cooling channels, without the need for long conditioning times, even in the presence of strong external magnetic fields. This positive result was expected because the dense gas can practically eliminate dark currents and multipacting. In this project we used this high pressure technique to suppress effects of residual vacuum and geometry that are found in evacuated cavities in order to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. One of the interesting and useful outcomes of this project was the unanticipated collaborations with LANL and Fermilab that led to new insights as to the operation of evacuated normal-conducting RF cavities in high external magnetic fields. Other accomplishments included: (1) RF breakdown experiments to test the effects of SF6 dopant in H2 and He gases with Sn, Al, and Cu electrodes were carried out in an 805 MHz cavity and compared to calculations and computer simulations. The heavy corrosion caused by the SF6 components led to the suggestion that a small admixture of oxygen, instead of SF6, to the hydrogen would allow the same advantages without the corrosion in a practical muon beam line. (2) A 1.3 GHz RF test cell capable of operating both at high pressure and in vacuum with replaceable electrodes was designed, built, and power tested in preparation for testing the frequency and geometry effects of RF breakdown at Argonne National Lab. At the time of this report this cavity is still waiting for the 1.3 GHz klystron to be available at the Wakefield Test Facility. (3) Under a contract with Los Alamos National Lab, an 805 MHz RF test cavity, known as the All-Seasons Cavity (ASC), was designed and built by Muons, Inc. to operate either at high pressure or under vacuum. The LANL project to use the (ASC) was cancelled and the testing of the cavity has been continued under the grant reported on here using the Fermilab Mucool Test Area (MTA). The ASC is a true pillbox cavity that has performed under vacuum in high external magnetic field better than any other and has demonstrated that the high required accelerating gradients for many muon cooling beam line designs are possible. (4) Under ongoing support from the Muon Acceleration Program, microscopic surface analysis and computer simulations have been used to develop models of RF breakdown that apply to both pressurized and vacuum cavities. The understanding of RF breakdown will lead to better designs of RF cavities for many applications. An increase in the operating accelerating gradient, improved reliability and shorter conditioning times can generate very significant cost savings in many accelerator projects.

  16. Progress on a Cavity with Beryllium Walls for Muon Ionization Cooling Channel R&D.

    E-Print Network [OSTI]

    Bowring, D.L.

    2014-01-01T23:59:59.000Z

    ON A CAVITY WITH BERYLLIUM WALLS FOR MUON IONIZATION COOLINGFabricating a cavity with beryllium walls would mitigatepillbox RF cavity with beryllium walls, in order to evaluate

  17. Superconducting RF cavity R&D for future accelerators

    E-Print Network [OSTI]

    C. M. Ginsburg

    2009-10-22T23:59:59.000Z

    High-beta superconducting radiofrequency (SRF) elliptical cavities are being developed for several accelerator projects including Project X, the European XFEL, and the International Linear Collider (ILC). Fermilab has recently established an extensive infrastructure for SRF cavity R&D for future accelerators, including cavity surface processing and testing and cavity assembly into cryomodules. Some highlights of the global effort in SRF R&D toward improving cavity performance, and Fermilab SRF cavity R&D in the context of global projects are reviewed.

  18. Atomic Layer Deposition for SRF Cavities

    SciTech Connect (OSTI)

    Proslier, Th.; Ha, Y.; Zasadzinski, J.; /IIT, Chicago; Ciovati, G.; Kneissel, P.; Reece, C.; Rimmer, R.; /Jefferson Lab; Gurevich, A.; /Natl. High Mag. Field Lab.; Cooley, L.; Wu, G.; /Fermilab; Pellin, M.; /Argonne

    2009-05-01T23:59:59.000Z

    We have begun using Atomic Layer Deposition (ALD) to synthesize a variety of surface coatings on coupons and cavities as part of an effort to produce rf structures with significantly better performance and yield than those obtained from bulk niobium, The ALD process offers the possibility of conformally coating complex cavity shapes with precise layered structures with tightly constrained morphology and chemical properties. Our program looks both at the metallurgy and superconducting properties of these coatings, and also their performance in working structures. Initial results include: (1) results from ALD coated cavities and coupons, (2) new evidence from point contact tunneling (PCT) showing magnetic oxides can be a significant limitation to high gradient operation, (3) a study of high pressure rinsing damage on niobium samples.

  19. Crystal structure and chemistry of a complex indium phosphate framework material, (ethylenediammonium)In{sub 3}P{sub 3}O{sub 12}(OH){sub 2}

    SciTech Connect (OSTI)

    Broach, Robert W., E-mail: robert.broach@uop.com [UOP, a Honeywell Co., 50 E. Algonquin Rd., Des Plaines, IL 60017 (United States); Bedard, Robert L. [UOP, a Honeywell Co., 50 E. Algonquin Rd., Des Plaines, IL 60017 (United States)] [UOP, a Honeywell Co., 50 E. Algonquin Rd., Des Plaines, IL 60017 (United States); King, Lisa M., E-mail: lisa.king@uop.com [UOP, a Honeywell Co., 50 E. Algonquin Rd., Des Plaines, IL 60017 (United States); Pluth, Joseph J., E-mail: pluth@cars.uchicago.edu [The University of Chicago, Department of the Geophysical Sciences, Consortium for Advanced Radiation Sources, Chicago, IL 60637 (United States); The University of Chicago, The Materials Research Science and Engineering Center, Chicago, IL 60637 (United States); Smith, Joseph V. [The University of Chicago, Department of the Geophysical Sciences, Consortium for Advanced Radiation Sources, Chicago, IL 60637 (United States)] [The University of Chicago, Department of the Geophysical Sciences, Consortium for Advanced Radiation Sources, Chicago, IL 60637 (United States); Kirchner, Richard M., E-mail: richard.kirchner@manhattan.edu [Manhattan College, Chemistry Department, Bronx, NY 10471 (United States)

    2012-12-15T23:59:59.000Z

    The chemistry and structure of a novel indium phosphate material (RIPS-4), (H{sub 3}NCH{sub 2}CH{sub 2}NH{sub 3})In{sub 3}-P{sub 3}O{sub 12}(OH){sub 2}, are described. RIPS-4 was synthesized using ethylene diamine as a structure-directing organic agent. The X-ray crystal structure was determined from a 12 Multiplication-Sign 12 Multiplication-Sign 42 {mu}m{sup 3} crystal in space group C2/m with a=18.662(4) A, b=6.600(2) A, c=12.573(3) A and {beta}=120.92(1) Degree-Sign . The structure consists of a complex edge- and vertex-shared open framework of InO{sub 6} octahedra and PO{sub 4} tetrahedra enclosing cavities occupied by ethylenediamonium ions. One set of octahedra share opposing edges to form chains along the b-axis matching the structural unit in rutile (TiO{sub 2}). This rutile edge-shared chain has its projecting oxygen atoms shared with the vertexes of either a PO{sub 4} tetrahedron or a second type of InO{sub 6} octahedron. The O atoms are 2-connected, each to one In and one P, except for two protonated O atoms (hydroxyl groups) that connect to two and three In atoms, giving three- and four-coordinate O atoms, respectively. - Graphical abstract: The unique topology contains an unusual 4-connected oxygen atom (O{sub 1}) in a complex edge- and vertex-shared open framework of InO{sub 6} octahedra (blue) and PO{sub 4} tetrahedra (yellow) that encloses cavities occupied by ethylenediammonium ions. Highlights: Black-Right-Pointing-Pointer The structure has a unique open-framework topology. Black-Right-Pointing-Pointer The framework contains an unusual 4-connected oxygen atom. Black-Right-Pointing-Pointer Hydrogen bonds hold the ethylenediammonium ions in the cavities.

  20. Cavity sideband cooling of trapped molecules

    SciTech Connect (OSTI)

    Kowalewski, Markus; Vivie-Riedle, Regina de [Department of Chemistry, Ludwig-Maximilian-Universitaet, D-81377 Munich (Germany); Morigi, Giovanna [Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Theoretische Physik, Universitaet des Saarlandes, D-66041 Saarbruecken (Germany); Pinkse, Pepijn W. H. [MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands)

    2011-09-15T23:59:59.000Z

    The efficiency of cavity sideband cooling of trapped molecules is theoretically investigated for the case in which the infrared transition between two rovibrational states is used as a cycling transition. The molecules are assumed to be trapped either by a radiofrequency or optical trapping potential, depending on whether they are charged or neutral, and confined inside a high-finesse optical resonator that enhances radiative emission into the cavity mode. Using realistic experimental parameters and COS as a representative molecular example, we show that in this setup, cooling to the trap ground state is feasible.

  1. Kinematic entanglement degradation of fermionic cavity modes

    E-Print Network [OSTI]

    Nicolai Friis; Antony R. Lee; David Edward Bruschi; Jorma Louko

    2012-01-23T23:59:59.000Z

    We analyse the entanglement and the non-locality of a (1+1)-dimensional massless Dirac field confined to a cavity on a worldtube that consists of inertial and uniformly accelerated segments, for small accelerations but arbitrarily long travel times. The correlations between the accelerated field modes and the modes in an inertial reference cavity are periodic in the durations of the individual trajectory segments, and degradation of the correlations can be entirely avoided by fine-tuning the individual or relative durations of the segments. Analytic results for selected trajectories are presented. Differences from the corresponding bosonic correlations are identified and extensions to massive fermions are discussed.

  2. Fundamental Research in Superconducting RF Cavity Design

    SciTech Connect (OSTI)

    Georg Hoffstaetter

    2012-11-13T23:59:59.000Z

    This is a 3-year SRF R&D proposal with two main goals: 1) to benefit near term high gradient SRF applications by understanding the causes of quench at high fields in present-day niobium cavities 2) to open the long-range prospects for SRF applications by experimentally verifying the recent exciting theoretical predication for new cavity materials such as Nb3Sn and MgB2. These predictions shwo that ultimately gradients of 100Mv/m to 200MV/m may become possible as material imperfections are overcome.

  3. Coupled Geomechanical Simulations of UCG Cavity Evolution

    SciTech Connect (OSTI)

    Morris, J P; Buscheck, T A; Hao, Y

    2009-07-13T23:59:59.000Z

    This paper presents recent work from an ongoing project to develop predictive tools for cavity/combustion-zone growth and to gain quantitative understanding of the processes and conditions (both natural and engineered) affecting underground coal gasification (UCG). In this paper we will focus upon the development of coupled geomechanical capabilities for simulating the evolution of the UCG cavity using discrete element methodologies. The Discrete Element Method (DEM) has unique advantages for facilitating the prediction of the mechanical response of fractured rock masses, such as cleated coal seams. In contrast with continuum approaches, the interfaces within the coal can be explicitly included and combinations of both elastic and plastic anisotropic response are simulated directly. Additionally, the DEM facilitates estimation of changes in hydraulic properties by providing estimates of changes in cleat aperture. Simulation of cavity evolution involves a range of coupled processes and the mechanical response of the host coal and adjoining rockmass plays a role in every stage of UCG operations. For example, cavity collapse during the burn has significant effect upon the rate of the burn itself. In the vicinity of the cavity, collapse and fracturing may result in enhanced hydraulic conductivity of the rock matrix in the coal and caprock above the burn chamber. Even far from the cavity, stresses due to subsidence may be sufficient to induce new fractures linking previously isolated aquifers. These mechanical processes are key in understanding the risk of unacceptable subsidence and the potential for groundwater contamination. These mechanical processes are inherently non-linear, involving significant inelastic response, especially in the region closest to the cavity. In addition, the response of the rock mass involves both continuum and discrete mechanical behavior. We have recently coupled the LDEC (Livermore Distinct Element Code) and NUFT (Non-isothermal Unsaturated Flow and Transport) codes to investigate the interaction between combustion, water influx and mechanical response. The modifications to NUFT are described in detail in a companion paper. This paper considers the extension of the LDEC code and the application of the coupled tool to the simulation of cavity growth and collapse. The distinct element technology incorporated into LDEC is ideally suited to simulation of the progressive failure of the cleated coal mass by permitting the simulation of individual planes of weakness. We will present details of the coupling approach and then demonstrate the capability through simulation of several test cases.

  4. Bent core liquid crystal elastomers

    SciTech Connect (OSTI)

    Verduzco, R.; DiMasi, E.; Luchette, P.; Ho Hong, S.; Harden, J.; Palffy-Muhoray, P.; Kilbey II, S.M.; Sprunt, S.; Gleeson, G.T. Jakli, A.

    2010-07-28T23:59:59.000Z

    Liquid crystal (LC) elastomers with bent-core side-groups incorporate the properties of bent-core liquid crystals in a flexible and self-supporting polymer network. Bent-core liquid crystal elastomers (BCEs) with uniform alignment were prepared by attaching a reactive bent-core LC to poly(hydrogenmethylsiloxane) and crosslinking with a divinyl crosslinker. Phase behavior studies indicate a nematic phase over a wide temperature range that approaches room temperature, and thermoelastic measurements show that these BCEs can reversibly change their length by more than a factor of two upon heating and cooling. Small-angle X-ray scattering studies reveal multiple, broad low-angle peaks consistent with short-range smectic C order of the bent-core side groups. A comparison of these patterns with predictions of a Landau model for short-range smectic C order shows that the length scale for smectic ordering in BCEs is similar to that seen in pure bent-core LCs. The combination of rubber elasticity and smectic ordering of the bent-core side groups suggests that BCEs may be promising materials for sensing, actuating, and other advanced applications.

  5. Defect- and Strain-enhanced Cavity Formation and Au Precipitation...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Defect- and Strain-enhanced Cavity Formation and Au Precipitation at nano-crystalline ZrO2SiO2Si Interfaces . Defect- and Strain-enhanced Cavity Formation and Au Precipitation at...

  6. Nonlinear harmonic generation and devices in doubly resonant Kerr cavities

    E-Print Network [OSTI]

    Hashemi, Hila

    We describe a theoretical analysis of the nonlinear dynamics of third-harmonic generation (??3?) via Kerr (?(3)) nonlinearities in a resonant cavity with resonances at both ? and 3?. Such a doubly resonant cavity greatly ...

  7. Emittance control in rf cavities and solenoids

    E-Print Network [OSTI]

    Eshraqi, Mohammad; Lombardi, Alessandra M

    2009-01-01T23:59:59.000Z

    We study emittance growth for transport of uniform and Gaussian beams of particles in rf cavities and solenoids and show analytically its dependence on initial beam parameters. Analytical results are confirmed with simulation studies over a broad range of different initial beams.

  8. Coupling coefficients for coupled-cavity lasers

    SciTech Connect (OSTI)

    Lang, R.J.; Yariv, A.

    1987-03-01T23:59:59.000Z

    The authors derive simple, analytic formulas for the field coupling coefficients in a two-section coupled-cavity laser using a local field rate equation treatment. They show that there is a correction to the heuristic formulas based on power flow calculated by Marcuse; the correction is in agreement with numerical calculations from a coupled-mode approach.

  9. TESLA Report 2003-32 FPGA based TESLA cavity SIMCON

    E-Print Network [OSTI]

    TESLA Report 2003-32 FPGA based TESLA cavity SIMCON DOOCS server design, implementation of the laboratory solution of the FPGA based TESLA cavity simulator and controller (SIMCON) is presented. The major is a first description of the working DOOCS server for the FPGA based TESLA cavity SIMCON (which is a part

  10. VERTICAL ELECTROPOLISHING NIOBIUM CAVITIES , C. Crawford, H. Padamsee, A. Seaman

    E-Print Network [OSTI]

    Geng, Rong-Li

    VERTICAL ELECTROPOLISHING NIOBIUM CAVITIES R.L. Geng ¡ , C. Crawford, H. Padamsee, A. Seaman LEPP Superconductivity, July 10-15, 2005, Ithaca, NY, USA. SRF060419-02 Abstract Vertical electropolishing niobium-gradient superconducting niobium cavities [1]. Many labs now have acquired the ca- pability of EP multi-cell cavities

  11. Surface Superconductivity in Niobium for Superconducting RF Cavities0

    E-Print Network [OSTI]

    Surface Superconductivity in Niobium for Superconducting RF Cavities0 S. Casalbuoni1,2 , E) parameters of the ultrapure niobium used for the fabrication of the nine-cell 1.3 GHz cavities for the lin.3 GHz nine-cell cavities which are made from pure niobium and cooled by superfluid helium at 2 K. The 0

  12. October 1988 SUPERCONDUCTING CAVITIES IN THE LIGHT SOURCE STORAGE RING

    E-Print Network [OSTI]

    Kemner, Ken

    LS-86 T. K. Khoe October 1988 SUPERCONDUCTING CAVITIES IN THE LIGHT SOURCE STORAGE RING superconducting cavities. Several laboratories (CERN, KEK, DESY) are making definite plans to use them the problem of multipactoring. The main problems of using superconducting cavities in "high current" storage

  13. Superconducting multicell cavity development program at Los Alamos

    SciTech Connect (OSTI)

    Rusnak, B.; Spalek, G.: Gray, E.; DiMarco, J.N.; DeHaven, R.; Novak, J.; Walstrom, P.; Zumbro, J.; Thiessen, H.A. [Los Alamos National Lab., NM (United States); Langenbrunner, J. [Minnesota Univ., Minneapolis, MN (United States)

    1993-06-01T23:59:59.000Z

    The superconducting rf (SCRF) cavity Development Program at Los Alamos has designed, fabricated, and tested single-cell niobium cavities at 3-GHz and 805-MHz. This work is being done in preparation for procuring and testing a multicell niobium cavity. The multicell cavity is designed to accelerate protons at {beta} = 0.9; initial tests will be without beam. Progammmatic changes have required us to modify our plans to install a 6800-liter helium cryostat and a 12.8-g/s helium pump. We will use an installed cryostat to test the multicell cavity. Also, the cavity will be modified from a seven-cell to a four-cell structure to match the dimensions of the installed cryostat. Previous reports concentrated on 3-GHz results. In this paper, some of the latest results of the 805-MHz cavity tests are presented. Modifications to allow high pulsed power (HPP) testing on 805-MHz single- and four-cell cavities are proceeding. Glow discharge cleaning of an 805-MHz niobium cavity resulted in a decrease in cavity performance. The cavity was restored to previous performance levels with buffered chemical polishing (bcp). Initial results with high-pressure water cleaning show the process is useful in restoring cavity performance.

  14. Superconducting multicell cavity development program at Los Alamos

    SciTech Connect (OSTI)

    Rusnak, B.; Spalek, G.: Gray, E.; DiMarco, J.N.; DeHaven, R.; Novak, J.; Walstrom, P.; Zumbro, J.; Thiessen, H.A. (Los Alamos National Lab., NM (United States)); Langenbrunner, J. (Minnesota Univ., Minneapolis, MN (United States))

    1993-01-01T23:59:59.000Z

    The superconducting rf (SCRF) cavity Development Program at Los Alamos has designed, fabricated, and tested single-cell niobium cavities at 3-GHz and 805-MHz. This work is being done in preparation for procuring and testing a multicell niobium cavity. The multicell cavity is designed to accelerate protons at [beta] = 0.9; initial tests will be without beam. Progammmatic changes have required us to modify our plans to install a 6800-liter helium cryostat and a 12.8-g/s helium pump. We will use an installed cryostat to test the multicell cavity. Also, the cavity will be modified from a seven-cell to a four-cell structure to match the dimensions of the installed cryostat. Previous reports concentrated on 3-GHz results. In this paper, some of the latest results of the 805-MHz cavity tests are presented. Modifications to allow high pulsed power (HPP) testing on 805-MHz single- and four-cell cavities are proceeding. Glow discharge cleaning of an 805-MHz niobium cavity resulted in a decrease in cavity performance. The cavity was restored to previous performance levels with buffered chemical polishing (bcp). Initial results with high-pressure water cleaning show the process is useful in restoring cavity performance.

  15. Dirk Lipka, MDI, DESY Hamburg Status Cavity BPM's

    E-Print Network [OSTI]

    Dirk Lipka, MDI, DESY Hamburg Status Cavity BPM's for E-XFEL #12;2 08.12.2009, FLASH seminar D. Lipka, MDI, DESY Hamburg Status Cavity BPM's Content 1. Requirements 2. Overview (all BPM's) 3. In kind contribution (Saclay, DESY, PSI) 4. Cavity BPM: principle 5. Design 6. Measurements: a. Laboratory measurements

  16. Photonic crystal light source

    DOE Patents [OSTI]

    Fleming, James G. (Albuquerque, NM); Lin, Shawn-Yu (Albuquerque, NM); Bur, James A. (Corrales, NM)

    2004-07-27T23:59:59.000Z

    A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

  17. Steering matter wave superradiance with an ultra-narrowband optical cavity

    E-Print Network [OSTI]

    H. Keßler; J. Klinder; M. Wolke; A. Hemmerich

    2014-07-18T23:59:59.000Z

    A superfluid atomic gas is prepared inside an optical resonator with an ultra-narrow band width on the order of the single photon recoil energy. When a monochromatic off-resonant laser beam irradiates the atoms, above a critical intensity the cavity emits superradiant light pulses with a duration on the order of its photon storage time. The atoms are collectively scattered into coherent superpositions of discrete momentum states, which can be precisely controlled by adjusting the cavity resonance frequency. With appropriate pulse sequences the entire atomic sample can be collectively accelerated or decelerated by multiples of two recoil momenta. The instability boundary for the onset of matter wave superradiance is recorded and its main features are explained by a mean field model.

  18. Atom-photon interactions in a system of coupled cavities

    E-Print Network [OSTI]

    Abdelkrim El Amili; Sébastien Gleyzes; Christoph I Westbrook

    2012-06-18T23:59:59.000Z

    We give a theoretical treatment of single atom detection in an compound, optical micro cavity. The cavity consists of a single mode semiconductor waveguide with a gap to allow atoms to interact with the optical field in the cavity. Optical losses, both in the semiconductor and induced by the gap are considered and we give an estimate of the cavity finesse. We also compute the cooperativity parameter and show how it depends on the gap width and cavity length. Maximization of the cooperativity does not always correspond to maximization of the coupling.

  19. Capillary toroid cavity detector for high pressure NMR

    DOE Patents [OSTI]

    Gerald, II, Rex E. (Brookfield, IL); Chen, Michael J. (Downers Grove, IL); Klingler, Robert J. (Glenview, IL); Rathke, Jerome W. (Honer Glen, IL); ter Horst, Marc (Chapel Hill, NC)

    2007-09-11T23:59:59.000Z

    A Toroid Cavity Detector (TCD) is provided for implementing nuclear magnetic resonance (NMR) studies of chemical reactions under conditions of high pressures and temperatures. A toroid cavity contains an elongated central conductor extending within the toroid cavity. The toroid cavity and central conductor generate an RF magnetic field for NMR analysis. A flow-through capillary sample container is located within the toroid cavity adjacent to the central conductor to subject a sample material flowing through the capillary to a static magnetic field and to enable NMR spectra to be recorded of the material in the capillary under a temperature and high pressure environment.

  20. Technique for measuring D{sub 2} pellet mass loss through a curved guide tube using two microwave cavity detectors

    SciTech Connect (OSTI)

    Combs, S. K.; Caughman, J. B. O.; Wilgen, J. B. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States)

    2006-07-15T23:59:59.000Z

    Two microwave cavity mass detectors have been used to measure the mass loss of deuterium (D{sub 2}) pellets transported through a curved guide tube. The test tube was a mock-up of the pellet injection guide tube for the proposed ITER experiment, which will be used to transport pellets, including deuterium-tritium (D-T), from the pellet acceleration device to the inner wall (or magnetic high-field side) of the large tokamak for pellet injection and core fueling of plasmas. An accurate estimate of the mass loss is particularly important for D-T injection, because the inventory of the radioactive isotope (T) for ITER is limited and accountability and recycling will be crucial issues. In the laboratory, frozen cylindrical D{sub 2} pellets of nominal 5.3-mm diameter were shot through the stainless steel test tube ({approx_equal}10 m in length and 10-mm inside diameter), with each end equipped with a microwave cavity. As the pellet passes through each tuned microwave cavity, the peak output signal from the electronics is directly proportional to the pellet mass. An absolute calibration of the cavities, which can be problematic, is not needed for the nondestructive technique described here. Instead, a cross calibration of the two cavities with pellets of varying masses provides the relationship to determine mass loss more precisely than any other technique previously reported. In addition, the individual output signals from the cavities can be used to identify intact pellets (a single signal peak) or broken pellets (multiple signal peaks). For the pellet speed range tested in this study (100-500 m/s), the mass loss for intact pellets was directly dependent on the pellet speed, with {approx_equal}10% mass loss at 300 m/s. The microwave cavities and the associated electronics, as well as some basic theory, are described; calibration and experimental data are presented and discussed.

  1. Nano Positioning of Single Atoms in a Micro Cavity

    E-Print Network [OSTI]

    Stefan Nussmann; Markus Hijlkema; Bernhard Weber; Felix Rohde; Gerhard Rempe; Axel Kuhn

    2005-06-10T23:59:59.000Z

    The coupling of individual atoms to a high-finesse optical cavity is precisely controlled and adjusted using a standing-wave dipole-force trap, a challenge for strong atom-cavity coupling. Ultracold Rubidium atoms are first loaded into potential minima of the dipole trap in the center of the cavity. Then we use the trap as a conveyor belt that we set into motion perpendicular to the cavity axis. This allows us to repetitively move atoms out of and back into the cavity mode with a repositioning precision of 135 nm. This makes possible to either selectively address one atom of a string of atoms by the cavity, or to simultaneously couple two precisely separated atoms to a higher mode of the cavity.

  2. Recent Progress of RF Cavity Study at Mucool Test Area

    SciTech Connect (OSTI)

    Yonehara, Katsuya; /Fermilab

    2011-12-02T23:59:59.000Z

    Summar of presentation is: (1) MTA is a multi task working space to investigate RF cavities for R&D of muon beam cooling channel - (a) Intense 400 MeV H{sup -} beam, (b) Handle hydrogen (flammable) gas, (c) 5 Tesla SC solenoid magnet, (d) He cryogenic/recycling system; (2) Pillbox cavity has been refurbished to search better RF material - Beryllium button test will be happened soon; (3) E x B effect has been tested in a box cavity - Under study (result seems not to be desirable); (4) 201 MHz RF cavity with SRF cavity treatment has been tested at low magnetic field - (a) Observed some B field effect on maximum field gradient and (b) Further study is needed (large bore SC magnet will be delivered end of 2011); and (5) HPRF cavity beam test has started - (a) No RF breakdown observed and (b) Design a new HPRF cavity to investigate more plasma loading effect.

  3. Evaluating and Minimizing Distributed Cavity Phase Errors in Atomic Clocks

    E-Print Network [OSTI]

    Li, Ruoxin

    2010-01-01T23:59:59.000Z

    We perform 3D finite element calculations of the fields in microwave cavities and analyze the distributed cavity phase errors of atomic clocks that they produce. The fields of cylindrical cavities are treated as an azimuthal Fourier series. Each of the lowest components produces clock errors with unique characteristics that must be assessed to establish a clock's accuracy. We describe the errors and how to evaluate them. We prove that sharp structures in the cavity do not produce large frequency errors, even at moderately high powers, provided the atomic density varies slowly. We model the amplitude and phase imbalances of the feeds. For larger couplings, these can lead to increased phase errors. We show that phase imbalances produce a novel distributed cavity phase error that depends on the cavity detuning. We also design improved cavities by optimizing the geometry and tuning the mode spectrum so that there are negligible phase variations, allowing this source of systematic error to be dramatically reduced.

  4. Evaluating and Minimizing Distributed Cavity Phase Errors in Atomic Clocks

    E-Print Network [OSTI]

    Ruoxin Li; Kurt Gibble

    2010-08-09T23:59:59.000Z

    We perform 3D finite element calculations of the fields in microwave cavities and analyze the distributed cavity phase errors of atomic clocks that they produce. The fields of cylindrical cavities are treated as an azimuthal Fourier series. Each of the lowest components produces clock errors with unique characteristics that must be assessed to establish a clock's accuracy. We describe the errors and how to evaluate them. We prove that sharp structures in the cavity do not produce large frequency errors, even at moderately high powers, provided the atomic density varies slowly. We model the amplitude and phase imbalances of the feeds. For larger couplings, these can lead to increased phase errors. We show that phase imbalances produce a novel distributed cavity phase error that depends on the cavity detuning. We also design improved cavities by optimizing the geometry and tuning the mode spectrum so that there are negligible phase variations, allowing this source of systematic error to be dramatically reduced.

  5. Heat loss from an open cavity

    SciTech Connect (OSTI)

    McDonald, C.G. [California State Polytechnic Univ., Pomona, CA (United States). Coll. of Engineering

    1995-12-01T23:59:59.000Z

    Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, receiver operating temperature, and receiver angle is presented. The resulting data is a source to evaluate the STEP measurements.

  6. Dielectric supported radio-frequency cavities

    DOE Patents [OSTI]

    Yu, David U. L. (Rancho Palos Verdes, CA); Lee, Terry G. (Cupertino, CA)

    2000-01-01T23:59:59.000Z

    A device which improves the electrical and thermomechanical performance of an RF cavity, for example, in a disk-loaded accelerating structure. A washer made of polycrystalline diamond is brazed in the middle to a copper disk washer and at the outer edge to the plane wave transformer tank wall, thus dissipating heat from the copper disk to the outer tank wall while at the same time providing strong mechanical support to the metal disk. The washer structure eliminates the longitudinal connecting rods and cooling channels used in the currently available cavities, and as a result minimizes problems such as shunt impedance degradation and field distortion in the plane wave transformer, and mechanical deflection and uneven cooling of the disk assembly.

  7. Polarization degenerate solid-state cavity QED

    E-Print Network [OSTI]

    Morten P. Bakker; Ajit V. Barve; Thomas Ruytenberg; Wolfgang Loffler; Larry A. Coldren; Dirk Bouwmeester; Martin P. van Exter

    2015-03-27T23:59:59.000Z

    A polarization degenerate microcavity containing charge-controlled quantum dots (QDs) enables equal coupling of all polarization degrees of freedom of light to the cavity QED system, which we explore through resonant laser spectroscopy. We first measure interference of the two fine-split neutral QD transitions and find very good agreement of this V-type three-level system with a coherent polarization dependent cavity QED model. We also study a charged QD that suffers from decoherence, and find also in this case that availability of the full polarization degrees of freedom is crucial to reveal the dynamics of the QD transitions. Our results pave the way for postselection-free quantum devices based on electron spin-photon polarization entanglement.

  8. Final Report for "Compact Crab Cavity Design"

    SciTech Connect (OSTI)

    Smithe, David N

    2012-11-08T23:59:59.000Z

    The goal of this project is to provide an innovative, new crab cavity design relevant to the MEIC. Through this work, we will provide comprehensive modeling of this new cavity design, including electromagnetic, thermal, and microphonic effects. One most likely candidate configuration is the design put forward by JLab and Lancaster University, UK, researchers known as the four-rod configuration. In the Phase I, Tech-X Corporation researchers performed analysis and design optimization and iteration, utilizing their state-of-the art time-domain particle-in-cell software, on a 400 MHz design for the LHC by JLab and Lancaster University, UK, researchers known as the four-rod design.

  9. Atomic Layer Deposition for SRF Cavities

    SciTech Connect (OSTI)

    Norem, J; Pellin, M J; Antoine, C Z; Ciovati, G; Kneisel, P; Reece, C E; Rimmer, R A; Cooley, L; Gurevich, A V; Ha, Y; Proslier, Th

    2009-05-01T23:59:59.000Z

    We have begun using Atomic Layer Deposition (ALD) to synthesize a variety of surface coatings on coupons and cavities as part of an effort to produce rf structures with significantly better performance and yield than those obtained from bulk niobium, The ALD process offers the possibility of conformally coating complex cavity shapes with precise layered structures with tightly constrained morphology and chemical properties. Our program looks both at the metallurgy and superconducting properties of these coatings, and also their performance in working structures. Initial results include: 1) evidence from point contact tunneling showing magnetic oxides can be a significant limitation to high gradient operation, 2) experimental results showing the production sharp niobium/oxide interfaces from a high temperature bake of ALD coated Al2O3 on niobium surfaces, 3) results from ALD coated structures.

  10. HARMONIC CAVITY PERFORMANCE FOR NSLS-II

    SciTech Connect (OSTI)

    BLEDNYKH, A.; KRINSKY, S.; PODOBEDOV, B.; ROSE, J.; TOWNE, N.; WANG, J.M.

    2005-05-15T23:59:59.000Z

    NSLS-II is a 3 GeV ultra-high brightness storage ring planned to succeed the present NSLS rings at BNL. Ultralow emittance combined with short bunch length means that it is critical to minimize the effects of Touschek scattering and coherent instabilities. Improved lifetime and stability can be achieved by including a third-harmonic RF cavity in the baseline design. This paper describes the required harmonic RF parameters and the expected system performance.

  11. Ion Coulomb Crystals

    E-Print Network [OSTI]

    Richard C. Thompson

    2014-11-18T23:59:59.000Z

    Ion Coulomb crystals (ICC), formed by atomic ions at low temperatures in radiofrequency and Penning ion traps, are structures that have remarkable properties and many applications. Images of Coulomb crystals are striking and reveal the crystal structure, which arises from a balance between the trapping forces acting on the ions and their mutual Coulomb repulsion. Applications of these structures range from frequency standards and quantum simulation through to measurement of the cross sections of chemical reactions of ions.

  12. Phononic crystal devices

    DOE Patents [OSTI]

    El-Kady, Ihab F. (Albuquerque, NM); Olsson, Roy H. (Albuquerque, NM)

    2012-01-10T23:59:59.000Z

    Phononic crystals that have the ability to modify and control the thermal black body phonon distribution and the phonon component of heat transport in a solid. In particular, the thermal conductivity and heat capacity can be modified by altering the phonon density of states in a phononic crystal. The present invention is directed to phononic crystal devices and materials such as radio frequency (RF) tags powered from ambient heat, dielectrics with extremely low thermal conductivity, thermoelectric materials with a higher ratio of electrical-to-thermal conductivity, materials with phononically engineered heat capacity, phononic crystal waveguides that enable accelerated cooling, and a variety of low temperature application devices.

  13. Liquid Crystal Optofluidics

    SciTech Connect (OSTI)

    Vasdekis, Andreas E.; Cuennet, J. G.; Psaltis, D.

    2012-10-11T23:59:59.000Z

    By employing anisotropic fluids and namely liquid crystals, fluid flow becomes an additional degree of freedom in designing optofluidic devices. In this paper, we demonstrate optofluidic liquid crystal devices based on the direct flow of nematic liquid crystals in microfluidic channels. Contrary to previous reports, in the present embodiment we employ the effective phase delay acquired by light travelling through flowing liquid crystal, without analysing the polarisation state of the transmitted light. With this method, we demonstrate the variation in the diffraction pattern of an array of microfluidic channels acting as a grating. We also discuss our recent activities in integrating mechanical oscillators for on-chip peristaltic pumping.

  14. Subsidence associated with single and multi-cavities for underground coal gasification

    SciTech Connect (OSTI)

    Avasthi, J.M.; Harloff, G.J.

    1982-06-01T23:59:59.000Z

    An extension of the 3-dimensional theoretical development of Berry and Sales has brought their subsidence predictions into agreement with the NCB's comprehensive set of empirical data. The new elastic parameters fit the amplitude of ground level subsidence. Another modification of the theory makes the subsidence profiles agree with the NCB data. The extended theory has predicted: (1) subsidence for an actual US coalmining case with multiple cavities, and (2) subsidence level and profile for a recent in situ coal-gasification test carried out in Wyoming in a steeply dipping seam.

  15. Nonclassical light from few emitters in a cavity

    E-Print Network [OSTI]

    D. Pagel; A. Alvermann; H. Fehske

    2015-04-10T23:59:59.000Z

    We study the characteristics of the light generated by few emitters in a cavity at strong light-matter coupling. By means of the Glauber $g^{(2)}$-function we can identify clearly distinguished parameter regimes with super-Poissonian and sub-Poissonian photon statistics. We establish a relation between the emission characteristics for one and multiple emitters, and explain its origin in terms of the photon-dressed emitter states. Cooperative effects lead to the generation of nonclassical light already at reduced light-matter coupling if the number of emitters is increased. Our results are obtained with a full input-output formalism and master equation valid also at strong light-matter coupling. We compare the behavior obtained with and without counter-rotating light-matter interaction terms in the Hamiltonian, and find that the generation of nonclassical light is robust against such modifications. Finally, we contrast our findings with the predictions of the quantum optical master equation and find that it fails entirely at predicting regimes with different photon statistics.

  16. Proposal for efficient mode converter based on cavity quantum electrodynamics dark mode in a semiconductor quantum dot coupled to a bimodal microcavity

    SciTech Connect (OSTI)

    Li, Jiahua [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Key Laboratory of Fundamental Physical Quantities Measurement of Ministry of Education, Wuhan 430074 (China); Yu, Rong, E-mail: yurong321@126.com [School of Science, Hubei Province Key Laboratory of Intelligent Robot, Wuhan Institute of Technology, Wuhan 430073 (China); Ma, Jinyong; Wu, Ying, E-mail: yingwu2@163.com [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-10-28T23:59:59.000Z

    The ability to engineer and convert photons between different modes in a solid-state approach has extensive technological implications not only for classical communication systems but also for future quantum networks. In this paper, we put forward a scheme for coherent mode conversion of optical photons by utilizing the intermediate coupling between a single quantum dot and a bimodal photonic crystal microcavity via a waveguide. Here, one mode of the photonic crystal microcavity is coherently driven by an external single-frequency continuous-wave laser field and the two cavity modes are not coupled to each other due to their orthogonal polarizations. The undriven cavity mode is thus not directly coupled to the input driving laser and the only way it can get light is via the quantum dot. The influences of the system parameters on the photon-conversion efficiency are analyzed in detail in the limit of weak probe field and it is found that high photon-conversion efficiency can be achieved under appropriate conditions. It is shown that the cavity dark mode, which is a superposition of the two optical modes and is decoupled from the quantum dot, can appear in such a hybrid optical system. We discuss the properties of the dark mode and indicate that the formation of the dark mode enables the efficient transfer of optical fields between the two cavity modes.

  17. Electrically injected visible vertical cavity surface emitting laser diodes

    DOE Patents [OSTI]

    Schneider, R.P.; Lott, J.A.

    1994-09-27T23:59:59.000Z

    Visible laser light output from an electrically injected vertical cavity surface emitting laser (VSCEL) diode is enabled by the addition of phase-matching spacer layers on either side of the active region to form the optical cavity. The spacer layers comprise InAlP which act as charge carrier confinement means. Distributed Bragg reflector layers are formed on either side of the optical cavity to act as mirrors. 5 figs.

  18. Cryogenic Testing of High-Velocity Spoke Cavities

    SciTech Connect (OSTI)

    Hopper, Christopher S. [Old Dominion University; Delayen, Jean R. [Old Dominion University; Park, HyeKyoung [JLAB

    2014-12-01T23:59:59.000Z

    Spoke-loaded cavities are being investigated for the high-velocity regime. The relative compactness at low-frequency makes them attractive for applications requiring, or benefiting from, 4 K operation. Additionally, the large velocity acceptance makes them good candidates for the acceleration of high-velocity protons and ions. Here we present the results of cryogenic testing of a 325 MHz, ?0= 0.82 single-spoke cavity and a 500 MHz, ?0 = 1 double-spoke cavity.

  19. Turbine inter-disk cavity cooling air compressor

    DOE Patents [OSTI]

    Chupp, Raymond E. (Oviedo, FL); Little, David A. (Oviedo, FL)

    1998-01-01T23:59:59.000Z

    The inter-disk cavity between turbine rotor disks is used to pressurize cooling air. A plurality of ridges extend radially outwardly over the face of the rotor disks. When the rotor disks are rotated, the ridges cause the inter-disk cavity to compress air coolant flowing through the inter-disk cavity en route to the rotor blades. The ridges eliminate the need for an external compressor to pressurize the air coolant.

  20. Turbine inter-disk cavity cooling air compressor

    DOE Patents [OSTI]

    Chupp, R.E.; Little, D.A.

    1998-01-06T23:59:59.000Z

    The inter-disk cavity between turbine rotor disks is used to pressurize cooling air. A plurality of ridges extend radially outwardly over the face of the rotor disks. When the rotor disks are rotated, the ridges cause the inter-disk cavity to compress air coolant flowing through the inter-disk cavity en route to the rotor blades. The ridges eliminate the need for an external compressor to pressurize the air coolant. 5 figs.

  1. T-542: SAP Crystal Reports Server Multiple Vulnerabilities | Department of

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn April 23, 2014,Zaleski -BlueprintThis

  2. Control System Design for Automatic Cavity Tuning Machines

    SciTech Connect (OSTI)

    Carcagno, R.; Khabiboulline, T.; Kotelnikov, S.; Makulski, A.; Nehring, R.; Nogiec, J.; Ross, M.; Schappert, W.; /Fermilab; Goessel, A.; Iversen, J.; Klinke, D.; /DESY

    2009-05-01T23:59:59.000Z

    A series of four automatic tuning machines for 9-cell TESLA-type cavities are being developed and fabricated in a collaborative effort among DESY, FNAL, and KEK. These machines are intended to support high-throughput cavity fabrication for construction of large SRF-based accelerator projects. Two of these machines will be delivered to cavity vendors for the tuning of XFEL cavities. The control system for these machines must support a high level of automation adequate for industrial use by non-experts operators. This paper describes the control system hardware and software design for these machines.

  3. HOM Survey of the First CEBAF Upgrade Style Cavity Pair

    SciTech Connect (OSTI)

    Marhauser, Frank; Davis, G; Drury, Michael; Grenoble, Christiana; Hogan, John; Manus, Robert; Preble, Joseph; Reece, Charles; Rimmer, Robert; Tian, Kai

    2009-05-01T23:59:59.000Z

    The planned upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Laboratory (JLab) requires ten new superconducting rf (SRF) cavity cryomodules to double the beam energy to the envisaged 12 GeV. Adequate cavity Higher Order Mode (HOM) suppression is essential to avoid multipass, multibunch beam break-up (BBU) instabilities of the recirculating beam. We report on detailed HOM surveys performed for the first two upgrade style cavities tested in a dedicated cavity pair cryomodule at 2K. The safety margin to the BBU threshold budget at 12 GeV has been assessed.

  4. Ring cavity for a Raman capillary waveguide amplifier

    DOE Patents [OSTI]

    Kurnit, N.A.

    1981-01-27T23:59:59.000Z

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  5. Ring cavity for a Raman capillary waveguide amplifir

    DOE Patents [OSTI]

    Kurnit, N.A.

    1981-01-27T23:59:59.000Z

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  6. Ring cavity for a Raman capillary waveguide amplifier

    DOE Patents [OSTI]

    Kurnit, N.A.

    1983-07-19T23:59:59.000Z

    Disclosed is a regenerative ring amplifier and regenerative ring oscillator which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO[sub 2] laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplifier Stokes signal is synchronous with the mode-locked spikes of the incoming CO[sub 2] laser pump signal. 6 figs.

  7. HOMs Simulation and Measurement Results of IHEP02 Cavity

    E-Print Network [OSTI]

    Hongjuan Zheng; Jiyuan Zhai; Tongxian Zhao; Jie Gao

    2015-02-06T23:59:59.000Z

    In cavities, there exists not only the fundamental mode which is used to accelerate the beam but also higher order modes (HOMs). The higher order modes excited by beam can seriously affect beam quality, especially for the higher R/Q modes. This paper reports on measured results of higher order modes in the IHEP02 1.3GHz low-loss 9-cell superconducting cavity. Using different methods, Qe of the dangerous modes passbands have been got. The results are compared with TESLA cavity results. R/Q of the first three passbands have also been got by simulation and compared with the results of TESLA cavity.

  8. HOMs Simulation and Measurement Results of IHEP02 Cavity

    E-Print Network [OSTI]

    Zheng, Hongjuan; Zhao, Tongxian; Gao, Jie

    2015-01-01T23:59:59.000Z

    In cavities, there exists not only the fundamental mode which is used to accelerate the beam but also higher order modes (HOMs). The higher order modes excited by beam can seriously affect beam quality, especially for the higher R/Q modes. This paper reports on measured results of higher order modes in the IHEP02 1.3GHz low-loss 9-cell superconducting cavity. Using different methods, Qe of the dangerous modes passbands have been got. The results are compared with TESLA cavity results. R/Q of the first three passbands have also been got by simulation and compared with the results of TESLA cavity.

  9. Diagnostic resonant cavity for a charged particle accelerator

    DOE Patents [OSTI]

    Barov, Nikolai (San Diego, CA)

    2007-10-02T23:59:59.000Z

    Disclosed is a diagnostic resonant cavity for determining characteristics of a charged particle beam, such as an electron beam, produced in a charged particle accelerator. The cavity is based on resonant quadrupole-mode and higher order cavities. Enhanced shunt impedance in such cavities is obtained by the incorporation of a set of four or more electrically conductive rods extending inwardly from either one or both of the end walls of the cavity, so as to form capacitive gaps near the outer radius of the beam tube. For typical diagnostic cavity applications, a five-fold increase in shunt impedance can be obtained. In alternative embodiments the cavity may include either four or more opposing pairs of rods which extend coaxially toward one another from the opposite end walls of the cavity and are spaced from one another to form capacitative gaps; or the cavity may include a single set of individual rods that extend from one end wall to a point adjacent the opposing end wall.

  10. Research on Field Emission and Dark Current in ILC Cavities

    SciTech Connect (OSTI)

    Liu, Kexin; Li, Yongming; Palczewski, Ari; Geng, Rongli

    2013-09-01T23:59:59.000Z

    Field emission and dark current are issues of concern for SRF cavity performance and SRF linac operation. Complete understanding and reliable control of the issue are still needed, especially in full-scale multi-cell cavities. Our work aims at developing a generic procedure for finding an active field emitter in a multi-cell cavity and benchmarking the procedure through cavity vertical test. Our ultimate goal is to provide feedback to cavity preparation and cavity string assembly in order to reduce or eliminate filed emission in SRF cavities. Systematic analysis of behaviors of field emitted electrons is obtained by ACE3P developed by SLAC. Experimental benchmark of the procedure was carried out in a 9-cell cavity vertical test at JLab. The energy spectrum of Bremsstrahlung X-rays is measured using a NaI(Tl) detector. The end-point energy in the X-ray energy spectrum is taken as the highest kinetic electron energy to predict longitudinal position of the active field emitter. Angular location of the field emitter is determined by an array of silicon diodes around irises of the cavity. High-resolution optical inspection was conducted at the predicted field emitter location.

  11. An optical cavity with a strongly focused mode

    SciTech Connect (OSTI)

    Durak, Kadir; Victor, Leong Xu Heng; Huan, Nguyen Chi; Maslennikov, Gleb; Kurtsiefer, Christian [NUS, Center for Quantum Technologies/Physics Dept, 3 Science Drive 2, 117543 (Singapore); Straupe, Stanislav [NUS, Center for Quantum Technologies/Physics Dept, 3 Science Drive 2, 117543, Singapore and Faculty of Physics, Moscow State University (Russian Federation)

    2013-12-16T23:59:59.000Z

    Atom-photon interfaces are one of the building blocks of the future quantum information protocols. Accomplishing a strong interaction between the atom and the photons can be successfully done by high finesse and small mode volume cavities. However, this method requires sophisticated dielectric coatings and stabilization of the cavity against even small vibrations and small line width of those cavities impose higher input photon numbers if spontaneously emitted photons are to be used, which make it seem hard to scale up such atom-light interfaces to form quantum networks. An alternative method is to use a nearly concentric cavity, which has a strongly focused optical mode.

  12. Multi-Physics Analysis of the Fermilab Booster RF Cavity

    SciTech Connect (OSTI)

    Awida, M.; Reid, J.; Yakovlev, V.; Lebedev, V.; Khabiboulline, T.; Champion, M.; /Fermilab

    2012-05-14T23:59:59.000Z

    After about 40 years of operation the RF accelerating cavities in Fermilab Booster need an upgrade to improve their reliability and to increase the repetition rate in order to support a future experimental program. An increase in the repetition rate from 7 to 15 Hz entails increasing the power dissipation in the RF cavities, their ferrite loaded tuners, and HOM dampers. The increased duty factor requires careful modelling for the RF heating effects in the cavity. A multi-physic analysis investigating both the RF and thermal properties of Booster cavity under various operating conditions is presented in this paper.

  13. Chapter 3 Cavity Scattering 3.1 Introduction

    E-Print Network [OSTI]

    2010-09-30T23:59:59.000Z

    found many practical applications including the design of modern stealth ... the interior of the open cavity is filled with a nonmagnetic material which may be.

  14. Accelerator Cavities as a Probe of Millicharged Particles

    E-Print Network [OSTI]

    H. Gies; J. Jaeckel; A. Ringwald

    2006-08-21T23:59:59.000Z

    We investigate Schwinger pair production of millicharged fermions in the strong electric field of cavities used for particle accelerators. Even without a direct detection mechanism at hand, millicharged particles, if they exist, contribute to the energy loss of the cavity and thus leave an imprint on the cavity's quality factor. Already conservative estimates substantially constrain the electric charge of these hypothetical particles; the resulting bounds are competitive with the currently best laboratory bounds which arise from experiments based on polarized laser light propagating in a magnetic field. We propose an experimental setup for measuring the electric current comprised of the millicharged particles produced in the cavity.

  15. 805 MHz and 201 MHz RF cavity development for MUCOOL

    SciTech Connect (OSTI)

    DLi@lbl.gov

    2002-10-10T23:59:59.000Z

    A muon cooling channel calls for very high acceleratinggradient RF structures to restore the energy lost by muons in theabsorbers. The RF structures have to be operated in a strong magneticfield and thus the use of superconducting RF cavities is excluded. Toachieve a high shunt impedance while maintaining a large enough apertureto accommodate a large transverse emittance muon beam, the cavity designadopted is a pillbox-like geometry with thin Be foils to terminate theelectromagnetic field at the cavity iris. The possibility of using gridsof thin-walled metallic tubes for the termination is also being explored.Many of the RF-related issues for muon cooling channels are being studiedboth theoretically and experimentally using an 805 MHz cavity that has apillbox-like geometry with thin Be windows to terminate the cavityaperture. The design and performance of this cavity are reported here.High-power RF tests of the 805 MHz cavity are in progress at Lab G inFermilab. The cavity has exceeded its design gradient of 30 MV/m,reaching 34 MV/m without external magnetic field. No surface damage wasobserved at this gradient. The cavity is currently under conditioning atLab G with an external magnetic field of 2.5 T. We also present here a201 MHz cavity design for muoncooling channels. The proposed cavitydesign is also suitable for use in a proof-of-principle Muon IonizationCooling Experiment (MICE).

  16. Fabrication Processes for the PEP II RF Cavities

    SciTech Connect (OSTI)

    Franks, R.Mark; /LLNL, Livermore; Rimmer, Robert A.; /LBL, Berkeley; Schwarz, Heinz; /SLAC

    2011-09-01T23:59:59.000Z

    This paper presents the major steps used in the fabrication of the 26 RF Cavities required for the PEP-II B-factory. Several unique applications of conventional processes have been developed and successfully implemented: electron beam welding (EBW), with minimal porosity, of .75 inch (19 mm) copper cross-sections; extensive 5-axis milling of water channels; electroplating of .37 inch (10 mm) thick OFE copper; tuning of the cavity by profiling beam noses prior to final joining with the cavity body; and machining of the cavity interior, are described here.

  17. Superconducting spoke cavities for high-velocity applications

    SciTech Connect (OSTI)

    Hopper, Christopher S. [Old Dominion U.; Delayen, Jean R. [Old Dominion U., JLAB

    2013-10-01T23:59:59.000Z

    To date, superconducting spoke cavities have been designed, developed, and tested for particle velocities up to {beta}{sub 0}~0.6, but there is a growing interest in possible applications of multispoke cavities for high-velocity applications. We have explored the design parameter space for low-frequency, high-velocity, double-spoke superconducting cavities in order to determine how each design parameter affects the electromagnetic properties, in particular the surface electromagnetic fields and the shunt impedance. We present detailed design for cavities operating at 325 and 352 MHz and optimized for {beta}{sub 0}~=0.82 and 1.

  18. Resonantly pumped optical pumping injection cavity lasers

    E-Print Network [OSTI]

    Santilli, Michael Robert; McAlpine, T. C.; Greene, K. R.; Olafsen, L. J.; Bewley, W. W.; Felix, C. L.; Vurgaftman, I.; Meyer, J. R.; Lee, H.; Martinelli, R. U.

    2004-11-01T23:59:59.000Z

    , the optically pumped devices have thus far produced much higher powers than their diode counterparts. 4–8 To en- sure the efficient injection of carriers, these optically pumped lasers have employed two main approaches to maximize the absorption of pump photons... of active QWs. The first OPIC lasers to be investigated 12,13 were de- signed for pumping by a Q-switched Ho:YAG laser emitting at 2100 nm. Whereas the cavity resonance wavelength sl cav d for normal incidence, as determined from the transmittance spectrum...

  19. Cavity enhanced rephased amplified spontaneous emission

    E-Print Network [OSTI]

    Lewis A Williamson; Jevon J Longdell

    2014-05-20T23:59:59.000Z

    Amplified spontaneous emission is usually treated as an incoherent noise process. Recent theoretical and experimental work using rephasing optical pulses has shown that rephased amplified spontaneous emission (RASE) is a potential source of wide bandwidth time-delayed entanglement. Due to poor echo efficiency the plain RASE protocol doesn't in theory achieve perfect entanglement. Experiments done to date show a very small amount of entanglement at best. Here we show that rephased amplified spontaneous emission can, in principle, produce perfect multimode time-delayed two mode squeezing when the active medium is placed inside a Q-switched cavity.

  20. Low-Threshold Surface-Passivated Photonic Crystal Nanocavity Laser

    E-Print Network [OSTI]

    Dirk Englund; Hatice Altug; Jelena Vuckovic

    2007-06-21T23:59:59.000Z

    The efficiency and operating range of a photonic crystal laser is improved by passivating the InGaAs quantum well (QW) gain medium and GaAs membrane using an (NH4)S treatment. The passivated laser shows a four-fold reduction in nonradiative surface recombination rate, resulting in a four-fold reduction in lasing threshold. A three-level carrier dynamics model explains the results and shows that lasing threshold is as much determined by surface recombination losses as by the cavity quality factor (Q). Surface passivation therefore appears crucial in operating such lasers under practical conditions.

  1. Waveguide-integrated photonic crystal spectrometer with camera readout

    SciTech Connect (OSTI)

    Meng, Fan; Shiue, Ren-Jye; Li, Luozhou; Nie, Jing; Harris, Nicholas C.; Chen, Edward H.; Schröder, Tim; Englund, Dirk, E-mail: englund@mit.edu [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139 (United States); Wan, Noel [Department of Physics, Columbia University, New York, New York 10027 (United States); Pervez, Nadia [Chromation Partners LLC, 18 Bridge Street Suite 2J, Brooklyn, New York 11201 (United States); Kymissis, Ioannis [Chromation Partners LLC, 18 Bridge Street Suite 2J, Brooklyn, New York 11201 (United States); Department of Electrical Engineering, Columbia University, New York, New York 10027 (United States)

    2014-08-04T23:59:59.000Z

    We demonstrate an infrared spectrometer based on waveguide-coupled nanocavity filters in a planar photonic crystal structure. The input light is coupled into the waveguide, from which spectral components are dropped into the cavities and radiated off-chip for detection on a commercial InGaAs camera. The spectrometer has a footprint of only 60??m by 8??m. The spectral resolution is about 1?nm in the operation bandwidth of 1522–1545?nm. By substituting the membrane material and structure parameters, this design can be easily extended into the visible regime and developed for a variety of highly efficient, miniature photonic applications.

  2. Cavity Microwave Searches for Cosmological Axions

    SciTech Connect (OSTI)

    Carosi, G; van Bibber, K

    2007-01-22T23:59:59.000Z

    This chapter will cover the search for dark matter axions based on microwave cavity experiments proposed by Pierre Sikivie. We will start with a brief overview of halo dark matter and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described as well as practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of this chapter will be the two complementary strategies for ultra-low noise detection of the microwave photons--the 'photon-as-wave' approach (i.e. conventional heterojunction amplifiers and soon to be quantum-limited SQUID devices), and 'photon-as-particle' (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The section will conclude with a discussion of future plans and challenges for the microwave cavity experiment.

  3. Properties of localization in silicon-based lattice periodicity breaking photonic crystal waveguides

    SciTech Connect (OSTI)

    Wu, Yuquan; Wang, Xiaofei; Wang, Yufang; Zhang, Guoquan; Fan, Wande; Cao, Xuewei, E-mail: xwcao@nankai.edu.cn [School of Physics, Nankai University, Tianjin, 300071 (China)] [School of Physics, Nankai University, Tianjin, 300071 (China); Wu, Yuanbin [School of Physics, Nankai University, Tianjin, 300071 (China) [School of Physics, Nankai University, Tianjin, 300071 (China); Dip. di Fisica, Università di Roma “La Sapienza”, Piazzale Aldo Moro 5, I-00185 Roma (Italy); EDSFA, Université de Nice Sophia Antipolis, 06103 Nice (France)

    2013-11-15T23:59:59.000Z

    The light localization effects in silicon photonic crystal cavities at different disorder degrees have been studied using the finite difference time domain (FDTD) method in this paper. Numerical results showed that localization occurs and enhancement can be gained in the region of the cavity under certain conditions. The stabilities of the localization effects due to the structural perturbations have been investigated too. Detailed studies showed that when the degree of structural disorder is small(about 10%), the localization effects are stable, the maximum enhancement factor can reach 16.5 for incident wavelength of 785 nm and 23 for 850 nm in the cavity, with the degree of disorder about 8%. The equivalent diameter of the localized spot is almost constant at different disorder degrees, approximating to ?/7, which turned out to be independent on the structural perturbation.

  4. Optical and mechanical mode tuning in an optomechanical crystal with light-induced thermal effects

    SciTech Connect (OSTI)

    Navarro-Urrios, D., E-mail: daniel.navarrourrios@nano.cnr.it [Catalan Institute of Nanoscience and Nanotechnology, Campus UAB, Edifici ICN2, 08193 Bellaterra (Spain); NEST, Istituto Nanoscienze–CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127 (Italy); Gomis-Bresco, J.; Alzina, F. [Catalan Institute of Nanoscience and Nanotechnology, Campus UAB, Edifici ICN2, 08193 Bellaterra (Spain); Capuj, N. E. [Depto. Física, Universidad de la Laguna, 38206 La Laguna (Spain); Griol, A.; Puerto, D.; Martínez, A. [Nanophotonics Technology Center, Universitat Politècnica de València, Valencia (Spain); Sotomayor-Torres, C. M. [Catalan Institute of Nanoscience and Nanotechnology, Campus UAB, Edifici ICN2, 08193 Bellaterra (Spain); Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona (Spain)

    2014-09-07T23:59:59.000Z

    We report on the modification of the optical and mechanical properties of a silicon 1D optomechanical crystal cavity due to thermo-optic effects in a high phonon/photon population regime. The cavity heats up due to light absorption in a way that shifts the optical modes towards longer wavelengths and the mechanical modes to lower frequencies. By combining the experimental optical results with finite-difference time-domain simulations, we establish a direct relation between the observed wavelength drift and the actual effective temperature increase of the cavity. By assuming that the Young's modulus decreases accordingly to the temperature increase, we find a good agreement between the mechanical mode drift predicted using a finite element method and the experimental one.

  5. Controlling the Spontaneous Emission Rate of Single Quantum Dots in a 2D Photonic Crystal

    E-Print Network [OSTI]

    Dirk Englund; David Fattal; Edo Waks; Glenn Solomon; Bingyang Zhang; Toshihiro Nakaoka; Yasuhiko Arakawa; Yoshihisa Yamamoto; Jelena Vuckovic

    2005-04-20T23:59:59.000Z

    We observe large spontaneous emission rate modification of individual InAs Quantum Dots (QDs) in 2D a photonic crystal with a modified, high-Q single defect cavity. Compared to QDs in bulk semiconductor, QDs that are resonant with the cavity show an emission rate increase by up to a factor of 8. In contrast, off-resonant QDs indicate up to five-fold rate quenching as the local density of optical states (LDOS) is diminished in the photonic crystal. In both cases we demonstrate photon antibunching, showing that the structure represents an on-demand single photon source with pulse duration from 210 ps to 8 ns. We explain the suppression of QD emission rate using Finite Difference Time Domain (FDTD) simulations and find good agreement with experiment.

  6. 108 GHz passive mode locking of a multiple quantum well semiconductor laser with an intracavity absorber

    SciTech Connect (OSTI)

    Sanders, S.; Eng, L.; Paslaski, J.; Yariv, A. (Department of Applied Physics 128-95, California Institute of Technology, Pasadena, California 91125 (US))

    1990-01-22T23:59:59.000Z

    A two-section multiple quantum well laser is passively mode locked without an external cavity at {similar to}108 GHz. The pulse widths average 2.4 ps and have a time-bandwidth product of 1.1. Self-pulsations at frequencies up to 8 GHz are also observed.

  7. The cavity of the optimal shape under the shear stresses

    E-Print Network [OSTI]

    Cherkaev, Andrej

    at infinity. The cavity of fixed area is said to be optimal if it provides the minimal energy change between the eigenvalues of different sign, the shape of cavity (of fixed area) minimizing the energy 1 #12; increment.B.Movchanz, S.K.Serkovz y Departments of Mathematics, University of Utah, Salt Lake City, UT 84112, USA z School

  8. Phonon Mediated Off-Resonant Quantum Dot-Cavity Coupling

    E-Print Network [OSTI]

    Arka Majumdar; Yiyang Gong; Erik D. Kim; Jelena Vuckovic

    2010-12-14T23:59:59.000Z

    A theoretical model for the phonon-mediated off-resonant coupling between a quantum dot and a cavity, under resonant excitation of the quantum dot, is presented. We show that the coupling is caused by electron-phonon interaction in the quantum dot and is enhanced by the cavity. We analyze recently observed resonant quantum dot spectroscopic data by our theoretical model.

  9. Optical-cavity tests of higher-order Lorentz violation

    E-Print Network [OSTI]

    Matthew Mewes

    2012-06-22T23:59:59.000Z

    The effects of Lorentz-violating operators of nonrenormalizable dimension in optical resonate cavities are studied. Optical-frequency experiments are shown to provide sensitivity to nondispersive nonbirefringent violations that is many orders of magnitude beyond current constraints from microwave cavities. Existing experiments based on Fabry-Perot and ring resonators are considered as illustrations.

  10. High pressure discharges in cavities formed by microfabrication techniques

    SciTech Connect (OSTI)

    Khan, B.A.; Cammack, D.A.; Pinker, R.D.; Racz, J. [Philips Electronics North America Corporation, Philips Research, Briarcliff Manor, New York 10510 (United States)] [Philips Electronics North America Corporation, Philips Research, Briarcliff Manor, New York 10510 (United States)

    1997-07-01T23:59:59.000Z

    High pressure discharges are the basis of small high intensity light sources. In this work, we demonstrate the formation of high pressure discharges, in cavities formed by applying micromachining and integrated circuit techniques to quartz substrates. Cavities containing varying amounts of mercury and argon were fabricated to obtain high pressure discharges. A high pressure mercury discharge was formed in the electrodeless cavities by exciting them with a microwave source, operating at 2.45 GHz and in the electroded cavities by applying a dc voltage. The contraction of the discharge into a high pressure arc was observed. A broad emission spectrum due to self-absorption and collisions between excited atoms and normal atoms, typical of high pressure mercury discharges, was measured. The light output and efficacy increased with increasing pressure. The measured voltage was used to estimate the pressure within the electroded cavities, which is as high as 127 atm for one of the two cavities discussed in this work. Efficacies over 40 lumens per watt were obtained for the electrodeless cavities and over 50 scr(l)m/W for the electroded cavities. {copyright} {ital 1997 American Institute of Physics.}

  11. Estimation of Convection Loss from Paraboloidal Dish Cavity Receivers

    E-Print Network [OSTI]

    In general, cavity receivers employed in the sun-tracking paraboloidal dish concentrator are subjected the numerical investigation of natural and combined convection loss from cavity receivers employed in solar is a significant source of energy loss from thermal receivers used with dish solar concentrators. This paper

  12. TESLA Report 2003-08 Cavity control system

    E-Print Network [OSTI]

    with signal and power considerations is presented. Two alternative simulation models of cavity control systemTESLA Report 2003-08 Cavity control system essential modeling for TESLA linear accelerator Tomasz' interaction point and high beam luminosity. The complex control system for the relativistic beam has been

  13. High-R Walls for Remodeling: Wall Cavity Moisture Monitoring

    SciTech Connect (OSTI)

    Wiehagen, J.; Kochkin, V.

    2012-12-01T23:59:59.000Z

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  14. STANDARDIZATION OF CEBAF 12 GEV UPGRADE CAVITY TESTING

    SciTech Connect (OSTI)

    Tiffany Bass, G. Davis, Christiana Wilson, Mircea Stirbet

    2012-07-01T23:59:59.000Z

    CEBAF 12GeV upgrade project includes 80 new 7-cell cavities to form 10 cryomodules. Each cavity underwent RF qualification at 2.07K using a high power accelerating gradient test and an HOM survey in Jefferson Lab's Vertical Testing Area (VTA) before cavity string assembly. In order to ensure consistently high quality data, updated cavity testing procedures and analysis were implemented and used by a group of VTA operators. For high power tests, a cavity testing procedure was developed and used in conjunction with a LabVIEW program to collect the test data. Additionally while the cavity was at 2.07K, an HOM survey was performed using a network analyzer and a combination of Excel and Mathematica programs. Data analysis was standardized and an online logbook, Pansophy, was used for data storage and mining. The Pansophy system allowed test results to be easily summarized and searchable across all cavity tests. In this presentation, the CEBAF 12GeV upgrade cavity testing procedure, method for data analysis, and results reporting results will be discussed.

  15. High Gain, High Efficiency Vertical-Cavity Semiconductor Optical Amplifiers

    E-Print Network [OSTI]

    Bowers, John

    -cavity semiconductor optical amplifiers (VCSOAs) are interesting devices for applications such as wavelength selective coupling efficiency to optical fiber (yielding a low noise figure), small form factor, and the potential of fabricating high-density 2D arrays on wafer. Furthermore, the vertical-cavity design is compatible with low

  16. RF cavity using liquid dielectric for tuning and cooling

    DOE Patents [OSTI]

    Popovic, Milorad (Warrenville, IL); Johnson, Rolland P. (Newport News, VA)

    2012-04-17T23:59:59.000Z

    A system for accelerating particles includes an RF cavity that contains a ferrite core and a liquid dielectric. Characteristics of the ferrite core and the liquid dielectric, among other factors, determine the resonant frequency of the RF cavity. The liquid dielectric is circulated to cool the ferrite core during the operation of the system.

  17. Active absorption of electromagnetic pulses in a cavity

    E-Print Network [OSTI]

    Horsley, S A R; Tyc, T; Philbin, T G

    2014-01-01T23:59:59.000Z

    We show that a pulse of electromagnetic radiation launched into a cavity can be completely absorbed into an infinitesimal region of space, provided one has a high degree of control over the current flowing through this region. We work out explicit examples of this effect in a cubic cavity and a cylindrical one, and experimentally demonstrate the effect in the microwave regime.

  18. Interfacing Superconducting Qubits and Telecom Photons via a Rare-Earth Doped Crystal

    E-Print Network [OSTI]

    Christopher O'Brien; Nikolai Lauk; Susanne Blum; Giovanna Morigi; Michael Fleischhauer

    2014-07-25T23:59:59.000Z

    We propose a scheme to couple short single photon pulses to superconducting qubits. An optical photon is first absorbed into an inhomogeneously broadened rare-earth doped crystal using controlled reversible inhomogeneous broadening. The optical excitation is then mapped into a spin state using a series of $\\pi$-pulses and subsequently transferred to a superconducting qubit via a microwave cavity. To overcome the intrinsic and engineered inhomogeneous broadening of the optical and spin transitions in rare earth doped crystals, we make use of a special transfer protocol using staggered $\\pi$-pulses. We predict total transfer efficiencies on the order of 90%.

  19. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    SciTech Connect (OSTI)

    KOETZLE,T.F.

    2001-03-13T23:59:59.000Z

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  20. Frequency-doubled vertical-external-cavity surface-emitting laser

    DOE Patents [OSTI]

    Raymond, Thomas D. (Edgewood, NM); Alford, William J. (Albuquerque, NM); Crawford, Mary H. (Albuquerque, NM); Allerman, Andrew A. (Albuquerque, NM)

    2002-01-01T23:59:59.000Z

    A frequency-doubled semiconductor vertical-external-cavity surface-emitting laser (VECSEL) is disclosed for generating light at a wavelength in the range of 300-550 nanometers. The VECSEL includes a semiconductor multi-quantum-well active region that is electrically or optically pumped to generate lasing at a fundamental wavelength in the range of 600-1100 nanometers. An intracavity nonlinear frequency-doubling crystal then converts the fundamental lasing into a second-harmonic output beam. With optical pumping with 330 milliWatts from a semiconductor diode pump laser, about 5 milliWatts or more of blue light can be generated at 490 nm. The device has applications for high-density optical data storage and retrieval, laser printing, optical image projection, chemical-sensing, materials processing and optical metrology.

  1. Niobium thin film deposition studies on copper surfaces for superconducting radio frequency cavity applications

    SciTech Connect (OSTI)

    W. M. Roach, D. B. Beringer, J. R. Skuza, W. A. Oliver, C. Clavero, C. E. Reece, R. A. Lukaszew

    2012-06-01T23:59:59.000Z

    Thin film coatings have the potential to increase both the thermal efficiency and accelerating gradient in superconducting radio frequency accelerator cavities. However, before this potential can be realized, systematic studies on structure-property correlations in these thin films need to be carried out since the reduced geometry, combined with specific growth parameters, can modify the physical properties of the materials when compared to their bulk form. Here, we present our systematic studies of Nb thin films deposited onto Cu surfaces to clarify possible reasons for the limited success that this process exhibited in previous attempts. We compare these films with Nb grown on other surfaces. In particular, we study the crystal structure and surface morphology and their effect on superconducting properties, such as critical temperature and lower critical field. We found that higher deposition temperature leads to a sharper critical temperature transition, but also to increased roughness indicating that there are competing mechanisms that must be considered for further optimization.

  2. Enhancement of accelerating field of microwave cavities by magnetic insulation

    SciTech Connect (OSTI)

    Stratakis, D.; Gallardo, J.; Palmer, R.B.

    2011-04-15T23:59:59.000Z

    Limitations on the maximum achievable accelerating gradient of microwave cavities can strongly influence the performance, length, and cost of particle accelerators. Gradient limitations are widely believed to be initiated by electron emission from the cavity surfaces. Here, we show that the deleterious effects of field emission are effectively suppressed by applying a tangential magnetic field to the cavity walls. With the aid of numerical simulations we compute the field strength required to insulate an 805 MHz cavity and estimate the cavity's tolerances to typical experimental errors such as magnet misalignments and positioning errors. Then, we review an experimental program, currently under progress, to further study the concept. Finally, we report on two specific examples that illustrate the feasibility of magnetic insulation into prospective particle accelerator applications.

  3. Hydrogen-filled RF Cavities for Muon Beam Cooling

    SciTech Connect (OSTI)

    CHARLES, Ankenbrandt

    2009-04-17T23:59:59.000Z

    Ionization cooling requires low-Z energy absorbers immersed in a strong magnetic field and high-gradient, large-aperture RF cavities to be able to cool a muon beam as quickly as the short muon lifetime requires. RF cavities that operate in vacuum are vulnerable to dark-current- generated breakdown, which is exacerbated by strong magnetic fields, and they require extra safety windows that degrade cooling, to separate RF regions from hydrogen energy absorbers. RF cavities pressurized with dense hydrogen gas will be developed that use the same gas volume to provide the energy absorber and the RF acceleration needed for ionization cooling. The breakdown suppression by the dense gas will allow the cavities to operate in strong magnetic fields. Measurements of the operation of such a cavity will be made as functions of external magnetic field and charged particle beam intensity and compared with models to understand the characteristics of this technology and to develop mitigating strategies if necessary.

  4. Proposal for high pressure RF cavity test in the MTA

    SciTech Connect (OSTI)

    Yonehara, K.; /Fermilab

    2010-09-01T23:59:59.000Z

    In order to demonstrate the feasibility of high pressure hydrogen gas filled RF (HPRF) cavities for muon ionization cooling, an HPRF cavity must be tested with a high intensity charged beam. When an HPRF cavity is irradiated with an intense beam each incident particle generates about 1000 electrons and ions per cubic centimeter in a high pressure cavity via ionization. These ionization electrons are influenced by the RF field and the RF quality factor goes down. This Q factor reduction will be a problem with a multi bunch beam, e.g., a muon beam for a muon collider consists of a 12 to 20 bunch train beam with 5 ns timing gap. Thus, the RF field must recover in few nano seconds. We propose to use a 400 MeV proton beam in the MTA and measure a beam loading effect in the HPRF cavity and study the recovery mechanism of the RF field.

  5. A new microphonics measurement method for superconducting RF cavities

    SciTech Connect (OSTI)

    Gao,Zheng; He,Yuan; Chang,Wei; Powers, Tom [JLAB; Yue,Wei-ming; Zhu,Zheng-long; Chen,Qi

    2014-09-01T23:59:59.000Z

    Mechanical vibrations of the superconducting cavity, also known as microphonics, cause shifts in the resonant frequency of the cavity. In addition to requiring additional RF power, these frequency shifts can contribute to errors in the closed loop phase and amplitude regulation. In order to better understand these effects, a new microphonics measurement method was developed, and the method was successfully used to measure microphonics on the half-wave superconducting cavity when it was operated in a production style cryostat. The test cryostat held a single ?=0.1 half-wave cavity which was operated at 162.5 MHz [1] and [2]. It's the first time that the National Instruments PXIe-5641R intermediate frequency transceiver has been used for microphonics measurements in superconducting cavities. The new microphonics measurement method and results will be shown and analyzed in this paper.

  6. Einstein-Maxwell equations for asymmetric resonant cavities

    E-Print Network [OSTI]

    Frasca, Marco

    2015-01-01T23:59:59.000Z

    We analyze the behavior of electromagnetic fields inside a resonant cavity by solving Einstein--Maxwell field equations. It is shown that the modified geometry of space-time inside the cavity due to a propagating mode can affect the propagation of a laser beam. It is seen that components of laser light with a shifted frequency appear originating from the coupling between the laser field and the mode cavity due to gravity. The analysis is extended to the case of an asymmetric resonant cavity taken to be a truncated cone. It is shown that a proper choice of the geometrical parameters of the cavity and dielectric can make the gravitational effects significant for an interferometric setup. This could make possible to realize table-top experiments involving gravitational effects.

  7. Theory and Practice of Cavity RF Test Systems

    SciTech Connect (OSTI)

    Tom Powers

    2006-08-28T23:59:59.000Z

    Over the years Jefferson Lab staff members have performed about 2500 cold cavity tests on about 500 different superconducting cavities. Most of these cavities were later installed in 73 different cryomodules, which were used in three different accelerators. All of the cavities were tested in our vertical test area. About 25% of the cryomodules were tested in our cryomodule test facility and later commissioned in an accelerator. The remainder of the cryomodules were tested and commissioned after they were installed in their respective accelerator. This paper is an overview which should provide a practical background in the RF systems used to test the cavities as well as provide the mathematics necessary to convert the raw pulsed or continuous wave RF signals into useful information such as gradient, quality factor, RF-heat loads and loaded Q?s. Additionally, I will provide the equations necessary for determining the measurement error associated with these values.

  8. RF properties of high temperature superconductors: Cavity methods

    SciTech Connect (OSTI)

    Portis, A.M. (California Univ., Berkeley, CA (USA)); Cooke, D.W.; Gray, E.R. (Los Alamos National Lab., NM (USA))

    1990-01-01T23:59:59.000Z

    A description of cavities used in the study of the microwave properties of the high-temperature superconductors is followed by a lumped-circuit analysis of the coupling of transmission lines and resonators. The frequency dependence of the reflected and transmitted microwave power and the character of transient cavity response are analyzed. Techniques are discussed for the introduction of samples of the high-temperature superconductors into microwave cavities. Following a discussion of sample surface impedance and sample geometry factor, the connection between surface resistance and cavity Q is examined as well as the connection between cavity frequency shift and surface reactance. Measurement techniques that utilize reflected or transmitted power or transient response are described. 35 refs., 1 fig.

  9. Apparatus and process for passivating an SRF cavity

    DOE Patents [OSTI]

    Myneni, Ganapati Rao; Wallace, John P

    2014-12-02T23:59:59.000Z

    An apparatus and process for the production of a niobium cavity exhibiting high quality factors at high gradients is provided. The apparatus comprises a first chamber positioned within a second chamber, an RF generator and vacuum pumping systems. The process comprises placing the niobium cavity in a first chamber of the apparatus; thermally treating the cavity by high temperature in the first chamber while maintaining high vacuum in the first and second chambers; and applying a passivating thin film layer to a surface of the cavity in the presence of a gaseous mixture and an RF field. Further a niobium cavity exhibiting high quality factors at high gradients produced by the method of the invention is provided.

  10. Omega3P: A Parallel Finite-Element Eigenmode Analysis Code for Accelerator Cavities

    SciTech Connect (OSTI)

    Lee, Lie-Quan; Li, Zenghai; Ng, Cho; Ko, Kwok; /SLAC

    2009-03-04T23:59:59.000Z

    Omega3P is a parallel eigenmode calculation code for accelerator cavities in frequency domain analysis using finite-element methods. In this report, we will present detailed finite-element formulations and resulting eigenvalue problems for lossless cavities, cavities with lossy materials, cavities with imperfectly conducting surfaces, and cavities with waveguide coupling. We will discuss the parallel algorithms for solving those eigenvalue problems and demonstrate modeling of accelerator cavities through different examples.

  11. Momentum space design of high-Q photonic crystal optical cavities

    E-Print Network [OSTI]

    Painter, Oskar

    ­5758 (1999). 11. A. Yariv, Y. Xu, R. K. Lee, and A. Scherer, "Coupled-resonator optical waveguide: a proposal Microcavities," Science 256, 66­70 (1992). 2. J. L. Jewell, J. P. Harbison, A. Scherer, Y. H. Lee, and L. T. Quan. Elec. 27, 1332­ 1346 (1991). 3. S. L. McCall, A. F. J. Levi, R. E. Slusher, S. J. Pearton, and R

  12. Compact and highly efficient laser pump cavity

    DOE Patents [OSTI]

    Chang, Jim J. (Dublin, CA); Bass, Isaac L. (Castro Valley, CA); Zapata, Luis E. (Livermore, CA)

    1999-01-01T23:59:59.000Z

    A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

  13. AGN Heating through Cavities and Shocks

    E-Print Network [OSTI]

    P. E. J. Nulsen; C. Jones; W. R. Forman; L. P. David; B. R. McNamara; D. A. Rafferty; L. Birzan; M. W. Wise

    2006-11-04T23:59:59.000Z

    Three comments are made on AGN heating of cooling flows. A simple physical argument is used to show that the enthalpy of a buoyant radio lobe is converted to heat in its wake. Thus, a significant part of ``cavity'' enthalpy is likely to end up as heat. Second, the properties of the repeated weak shocks in M87 are used to argue that they can plausibly prevent gas close to the AGN from cooling. As the most significant heating mechanism at work closest to the AGN, shock heating probably plays a critical role in the feedback mechanism. Third, results are presented from a survey of AGN heating rates in nearby giant elliptical galaxies. With inactive systems included, the overall AGN heating rate is reasonably well matched to the total cooling rate for the sample. Thus, intermittent AGN outbursts are energetically capable of preventing the hot atmospheres of these galaxies from cooling and forming stars.

  14. Cavity cooling of an ensemble spin system

    E-Print Network [OSTI]

    Christopher J. Wood; Troy W. Borneman; David G. Cory

    2014-02-24T23:59:59.000Z

    We describe how sideband cooling techniques may be applied to large spin ensembles in magnetic resonance. Using the Tavis-Cummings model in the presence of a Rabi drive, we solve a Markovian master equation describing the joint spin-cavity dynamics to derive cooling rates as a function of ensemble size. Our calculations indicate that the coupled angular momentum subspaces of a spin ensemble containing roughly $10^{11}$ electron spins may be polarized in a time many orders of magnitude shorter than the typical thermal relaxation time. The described techniques should permit efficient removal of entropy for spin-based quantum information processors and fast polarization of spin samples. The proposed application of a standard technique in quantum optics to magnetic resonance also serves to reinforce the connection between the two fields, which has recently begun to be explored in further detail due to the development of hybrid designs for manufacturing noise-resilient quantum devices.

  15. Method for filling the cavities of cells with a chromogenic fluid

    DOE Patents [OSTI]

    Tonazzi, Juan C. Lopez (Tucson, AZ); Kucharczyk, Jr., Joseph E. (Tucson, AZ); Agrawal, Anoop (Tucson, AZ)

    1999-01-01T23:59:59.000Z

    A method and apparatus are disclosed for filling a cell cavity positioned between a first substrate and a second substrate with a cell filling liquid. The method entails forming at least one evacuation cavity encompassing at least a portion of an outer surface of each of the first and second substrates of a cell containing a cell cavity and isolating the cell cavity from the evacuation cavity; reducing a pressure in each of the evacuation cavity and the cell cavity; and dispensing the cell filling fluid into the cell cavity.

  16. Method for filling the cavities of cells with a chromogenic fluid

    DOE Patents [OSTI]

    Tonazzi, J.C.L.; Kucharczyk, J.E. Jr.; Agrawal, A.

    1999-01-05T23:59:59.000Z

    A method and apparatus are disclosed for filling a cell cavity positioned between a first substrate and a second substrate with a cell filling liquid. The method entails forming at least one evacuation cavity encompassing at least a portion of an outer surface of each of the first and second substrates of a cell containing a cell cavity and isolating the cell cavity from the evacuation cavity; reducing a pressure in each of the evacuation cavity and the cell cavity; and dispensing the cell filling fluid into the cell cavity. The application is to the fabrication of electrochromic windows. 22 figs.

  17. A Light-Matter Interface based on a Single InAs/GaAs Quantum Dot in a Nanometallic Cavity

    E-Print Network [OSTI]

    Thomas M. Babinec; Yousif A. Kelaita; Kevin A. Fischer; Konstantinos G. Lagoudakis; Tomas Sarmiento; Armand Rundquist; Arka Majumdar; Jelena Vuckovic

    2014-06-27T23:59:59.000Z

    Progress in solid-state optical cavities is tracked on a timeline of miniaturization. Here, we demonstrate a coupled emitter-cavity system consisting of an InAs/GaAs Quantum Dot embedded in a hybrid metal/semiconductor nanocavity. Key features of our nanometallic light-matter interface include: (i) order of magnitude reduction in mode volume compared to that of leading photonic crystal cQED systems, resulting in maximum atom-field coupling rate g/(2{\\pi})~180GHz; (ii) surface-emitting nanocylinder geometry and therefore good collection efficiency compared to the bulk (~5X enhancement); (iii) strong and broadband spontaneous emission rate enhancement (Purcell factor ~8); and finally (iv) the ability to efficiently optically address a multi-level quantum emitter based on a charged quantum dot inside the nanocavity. This light-matter interface could play an important role in studies of the cavity quantum electrodynamics as well as in its application to optical interconnects and quantum networks.

  18. Novel deflecting cavity design for eRHIC

    SciTech Connect (OSTI)

    Wu, Q.; Belomestnykh, S.; Ben-Zvi, I.

    2011-07-25T23:59:59.000Z

    To prevent significant loss of the luminosity due to large crossing angle in the future ERL based Electron Ion Collider at BNL (eRHIC), there is a demand for crab cavities. In this article, we will present a novel design of the deflecting/crabbing 181 MHz superconducting RF cavity that will fulfil the requirements of eRHIC. The quarter-wave resonator structure of the new cavity possesses many advantages, such as compact size, high R{sub t}/Q, the absence of the same order mode and lower order mode, and easy higher order mode damping. We will present the properties and characteristics of the new cavity in detail. As the accelerator systems grow in complexity, developing compact and efficient deflecting cavities is of great interest. Such cavities will benefit situations where the beam line space is limited. The future linac-ring type electron-ion collider requires implementation of a crab-crossing scheme for both beams at the interaction region. The ion beam has a long bunches and high rigidity. Therefore, it requires a low frequency, large kicking angle deflector. The frequency of the deflecting mode for the current collider design is 181 MHz, and the deflecting angle is {approx}5 mrad for each beam. At such low frequency, the previous designs of the crab cavities will have very large dimensions, and also will be confronted by typical problems of damping the Lower Order Mode (LOM), the Same Order Mode (SOM), and as usual, the Higher Order Modes (HOM). In this paper we describe how one can use the concept of a quarter-wave (QW) resonator for a deflecting/crabbing cavity, and use its fundamental mode to deflect the beam. The simplicity of the cavity geometry and the large separation between its fundamental mode and the first HOM make it very attractive.

  19. Optical re-injection in cavity-enhanced absorption spectroscopy

    SciTech Connect (OSTI)

    Leen, J. Brian, E-mail: b.leen@lgrinc.com; O’Keefe, Anthony [Los Gatos Research, 67 E. Evelyn Avenue, Suite 3, Mountain View, California 94041 (United States)

    2014-09-15T23:59:59.000Z

    Non-mode-matched cavity-enhanced absorption spectrometry (e.g., cavity ringdown spectroscopy and integrated cavity output spectroscopy) is commonly used for the ultrasensitive detection of trace gases. These techniques are attractive for their simplicity and robustness, but their performance may be limited by the reflection of light from the front mirror and the resulting low optical transmission. Although this low transmitted power can sometimes be overcome with higher power lasers and lower noise detectors (e.g., in the near-infrared), many regimes exist where the available light intensity or photodetector sensitivity limits instrument performance (e.g., in the mid-infrared). In this article, we describe a method of repeatedly re-injecting light reflected off the front mirror of the optical cavity to boost the cavity's circulating power and deliver more light to the photodetector and thus increase the signal-to-noise ratio of the absorption measurement. We model and experimentally demonstrate the method's performance using off-axis cavity ringdown spectroscopy (OA-CRDS) with a broadly tunable external cavity quantum cascade laser. The power coupled through the cavity to the detector is increased by a factor of 22.5. The cavity loss is measured with a precision of 2 × 10{sup ?10} cm{sup ?1}/?(Hz;) an increase of 12 times over the standard off-axis configuration without reinjection and comparable to the best reported sensitivities in the mid-infrared. Finally, the re-injected CRDS system is used to measure the spectrum of several volatile organic compounds, demonstrating the improved ability to resolve weakly absorbing spectroscopic features.

  20. A rate equation approach to cavity mediated laser cooling

    E-Print Network [OSTI]

    Tony Blake; Andreas Kurcz; Almut Beige

    2012-07-09T23:59:59.000Z

    The cooling rate for cavity mediated laser cooling scales as the Lamb-Dicke parameter eta squared. A proper analysis of the cooling process hence needs to take terms up to eta^2 in the system dynamics into account. In this paper, we present such an analysis for a standard scenario of cavity mediated laser cooling with eta cooling. However, for a weakly confined particle inside a strongly coupled cavity, which is the most interesting case for the cooling of molecules, numerical results indicate that even more detailed calculations are needed to model the cooling process accurately.

  1. Chaos-assisted emission from asymmetric resonant cavity microlasers

    E-Print Network [OSTI]

    Susumu Shinohara; Takahisa Harayama; Takehiro Fukushima; Martina Hentschel; Satoshi Sunada; Evgenii E. Narimanov

    2011-06-01T23:59:59.000Z

    We study emission from quasi-one-dimensional modes of an asymmetric resonant cavity that are associated with a stable periodic ray orbit confined inside the cavity by total internal reflection. It is numerically demonstrated that such modes exhibit directional emission, which is explained by chaos-assisted emission induced by dynamical tunneling. Fabricating semiconductor microlasers with the asymmetric resonant cavity, we experimentally demonstrate the selective excitation of the quasi-one-dimensional modes by employing the device structure to preferentially inject currents to these modes and observe directional emission in good accordance with the theoretical prediction based on chaos-assisted emission.

  2. Wakefield calculation for superconducting TM110 cavity without azimuthal symmetry

    SciTech Connect (OSTI)

    Bellantoni, Leo; /Fermilab; Burt, Graeme; /Lancaster U.

    2006-08-01T23:59:59.000Z

    The 3.9GHz TM{sub 110} mode deflecting cavity developed at FNAL has many applications, including use as a longitudinal bunch profile diagnostic, and as a crab cavity candidate for the ILC. These applications involve beams with substantial time structure. For the 13-cell version intended for the bunch profile application, long-range wakes have been evaluated in the frequency domain and short-range wakes have been evaluated in the time domain. Higher-order interactions of the main field in the cavity with the beam have also been parameterized. Pedagogic derivations are included as appendices.

  3. Towards a monolithic optical cavity for atom detection and manipulation

    E-Print Network [OSTI]

    Sébastien Gleyzes; Abdelkrim El Amili; Ronald Cornelussen; Philippe Lalanne; Christoph I Westbrook; Alain Aspect; Jérôme Estève; Gauthier Moreau; Antony Martinez; Xavier Lafosse; Laurence Ferlazzo; Jean-Christophe Harmand; Dominique Mailly; Abderrahim Ramdane

    2009-04-15T23:59:59.000Z

    We study a Fabry-Perot cavity formed from a ridge waveguide on a AlGaAs substrate. We experimentally determined the propagation losses in the waveguide at 780 nm, the wavelength of Rb atoms. We have also made a numerical and analytical estimate of the losses induced by the presence of the gap which would allow the interaction of cold atoms with the cavity field. We found that the intrinsic finesse of the gapped cavity can be on the order of F ~ 30, which, when one takes into account the losses due to mirror transmission, corresponds to a cooperativity parameter for our system C ~ 1.

  4. Fabrication and Measurements of 500 MHz Double Spoke Cavity

    SciTech Connect (OSTI)

    Park, HyeKyoung [JLAB; Hopper, Christopher S. [Old Dominion University; Delayen, Jean R. [Old Dominion University

    2014-12-01T23:59:59.000Z

    A 500 MHz ?0=1 double spoke cavity has been designed and optimized for a high velocity application such as a compact electron accelerator at the Center for Accelerator Science at Old Dominion University [1] and the fabrication was recently completed at Jefferson Lab. The geometry specific to the double spoke cavity required a variety of tooling and fixtures. Also a number of asymmetric weld joints were expected to make it difficult to maintain minimal geometric deviation from the design. This paper will report the fabrication procedure, resulting tolerance from the design, initial test results and the lessons learned from the first ?0=1 double spoke cavity fabrication.

  5. SRF cavities for CW option of Project X Linac

    SciTech Connect (OSTI)

    Solyak, N.; Gonin, I.; Khabiboulline, T.; Lunin, A.; Perunov, N.; Yakovlev, V.; /Fermilab

    2009-09-01T23:59:59.000Z

    Alternative option of Project X is based on the CW SC 2GeV Linac with the average current 1mA. Possible option of the CW Linac considered in the paper includes low energy part consisted of a few families SC Spoke cavities (from 2.5 MeV to 466 MeV) and high energy part consisted of 2 types of elliptical cavities (v/c=0.81 and v/c=1). Requirements and designed parameters of cavities are considered.

  6. Commissioning Cornell OSTs for SRF cavity testing at Jlab

    SciTech Connect (OSTI)

    Grigory Eremeev

    2011-07-01T23:59:59.000Z

    Understanding the current quench limitations in SRF cavities is a topic#11;essential for any SRF accelerator that requires high fields. This understanding crucially depends on correct and precise quench identification. Second sound quench detection in superfluid liquid helium with oscillating superleak transducers is a technique recently applied at Cornell University as a fast and versatile method for quench identification in SRF cavities. Having adopted Cornell design, we report in this contribution on our experience with OST for quench identification in different cavities at JLab.

  7. Frequency doubling crystals

    DOE Patents [OSTI]

    Wang, Francis (Danville, CA); Velsko, Stephan P. (Livermore, CA)

    1989-01-01T23:59:59.000Z

    A systematic approach to the production of frequency conversion crystals is described in which a chiral molecule has attached to it a "harmonic generating unit" which contributes to the noncentrosymmetry of the molecule. Certain preferred embodiments of such harmonic generating units include carboxylate, guanadyly and imidazolyl units. Certain preferred crystals include L-arginine fluoride, deuterated L-arginine fluoride, L-arginine chloride monohydrate, L-arginine acetate, dithallium tartrate, ammonium N-acetyl valine, N-acetyl tyrosine and N-acetyl hydroxyproline. Chemical modifications of the chiral molecule, such as deuteration, halogenation and controlled counterion substitution are available to adapt the dispersive properties of a crystal in a particular wavelength region.

  8. Absorption in quantum electrodynamics cavities in terms of a quantum jump operator

    E-Print Network [OSTI]

    V. Debierre; G. Demésy; T. Durt; A. Nicolet; B. Vial; F. Zolla

    2014-03-17T23:59:59.000Z

    We describe the absorption by the walls of a quantum electrodynamics cavity as a process during which the elementary excitations (photons) of an internal mode of the cavity exit by tunneling through the cavity walls. We estimate by classical methods the survival time of a photon inside the cavity and the quality factor of its mirrors.

  9. accelerating cavity field: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    at different Q values, the onset field for emitters, and the number taken from the Tesla RF cavity database 2. Quality factor vs. E-field curves were taken from 32 1-cell 14...

  10. A piezo-tunable gigahertz cavity microelectromechanical resonator

    E-Print Network [OSTI]

    Hou, Stephen Ming-Chang, 1981-

    2004-01-01T23:59:59.000Z

    RF systems need high-frequency widely-tunable high-Q bandpass filters for channel selection filters and local oscillators. This thesis describes the design, fabrication and testing of a electromagnetic cavity resonator ...

  11. Casimir Energy in a Conical Wedge and a Conical Cavity

    E-Print Network [OSTI]

    H. Ahmedov; I. H. Duru

    2004-08-26T23:59:59.000Z

    Casimir energy for a massless scalar field for a conical wedge and a conical cavity are calculated. The group generated by the images is employed in deriving the Green functions as well as the wave functions and the energy spectrum.

  12. Near-Field Imaging of Interior Cavities 1 Introduction

    E-Print Network [OSTI]

    2014-10-21T23:59:59.000Z

    The scattering data is taken on a circle centered at the source. The ... where a>0 is the base radius and f(?) is the cavity surface function. We assume that f is.

  13. The Study of Media Beta Elliptical Cavities for CIADS

    E-Print Network [OSTI]

    Liangjian, Wen; Yongming, Li; Ruoxu, Wang; Hao, Guo; Cong, Zhang; Huan, Jia; Tiancai, Jiang; Chunlong, Li; Yuan, He

    2015-01-01T23:59:59.000Z

    The China Accelerator Driven Sub-critical System (CADS) is a high intensity proton facility to dispose of nuclear waste and generate electric power. CADS is based on 1.5GeV, 10mA CW superconducting (SC) linac as a driver. The high-energy section of the linac is compose of two families of SC elliptical cavities which are designed for the geometrical beta 0.63 and 0.82. In this paper, the 650 MHz \\b{eta}=0.63 SC elliptical cavity was studied including cavity optimization, multipacting, high order modes (HOMs) and generator RF power calculation. Keywords: high current, medium beta, ADS, superconducting cavity, HOMs

  14. Method for pressure modulation of turbine sidewall cavities

    DOE Patents [OSTI]

    Leone, Sal Albert (Scotia, NY); Book, Matthew David (Altamont, NY); Banares, Christopher R. (Schenectady, NY)

    2002-01-01T23:59:59.000Z

    A method is provided for controlling cooling air flow for pressure modulation of turbine components, such as the turbine outer sidewall cavities. The pressure at which cooling and purge air is supplied to the turbine outer side wall cavities is modulated, based on compressor discharge pressure (Pcd), thereby to generally maintain the back flow margin (BFM) so as to minimize excessive leakage and the consequent performance deterioration. In an exemplary embodiment, the air pressure within the third stage outer side wall cavity and the air pressure within the fourth stage outer side wall cavity are each controlled to a respective value that is a respective prescribed percentage of the concurrent compressor discharge pressure. The prescribed percentage may be determined from a ratio of the respective outer side wall pressure to compressor discharge pressure at Cold Day Turn Down (CDTD) required to provide a prescribed back flow margin.

  15. System for pressure modulation of turbine sidewall cavities

    DOE Patents [OSTI]

    Leone, Sal Albert (Scotia, NY); Book, Matthew David (Altamont, NY); Banares, Christopher R. (Schenectady, NY)

    2002-01-01T23:59:59.000Z

    A system and method are provided for controlling cooling air flow for pressure modulation of turbine components, such as the turbine outer sidewall cavities. The pressure at which cooling and purge air is supplied to the turbine outer side wall cavities is modulated, based on compressor discharge pressure (Pcd), thereby to generally maintain the back flow margin (BFM) so as to minimize excessive leakage and the consequent performance deterioration. In an exemplary embodiment, the air pressure within the third stage outer side wall cavity and the air pressure within the fourth stage outer side wall cavity are each controlled to a respective value that is a respective prescribed percentage of the concurrent compressor discharge pressure. The prescribed percentage may be determined from a ratio of the respective outer side wall pressure to compressor discharge pressure at Cold Day Turn Down (CDTD) required to provide a prescribed back flow margin.

  16. Magnetic shielding for the Fermilab Vertical Cavity Test Facility

    SciTech Connect (OSTI)

    Ginsburg, Camille M.; Reid, Clark; Sergatskov, Dmitri A.; /Fermilab

    2008-09-01T23:59:59.000Z

    A superconducting RF cavity has to be shielded from magnetic fields present during cool down below the critical temperature to avoid freezing in the magnetic flux at localized impurities, thereby degrading the cavity intrinsic quality factor Q{sub 0}. The magnetic shielding designed for the Fermilab vertical cavity test facility (VCTF), a facility for CW RF vertical testing of bare ILC 1.3 GHz 9-cell SRF cavities, was recently completed. For the magnetic shielding design, we used two cylindrical layers: a room temperature 'outer' shield of Amumetal (80% Ni alloy), and a 2K 'inner' shield of Cryoperm 10. The magnetic and mechanical design of the magnetic shielding and measurement of the remanent magnetic field inside the shielding are described.

  17. First Characterization of a Fully Superconducting RF Photoinjector Cavity

    SciTech Connect (OSTI)

    Neumann, A; Barday, R; Jankowiak, A; Kamps, T; Knobloch, J; Kugeler, O; Matveenko, A N; Quast, T; Rudolph, J; Schubert, S G; Volker, J; Kneisel, P; Nietubyc, R; Sekutowicz, J K; Smedley, J; Volkov, V; Weinberg, G

    2011-09-01T23:59:59.000Z

    As a first step towards a high brightness, high average current electron source for the BERLinPro ERL a fully superconducting photo-injector was developed by HZB in collaboration with JLab, DESY and the A. Soltan Institute. This cavity-injector ensemble is made up of a 1.6-cell superconducting cavity with a superconducting lead cathode deposited on the half-cell backwall. A superconducting solenoid is used for emittance compensation. This system, including a diagnostics beamline, has been installed in the HoBiCaT facility to serve as a testbed for beam dynamics studies and to test the combination SRF cavity and superconducting solenoid. This paper summarizes the characterization of the cavity in this configuration including Q measurements, dark current tests and field-stability analyses.

  18. Intraoperative Brain Tumor Resection Cavity Characterization with Conoscopic Holography

    E-Print Network [OSTI]

    Webster III, Robert James

    Intraoperative Brain Tumor Resection Cavity Characterization with Conoscopic Holography Amber L ABSTRACT Brain shift compromises the accuracy of neurosurgical image-guided interventions if not corrected approach to correcting for brain shift. Laser range scan, instrument swabbing, and conoscopic holography

  19. Progress on the Mice 201 MNz RF Cavity at LBNL

    E-Print Network [OSTI]

    Luo, Tianhuan

    2014-01-01T23:59:59.000Z

    like to thank people at LBNL EH&S and Main Machine Shop forMICE 201 MHz RF CAVITY AT LBNL* Tianhuan Luol, Don Summers,Virostek, Michael Zisman, LBNL, Berkeley, CA 94720, USA

  20. Magnetic Flux Dynamics in Horizontally Cooled Superconducting Cavities

    E-Print Network [OSTI]

    Martinello, M; Grassellino, A; Crawford, A C; Melnychuk, O; Romanenko, A; Sergatkov, D A

    2015-01-01T23:59:59.000Z

    Previous studies on magnetic flux expulsion as a function of cooling details have been performed for superconducting niobium cavities with the cavity beam axis placed parallel respect to the helium cooling flow, and findings showed that for sufficient cooling thermogradients all magnetic flux could be expelled and very low residual resistance could be achieved. In this paper we investigate the flux trapping and its impact on radio frequency surface resistance when the resonators are positioned perpendicularly to the helium cooling flow, which is representative of how superconducting radio-frequency (SRF) cavities are cooled in an accelerator. We also extend the studies to different directions of applied magnetic field surrounding the resonator. Results show that in the cavity horizontal configuration there is a different impact of the various field components on the final surface resistance, and that several parameters have to be considered to understand flux dynamics. A newly discovered phenomenon of concent...

  1. acceleration cavity tuner: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    power proton linear accelerators. In terms of structure design, a triple-spoke superconduct- ing cavity of the proton linac in the Eurisol project 3. Meanwhile, the study of...

  2. Demixing cascades in cluster crystals

    E-Print Network [OSTI]

    Nigel B. Wilding; Peter Sollich

    2014-07-14T23:59:59.000Z

    In a cluster crystal, each lattice site is occupied by multiple soft-core particles. As the number density is increased at zero temperature, a `cascade' of isostructural phase transitions can occur between states whose site occupancy differs by unity. For low but finite temperature, each of these transitions terminates in a critical point. Using tailored Monte Carlo simulation techniques we have studied such demixing cascades in systems of soft particles interacting via potentials of the generalized exponential form $u(r)=\\epsilon\\exp[-(r/\\sigma)^n]$. We have estimated the critical parameters of the first few transitions in the cascade as a function of the softness parameter $n$. The critical temperature and pressure exhibit non-monotonic behaviour as $n$ is varied, although the critical chemical potential remains monotonic. The trends for the pressure and chemical potential are confirmed by cell model calculations at zero temperature. As $n\\to 2^+$, all the transitions that we have observed are preempted by melting although we cannot rule out that clustering transitions survive at high density.

  3. A high resolution cavity BPM for the CLIC Test Facility

    E-Print Network [OSTI]

    Chritin, N; Soby, L; Lunin, A; Solyak, N; Wendt, M; Yakovlev, V

    2012-01-01T23:59:59.000Z

    In frame of the development of a high resolution BPM system for the CLIC Main Linac we present the design of a cavity BPM prototype. It consists of a waveguide loaded dipole mode resonator and a monopole mode reference cavity, both operating at 15 GHz, to be compatible with the bunch frequencies at the CLIC Test Facility. Requirements, design concept, numerical analysis, and practical considerations are discussed.

  4. RF Gun cavities cooling regime study. K. Floettmann1

    E-Print Network [OSTI]

    RF power of Pa 68kW corre- sponds to a heat load of 300kW m . To remove such a high heat value from of RF fields in the cavity at an operating frequency is calculated in the usual way. The temperature) with the boundary condition at the RF cavity surface: kc(ngradT) = Ps, (2) where kc = 391 W m·K is the heat

  5. Journal of Crystal Growth ] (

    E-Print Network [OSTI]

    ) at high pressure of CO2 (initial PCO2 ¼ 55 bar) and moderate to high temperature (30 and 90 1C) was used and the dissolved quantity of CO2 have a significant effect on the average particle size, specific surface areaJournal of Crystal Growth ] (

  6. Silicon crystal growing by oscillating crucible technique

    DOE Patents [OSTI]

    Schwuttke, G.H.; Kim, K.M.; Smetana, P.

    1983-08-03T23:59:59.000Z

    A process for growing silicon crystals from a molten melt comprising oscillating the container during crystal growth is disclosed.

  7. Cavity-Modified Collective Rayleigh Scattering of Two Atoms

    E-Print Network [OSTI]

    René Reimann; Wolfgang Alt; Tobias Kampschulte; Tobias Macha; Lothar Ratschbacher; Natalie Thau; Seokchan Yoon; Dieter Meschede

    2015-01-15T23:59:59.000Z

    We report on the observation of cooperative radiation of exactly two neutral atoms strongly coupled to the single mode field of an optical cavity, which is close to the lossless-cavity limit. Monitoring the cavity output power, we observe constructive and destructive interference of collective Rayleigh scattering for certain relative distances between the two atoms. Because of cavity backaction onto the atoms, the cavity output power for the constructive two-atom case ($N=2$) is almost equal to the single-emitter case ($N=1$), which is in contrast to free-space where one would expect an $N^2$ scaling of the power. These effects are quantitatively explained by a classical model as well as by a quantum mechanical model based on Dicke states. We extract information on the relative phases of the light fields at the atom positions and employ advanced cooling to reduce the jump rate between the constructive and destructive atom configurations. Thereby we improve the control over the system to a level where the implementation of two-atom entanglement schemes involving optical cavities becomes realistic.

  8. Superfluid helium cryogenic systems for superconducting RF cavities at KEK

    SciTech Connect (OSTI)

    Nakai, H.; Hara, K.; Honma, T.; Hosoyama, K.; Kojima, Y.; Nakanishi, K. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0033 (Japan); Kanekiyo, T. [Hitachi Plant Technologies, Ltd., Toshima-ku, Tokyo 170-8466 (Japan); Morita, S. [Hitachi Plant Mechanics Co., Ltd., Kudamatsu, Yamaguchi 744-0061 (Japan)

    2014-01-29T23:59:59.000Z

    Recent accelerator projects at KEK, such as the Superconducting RF Test Facility (STF) for R and D of the International Linear Collider (ILC) project and the compact Energy Recovery Linac (cERL), employ superconducting RF cavities made of pure niobium, which can generate high gradient acceleration field. Since the operation temperature of these cavities is selected to be 2 K, we have developed two 2 K superfluid helium cryogenic systems for stable operation of superconducting RF cavities for each of STF and cERL. These two 2 K superfluid helium cryogenic systems are identical in principle. Since the operation mode of the cavities is different for STF and cERL, i.e. the pulse mode for STF and the continuous wave mode for cERL, the heat loads from the cavities are quite different. The 2 K superfluid helium cryogenic systems mainly consists of ordinary helium liquefiers/refrigerators, 2 K refrigerator cold boxes, helium gas pumping systems and high-performance transfer lines. The 2 K refrigerators and the high-performance transfer lines are designed by KEK. Some superconducting RF cavity cryomodules have been already connected to the 2 K superfluid helium cryogenic systems for STF and cERL respectively, and cooled down to 2 K successfully.

  9. Thermalization and condensation in an incoherently pumped passive optical cavity

    SciTech Connect (OSTI)

    Michel, C.; Picozzi, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, CNRS, Universite de Bourgogne, F-21078 Dijon (France); Haelterman, M. [Service OPERA, Universite Libre de Bruxelles, B-1050 Brussels (Belgium); Suret, P.; Randoux, S. [Laboratoire de Physique des Lasers, Atomes et Molecules, CNRS, Universite de Lille, F-59655 Villeneuve d'Ascq (France); Kaiser, R. [Institut Non Lineaire de Nice, CNRS, Universite de Nice Sophia-Antipolis, F-06560 Valbonne (France)

    2011-09-15T23:59:59.000Z

    We study theoretically and numerically the condensation and the thermalization of classical optical waves in an incoherently pumped passive Kerr cavity. We show that the dynamics of the cavity exhibits a turbulent behavior that can be described by the wave turbulence theory. A mean-field kinetic equation is derived, which reveals that, in its high finesse regime, the cavity behaves essentially as a conservative Hamiltonian system. In particular, the intracavity turbulent field is shown to relax adiabatically toward a thermodynamic equilibrium state of energy equipartition. As a consequence of this effect of wave thermalization, the incoherent optical field undergoes a process of condensation, characterized by the spontaneous emergence of a plane wave from the incoherently pumped cavity. The condensation process is an equilibrium phase transition that occurs below a critical value of the (kinetic) energy of the incoherent pump. In spite of the dissipative nature of the cavity dynamics, the condensate fraction of the high-finesse cavity field is found in quantitative agreement with the theory inherited from the purely conservative (Hamiltonian) nonlinear Schroedinger equation.

  10. Progress towards crab cavity solutions for the ILC

    SciTech Connect (OSTI)

    Burt, G.; Dexter, A.; /Lancaster U.; Bellantoni, L.; /Fermilab; Beard, C.; Goudket, P.; /Cockcroft Inst. Accel. Sci. Tech.

    2006-06-01T23:59:59.000Z

    In order to achieve acceptable luminosity for ILC crossing angles greater than 2 mrad, RF deflection cavities must be used to rotate electron and position bunches leading up to the IP. A bunch that passes through a deflection cavity at a phase where the deflection averages to zero, receives a crab kick leading to a finite rotation at the IP. For a beam energy of 500 GeV and a crossing angle of 20 mrad the required crab kick is about 11.4 MV at 1.3 GHz and 3.8 MV at 3.9 GHz. Cavities are needed on both beams and are likely to be positioned about 12 m before the IP. Any RF phase error between the bunch and the cavity leads to a deflection of the bunch in addition to a rotation of the bunch. Any differential phase error between the cavities leads to differing deflections and consequential loss in luminosity. An updated analysis of system requirements and phase tolerances with respect to original calculations [1] is given. Issues on cavity and frequency choice are discussed.

  11. Camera assembly design proposal for SRF cavity image collection

    SciTech Connect (OSTI)

    Tuozzolo, S.

    2011-10-10T23:59:59.000Z

    This project seeks to collect images from the inside of a superconducting radio frequency (SRF) large grain niobium cavity during vertical testing. These images will provide information on multipacting and other phenomena occurring in the SRF cavity during these tests. Multipacting, a process that involves an electron buildup in the cavity and concurrent loss of RF power, is thought to be occurring near the cathode in the SRF structure. Images of electron emission in the structure will help diagnose the source of multipacting in the cavity. Multipacting sources may be eliminated with an alteration of geometric or resonant conditions in the SRF structure. Other phenomena, including unexplained light emissions previously discovered at SLAC, may be present in the cavity. In order to effectively capture images of these events during testing, a camera assembly needs to be installed to the bottom of the RF structure. The SRF assembly operates under extreme environmental conditions: it is kept in a dewar in a bath of 2K liquid helium during these tests, is pumped down to ultra-high vacuum, and is subjected to RF voltages. Because of this, the camera needs to exist as a separate assembly attached to the bottom of the cavity. The design of the camera is constrained by a number of factors that are discussed.

  12. Resonant-cavity apparatus for cytometry or particle analysis

    DOE Patents [OSTI]

    Gourley, Paul L. (Albuquerque, NM)

    1998-01-01T23:59:59.000Z

    A resonant-cavity apparatus for cytometry or particle analysis. The apparatus comprises a resonant optical cavity having an analysis region within the cavity for containing one or more biological cells or dielectric particles to be analyzed. In the presence of a cell or particle, a light beam in the form of spontaneous emission or lasing is generated within the resonant optical cavity and is encoded with information about the cell or particle. An analysis means including a spectrometer and/or a pulse-height analyzer is provided within the apparatus for recovery of the information from the light beam to determine a size, shape, identification or other characteristics about the cells or particles being analyzed. The recovered information can be grouped in a multi-dimensional coordinate space for identification of particular types of cells or particles. In some embodiments of the apparatus, the resonant optical cavity can be formed, at least in part, from a vertical-cavity surface-emitting laser. The apparatus and method are particularly suited to the analysis of biological cells, including blood cells, and can further include processing means for manipulating, sorting, or eradicating cells after analysis thereof.

  13. Wall recession rates in cavity-growth modeling

    SciTech Connect (OSTI)

    Grens, E.A. II; Thorsness, C.B.

    1984-08-01T23:59:59.000Z

    The predictions of resource utilization obtained from cavity-growth models depend on the methods used to represent the recession rates of the walls of the cavity. Under many circumstances the cavity is largely filled with a bed char rubble. Examination of the mechanisms for recession at walls adjacent to these char beds indicates that the recession rates are controlled by convective heat transfer from the bed to the walls coupled with the thermomechanical breakdown of the walls. A recession-rate representation has been developed, based on this concept, for use in cavity-growth simulation programs. This representation characterizes wall breakdown by either a failure temperature or by a thickness of char layer at failure, and determines rates from a model of heat transfer under these conditions. It gives recession rates that are functions of gas temperature and mass flow rate in the cavity, and depend on effective particle size in the char bed. Wall recession rates calculated for WIDCO, Hoe Creek, and Hanna coals are in the range of 0.1 to 0.8 m/day at a 1300 K cavity temperature, and are consistent with the general rates observed for field tests. 27 references, 10 figures, 1 table.

  14. Multiple mass solvers

    E-Print Network [OSTI]

    B. Jegerlehner

    1997-08-29T23:59:59.000Z

    We present a general method to construct multiple mass solvers from standard algorithms. As an example, the BiCGstab-M algorithm is derived.

  15. Multiple System Rate Process

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    DSW Multiple System Transmission Rate Process Federal Register Notice Withdrawing Rate Proposal (PDF) Formal Process Extension Federal Register Notice (PDF) Customer Savisngs Under...

  16. Design and Development of Superconducting Parallel-Bar Deflecting/Crabbing Cavities

    SciTech Connect (OSTI)

    Payagalage Subashini Uddi De Silva, Jean Delayen

    2012-07-01T23:59:59.000Z

    The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties that is being considered for a number of applications. We present the designs of a 499 MHz deflecting cavity developed for the Jefferson Lab 12 GeV Upgrade and a 400 MHz crabbing cavity for the LHC High Luminosity Upgrade. Prototypes of these two cavities are now under development and fabrication.

  17. Controlled switching of ultrafast circular polarization oscillations in spin-polarized vertical-cavity surface-emitting lasers

    SciTech Connect (OSTI)

    Höpfner, Henning, E-mail: henning.hoepfner@rub.de; Lindemann, Markus; Gerhardt, Nils C.; Hofmann, Martin R. [Photonics and Terahertz Technology, Ruhr-University Bochum, D-44780 Bochum (Germany)

    2014-01-13T23:59:59.000Z

    We demonstrate a scheme for controlled switching of polarization oscillations in spin-polarized vertical-cavity surface-emitting lasers (spin-VCSEL). Under hybrid electrical and optical pumping conditions, our VCSEL devices show polarization oscillations with frequencies far above the VCSEL's electrical modulation bandwidth. Using multiple optical pulses, we are able to excite and amplify these polarization oscillations. When specific phase and amplitude conditions for the optical excitation pulses are met, destructive interference leads to switch-off of the polarization oscillation, enabling the generation of controlled short polarization bursts.

  18. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, Terry W. (Tracy, CA)

    1994-01-01T23:59:59.000Z

    A multiple density layered insulator for use with a laser is disclosed wh provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation.

  19. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, T.W.

    1994-09-06T23:59:59.000Z

    A multiple density layered insulator for use with a laser is disclosed which provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation. 4 figs.

  20. Thoracic cavity segmentation algorithm using multiorgan extraction and surface fitting in volumetric CT

    SciTech Connect (OSTI)

    Bae, JangPyo [Interdisciplinary Program, Bioengineering Major, Graduate School, Seoul National University, Seoul 110-744, South Korea and Department of Radiology, University of Ulsan College of Medicine, 388-1 Pungnap2-dong, Songpa-gu, Seoul 138-736 (Korea, Republic of)] [Interdisciplinary Program, Bioengineering Major, Graduate School, Seoul National University, Seoul 110-744, South Korea and Department of Radiology, University of Ulsan College of Medicine, 388-1 Pungnap2-dong, Songpa-gu, Seoul 138-736 (Korea, Republic of); Kim, Namkug, E-mail: namkugkim@gmail.com; Lee, Sang Min; Seo, Joon Beom [Department of Radiology, University of Ulsan College of Medicine, 388-1 Pungnap2-dong, Songpa-gu, Seoul 138-736 (Korea, Republic of)] [Department of Radiology, University of Ulsan College of Medicine, 388-1 Pungnap2-dong, Songpa-gu, Seoul 138-736 (Korea, Republic of); Kim, Hee Chan [Department of Biomedical Engineering, College of Medicine and Institute of Medical and Biological Engineering, Medical Research Center, Seoul National University, Seoul 110-744 (Korea, Republic of)] [Department of Biomedical Engineering, College of Medicine and Institute of Medical and Biological Engineering, Medical Research Center, Seoul National University, Seoul 110-744 (Korea, Republic of)

    2014-04-15T23:59:59.000Z

    Purpose: To develop and validate a semiautomatic segmentation method for thoracic cavity volumetry and mediastinum fat quantification of patients with chronic obstructive pulmonary disease. Methods: The thoracic cavity region was separated by segmenting multiorgans, namely, the rib, lung, heart, and diaphragm. To encompass various lung disease-induced variations, the inner thoracic wall and diaphragm were modeled by using a three-dimensional surface-fitting method. To improve the accuracy of the diaphragm surface model, the heart and its surrounding tissue were segmented by a two-stage level set method using a shape prior. To assess the accuracy of the proposed algorithm, the algorithm results of 50 patients were compared to the manual segmentation results of two experts with more than 5 years of experience (these manual results were confirmed by an expert thoracic radiologist). The proposed method was also compared to three state-of-the-art segmentation methods. The metrics used to evaluate segmentation accuracy were volumetric overlap ratio (VOR), false positive ratio on VOR (FPRV), false negative ratio on VOR (FNRV), average symmetric absolute surface distance (ASASD), average symmetric squared surface distance (ASSSD), and maximum symmetric surface distance (MSSD). Results: In terms of thoracic cavity volumetry, the mean ± SD VOR, FPRV, and FNRV of the proposed method were (98.17 ± 0.84)%, (0.49 ± 0.23)%, and (1.34 ± 0.83)%, respectively. The ASASD, ASSSD, and MSSD for the thoracic wall were 0.28 ± 0.12, 1.28 ± 0.53, and 23.91 ± 7.64 mm, respectively. The ASASD, ASSSD, and MSSD for the diaphragm surface were 1.73 ± 0.91, 3.92 ± 1.68, and 27.80 ± 10.63 mm, respectively. The proposed method performed significantly better than the other three methods in terms of VOR, ASASD, and ASSSD. Conclusions: The proposed semiautomatic thoracic cavity segmentation method, which extracts multiple organs (namely, the rib, thoracic wall, diaphragm, and heart), performed with high accuracy and may be useful for clinical purposes.

  1. Multiple piece turbine engine airfoil with a structural spar

    DOE Patents [OSTI]

    Vance, Steven J. (Orlando, FL)

    2011-10-11T23:59:59.000Z

    A multiple piece turbine airfoil having an outer shell with an airfoil tip that is attached to a root with an internal structural spar is disclosed. The root may be formed from first and second sections that include an internal cavity configured to receive and secure the one or more components forming the generally elongated airfoil. The internal structural spar may be attached to an airfoil tip and place the generally elongated airfoil in compression. The configuration enables each component to be formed from different materials to reduce the cost of the materials and to optimize the choice of material for each component.

  2. Optimization of the Low Loss SRF Cavity for the ILC

    SciTech Connect (OSTI)

    Sekutowicz, J.S.; /DESY; Kneisel, P.; /Jefferson Lab; Higo, T.; Morozumi, Y.; Saito, K.; /KEK, Tsukuba; Ge, L.; Ko, Yong-kyu; Lee, L.; Li, Z.; Ng, C.K.; Schussman, G.L.; Xiao, L.; /SLAC

    2008-01-18T23:59:59.000Z

    The Low-Loss shape cavity design has been proposed as a possible alternative to the baseline TESLA cavity design for the ILC main linacs. The advantages of this design over the TESLA cavity are its lower cryogenic loss, and higher achievable gradient due to lower surface fields. High gradient prototypes for such designs have been tested at KEK (ICHIRO) and TJNAF (LL). However, issues related to HOM damping and multipacting still need to be addressed. Preliminary numerical studies of the prototype cavities have shown unacceptable damping factors for some higher-order dipole modes if the typical TESLA HOM couplers are directly adapted to the design. The resulting wakefield will dilute the beam emittance thus reducing the machine luminosity. Furthermore, high gradient tests on a 9-cell prototype at KEK have experienced multipacting barriers although a single LL cell had achieved a high gradient. From simulations, multipacting activities are found to occur in the end-groups of the cavity. In this paper, we will present the optimization results of the end-groups for the Low-Loss designs for effective HOM damping and alleviation of multipacting.

  3. Eddy current scanning of niobium for SRF cavities at Fermilab

    SciTech Connect (OSTI)

    Boffo, C.; Bauer, P.; Foley, M.; Antoine, C.; Cooper, C.; /Fermilab; Brinkmann, A.; /DESY

    2006-08-01T23:59:59.000Z

    In the framework of SRF cavity development, Fermilab is creating the infrastructure needed for the characterization of the material used in the cavity fabrication. An important step in the characterization of ''as received'' niobium sheets is eddy current scanning. Eddy current scanning is a non-destructive technique first adopted and further developed by DESY with the purpose of checking the cavity material for subsurface defects and inclusions. Fermilab has received and further upgraded a commercial eddy current scanner previously used for the SNS project. This scanner is now used daily to scan the niobium sheets for the Fermilab third harmonic, the ILC, and the Proton Driver cavities. After optical inspection, more than 400 squares and disks have been scanned and when necessary checked at the optical and electron microscopes, anodized, or measured with profilometers looking for surface imperfections that might limit the performance of the cavities. This paper gives a status report on the scanning results obtained so far, including a discussion of the classification of signals being detected.

  4. Optimizing SRF Gun Cavity Profiles in a Genetic Algorithm Framework

    SciTech Connect (OSTI)

    Alicia Hofler, Pavel Evtushenko, Frank Marhauser

    2009-09-01T23:59:59.000Z

    Automation of DC photoinjector designs using a genetic algorithm (GA) based optimization is an accepted practice in accelerator physics. Allowing the gun cavity field profile shape to be varied can extend the utility of this optimization methodology to superconducting and normal conducting radio frequency (SRF/RF) gun based injectors. Finding optimal field and cavity geometry configurations can provide guidance for cavity design choices and verify existing designs. We have considered two approaches for varying the electric field profile. The first is to determine the optimal field profile shape that should be used independent of the cavity geometry, and the other is to vary the geometry of the gun cavity structure to produce an optimal field profile. The first method can provide a theoretical optimal and can illuminate where possible gains can be made in field shaping. The second method can produce more realistically achievable designs that can be compared to existing designs. In this paper, we discuss the design and implementation for these two methods for generating field profiles for SRF/RF guns in a GA based injector optimization scheme and provide preliminary results.

  5. COMPARISON OF RF CAVITY TRANSPORT MODELS FOR BBU SIMULATIONS

    SciTech Connect (OSTI)

    Ilkyoung Shin,Byung Yunn,Todd Satogata,Shahid Ahmed

    2011-03-01T23:59:59.000Z

    The transverse focusing effect in RF cavities plays a considerable role in beam dynamics for low-energy beamline sections and can contribute to beam breakup (BBU) instability. The purpose of this analysis is to examine RF cavity models in simulation codes which will be used for BBU experiments at Jefferson Lab and improve BBU simulation results. We review two RF cavity models in the simulation codes elegant and TDBBU (a BBU simulation code developed at Jefferson Lab). elegant can include the Rosenzweig-Serafini (R-S) model for the RF focusing effect. Whereas TDBBU uses a model from the code TRANSPORT which considers the adiabatic damping effect, but not the RF focusing effect. Quantitative comparisons are discussed for the CEBAF beamline. We also compare the R-S model with the results from numerical simulations for a CEBAF-type 5-cell superconducting cavity to validate the use of the R-S model as an improved low-energy RF cavity transport model in TDBBU. We have implemented the R-S model in TDBBU. It will improve BBU simulation results to be more matched with analytic calculations and experimental results.

  6. Superconducting Accelerating Cavity Pressure Sensitivity Analysis and Stiffening

    SciTech Connect (OSTI)

    Rodnizki, J [Soreq NRC, Yavne, Israel; Ben Aliz, Y [Soreq NRC, Yavne, Israel; Grin, A [Soreq NRC, Yavne, Israel; Horvitz, Z [Soreq NRC, Yavne, Israel; Perry, A [Soreq NRC, Yavne, Israel; Weissman, L [Soreq NRC, Yavne, Israel; Davis, G Kirk [JLAB; Delayen, Jean R. [Old Dominion Universtiy

    2014-12-01T23:59:59.000Z

    The Soreq Applied Research Accelerator Facility (SARAF) design is based on a 40 MeV 5 mA light ions superconducting RF linac. Phase-I of SARAF delivers up to 2 mA CW proton beams in an energy range of 1.5 - 4.0 MeV. The maximum beam power that we have reached is 5.7 kW. Today, the main limiting factor to reach higher ion energy and beam power is related to the HWR sensitivity to the liquid helium coolant pressure fluctuations. The HWR sensitivity to helium pressure is about 60 Hz/mbar. The cavities had been designed, a decade ago, to be soft in order to enable tuning of their novel shape. However, the cavities turned out to be too soft. In this work we found that increasing the rigidity of the cavities in the vicinity of the external drift tubes may reduce the cavity sensitivity by a factor of three. A preliminary design to increase the cavity rigidity is presented.

  7. Performance of 3.9 GHz SRF cavities at Fermilab's ILCTA_MDB nhorizontal test stand

    SciTech Connect (OSTI)

    Harms, Elvin; Hocker, Andy; /Fermilab

    2008-08-01T23:59:59.000Z

    Fermilab is building a cryomodule containing four 3.9 GHz superconducting radio frequency (SRF) cavities for the Free electron LASer in Hamburg (FLASH) facility at the Deutsches Elektronen-SYnchrotron (DESY) laboratory. Before assembling the cavities into the cryomodule, each individual cavity is tested at Fermilab's Horizontal Test Stand (HTS). The HTS provides the capability to test fully-dressed SRF cavities at 1.8 K with high-power pulsed RF in order to verify that the cavities achieve performance requirements under these conditions. The performance at the HTS of the 3.9 GHz cavities built for FLASH is presented here.

  8. Measurements of SCRF cavity dynamic heat load in horizontal test system

    SciTech Connect (OSTI)

    DeGraff, B.D.; Bossert, R.J.; Pei, L.; Soyars, W.M.; /Fermilab

    2009-11-01T23:59:59.000Z

    The Horizontal Test System (HTS) at Fermilab is currently testing fully assembled, dressed superconducting radio frequency (SCRF) cavities. These cavities are cooled in a bath of superfluid helium at 1.8K. Dissipated RF power from the cavities is a dynamic heat load on the cryogenic system. The magnitude of heat flux from these cavities into the helium is also an important variable for understanding cavity performance. Methods and hardware used to measure this dynamic heat load are presented. Results are presented from several cavity tests and testing accuracy is discussed.

  9. Measurements of SCRF cavity dynamic heat load in horizontal test system

    E-Print Network [OSTI]

    DeGraff, B D; Pei, L; Soyars, W M; 10.1063/1.3422409

    2012-01-01T23:59:59.000Z

    The Horizontal Test System (HTS) at Fermilab is currently testing fully assembled, dressed superconducting radio frequency (SCRF) cavities. These cavities are cooled in a bath of superfluid helium at 1.8K. Dissipated RF power from the cavities is a dynamic heat load on the cryogenic system. The magnitude of heat flux from these cavities into the helium is also an important variable for understanding cavity performance. Methods and hardware used to measure this dynamic heat load are presented. Results are presented from several cavity tests and testing accuracy is discussed.

  10. Entanglement of fields in coupled-cavities: effects of pumping and fluctuations

    E-Print Network [OSTI]

    S Sivakumar

    2010-02-04T23:59:59.000Z

    A system of two coupled cavities is studied in the context of bipartite, continuous variable entanglement. One of the cavities is pumped by an external classical source that is coupled quadratically, to the cavity field. Dynamics of entanglement, quantified by covariance measure [Dodonov {\\it et al}, Phys. Lett A {\\bf 296}, (2002) 73], in the presence of cavity-cavity coupling and external pumping is investigated. The importance of tailoring the coupling between the cavities is brought out by studying the effects of pump fluctuations on the entanglement.

  11. Gas turbine engine combustor can with trapped vortex cavity

    DOE Patents [OSTI]

    Burrus, David Louis; Joshi, Narendra Digamber; Haynes, Joel Meier; Feitelberg, Alan S.

    2005-10-04T23:59:59.000Z

    A gas turbine engine combustor can downstream of a pre-mixer has a pre-mixer flowpath therein and circumferentially spaced apart swirling vanes disposed across the pre-mixer flowpath. A primary fuel injector is positioned for injecting fuel into the pre-mixer flowpath. A combustion chamber surrounded by an annular combustor liner disposed in supply flow communication with the pre-mixer. An annular trapped dual vortex cavity located at an upstream end of the combustor liner is defined between an annular aft wall, an annular forward wall, and a circular radially outer wall formed therebetween. A cavity opening at a radially inner end of the cavity is spaced apart from the radially outer wall. Air injection first holes are disposed through the forward wall and air injection second holes are disposed through the aft wall. Fuel injection holes are disposed through at least one of the forward and aft walls.

  12. SUPERCONDUCTING RF-DIPOLE DEFLECTING AND CRABBING CAVITIES

    SciTech Connect (OSTI)

    Delayen, Jean [ODU, JLAB; De Silva, Paygalage Subashini [ODU, JLAB

    2013-09-01T23:59:59.000Z

    Recent interests in designing compact deflecting and crabbing structures for future accelerators and colliders have initiated the development of novel rf structures. The superconducting rf-dipole cavity is one of the first compact designs with attractive properties such as higher gradients, higher shunt impedance, the absence of lower order modes and widely separated higher order modes. Two rf-dipole designs of 400 MHz and 499 MHz have been designed, fabricated and tested as proof-of-principle designs of compact deflecting and crabbing cavities for the LHC high luminosity upgrade and Jefferson Lab 12 GeV upgrade. The first rf tests have been performed on the rf-dipole geometries at 4.2 K and 2.0 K in a vertical test assembly with excellent results. The cavities have achieved high gradients with high intrinsic quality factors, and multipacting levels were easily processed.

  13. Springback in Deep Drawn High Purity Niobium for Superconductor Cavities

    SciTech Connect (OSTI)

    Ganapati Rao Myneni; Peter Kneisel

    2005-09-01T23:59:59.000Z

    Superconducting radio frequency (SRF) cavities made from deep drawn high-purity niobium have become a popular approach for the design of particle accelerators. A number of current accelerators use this technology and it is a leading candidate for future designs. The development of this technology has required significant advances in many scientific fields including metallurgy, high vacuum physics, surface science, and forming. Recently proposed modifications to the current process for fabrication of these cavities has resulted in increased concern about the distribution of deformation, residual stress patterns, and springback. This presentation will report on the findings of a recently initiated program to study plastic flow and springback in the fabrication of these cavities and the influence of metallurgical variables including grain size and impurity content.

  14. Intermodal stability of a coupled-cavity semiconductor laser

    SciTech Connect (OSTI)

    Lang, R.J.; Yariv, A.

    1986-05-01T23:59:59.000Z

    The authors present an analysis of the steady-state operation of a two-element coupled-cavity laser near a mode hop. The equations of motion for the two cavities and two relevant modes of longitudinally coupled-cavity laser are reduced to a system of nondimensional nonlinear ordinary differential equations which describe a general two-element laser. The equations are then solved and the stability of their solutions is analyzed. Depending upon the fill factors for the two modes, there exists an intrinsically multimode oscillation for operating conditions under which it was previously thought that no steady state existed. Under conditions where the multimode state is unstable, both of the single-mode states are stable with bistable transitions occurring only on the boundaries of the unstable multimode regimes.

  15. Tensile tests of niobium material for SRF cavities

    SciTech Connect (OSTI)

    Wu, G.; Dhanaraj, N.; Cooley, L.; Hicks, D.; Hahn, E.; Burk, D.; Muranyi, W.; Foley, N.; Edwards, H.; Harms, E.; Champion, M.; /Fermilab /Michigan State U.

    2009-06-01T23:59:59.000Z

    Mechanical tests of cavity-grade niobium samples were conducted to provide engineering information for the certification of 3rd-harmonic superconducting radio-frequency cavities and cryomodules. Large changes of mechanical properties occur throughout the cavity fabrication process due to the cold work introduced by forming, the heating introduced by electron beam welding, and the recovery of cold work during the anneal used to degas hydrogen after chemical processing. Data is provided here to show the different properties at various stages of fabrication, including both weld regions and samples from the bulk niobium far away from the weld. Measurements of RRR were used to assure that any contamination during annealing was negligible.

  16. New HOM coupler design for high current SRF cavity

    SciTech Connect (OSTI)

    Xu, W.; Ben-Zvi, I.; Belomestnykh, S.; Hahn, H.; Johnson, E.

    2011-03-28T23:59:59.000Z

    Damping higher order modes (HOMs) significantly to avoid beam instability is a challenge for the high current Energy Recovery Linac-based eRHIC at BNL. To avoid the overheating effect and high tuning sensitivity, current, a new band-stop HOM coupler is being designed at BNL. The new HOM coupler has a bandwidth of tens of MHz to reject the fundamental mode, which will avoid overheating due to fundamental frequency shifting because of cooling down. In addition, the S21 parameter of the band-pass filter is nearly flat from first higher order mode to 5 times the fundamental frequency. The simulation results showed that the new couplers effectively damp HOMs for the eRHIC cavity with enlarged beam tube diameter and 2 120{sup o} HOM couplers at each side of cavity. This paper presents the design of HOM coupler, HOM damping capacity for eRHIC cavity and prototype test results.

  17. Superconducting Radio Frequency Cavities as Axion Dark Matter Detectors

    E-Print Network [OSTI]

    P. Sikivie

    2013-01-20T23:59:59.000Z

    A modification of the cavity technique for axion dark matter detection is described in which the cavity is driven with input power instead of being permeated by a static magnetic field. A small fraction of the input power is pumped by the axion field to a receiving mode of frequency $\\omega_1$ when the resonance condition $\\omega_1 = \\omega_0 \\pm m_a$ is satisfied, where $\\omega_0$ is the frequency of the input mode and $m_a$ the axion mass. The relevant form factor is calculated for any pair of input and output modes in a cylindrical cavity. The overall search strategy is discussed and the technical challenges to be overcome by an actual experiment are listed.

  18. A Multiple Procedure DDT

    E-Print Network [OSTI]

    Knight, Thomas

    1968-01-01T23:59:59.000Z

    This Memo. Describes a version of DDT used as the command level of the A.I. Group PDP-6 Time Sharing System (ITS). Special features include capability to handle multiple jobs, ability to stop open read or write references ...

  19. Multiple jet interactions

    E-Print Network [OSTI]

    Hehr, Roger James

    1983-01-01T23:59:59.000Z

    MULTIPLE JET INTERACTIONS A Thesis by ROGER JAMES HEHR Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1983 Major Subject: Aerospace Engineering... MULTIPLE JET INTERACTIONS A Thesis by ROGER JAMES HEHR Approved as to style and content by: David . Norton (Chairman of Committee) raid L. orrison (Mem er) Leland A. Carlson (Member) Er est . Cross, r. (Head of Department) August 1983 ABSTRACT...

  20. Crystal face temperature determination means

    DOE Patents [OSTI]

    Nason, D.O.; Burger, A.

    1994-11-22T23:59:59.000Z

    An optically transparent furnace having a detection apparatus with a pedestal enclosed in an evacuated ampule for growing a crystal thereon is disclosed. Temperature differential is provided by a source heater, a base heater and a cold finger such that material migrates from a polycrystalline source material to grow the crystal. A quartz halogen lamp projects a collimated beam onto the crystal and a reflected beam is analyzed by a double monochromator and photomultiplier detection spectrometer and the detected peak position in the reflected energy spectrum of the reflected beam is interpreted to determine surface temperature of the crystal. 3 figs.

  1. Florida Nuclear Profile - Crystal River

    U.S. Energy Information Administration (EIA) Indexed Site

    Crystal River1" "Unit","Summer capacity (mw)","Net generation (thousand mwh)","Summer capacity factor (percent)","Type","Commercial operation date","License expiration date"...

  2. Coupled cavity model based on the mode matching technique

    E-Print Network [OSTI]

    Ayzatsky, M I

    2015-01-01T23:59:59.000Z

    We have developed the mode matching technique that is based on the using the eigenmodes of circular cavities and the eigenwaves of circular waveguides as the basic functions for calculation the properties of nonuniform disc-loaded waveguides. We have obtained exact infinite systems of coupled equations which can be reduced by making some assumptions. Under such procedure we can receive more exact parameters of nonuniform equivalent circuits by solving the appropriative algebraic systems. These parameters of equivalent circuits are functions both geometric sizes and frequency. Moreover, under such approach all used values have interpretation. We called this approach as coupled cavity model.

  3. Recent Progress of RF Cavity Study at Mucool Test Area

    E-Print Network [OSTI]

    Yonehara, Katsuya

    2012-01-01T23:59:59.000Z

    In order to develop an RF cavity that is applicable for a muon beam cooling channel, a new facility, called Mucool Test Area (MTA) has been built at Fermilab. MTA is a unique facility whose purpose is to test RF cavities in various conditions. There are 201 and 805 MHz high power sources, a 4-Tesla solenoid magnet, a cryogenic system including a Helium liquifier, an explosion proof apparatus to operate gaseous/liquid Hydrogen, and a beam transport line to send an intense H- beam from the Fermilab Linac accelerator to the MTA hall. Recent activities at MTA will be discussed in this document.

  4. RF Characterization of Niobium Films for Superconducting Cavities

    E-Print Network [OSTI]

    Aull† , S; Doebert, S; Junginger, T; Ehiasarian, AP; Knobloch, J; Terenziani, G

    2013-01-01T23:59:59.000Z

    The surface resistance RS of superconductors shows a complex dependence on the external parameters such as temperature, frequency or radio-frequency (RF) field. The Quadrupole Resonator modes of 400, 800 and 1200 MHz allow measurements at actual operating frequencies of superconducting cavities. Niobium films on copper substrates have several advantages over bulk niobium cavities. HIPIMS (High-power impulse magnetron sputtering) is a promising technique to increase the quality and therefore the performance of niobium films. This contribution will introduce CERNs recently developed HIPIMS coating apparatus. Moreover, first results of niobium coated copper samples will be presented, revealing the dominant loss mechanisms.

  5. Proximity breakdown of hydrides in superconducting niobium cavities

    E-Print Network [OSTI]

    Romanenko, A; Cooley, L D; Grassellino, A

    2012-01-01T23:59:59.000Z

    Many modern and proposed future particle accelerators rely on superconducting radio frequency cavities made of bulk niobium as primary particle accelerating structures. Such cavities suffer from the anomalous field dependence of their quality factors Q0. High field degradation - so-called high field Q-slope - is yet unexplained even though an empirical cure is known. Here we propose a mechanism based on the presence of proximity-coupled niobium hydrides, which can explain this effect. Furthermore, the same mechanism can be present in any surface-sensitive experiments or superconducting devices involving niobium.

  6. Efficiency of feedback process in cavity quantum electrodynamics

    E-Print Network [OSTI]

    H. T. Fung; P. T. Leung

    2007-08-02T23:59:59.000Z

    Utilizing the continuous frequency mode quantization scheme, we study from first principle the efficiency of a feedback scheme that can generate maximally entangled states of two atoms in an optical cavity through their interactions with a single input photon. The spectral function of the photon emitted from the cavity, which will be used as the input of the next round in the feedback process, is obtained analytically. We find that the spectral function of the photon is modified in each round and deviates from the original one. The efficiency of the feedback scheme consequently deteriorates gradually after several rounds of operation.

  7. Fresnel reflection from a cavity with net roundtrip gain

    E-Print Network [OSTI]

    Mansuripur, Tobias S

    2013-01-01T23:59:59.000Z

    A planewave incident on an active etalon with net roundtrip gain may be expected to diverge in field amplitude, yet Maxwell's equations admit only a convergent solution. By examining a Gaussian beam obliquely incident on such a cavity, we find that the "side-tail" of the beam leaks into the cavity and gives rise to a field that interferes with the main portion of the beam, which is ultimately responsible for the convergence of the field. This mechanism offers perspective for many phenomena, and we specifically discuss the implications for amplified total internal reflection.

  8. Entanglement in helium atom confined in an impenetrable cavity

    E-Print Network [OSTI]

    Przemyslaw Koscik; Jayanta K. Saha

    2015-05-24T23:59:59.000Z

    We explore ground-state entanglement properties of helium atom confined at the center of an impenetrable spherical cavity of varying radius by using explicitly correlated Hylleraas-type basis set. Results for the dependencies of the von Neumann and linear entanglement entropic measures on the cavity radius are discussed in details. Some highly accurate numerical results for the von Neumann and linear entropy are reported for the first time. It is found that the transition to the strong confinement regime is manifested by the entropies as an appearance of the inflection points on their variations.

  9. A New Cavity Design For Medium Beta Acceleration

    SciTech Connect (OSTI)

    He, Feisi [Peking University, Beijing (China); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Wang, Haipeng [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Rimmer, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-02-01T23:59:59.000Z

    Heavy duty or cw, superconducting proton and heavy ion accelerators are being proposed and constructed worldwide. The total length of the machine is one of the main drivers in terms of cost. Thus hwr and spoke cavities at medium beta are usually optimized to achieve low surface field and high gradient. A novel accelerating structure at beta=0.5 evolved from spoke cavity is proposed, with lower surface fields but slightly higher heat load. It would be an interesting option for pulsed and cw accelerators with beam energy of more than 200mev/u.

  10. Superconducting cavity transducer for resonant gravitational radiation antennas

    E-Print Network [OSTI]

    R. Ballantini; M. Bassan; A. Chincarini; G. Gemme; R. Parodi; R. Vaccarone

    2006-02-15T23:59:59.000Z

    Parametric transducers, such as superconducting rf cavities, can boost the bandwidth and sensitivity of the next generation resonant antennas, thanks to a readily available technology. We have developed a fully coupled dynamic model of the system "antenna--transducer" and worked out some estimates of signal--to--noise ratio and the stability conditions in various experimental configurations. We also show the design and the prototype of a rf cavity which, together with a suitable read--out electronic, will be used as a test bench for the parametric transducer.

  11. Organized Oscillations of Initially-Turbulent Flow Past a Cavity

    SciTech Connect (OSTI)

    J.C. Lin; D. Rockwell

    2002-09-17T23:59:59.000Z

    Flow past an open cavity is known to give rise to self-sustained oscillations in a wide variety of configurations, including slotted-wall, wind and water tunnels, slotted flumes, bellows-type pipe geometries, high-head gates and gate slots, aircraft components and internal piping systems. These cavity-type oscillations are the origin of coherent and broadband sources of noise and, if the structure is sufficiently flexible, flow-induced vibration as well. Moreover, depending upon the state of the cavity oscillation, substantial alterations of the mean drag may be induced. In the following, the state of knowledge of flow past cavities, based primarily on laminar inflow conditions, is described within a framework based on the flow physics. Then, the major unresolved issues for this class of flows will be delineated. Self-excited cavity oscillations have generic features, which are assessed in detail in the reviews of Rockwell and Naudascher, Rockwell, Howe and Rockwell. These features, which are illustrated in the schematic of Figure 1, are: (i) interaction of a vorticity concentration(s) with the downstream corner, (ii) upstream influence from this corner interaction to the sensitive region of the shear layer formed from the upstream corner of the cavity; (iii) conversion of the upstream influence arriving at this location to a fluctuation in the separating shear layer; and (iv) amplification of this fluctuation in the shear layer as it develops in the streamwise direction. In view of the fact that inflow shear-layer in the present investigation is fully turbulent, item (iv) is of particular interest. It is generally recognized, at least for laminar conditions at separation from the leading-corner of the cavity, that the disturbance growth in the shear layer can be described using concepts of linearized, inviscid stability theory, as shown by Rockwell, Sarohia, and Knisely and Rockwell. As demonstrated by Knisely and Rockwell, on the basis of experiments interpreted with the aid of linearized theory, not only the fundamental component of the shear layer instability may be present, but a number of additional, primarily lower frequency components can exist as well. In fact, the magnitude of these components can be of the same order as the fundamental component. These issues have not been addressed for the case of a fully-turbulent in-flow and its separation from the leading corner of the cavity.

  12. FOURIER TRANSFORM MULTIPLE QUANTUM NMR

    E-Print Network [OSTI]

    Drobny, G.

    2011-01-01T23:59:59.000Z

    of transition observed in Fourier transform multiple quantumDecember 18-19, 1979 FOURIER TRANSFORM MULTIPLE QUANTUM NMRof London, December 1978. FOURIER TRANSFO~~ MULTIPLE QUANTUM

  13. Effects of mode degeneracy in the LIGO Livingston Observatory recycling cavity

    E-Print Network [OSTI]

    Andri M. Gretarsson; Erika D'Ambrosio; Valery Frolov; Brian O'Reilly; Peter K. Fritschel

    2007-08-26T23:59:59.000Z

    We analyze the electromagnetic fields in a Pound-Drever-Hall locked, marginally unstable, Fabry-Perot cavity as a function of small changes in the cavity length during resonance. More specifically, we compare the results of a detailed numerical model with the behavior of the recycling cavity of the Laser Interferometer Gravitational-wave Observatory (LIGO) detector that is located in Livingston, Louisiana. In the interferometer's normal mode of operation, the recycling cavity is stabilized by inducing a thermal lens in the cavity mirrors with an external CO2 laser. During the study described here, this thermal compensation system was not operating, causing the cavity to be marginally optically unstable and cavity modes to become degenerate. In contrast to stable optical cavities, the modal content of the resonating beam in the uncompensated recycling cavity is significantly altered by very small cavity length changes. This modifies the error signals used to control the cavity length in such a way that the zero crossing point is no longer the point of maximum power in the cavity nor is it the point where the input beam mode in the cavity is maximized.

  14. Remote Macroscopic Entanglement on a Photonic Crystal Architecture

    E-Print Network [OSTI]

    H. Flayac; M. Minkov; V. Savona

    2015-05-04T23:59:59.000Z

    The outstanding progress in nanostructure fabrication and cooling technologies allows what was unthinkable a few decades ago: bringing single-mode mechanical vibrations to the quantum regime. The coupling between photon and phonon excitations is a natural source of nonclassical states of light and mechanical vibrations, and its study within the field of cavity optomechanics is developing lightning-fast. Photonic crystal cavities are highly integrable architectures that have demonstrated the strongest optomechanical coupling to date, and should therefore play a central role for such hybrid quantum state engineering. In this context, we propose a realistic heralding protocol for the on-chip preparation of remotely entangled mechanical states, relying on the state-of-the-art optomechanical parameters of a silicon-based nanobeam structure. Pulsed sideband excitation of a Stokes process, combined with single photon detection, allows writing a delocalised mechanical Bell state in the system, signatures of which can then be read out in the optical field. A measure of entanglement in this protocol is provided by the visibility of a characteristic quantum interference pattern in the emitted light.

  15. Multiple stage multiple filter hydrate store

    DOE Patents [OSTI]

    Bjorkman, H.K. Jr.

    1983-05-31T23:59:59.000Z

    An improved hydrate store for a metal halogen battery system is disclosed which employs a multiple stage, multiple filter means for separating the halogen hydrate from the liquid used in forming the hydrate. The filter means is constructed in the form of three separate sections which combine to substantially cover the interior surface of the store container. Exit conduit means is provided in association with the filter means for transmitting liquid passing through the filter means to a hydrate former subsystem. The hydrate former subsystem combines the halogen gas generated during the charging of the battery system with the liquid to form the hydrate in association with the store. Relief valve means is interposed in the exit conduit means for controlling the operation of the separate sections of the filter means, such that the liquid flow through the exit conduit means from each of the separate sections is controlled in a predetermined sequence. The three separate sections of the filter means operate in three discrete stages to provide a substantially uniform liquid flow to the hydrate former subsystem during the charging of the battery system. The separation of the liquid from the hydrate causes an increase in the density of the hydrate by concentrating the hydrate along the filter means. 7 figs.

  16. Multiple stage multiple filter hydrate store

    DOE Patents [OSTI]

    Bjorkman, Jr., Harry K. (Birmingham, MI)

    1983-05-31T23:59:59.000Z

    An improved hydrate store for a metal halogen battery system is disclosed which employs a multiple stage, multiple filter means or separating the halogen hydrate from the liquid used in forming the hydrate. The filter means is constructed in the form of three separate sections which combine to substantially cover the interior surface of the store container. Exit conduit means is provided in association with the filter means for transmitting liquid passing through the filter means to a hydrate former subsystem. The hydrate former subsystem combines the halogen gas generated during the charging of the battery system with the liquid to form the hydrate in association with the store. Relief valve means is interposed in the exit conduit means for controlling the operation of the separate sections of the filter means, such that the liquid flow through the exit conduit means from each of the separate sections is controlled in a predetermined sequence. The three separate sections of the filter means operate in three discrete stages to provide a substantially uniform liquid flow to the hydrate former subsystem during the charging of the battery system. The separation of the liquid from the hydrate causes an increase in the density of the hydrate by concentrating the hydrate along the filter means.

  17. Preparation of three-dimensional entanglement for distant atoms in coupled cavities via atomic spontaneous emission and cavity decay

    E-Print Network [OSTI]

    Shi-Lei Su; Xiao-Qiang Shao; Hong-Fu Wang; Shou Zhang

    2014-08-21T23:59:59.000Z

    We propose a dissipative scheme to prepare a three-dimensional entangled state for two atoms trapped in separate coupled cavities. Our work shows that both atomic spontaneous emission and cavity decay, which are two typical obstacles in unitary-dynamics-based schemes, could be utilized as resources for high-dimensional entangled state preparation without specifying initial state and controlling time precisely. Final numerical simulation with one group of experimental parameters indicates that the performance of our scheme is better than the unitary-dynamics-based scheme.

  18. Photothermal nano-cavities for ultra-sensitive chem-bio detection

    E-Print Network [OSTI]

    Hu, Juejun

    Nano-cavity photothermal spectroscopy is a novel technique for ultra-sensitive chem-bio detection. We illustrate that through simultaneous localization of optical and thermal interactions in a planar nano-cavity, detection ...

  19. Novel laser machining of optical fibers for long cavities with low birefringence

    E-Print Network [OSTI]

    Takahashi, Hiroki; Orucevic, Fedja; Noguchi, Atsushi; Kassa, Ezra; Keller, Matthias

    2015-01-01T23:59:59.000Z

    We present a novel method of machining optical fiber surfaces with a CO${}_2$ laser for use in Fiber-based Fabry-Perot Cavities (FFPCs). Previously FFPCs were prone to large birefringence and limited to relatively short cavity lengths ($\\le$ 200 $\\mu$m). These characteristics hinder their use in some applications such as cavity quantum electrodynamics with trapped ions. We optimized the laser machining process to produce large, uniform surface structures. This enables the cavities to achieve high finesse even for long cavity lengths. By rotating the fibers around their axis during the laser machining process the asymmetry resulting from the laser's transverse mode profile is eliminated. Consequently we are able to fabricate fiber mirrors with a high degree of rotational symmetry, leading to remarkably low birefringence. Through measurements of the cavity finesse over a range of cavity lengths and the polarization dependence of the cavity linewidth, we confirmed the quality of the produced fiber mirrors for us...

  20. INDUCED SEISMICITY MONITORING OF AN UNDERGROUND SALT CAVITY UNDER A TRANSIENT PRESSURE EXPERIMENT

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    INDUCED SEISMICITY MONITORING OF AN UNDERGROUND SALT CAVITY UNDER A TRANSIENT PRESSURE EXPERIMENT to 125 m in cemented boreholes drilled in thé vicinity of thé study area. The underground cavity under

  1. Coherence Optimization of Vertical Cavity Semiconductor Optical Michael Snchez*a

    E-Print Network [OSTI]

    Esener, Sadik C.

    Coherence Optimization of Vertical Cavity Semiconductor Optical Amplifiers Michael Sánchez Dept., University of California - San Diego ABSTRACT Vertical cavity semiconductor optical amplifiers (VCSOAs) are attractive devices for use in coherent optical amplification, especially where 2-D amplifier

  2. Design of optimal dispersive mirrors for femtosecond enhancement cavities and compressors by minimizing phase distortion power

    E-Print Network [OSTI]

    Birge, Jonathan R.

    The optimization of phase distortion spectral power density is proposed as an alternative to GDD minimization of ultrafast cavity mirrors. This criterion is shown to minimize the detuning of cavity resonances from a uniform comb.

  3. NMR STUDIES OF LIQUID CRYSTALS AND MOLECULES DISSOLVED IN LIQUID CRYSTAL SOLVENTS

    SciTech Connect (OSTI)

    Drobny, G.P.

    1982-11-01T23:59:59.000Z

    This thesis describes several studies in which nuclear magnetic resonance (nmr) spectroscopy has been used to probe the structure, orientation and dynamics of liquid crystal mesogens and molecules dissolved in liquid crystalline phases. In addition, a modern high field nmr spectrometer is described which has been used to perform such nmr studies. Chapter 1 introduces the quantum mechanical formalisms used throughout this thesis and briefly reviews the fundamentals of nuclear spin physics and pulsed nmr spectroscopy. First the density operator is described and a specific form for the canonical ensemble is derived. Then Clebsch-Gordon coefficients, Wigner rotation matrices, and irreducible tensor operators are reviewed. An expression for the equilibrium (Curie) magnetization is obtained and the linear response of a spin system to a strong pulsed r.f. irradiation is described. Finally, the spin interaction Hamiltonians relevant to this work are reviewed together with their truncated forms. Chapter 2 is a deuterium magnetic resonance study of two 'nom' liquid crystals which possess several low temperature mesomorphic phases. Specifically, deuterium quadrupolar echo spectroscopy is used to determine the orientation of the liquid crystal molecules in smectic phases, the changes in molecular orientation and motion that occur at smectic-smectic phase transitions, and the order of the phase transitions. For both compounds, the phase sequence is determined to be isotropic, nematic, smectic A, smectic C, smectic B{sub A}, smectic B{sub C}, and crystalline. The structure of the smectic A phase is found to be consistent with the well-known model of a two dimensional liquid in which molecules are rapidly rotating about their long axes and oriented at right angles to the plane of the layers. Molecules in the smectic C phase are found to have their long axes tilted with respect to the layer normal, and the tilt angle is temperature dependent, increasing from zero at the smectic A - smectic C transition and reaching a maximum at 9{sup o} at the smectic C - smectic B{sub A} transition. This finding contradicts the results of X-ray diffraction studies which indicate that the tilt angle is 18{sup o} and temperature independent. The smectic B{sub A} - smectic B{sub C} phase transition is observed for the first time, and is found to be first order, a result that contradicts the prediction of a mean theory by McMillian. Chapter 3 is a multiple quantum nmr study of n-hexane oriented in a nematic liquid crystal solvent. The basic three pulse multiple quantum experiment is discussed which enables the observation of transitions for which |{Delta}m|>1, and then the technique of the separation of multiple quantum orders by phase incrementation in the multiple quantum evolution period is reviewed (TPPI). An explicit example of multiple quantum nmr is given by the calculation of the multiple quantum spectrum of an oriented methyl group.

  4. Overview of high gradient SRF R&D for ILC cavities at Jefferson Lab

    SciTech Connect (OSTI)

    Geng, Rongli [JLAB

    2009-11-01T23:59:59.000Z

    We report the progress on high gradient R&D of ILC cavities at Jefferson Lab (JLab) since the Beijing workshop. Routine 9-cell cavity electropolishing (EP) processing and RF testing has been enhanced with added surface mapping and T-mapping instrumentations. 12 new 9-cell cavities (10 of them are baseline fine-grain TESLA-shape cavities: 5 built by ACCEL/Research Instruments, 4 by AES and 1 by JLab; 2 of them are alternative cavities: 1 fine-grain ICHIRO-shape cavity built by KEK/Japan industry and 1 large-grain TESLA-shape cavity built by JLab) are EP processed and tested. 76 EP cycles are accumulated, corresponding to more than 200 hours of active EP time. Field emission (FE) and quench behaviors of electropolished 9-cell cavities are studied. EP process continues to be optimized, resulting in advanced procedures and hence improved cavity performance. Several 9-cell cavities reached 35 MV/m after the first light EP processing. FE-free performance has been demonstrated in 9-cell cavities in 35-40 MV/m range. 1-cell cavity studies explore new techniques for defect removal as well as advanced integrated cavity processing. Surface studies of niobium samples electropolished together with real cavities provide new insight into the nature of field emitters. Close cooperation with the US cavity fabrication industry has been undertaking with the successful achievement of 41 MV/m for the first time in a 9-cell ILC cavity built by AES. As the size of the data set grows, it is now possible to construct gradient yield curves, from which one can see that significant progress has been made in raising the high gradient yield.

  5. Microphonics detuning compensation in 3.9 GHZ superconducting RF cavities

    SciTech Connect (OSTI)

    Ruben Carcagno et al.

    2003-10-20T23:59:59.000Z

    Mechanical vibrations can detune superconducting radio frequency (SCRF) cavities unless a tuning mechanism counteracting the vibrations is present. Due to their narrow operating bandwidth and demanding mechanical structure, the 13-cell 3.9GHz SCRF cavities for the Charged Kaons at Main Injector (CKM) experiment at Fermilab are especially susceptible to this microphonic phenomena. We present early results correlating RF frequency detuning with cavity vibration measurements for CKM cavities; initial detuning compensation results with piezoelectric actuators are also presented.

  6. Three-dimensional self-consistent simulations of multipacting in superconducting radio frequency cavities

    SciTech Connect (OSTI)

    Chet Nieter

    2010-12-01T23:59:59.000Z

    Superconducting radio frequency (SRF) cavities are a popular choice among researchers designing new accelerators because of the reduced power losses due to surface resistance. However, SRF cavities still have unresolved problems, including the loss of power to stray electrons. Sources of these electrons are field emission from the walls and ionization of background gas, but the predominant source is secondary emission yield (SEY) from electron impact. When the electron motion is in resonance with the cavity fields the electrons strike the cavity surface repeatedly creating a resonant build up of electrons referred to as multipacting. Cavity shaping has successfully reduced multipacting for cavities used in very high energy accelerators. However, multipacting is still a concern for the cavity power couplers, where shaping is not possible, and for cavities used to accelerate particles at moderate velocities. This Phase II project built upon existing models in the VORPAL simulation framework to allow for simulations of multipacting behavior in SRF cavities and their associated structures. The technical work involved allowed existing models of secondary electron generation to work with the complex boundary conditions needed to model the cavity structures. The types of data produced by VORPAL were also expanded to include data common used by cavity designers to evaluate cavity performance. Post-processing tools were also modified to provide information directly related to the conditions that produce multipacting. These new methods were demonstrated by running simulations of a cavity design being developed by researchers at Jefferson National Laboratory to attempt to identify the multipacting that would be an issue for the cavity design being considered. These simulations demonstrate that VORPAL now has the capabilities to assist researchers working with SRF cavities to understand and identify possible multipacting issues with their cavity designs.

  7. ESTIMATION OF OUTLET MASS FLOW FOR A MONO-TUBE CAVITY RECEIVER FOR DIRECT STEAM GENERATION

    E-Print Network [OSTI]

    contains recent developments on a dynamic heat transfer model for a mono-tube steam cavity boiler, which

  8. Coaxial Coupling Scheme for TESLA/ILC-type Cavities

    SciTech Connect (OSTI)

    J.K. Sekutowicz, P. Kneisel

    2010-05-01T23:59:59.000Z

    This paper reports about our efforts to develop a flangeable coaxial coupler for both HOM and fundamental coupling for 9-cell TESLA/ILC-type cavities. The cavities were designed in early 90‘s for pulsed operation with a low duty factor, less than 1 %. The proposed design of the coupler has been done in a way, that the magnetic flux B at the flange connection is minimized and only a field of <5 mT would be present at the accelerating field Eacc of ~ 36 MV/m (B =150 mT in the cavity). Even though we achieved reasonably high Q-values at low field, the cavity/coupler combination was limited in the cw mode to only ~ 7 MV/m, where a thermally initiated degradation occurred. We have improved the cooling conditions by initially drilling radial channels every 30 degrees, then every 15 degrees into the shorting plate. The modified prototype performed well up to 9 MV/m in cw mode. This paper reports about our experiences with the further modified coaxial coupler and about test results in cw and low duty cycle pulsed mode, similar to the TESLA/ILC operation conditions.

  9. Study of small-scale cavity growth mechanisms for UCG

    SciTech Connect (OSTI)

    Yeary, D.L.; Riggs, J.B.

    1987-01-01T23:59:59.000Z

    An experimental study has been conducted to evaluate previously proposed small-scale cavity growth mechanisms in Underground Coal Gasification (UCG). Quarried blocks of lignite from Rockdale, Texas, and subbituminous coal from Hanna, Wyoming, were exposed to high-temperature gases in a refractory chamber in order to access their behavior under UCG conditions. Effects of gas temperature, gas composition, and gas flow rate on the surface recession rates were studied for coal samples using the bedding plan orientation of the side wall of the cavity. The effect of gas temperature on the surface recession rate with cavity roof bedding plane orientation was also studied. For the side wall tests, structural failure of the char or ash was not observed. In addition, the surface recession rate was round to increase significantly with gas temperature and gas flow rate. These results indicate that the surface recession process was heat transfer controlled gasification. For the tests conducted using the bedding plane orientation of the cavity roof, it was found that significant structural failure of the lignite resulted while no structural failure of the subbituminous coal was observed. As a result, the surface recession rate for lignite was three times that for subbituminous coal at 1300/sup 0/K. It is theorized that the structural failure of the lignite is caused by clay stringers present in the lignite.

  10. Mathematical modeling of cavity growth during underground coal gasification

    SciTech Connect (OSTI)

    Jung, K.S.

    1987-01-01T23:59:59.000Z

    Four two-dimensional cavity growth models are developed based on the permeation process concept in order to understand what has happened in previous field tests, and to learn better methods for future field tests and commercial scale operations. The first model considers only a wet coal region beyond the cavity. In the second model, dried coal is added to the first model, so that there are two different coal regions: the wet coal and dried coal regions. The third model includes the effect of links formed by reverse combustion, but the dried coal region is not included. Also in this model, plugging phenomenon, due to particulates carried by the injectant to the cavity wall, is introduced. The final model incorporates nonisotropic permeability, a dried coal region, links and plugging phenomenon. Considerations of a wet coal region only or of wet coal and coal drying do not explain the high recovery of coal observed in field tests. However, plugging phenomenon prevents channeling of gases down high-permeability links, and thereby the recovery of coal is increased. Also link configurations have a marked effect on the coal source recovery. Computation results from the fourth model show that coal recovery is improved greatly if a large dried coal zone exists around the cavity.

  11. Propagation of elastic waves through a lattice of cylindrical cavities

    E-Print Network [OSTI]

    Propagation of elastic waves through a lattice of cylindrical cavities By S. Guo & P. Mc asymptotic homogenization to obtain low-frequency approximations to elastic wave propagation through periodic follows that of McIver (2007) who investigates acoustic-wave propagation through a lattice of rigid

  12. Laser Frequency Stabilization with Optical Cavities Anya M. Davis

    E-Print Network [OSTI]

    Blinov, Boris

    Laser Frequency Stabilization with Optical Cavities Anya M. Davis Walla Walla University University Effective laser cooling requires the laser's frequency to be precise, with a frequency drift of no more than lasers for correcting frequency drift. In the University of Washington Quantum Computing with Trapped

  13. Low-pressure debris dispersal from scaled reactor cavities

    SciTech Connect (OSTI)

    Nichols, R.T.; Tarbell, W.W.

    1988-01-01T23:59:59.000Z

    During a severe nuclear reactor accident, degradation of the core may result in debris accumulating in the lower head. Upon failure of the head, the melt may be ejected under pressure through the cavity and into the containment building. Under low system pressure conditions, understanding the mechanisms of debris dispersal is instrumental in assessing the response of the containment to pressurized melt ejection. Current analytical approaches rely on empirical correlations for debris entrainment criteria and very simple gas flow patterns in the cavity. The work reported here is directed toward performing scaled experiments that will develop a data base for refined scaling analyses. Subsequently, extrapolations from the analyses to reactor scale may be performed to provide insight for accident predictions. Mechanistic models for gas flow through the cavity and entrainment of the debris are also being developed from the results presented here. The objective of the test matrix is to vary key parameters to assess the effect on the physical processes of dispersal of the melt from the reactor cavity at low system pressures.

  14. Three-qubit phase gate based on cavity quantum electrodynamics

    E-Print Network [OSTI]

    Chang, Jun-Tao; Zubairy, M. Suhail

    2008-01-01T23:59:59.000Z

    We describe a three-qubit quantum phase gate which is implemented by passing a four-level atom in a cascade configuration initially in its ground state through a three-mode optical cavity. The three qubits are represented by the photons in the three...

  15. GEOPHYSICAL DETECTION OF UNDERGROUND CAVITIES DRIAD-LEBEAU1

    E-Print Network [OSTI]

    Boyer, Edmond

    GEOPHYSICAL DETECTION OF UNDERGROUND CAVITIES DRIAD-LEBEAU1 Lynda, PIWAKOWSKI2 Bogdan, STYLES3 & Environmental Geophysics Research Group, School of Physical and Geographical Sciences, Keele University, UK; p.lataste@ghymac.u- bordeaux1.fr ABSTRACT: In this paper, we present a synthesis of the geophysical investigations conducted

  16. Power efficiency for very high temperature solar thermal cavity receivers

    DOE Patents [OSTI]

    McDougal, Allan R. (LaCanada-Flintridge, CA); Hale, Robert R. (Upland, CA)

    1984-01-01T23:59:59.000Z

    This invention is an improved solar energy cavity receiver for exposing materials and components to high temperatures. The receiver includes a housing having an internal reflective surface defining a cavity and having an inlet for admitting solar radiation thereto. A photothermal absorber is positioned in the cavity to receive radiation from the inlet. A reflective baffle is positioned between the absorber and the inlet to severely restrict the re-radiation of energy through the inlet. The front surface of the baffle defines a narrow annulus with the internal reflective surface of the housing. The front surface of the baffle is contoured to reflect incoming radiation onto the internal surface of the housing, from which it is reflected through the annulus and onto the front surface of the absorber. The back surface of the baffle intercepts infrared radiation from the front of the absorber. With this arrangement, a high percentage of the solar power input is retained in the cavity; thus, high internal temperatures are attained.

  17. Wind observations of foreshock cavities: A case study

    E-Print Network [OSTI]

    California at Berkeley, University of

    in the ambient solar wind, ion temperatures do not rise greatly, thermal pressures are only slightly greater than (IMF) tangential discontinuities intersecting the bow shock. We attribute the cavities are far more common than hot flow anomalies. INDEX TERMS: 2154 Interplanetary Physics: Planetary bow

  18. Determination of normalized magnetic eigenfields in microwave cavities

    E-Print Network [OSTI]

    Helsing, Johan

    2014-01-01T23:59:59.000Z

    The magnetic field integral equation for axially symmetric cavities with perfectly conducting surfaces is discretized according to a high-order convergent Fourier--Nystr\\"om scheme. The resulting solver is used to determine eigenwavenumbers and normalized magnetic eigenfields to very high accuracy in the entire computational domain.

  19. State of the art of multicell SC Cavities and Perspectives

    SciTech Connect (OSTI)

    Peter Kneisel

    2002-06-01T23:59:59.000Z

    Superconducting cavity technology has made major progresses in the last decade with the introduction of high purity niobium on an industrial scale and, at the same time, by an improved understanding of the limiting processes in cavity performance, such as multipacting, field emission loading and thermal breakdown. Multicell niobium cavities for Beta=1 particle acceleration, e.g. for the TESLA project, are routinely exceeding gradients of E{sub acc}=20 MV/m after the application of surface preparation techniques such as buffered chemical polishing or electropolishing, high pressure ultrapure water rinsing, UHV heat treatment and clean-room assembly. The successes of the technology for Beta=1 accelerators has triggered a whole set of possible future applications for Beta < 1 particle acceleration such as spallation neutron sources (SNS, ESS), transmutation of nuclear waste (TRASCO, ASH) or rare isotopes (RIA). The most advanced of these projects is SNS now under construction at Oak Ridge National Laboratory. This paper will review the technical solutions adopted to advance SRF technology and their impact on cavity performance, based on the SNS prototyping efforts. Work supported by U.S. DOE contract DE-AC05-84ER40150

  20. Photon-like flying qubit in the coupled cavity array

    E-Print Network [OSTI]

    Ying Li; M. X. Huo; Z. Song; C. P. Sun

    2008-02-01T23:59:59.000Z

    We propose a feasible scheme to realize a spin network via a coupled cavity array with the appropriate arrangement of external multi-driving lasers. It is demonstrated that the linear photon-like dispersion is achievable and this property opens up the possibility of realizing the pre-engineered spin network which is beneficial to quantum information processing.

  1. Cavity growth patterns on the partial seam crip test

    SciTech Connect (OSTI)

    Hommert, P.J.

    1984-01-01T23:59:59.000Z

    The Partial Seam CRIP (PSC) test conducted by Lawrence Livermore National Laboratories was characterized by two distinctly different types of cavity growth. Portions of the thermal data from the test have been analyzed using conduction models to infer the dynamics of the cavity growth. Growth during the first phase of the test was characterized by rapid movement of the process to the top of the seam. The growth patterns during this time were remarkably similar to those observed on the Hoe Creek III test. Cavity growth observed later in the test, after the CRIP maneuver and when the horizontal production was in use, showed more lateral extent within the seam similar to patterns that were observed on the Hanna UCG tests. This type of growth resulted in improved process efficiency, at least for the early post-CRIP period. Calculations using a thermal-mechanical growth model are consistent with both types of growth observed. In particular, when stringers that were present in the seam are included in the model calculations, the more favorable growth patterns observed in the test are predicted. It is concluded that non-coal layers within the seam have the potential to significantly affect cavity growth and thus their presence should be accounted for when designing a process. 11 references, 10 figures, 1 table.

  2. Steam exit flow design for aft cavities of an airfoil

    DOE Patents [OSTI]

    Storey, James Michael (Clifton Park, NY); Tesh, Stephen William (Simpsonville, SC)

    2002-01-01T23:59:59.000Z

    Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. A skirt or flange structure is provided for shielding the steam cooling impingement holes adjacent the inner wall aerofoil fillet region of the nozzle from the steam flow exiting the aft nozzle cavities. Moreover, the gap between the flash rib boss and the cavity insert is controlled to minimize the flow of post impingement cooling media therebetween. This substantially confines outflow to that exiting via the return channels, thus furthermore minimizing flow in the vicinity of the aerofoil fillet region that may adversely affect impingement cooling thereof.

  3. crystal nickel a hree dimension

    E-Print Network [OSTI]

    Braun, Paul

    Zhenting 1 Department 2 Departmen ABSTRACT This pape crystal nickel a hree dimension photonic cryst polystyrene op silicon chips, volume fraction can be controlle nickel structure hen sacrificed volume fraction reports microm crystal structur or alumina she nickel microca microstructure further electrop volume

  4. A Fano cavity test for Monte Carlo proton transport algorithms

    SciTech Connect (OSTI)

    Sterpin, Edmond, E-mail: esterpin@yahoo.fr [Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Experimentale et Clinique, Avenue Hippocrate 54, 1200 Brussels (Belgium)] [Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Experimentale et Clinique, Avenue Hippocrate 54, 1200 Brussels (Belgium); Sorriaux, Jefferson; Souris, Kevin [Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Experimentale et Clinique, Avenue Hippocrate 54, 1200 Brussels, Belgium and Université catholique de Louvain, ICTEAM institute, Chemin du cyclotron 6, 1348 Louvain-la-Neuve (Belgium)] [Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Experimentale et Clinique, Avenue Hippocrate 54, 1200 Brussels, Belgium and Université catholique de Louvain, ICTEAM institute, Chemin du cyclotron 6, 1348 Louvain-la-Neuve (Belgium); Vynckier, Stefaan [Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Experimentale et Clinique, Avenue Hippocrate 54, 1200 Brussels, Belgium and Département de Radiothérapie, Cliniques Universitaires Saint-Luc, Avenue Hippocrate 54, 1200 Brussels (Belgium)] [Université catholique de Louvain, Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Experimentale et Clinique, Avenue Hippocrate 54, 1200 Brussels, Belgium and Département de Radiothérapie, Cliniques Universitaires Saint-Luc, Avenue Hippocrate 54, 1200 Brussels (Belgium); Bouchard, Hugo [Département de radio-oncologie, Centre hospitalier de l’Université de Montréal (CHUM), 1560 Sherbrooke est, Montréal, Québec H2L 4M1 (Canada)] [Département de radio-oncologie, Centre hospitalier de l’Université de Montréal (CHUM), 1560 Sherbrooke est, Montréal, Québec H2L 4M1 (Canada)

    2014-01-15T23:59:59.000Z

    Purpose: In the scope of reference dosimetry of radiotherapy beams, Monte Carlo (MC) simulations are widely used to compute ionization chamber dose response accurately. Uncertainties related to the transport algorithm can be verified performing self-consistency tests, i.e., the so-called “Fano cavity test.” The Fano cavity test is based on the Fano theorem, which states that under charged particle equilibrium conditions, the charged particle fluence is independent of the mass density of the media as long as the cross-sections are uniform. Such tests have not been performed yet for MC codes simulating proton transport. The objectives of this study are to design a new Fano cavity test for proton MC and to implement the methodology in two MC codes: Geant4 and PENELOPE extended to protons (PENH). Methods: The new Fano test is designed to evaluate the accuracy of proton transport. Virtual particles with an energy ofE{sub 0} and a mass macroscopic cross section of (?)/(?) are transported, having the ability to generate protons with kinetic energy E{sub 0} and to be restored after each interaction, thus providing proton equilibrium. To perform the test, the authors use a simplified simulation model and rigorously demonstrate that the computed cavity dose per incident fluence must equal (?E{sub 0})/(?) , as expected in classic Fano tests. The implementation of the test is performed in Geant4 and PENH. The geometry used for testing is a 10 × 10 cm{sup 2} parallel virtual field and a cavity (2 × 2 × 0.2 cm{sup 3} size) in a water phantom with dimensions large enough to ensure proton equilibrium. Results: For conservative user-defined simulation parameters (leading to small step sizes), both Geant4 and PENH pass the Fano cavity test within 0.1%. However, differences of 0.6% and 0.7% were observed for PENH and Geant4, respectively, using larger step sizes. For PENH, the difference is attributed to the random-hinge method that introduces an artificial energy straggling if step size is not small enough. Conclusions: Using conservative user-defined simulation parameters, both PENH and Geant4 pass the Fano cavity test for proton transport. Our methodology is applicable to any kind of charged particle, provided that the considered MC code is able to track the charged particle considered.

  5. Coupling an electron spin in a semiconductor quantum dot to an optical nano-cavity

    E-Print Network [OSTI]

    Arka Majumdar; Per Kaer; Michal Bajcsy; Erik D. Kim; Konstantinos G. Lagoudakis; Armand Rundquist; Jelena Vuckovic

    2013-04-07T23:59:59.000Z

    We propose a scheme to efficiently couple a single quantum dot electron spin to an optical nano-cavity, which enables us to simultaneously benefit from a cavity as an efficient photonic interface, as well as to perform high fidelity (nearly 100%) spin initialization and manipulation achievable in bulk semiconductors. Moreover, the presence of the cavity speeds up the spin initialization process beyond GHz.

  6. PROTOTYPE 350 MHZ NIOBIUM SPOKE-LOADED CAVITIES K. W. Shepard, M. Kedzie, ANL, Argonne, IL

    E-Print Network [OSTI]

    #12;PROTOTYPE 350 MHZ NIOBIUM SPOKE-LOADED CAVITIES K. W. Shepard, M. Kedzie, ANL, Argonne, IL J. R.4, and the other for v/c = 0.29. Construction of the prototype niobium cavities is nearly complete. Details in the form of an 855 MHz, single-cell niobium cavity [7,8]. For the linac contemplated here, a substantially

  7. DEVELOPMENT OF NIOBIUM SPOKE CAVITIES FOR A SUPERCONDUCTING LIGHT-ION LINAC

    E-Print Network [OSTI]

    DEVELOPMENT OF NIOBIUM SPOKE CAVITIES FOR A SUPERCONDUCTING LIGHT-ION LINAC K. W. Shepard and M the development of 350 MHz niobium superconducting cavities for the velocity range 0.2 geometries are presented. The design and construction status of prototype niobium cavities is discussed. 1

  8. RF PULSED TESTS ON 3GHZ NIOBIUM CAVITIES J. Le Duff, C. Thomas

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    RF PULSED TESTS ON 3GHZ NIOBIUM CAVITIES J. Le Duff, C. Thomas , G. Bienvenu, H.Sun LAL, Orsay limits have been pushed back thanks to improvements of niobium purity, cavity preparation, as- sembling mT or 50MV/m accelerating field Eacc for TESLA shape bulk niobium (Nb) cavities at T = 0 K

  9. Doppler-induced dynamics of fields in FabryPerot cavities with suspended mirrors

    E-Print Network [OSTI]

    Florida, University of

    The Doppler effect in Fabry­Perot cavities with suspended mirrors is analyzed. The Doppler shift, which by the Doppler effect that appears in a Fabry­Perot cavity with moving mirrors. The Doppler shift, whichDoppler-induced dynamics of fields in Fabry­Perot cavities with suspended mirrors Malik Rakhmanov

  10. Cavity availability and use in hardwood forests with emphasis on wood ducks

    E-Print Network [OSTI]

    Wolter, Derrick Wayne

    2002-01-01T23:59:59.000Z

    cavity use by vertebrates. Tree species, number of cavities by entrance size, stems per ha, basal area, and total cavities were recorded in 23, 15, and 15 plots in the cypress-tupelo (Taxodium distichum-Nyssa aquatica), mixed hardwood, and pine-oak...

  11. Some aspects of simulation and realization of an optical reference cavity

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    of the cavity can be achieved by choosing a tapered form for the cavity spacer. The gain with respect eigenfrequencies is estimated to be an order of magnitude larger than the dimensions of the cavity. In the present work, we have investigated the influence of different aspects of the spacer's geometry

  12. Four cavity efficiency enhanced magnetically insulated line oscillator

    DOE Patents [OSTI]

    Lemke, R.W.; Clark, M.C.; Calico, S.E.

    1998-04-21T23:59:59.000Z

    A four cavity, efficient magnetically insulated line oscillator (C4-E MILO) having seven vanes and six cavities formed within a tube-like structure surrounding a cathode is disclosed. The C4-E MILO has a primary slow wave structure which is comprised of four vanes and the four cavities located near a microwave exit end of the tube-like structure. The primary slow wave structure is the four cavity portion of the magnetically insulated line oscillator (MILO). An RF choke is provided which is comprised of three of the vanes and two of the cavities. The RF choke is located near a pulsed power source portion of the tube-like structure surrounding the cathode. The RF choke increases feedback in the primary slow wave structure, prevents microwaves generated in the primary slow wave structure from propagating towards the pulsed power source and modifies downstream electron current so as to enhance microwave power generation. A beam dump/extractor is located at the exit end of the oscillator tube for extracting microwave power from the oscillator, and in conjunction with an RF extractor vane, which comprises the fourth vane of the primary slow wave structure (nearest the exit) having a larger gap radius than the other vanes of the primary SWS, comprises an RF extractor. Uninsulated electron flow is returned downstream towards the exit along an anode/beam dump region located between the beam dump/extractor and the exit where the RF is radiated at said RF extractor vane located near the exit and the uninsulated electron flow is disposed at the beam dump/extractor. 34 figs.

  13. Four cavity efficiency enhanced magnetically insulated line oscillator

    DOE Patents [OSTI]

    Lemke, Raymond W. (Albuquerque, NM); Clark, Miles C. (Albuquerque, NM); Calico, Steve E. (Albuquerque, NM)

    1998-04-21T23:59:59.000Z

    A four cavity, efficient magnetically insulated line oscillator (C4-E MILO) having seven vanes and six cavities formed within a tube-like structure surrounding a cathode. The C4-E MILO has a primary slow wave structure which is comprised of four vanes and the four cavities located near a microwave exit end of the tube-like structure. The primary slow wave structure is the four cavity (C4) portion of the magnetically insulated line oscillator (MILO). An RF choke is provided which is comprised of three of the vanes and two of the cavities. The RF choke is located near a pulsed power source portion of the tube-like structure surrounding the cathode. The RF choke increases feedback in the primary slow wave structure, prevents microwaves generated in the primary slow wave structure from propagating towards the pulsed power source and modifies downstream electron current so as to enhance microwave power generation. A beam dump/extractor is located at the exit end of the oscillator tube for extracting microwave power from the oscillator, and in conjunction with an RF extractor vane, which comprises the fourth vane of the primary slow wave structure (nearest the exit) having a larger gap radius than the other vanes of the primary SWS, comprises an RF extractor. Uninsulated electron flow is returned downstream towards the exit along an anode/beam dump region located between the beam dump/extractor and the exit where the RF is radiated at said RF extractor vane located near the exit and the uninsulated electron flow is disposed at the beam dump/extractor.

  14. Tensile strained $In_{x}Ga_{1-x}P$ membranes for cavity optomechanics

    E-Print Network [OSTI]

    G. D. Cole; P. -L. Yu; C. Gärtner; K. Siquans; R. Moghadas Nia; J. Schmöle; J. Hoelscher-Obermaier; T. P. Purdy; W. Wieczorek; C. A. Regal; M. Aspelmeyer

    2014-03-31T23:59:59.000Z

    We investigate the optomechanical properties of tensile-strained ternary InGaP nanomembranes grown on GaAs. This material system combines the benefits of highly strained membranes based on stoichiometric silicon nitride, with the unique properties of thin-film semiconductor single crystals, as previously demonstrated with suspended GaAs. Here we employ lattice mismatch in epitaxial growth to impart an intrinsic tensile strain to a monocrystalline thin film (approximately 30 nm thick). These structures exhibit mechanical quality factors of 2*10^6 or beyond at room temperature and 17 K for eigenfrequencies up to 1 MHz, yielding Q*f products of 2*10^12 Hz for a tensile stress of ~170 MPa. Incorporating such membranes in a high finesse Fabry-Perot cavity, we extract an upper limit to the total optical loss (including both absorption and scatter) of 40 ppm at 1064 nm and room temperature. Further reductions of the In content of this alloy will enable tensile stress levels of 1 GPa, with the potential for a significant increase in the Q*f product, assuming no deterioration in the mechanical loss at this composition and strain level. This materials system is a promising candidate for the integration of strained semiconductor membrane structures with low-loss semiconductor mirrors and for realizing stacks of membranes for enhanced optomechanical coupling.

  15. Lamella settler crystallizer

    DOE Patents [OSTI]

    Maimoni, A.

    1990-12-18T23:59:59.000Z

    A crystallizer is described which incorporates a lamella settler and which is particularly applicable for use in batteries and power cells for electric vehicles or stationary applications. The lamella settler can be utilized for coarse particle separation or for agglomeration, and is particularly applicable to aluminum-air batteries or power cells for solving the hydrargillite (aluminum-hydroxide) removal problems from such batteries. This invention provides the advantages of very low energy consumption, turbulence, shear, cost and maintenance. Thus, due to the low shear and low turbulence of this invention, it is particularly effective in the control of aluminum hydroxide particle size distribution in the various sections of an aluminum-air system, as well as in other electrochemical systems requiring separation for phases of different densities. 3 figs.

  16. Lamella settler crystallizer

    DOE Patents [OSTI]

    Maimoni, Arturo (Orinda, CA)

    1990-01-01T23:59:59.000Z

    A crystallizer which incorporates a lamella settler and which is particularly applicable for use in batteries and power cells for electric vehicles or stationary applications. The lamella settler can be utilized for coarse particle separation or for agglomeration, and is particularly applicable to aluminum-air batteries or power cells for solving the hydrargillite (aluminum-hydroxide) removal problems from such batteries. This invention provides the advantages of very low energy consumption, turbulence, shear, cost and maintenance. Thus, due to the low shear and low turbulence of this invention, it is particularly effective in the control of aluminum hydroxide particle size distribution in the various sections of an aluminum-air system, as well as in other electrochemical systems requiring separation for phases of different densities.

  17. Optical nano-woodpiles: large-area metallic photonic crystals and metamaterials

    E-Print Network [OSTI]

    Ibbotson, Lindsey A.; Demetriadou, Angela; Stephen, Croxall; Hess, Ortwin; Baumberg, Jeremy J.

    2015-02-09T23:59:59.000Z

    to be flexible and stretch-tuneable without issues of bowing or collapse4,17. They also benefit from a high refractive index contrast due to the metal wires which exhibit negative permittivity below the metal’s plasma frequency, widening the band gap20,21. Gold... .-H., Kim, Y.-S., Constant, K. & Ho, K.-M. Woodpile metallic photonic crystals fabricated by using soft lithography for tailored thermal emission. Adv. Mater. 19, 791–794 (2007). 8. Rinne, S. A., Garcia-Santamaria, F. & Braun, P. V. Embedded cavities...

  18. Multiple gap photovoltaic device

    DOE Patents [OSTI]

    Dalal, Vikram L. (Newark, DE)

    1981-01-01T23:59:59.000Z

    A multiple gap photovoltaic device having a transparent electrical contact adjacent a first cell which in turn is adjacent a second cell on an opaque electrical contact, includes utilizing an amorphous semiconductor as the first cell and a crystalline semiconductor as the second cell.

  19. Polycrystal Plasticity -Multiple Slip"

    E-Print Network [OSTI]

    Rollett, Anthony D.

    Polycrystal Plasticity - Multiple Slip" 27-750 Texture, Microstructure & Anisotropy A.D. Rollett;2 Objective" The objective of this lecture is to show how plastic deformation in polycrystals requires of Los Alamos polycrystal plasticity, LApp; also the Viscoplastic Selfconsistent code, VPSC; also

  20. Structural contribution to the roughness of supersmooth crystal surface

    SciTech Connect (OSTI)

    Butashin, A. V.; Muslimov, A. E., E-mail: amuslimov@mail.ru; Kanevsky, V. M.; Deryabin, A. N.; Pavlov, V. A.; Asadchikov, V. E. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2013-05-15T23:59:59.000Z

    Technological advances in processing crystals (Si, sapphire {alpha}-Al{sub 2}O{sub 3}, SiC, GaN, LiNbO{sub 3}, SrTiO{sub 3}, etc.) of substrate materials and X-ray optics elements make it possible to obtain supersmooth surfaces with a periodicity characteristic of the crystal structure. These periodic structures are formed by atomically smooth terraces and steps of nano- and subnanometer sizes, respectively. A model surface with such nanostructures is proposed, and the relations between its roughness parameters and the height of atomic steps are determined. The roughness parameters calculated from these relations almost coincide with the experimental atomic force microscopy (AFM) data obtained from 1 Multiplication-Sign 1 and 10 Multiplication-Sign 10 {mu}m areas on the surface of sapphire plates with steps. The minimum roughness parameters for vicinal crystal surfaces, which are due to the structural contribution, are calculated based on the approach proposed. A comparative analysis of the relief and roughness parameters of sapphire plate surfaces with different degrees of polishing is performed. A size effect is established: the relief height distribution changes from stochastic to regular with a decrease in the surface roughness.

  1. The RF performance of cavity made from defective niobium material determined by Eddy Current Scanning

    SciTech Connect (OSTI)

    Wu, G.; Cooley, L.; Sergatskov, D.; Ozelis, J.; /Fermilab; Brinkmann, A.; Singer, W.; Singer, X.; /DESY; Pekeler, M.

    2010-10-01T23:59:59.000Z

    Eddy current scanning (ECS) has been used to screen niobium sheets to avoid defective material being used in costly cavity fabrication. The evaluation criterion of this quality control tool is not well understood. Past surface studies showed some features were shallow enough to be removed by chemical etching. The remaining features were identified to be small number of deeper inclusions, but mostly unidentifiable features (by chemical analysis). A real cavity made of defective niobium material has been tested. The cavity achieved high performance with comparable results to the cavities made from defect free cavities. Temperature mapping could help to define the control standard clearly.

  2. Dynamical Casimir–Polder force on a partially dressed atom in a cavity comprising a dielectric

    SciTech Connect (OSTI)

    Yang, H.; Zheng, T.Y., E-mail: zhengty@nenu.edu.cn; Zhang, X.; Shao, X.Q.; Pan, S.M., E-mail: pansm717@nenu.edu.cn

    2014-05-15T23:59:59.000Z

    We put a two-level atom into a cavity comprising a dielectric with output coupling. An analytical expression of the dynamical Casimir–Polder force in such a system is obtained when the system starts from a partially dressed state. And the effects of several relevant parameters of the system on the time-dependent force are also discussed. -- Highlights: •We get the dynamical CP force on a partially dressed atom in a dielectric cavity. •The force in this cavity is larger than that in infinite dielectric space. •The force is not symmetric with respect to the center of the cavity. •The oscillating time of the force increases with the cavity size.

  3. Result of MHI 2-Cell Seamless Dumb-Bell Cavity Vertical Test

    SciTech Connect (OSTI)

    Okihira, K. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Hara, H. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Ikeda, N. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Inoue, F. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Sennyu, K. [Mitsubishi Heavy Industries, Ltd, Mihara, Hiroshima, 729-0393, Japan; Geng, Rongli [JLAB; Rimmer, Robert A. [JLAB; Kako, E. [KEK

    2014-12-01T23:59:59.000Z

    MHI have supplied several 9-cell cavities for STF (R&D of ILC project at KEK) and have been considering production method for stable quality and cost reduction, seamless dumb-bell cavity was one of them. We had fabricated a 2 cell seamless dumb-bell cavity for cost reduction and measured RF performance in collaboration with JLab, KEK and MHI. Surface treatment recipe for ILC was applied for MHI 2-cell cavity and vertical test was performed at JLab. The cavity reached Eacc=32.4MV/m after BCP and EP. Details of the result are reported.

  4. High power tests of dressed supconducting 1.3 GHz RF cavities

    SciTech Connect (OSTI)

    Hocker, A.; Harms, E.R.; Lunin, A.; Sukhanov, A.; /Fermilab

    2011-03-01T23:59:59.000Z

    A single-cavity test cryostat is used to conduct pulsed high power RF tests of superconducting 1.3 GHz RF cavities at 2 K. The cavities under test are welded inside individual helium vessels and are outfitted ('dressed') with a fundamental power coupler, higher-order mode couplers, magnetic shielding, a blade tuner, and piezoelectric tuners. The cavity performance is evaluated in terms of accelerating gradient, unloaded quality factor, and field emission, and the functionality of the auxiliary components is verified. Test results from the first set of dressed cavities are presented here.

  5. Mechanical Design of a New Injector Cryomodule 2-Cell Cavity at CEBAF

    SciTech Connect (OSTI)

    Cheng, Guangfeng G. [JLAB; Henry, James E. [JLAB; Mammosser, John D. [JLAB; Rimmer, Robert A. [JLAB; Wang, Haipeng [JLAB; Wiseman, Mark A. [JLAB; Yang, Shuo [JLAB

    2013-12-01T23:59:59.000Z

    As a part of Jefferson Lab’s 12 GeV upgrade, a new injector superconducting RF cryomodule is required. This unit consists of a 2-cell and 7-cell cavity, with the latter being refurbished from an existing cavity. The new 2-cell cavity requires electromagnetic design and optimization followed by mechanical design analyses. The electromagnetic design is reported elsewhere. This paper aims to present the procedures and conclusions of the analyses on cavity tuning sensitivity, pressure sensitivity, upset condition pressure induced stresses, and structural vibration frequencies. The purposes of such analyses include: 1) provide reference data for cavity tuner design; 2) examine the structural integrity of the cavity; and 3) evaluate the 2-cell cavity’s resistance to microphonics. Design issues such as the location of stiffening rings, effect of tuner stiffness on cavity stress, choice of cavity wall thickness, etc. are investigated by conducting extensive finite element analyses. Progress in fabrication of the 2-cell cavity is also reported.

  6. Modeling Dispersive Coupling and Losses of Localized Optical and Mechanical Modes in Optomechanical Crystals

    E-Print Network [OSTI]

    Eichenfield, Matt; Safavi-Naeini, Amir H; Vahala, Kerry J; Painter, Oskar

    2009-01-01T23:59:59.000Z

    Periodically structured materials can sustain both optical and mechanical excitations which are tailored by the geometry. Here we analyze the properties of dispersively coupled planar photonic and phononic crystals: optomechanical crystals. In particular, the properties of co-resonant optical and mechanical cavities in quasi-1D (patterned nanobeam) and quasi-2D (patterned membrane) geometries are studied. It is shown that the mechanical Q and optomechanical coupling in these structures can vary by many orders of magnitude with modest changes in geometry. An intuitive picture is developed based upon a perturbation theory for shifting material boundaries that allows the optomechanical properties to be designed and optimized. Several designs are presented with mechanical frequency ~ 1-10 GHz, optical Q-factor Qo > 10^7, motional masses meff 100 femtograms, optomechanical coupling length LOM 10^7.

  7. Coherent Optical Spectroscopy of a Single Quantum Dot Via an Off-Resonant Cavity

    E-Print Network [OSTI]

    Arka Majumda; Alexander Papageorge; Erik D. Kim; Michal Bajscy; Hyochul Kim; Pierre Petroff; Jelena Vuckovic

    2011-03-14T23:59:59.000Z

    In recent experiments on coupled quantum dot (QD) optical cavity systems a pronounced interaction between the dot and the cavity has been observed even for detunings of many cavity linewidths. This interaction has been attributed to an incoherent phonon-mediated scattering process and is absent in atomic systems. Here, we demonstrate that despite its incoherent nature, this process preserves the signatures of coherent interaction between a QD and a strong driving laser, which may be observed via the optical emission from the off-resonant cavity. Under bichromatic driving of the QD, the cavity emission exhibits spectral features consistent with optical dressing of the QD transition. In addition to revealing new aspects of the off-resonant QD-cavity interaction, this result provides a new, simpler means of coherently probing QDs than traditional approaches and opens the possibility of employing off-resonant cavities to optically interface QD-nodes in quantum networks.

  8. The Rise of Ingot Niobium as a Material for Superconducting Radiofrequency Accelerating Cavities

    E-Print Network [OSTI]

    Kneisel, P; Dhakal, P; Saito, K; Singer, W; Singer, X; Myneni, G R

    2013-01-01T23:59:59.000Z

    As a result of a collaboration between Jefferson Lab and niobium manufacturer CBMM, ingot niobium was explored as a possible material for superconducting radiofrequency (SRF) cavity fabrication. The first single cell cavity from large grain high purity niobium was fabricated and successfully tested at Jefferson Lab in 2004. This pioneering work triggered research activities in other SRF laboratories around the world. Large grain niobium became not only an interesting alternative material for cavity builders, but also material scientists and surface scientists were eager to participate in the development of this material. Most of the original expectations for this material of being less costly and allowing less expensive fabrication and treatment procedures at the same performance levels in cavities have been met. Many single cell cavities made from material of different suppliers have been tested successfully and several multi-cell cavities have shown the performances comparable to the best cavities made from...

  9. Method for determining hydrogen mobility as a function of temperature in superconducting niobium cavities

    DOE Patents [OSTI]

    May, Robert (Virginia Beach, VA)

    2008-03-11T23:59:59.000Z

    A method for determining the mobility of hydrogen as a function of temperature in superconducting niobium cavities comprising: 1) heating a cavity under test to remove free hydrogen; 2) introducing hydrogen-3 gas into the cavity; 3) cooling the cavity to allow absorption of hydrogen-3; and 4) measuring the amount of hydrogen-3 by: a) cooling the cavity to about 4.degree. K while flowing a known and regulated amount of inert carrier gas such as argon or helium into the cavity; b) allowing the cavity to warm at a stable rate from 4.degree. K to room temperature as it leaves the chamber; and c) directing the exit gas to an ion chamber radiation detector.

  10. Cooling and control of a cavity opto-electromechanical system

    E-Print Network [OSTI]

    Lee, Kwan H; Harris, Glen I; Knittel, Joachim; Bowen, Warwick P

    2009-01-01T23:59:59.000Z

    Mechanical oscillators provide a quintessential example of the profound difference between quantum and classical behaviour. However, the quantum regime is yet to be observed. Rapid progress is underway in cavity optomechanical systems (COMS) and nanoelectromechanical systems (NEMS). COMS have superior mechanical transduction sensitivity, able to resolve mechanical zero-point fluctuations. However, the electrical actuation of NEMS provides far greater scope for quantum control. By combining electrical gradient forces from NEMS with the ultrasensitive transduction from COMS, we implement a cavity optoelectromechanical system (COEMS), demonstrating both control and feedback cooling capabilities. Out-of-loop mechanical transduction provides, for the first time, independent temperature verification even when opto-mechanical correlations exist due to strong interactions such as measurement backaction. This technology has significance in fundamental science, improving our capacity to engineer mechanical quantum syst...

  11. Performance of a High Resolution Cavity Beam Position Monitor System

    SciTech Connect (OSTI)

    Walston, S; Boogert, S; Chung, C; Fitsos, P; Frisch, J; Gronberg, J; Hayano, H; Honda, Y; Kolomensky, Y; Lyapin, A; Malton, S; May, J; McCormick, D; Meller, R; Miller, D; Orimoto, T; Ross, M; Slater, M; Smith, S; Smith, T; Terunuma, N; Thomson, M; Urakawa, J; Vogel, V; Ward, D; White, G

    2006-12-18T23:59:59.000Z

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {micro}rad over a dynamic range of approximately {+-} 20 {micro}m.

  12. Performance of a High Resolution Cavity Beam Position Monitor System

    SciTech Connect (OSTI)

    Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Joe; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David John; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; /Fermilab /UC,

    2007-06-08T23:59:59.000Z

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {mu}rad over a dynamic range of approximately {+-} 20 {mu}m.

  13. High-Q Optical Cavities in Hyperuniform Disordered Materials

    E-Print Network [OSTI]

    Amoah, Timothy

    2015-01-01T23:59:59.000Z

    We introduce the first designs for high-Q photonic cavities in slab architectures in hyperuniform disordered solids displaying isotropic band gaps. Despite their disordered character, hyperuniform disordered structures have the ability to tightly confine the TE-polarised radiation in slab configurations that are readily fabricable. The architectures are based on carefully designed local modifications of otherwise unperturbed hyperuniform dielectric structures. We identify a wide range of confined cavity modes, which can be classified according to their approximate symmetry (monopole, dipole, quadrupole, etc.) of the confined electromagnetic wave pattern. We demonstrate that quality factors ($Q$) $Q>10^{9}$ can be achieved for purely 2D structures, and that for three--dimensional finite-height photonic slabs, quality factors $Q>20,000$ can be maintained.

  14. Cooling atom-cavity systems into entangled states

    E-Print Network [OSTI]

    J. Busch; S. De; S. S. Ivanov; B. T. Torosov; T. P. Spiller; A. Beige

    2011-05-25T23:59:59.000Z

    Generating entanglement by simply cooling a system into a stationary state which is highly entangled has many advantages. Schemes based on this idea are robust against parameter fluctuations, tolerate relatively large spontaneous decay rates, and achieve high fidelities independent of their initial state. A possible implementation of this idea in atom-cavity systems has recently been proposed by Kastoryano et al. [Phys. Rev. Lett. 106, 090502 (2011)]. Here we propose an improved entanglement cooling scheme for two atoms inside an optical cavity which achieves higher fidelities for comparable single-atom cooperativity parameters C. For example, we predict fidelities above 90% even for C as low as 20 without requiring individual laser addressing and without having to detect photons.

  15. HOM Coupler Optimisation for the Superconducting RF Cavities in ESS

    E-Print Network [OSTI]

    Ainsworth, R; Calaga, R

    2012-01-01T23:59:59.000Z

    The European Spallation Source (ESS) will be the world’s most powerful next generation neutron source. It consists of a linear accelerator, target, and instruments for neutron experiments. The linac is designed to accelerate protons to a ?nal energy of 2.5 GeV, with an average design beam power of 5 MW, for collision with a target used to produce a high neutron ?ux. A section of the linac will contain Superconducting RF (SCRF) cavities designed at 704 MHz. Beam induced HOMs in these cavities may drive the beam unstable and increase the cryogenic load, therefore HOM couplers are installed to provide suf?cient damping. Previous studies have shown that these couplers are susceptible to multipacting, a resonant process which can absorb RF power and lead to heating effects. This paper will show how a coupler suffering from multipacting has been redesigned to limit this effect. Optimisation of the RF damping is also discussed.

  16. Crystal-Like geometric modeling

    E-Print Network [OSTI]

    Landreneau, Eric Benjamin

    2006-08-16T23:59:59.000Z

    faces, symmetry, and fractal geometry. The techniques have also been implemented in software, as a proof of concept. They are used in an interactive geometric modeling system, in which users can use these techniques to create crystal-like shapes...

  17. Arnold Schwarzenegger SINGLE CRYSTAL SILICON

    E-Print Network [OSTI]

    in this report. #12;ENERGY INNOVATIONS SMALL GRANT (EISG) PROGRAM INDEPENDENT ASSESSMENT REPORT (IAR) SINGLEArnold Schwarzenegger Governor SINGLE CRYSTAL SILICON SHEET GROWTH Prepared For: California Energy Commission Energy Innovations Small Grant Program Prepared By: Energy Materials Research

  18. Active materials in photonic crystals

    E-Print Network [OSTI]

    Bermel, Peter (Peter A.)

    2007-01-01T23:59:59.000Z

    I analyze new phenomena arising from embedding active materials inside of photonic crystal structures. These structures strongly modify the photonic local density of states (LDOS), leading to quantitative and qualitative ...

  19. Study on the multi-pass, multi-bunch beam breakup for 9-cell TESLA cavities in ERL

    E-Print Network [OSTI]

    Chen, Si; Li, Yong-Ming; Feng, Li-Wen; Zhu, Feng; Quan, Sheng-Wen; Liu, Ke-Xin; Chen, Jia-Er

    2013-01-01T23:59:59.000Z

    Generally, Energy Recovery Linac (ERL) needs special designed high current superconducting RF cavities. In this paper, the threshold current of BBU for compact ERL facilities with 9-cell Tesla type cavities are investigated. The results show that it is feasible to adopt 9-cell Tesla cavity for compact ERL test facilities with just a few cavities and beam current around tens mA.

  20. Minimizing radiation damage in nonlinear optical crystals

    DOE Patents [OSTI]

    Cooke, D. Wayne (Santa Fe, NM); Bennett, Bryan L. (Los Alamos, NM); Cockroft, Nigel J. (Santa Fe, NM)

    1998-01-01T23:59:59.000Z

    Methods are disclosed for minimizing laser induced damage to nonlinear crystals, such as KTP crystals, involving various means for electrically grounding the crystals in order to diffuse electrical discharges within the crystals caused by the incident laser beam. In certain embodiments, electrically conductive material is deposited onto or into surfaces of the nonlinear crystals and the electrically conductive surfaces are connected to an electrical ground. To minimize electrical discharges on crystal surfaces that are not covered by the grounded electrically conductive material, a vacuum may be created around the nonlinear crystal.

  1. Minimizing radiation damage in nonlinear optical crystals

    DOE Patents [OSTI]

    Cooke, D.W.; Bennett, B.L.; Cockroft, N.J.

    1998-09-08T23:59:59.000Z

    Methods are disclosed for minimizing laser induced damage to nonlinear crystals, such as KTP crystals, involving various means for electrically grounding the crystals in order to diffuse electrical discharges within the crystals caused by the incident laser beam. In certain embodiments, electrically conductive material is deposited onto or into surfaces of the nonlinear crystals and the electrically conductive surfaces are connected to an electrical ground. To minimize electrical discharges on crystal surfaces that are not covered by the grounded electrically conductive material, a vacuum may be created around the nonlinear crystal. 5 figs.

  2. Laser produced plasma diagnostics by cavity ringdown spectroscopy and applications

    SciTech Connect (OSTI)

    Milosevic, S. [Institute of Physics, Zagreb (Croatia)

    2012-05-25T23:59:59.000Z

    Laser-produced plasmas have many applications for which detailed characterization of the plume is requested. Cavity ring-down spectroscopy is a versatile absorption method which provides data on the plume and its surroundings, with spatial and temporal resolution. The measured absorption line shapes contain information about angular and velocity distributions within the plume. In various plasmas we have observed molecules or metastable atoms which were not present in the emission spectra.

  3. ForPeerReview Cavity expansion in cross anisotropic rock

    E-Print Network [OSTI]

    Wagner, Peter

    for Numerical and Analytical Methods in Geomechanics Manuscript ID: NAG-10-0026.R1 Wiley - Manuscript type in Geomechanics #12;ForPeerReview Only Cavity expansion in cross-anisotropic rock Dimitrios Kolymbas Peter Wagner://mc.manuscriptcentral.com/nag International Journal for Numerical and Analytical Methods in Geomechanics 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

  4. Filling of a cavity with zero-point electromagnetic radiation

    E-Print Network [OSTI]

    Jiri J. Mares; V. Spicka; J. Kristofik; P. Hubik

    2003-11-11T23:59:59.000Z

    In the present contribution we analyse a simple thought process at T = 0 in an idealized heat engine having partitions made of a material with an upper frequency cut-off and bathed in zero-point (ZP) electromagnetic radiation. As a result, a possible mechanism of filling real cavities with ZP radiation based on Doppler's effect has been suggested and corresponding entropy changes are discussed.

  5. Analysis of a Fabric/Desiccant Window Cavity Dehumidifier

    E-Print Network [OSTI]

    Hunn, B. D.; Grasso, M. M.; Vadlamani, V.

    1994-01-01T23:59:59.000Z

    were conducted to a) determine a suitable fabric/desiccant combination for use in the window cavity dehumidifier, and b) to estimate the moisture absorption (regain) capacity of the candidate fabriddesiccant combinations. After examining... the properties of various solid desiccants. we determined that silica gel beads, encapsulated in a fabric pouch, would be the best approach. ?bus, we measured the moisture regain characteristics of several fabrics used to encapsulate silica gel beads...

  6. Early cavity growth during forward burn. [Hoe Creek III problems

    SciTech Connect (OSTI)

    Shannon, M.J.; Thorsness, C.B.; Hill, R.W.

    1980-07-03T23:59:59.000Z

    During the early portion of the forward burn phase of the Hoe Creek III field experiment, the cavity progagated rapidly down the deviated borehole and to the top of the coal seam. As a first step to understanding this phenomena we have conducted small scale coal block experiments. Drying as well as combustion tests were performed. This paper describes the test hardware and the experimental results.

  7. Crystal Potential Formula for the Calculation of Crystal Lattice Sums1 Don Steiger and Calvin Ahlbrandt

    E-Print Network [OSTI]

    Glaser, Rainer

    Crystal Potential Formula for the Calculation of Crystal Lattice Sums1 Don Steiger and Calvin; In Final Form: April 7, 1998 A new formula is derived for the determination of the potential energy of the central unit cell of a finite crystal; this formula is called the crystal potential formula. The crystal

  8. Cavity Beam Position Monitor System for ATF2

    SciTech Connect (OSTI)

    Boogert, Stewart; /Oxford U., JAI; Boorman, Gary; /Oxford U., JAI; Swinson, Christina; /Oxford U., JAI; Ainsworth, Robert; /Royal Holloway, U. of London; Molloy, Stephen; /Royal Holloway, U. of London; Aryshev, Alexander; /KEK, Tsukuba; Honda, Yosuke; /KEK, Tsukuba; Tauchi, Toshiaki; /KEK, Tsukuba; Terunuma, Nobuhiro; /KEK, Tsukuba; Urakawa, Junji; /KEK, Tsukuba; Frisch, Josef; /SLAC; May, Justin; /SLAC; McCormick, Douglas; /SLAC; Nelson, Janice; /SLAC; Smith, Tonee; /SLAC; White, Glen; /SLAC; Woodley, Mark; /SLAC; Heo, Ae-young; /Kyungpook Natl. U.; Kim, Eun-San; /Kyungpook Natl. U.; Kim, Hyoung-Suk; /Kyungpook Natl. U.; Kim, Youngim; /Kyungpook Natl. U. /University Coll. London /Kyungpook Natl. U. /Fermilab /Pohang Accelerator Lab.

    2012-07-09T23:59:59.000Z

    The Accelerator Test Facility 2 (ATF2) in KEK, Japan, is a prototype scaled demonstrator system for the final focus required for a future high energy lepton linear collider. The ATF2 beam-line is instrumented with a total of 38 C and S band resonant cavity beam position monitors (CBPM) with associated mixer electronics and digitizers. The current status of the BPM system is described, with a focus on operational techniques and performance. The ATF2 C-band system is performing well, with individual CBPM resolution approaching or at the design resolution of 50 nm. The changes in the CBPM calibration observed over three weeks can probably be attributed to thermal effects on the mixer electronics systems. The CW calibration tone power will be upgraded to monitor changes in the electronics gain and phase. The four S-band CBPMs are still to be investigated, the main problem associated with these cavities is a large cross coupling between the x and y ports. This combined with the large design dispersion in that degion makes the digital signal processing difficult, although various techniques exist to determine the cavity parameters and use these coupled signals for beam position determination.

  9. Optical heterodyne detection for cavity ring-down spectroscopy

    DOE Patents [OSTI]

    Levenson, Marc D. (Saratoga, CA); Paldus, Barbara A. (Mountain View, CA); Zare, Richard N. (Stanford, CA)

    2000-07-25T23:59:59.000Z

    A cavity ring-down system for performing cavity ring-down spectroscopy (CRDS) using optical heterodyne detection of a ring-down wave E.sub.RD during a ring-down phase or a ring-up wave E.sub.RU during a ring up phase. The system sends a local oscillator wave E.sub.LO and a signal wave E.sub.SIGNAL to the cavity, preferably a ring resonator, and derives an interference signal from the combined local oscillator wave E.sub.LO and the ring-down wave E.sub.RD (or ring-up wave E.sub.RU). The local oscillator wave E.sub.LO has a first polarization and the ring-down wave E.sub.RD has a second polarization different from the first polarization. The system has a combining arrangement for combining or overlapping local oscillator wave E.sub.LO and the ring-down wave E.sub.RD at a photodetector, which receives the interference signal and generates a heterodyne current I.sub.H therefrom. Frequency and phase differences between the waves are adjustable.

  10. Investigation of Microscopic Materials Limitations of Superconducting RF Cavities

    SciTech Connect (OSTI)

    Anlage, Steven [University of Maryland

    2014-07-23T23:59:59.000Z

    The high-field performance of SRF cavities is often limited by breakdown events below the intrinsic limiting surface fields of Nb, and there is abundant evidence that these breakdown events are localized in space inside the cavity. Also, there is a lack of detailed understanding of the causal links between surface treatments and ultimate RF performance at low temperatures. An understanding of these links would provide a clear roadmap for improvement of SRF cavity performance, and establish a cause-and-effect ‘RF materials science’ of Nb. We propose two specific microscopic approaches to addressing these issues. First is a spatially-resolved local microwave-microscope probe that operates at SRF frequencies and temperatures to discover the microscopic origins of breakdown, and produce quantitative measurements of RF critical fields of coatings and films. Second, RF Laser Scanning Microscopy (LSM) has allowed visualization of RF current flow and sources of nonlinear RF response in superconducting devices with micro-meter spatial resolution. The LSM will be used in conjunction with surface preparation and characterization techniques to create definitive links between physical and chemical processing steps and ultimate cryogenic microwave performance. We propose to develop RF laser scanning microscopy of small-sample Nb pieces to establish surface-processing / RF performance relations through measurement of RF current distributions on micron-length scales and low temperatures.

  11. Fiber Optic Based Thermometry System for Superconducting RF Cavities

    SciTech Connect (OSTI)

    Dr. Kochergin, Vladimir [Microxact Inc.] [Microxact Inc.

    2013-05-06T23:59:59.000Z

    Thermometry is recognized as the best technique to identify and characterize losses in SRF cavities. The most widely used and reliable apparatus for temperature mapping at cryogenic temperatures is based on carbon resistors (RTDs). The use of this technology on multi-cell cavities is inconvenient due to the very large number of sensors required to obtain sufficient spatial resolution. Recent developments make feasible the use of multiplexible fiber optic sensors for highly distributed temperature measurements. However, sensitivity of multiplexible cryogenic temperature sensors was found extending only to 12K at best and thus was not sufficient for SRF cavity thermometry. During the course of the project the team of MicroXact, JLab and Virginia Tech developed and demonstrated the multiplexible fiber optic sensor with adequate response below 20K. The demonstrated temperature resolution is by at least a factor of 60 better than that of the best multiplexible fiber optic temperature sensors reported to date. The clear path toward at least 10times better temperature resolution is shown. The first to date temperature distribution measurements with ~2.5mm spatial resolution was done with fiber optic sensors at 2K to4K temperatures. The repeatability and accuracy of the sensors were verified only at 183K, but at this temperature both parameters significantly exceeded the state of the art. The results of this work are expected to find a wide range of applications, since the results are enabling the whole new testing capabilities, not accessible before.

  12. BERLinPro Booster Cavity Design, Fabrication and Test Plans

    SciTech Connect (OSTI)

    Burrill, Andrew [HZB; Anders, W [HZB; Frahm, A. [HZB; Knobloch, Jens [HZB; Neumann, Axel [HZB; Ciovati, Gianluigi [JLAB; Kneisel, Peter K. [JLAB; Turlington, Larry D. [JLAB

    2014-12-01T23:59:59.000Z

    The bERLinPro project, a 100 mA, 50 MeV superconducting RF (SRF) Energy Recovery Linac (ERL) is under construction at Helmholtz-Zentrum Berlin for the purpose of studying the technical challenges and physics of operating a high current, c.w., 1.3 GHz ERL. This machine will utilize three unique SRF cryomodules for the injector, booster and linac module respectively. The booster cryomodule will contain three 2-cell SRF cavities, based on the original design by Cornell University, and will be equipped with twin 115 kW RF power couplers in order to provide the appropriate acceleration to the high current electron beam. This paper will review the status of the fabrication of the 4 booster cavities that have been built for this project by Jefferson Laboratory and look at the challenges presented by the incorporation of fundamental power couplers capable of delivering 115 kW. The test plan for the cavities and couplers will be given along with a brief overview of the cryomodule design.

  13. Uppsala High Power Test Stand for ESS Spoke Cavities

    E-Print Network [OSTI]

    Yogi, RA; Dancila, D; Gajewski, K; Hermansson, L; Noor, M; Wedberg, R; Santiago-Kern, R; Ekelöf, T; Lofnes, T; Ziemann, V; Goryashko, V; Ruber, R

    2013-01-01T23:59:59.000Z

    The European Spallation Source (ESS) is one of the world’s most powerful neutron source. The ESS linac will accelerate 50mA pulse current of protons to 2.5GeV in 2.86 ms long pulses at a repetition rate of 14 Hz. It produces a beam with 5MW average power and 125MW peak power. ESS Spoke Linac consist of 28 superconducting spoke cavities, which will be developed by IPN Orsay, France. These Spoke Cavities will be tested at low power at IPN Orsay and high power testing will be performed in a high power test stand at Uppsala University. The test stand consists of tetrode based RF amplifier chain (352MHz, 350 kW) power and related RF distribution. Outputs of two tetrodes shall be combined with the hybrid coupler to produce 350 kW power. Preamplifier for a tetrode shall be solid state amplifier. As the spoke cavities are superconducting, the test stand also includes horizontal cryostat, Helium liquefier, test bunker etc. The paper describes features of the test stand in details.

  14. HOM identification by bead pulling in the Brookhaven ERL cavity

    SciTech Connect (OSTI)

    Hahn H.; Calaga, R.; Jain, P.; Johnson, E.C.; Xu, W.

    2012-06-25T23:59:59.000Z

    Several past measurements of the Brookhaven ERL at superconducting temperature produced a long list of higher order modes (HOMs). The Niobium 5-cell cavity is terminated with HOM ferrite dampers that successfully reduce the Q-factors to tolerable levels. However, a number of undamped resonances with Q {ge} 10{sup 6} were found at 4 K and their mode identification remained as a goal for this paper. The approach taken here consists in taking different S{sub 21} measurements on a copper cavity replica of the ERL which can be compared with the actual data and also with Microwave Studio computer simulations. Several different S{sub 21} transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, between probes in a single cell, and between beam-position monitor probes in the beam tubes. Mode identification is supported by bead pulling with a metallic needle or a dielectric sphere that are calibrated in the fundamental mode. This paper presents results for HOMs in the first two dipole bands with the prototypical 958 MHz trapped mode, the lowest beam tube resonances, and high-Q modes in the first quadrupole band and beyond.

  15. Coherent and incoherent radiation from high-energy electron and the LPM effect in oriented single crystal

    E-Print Network [OSTI]

    V. N. Baier; V. M. Katkov

    2005-12-01T23:59:59.000Z

    The process of radiation from high-energy electron in oriented single crystal is considered using the method which permits inseparable consideration of both coherent and incoherent mechanisms of photon emission. The total intensity of radiation is calculated. The theory, where the energy loss of projectile has to be taken into account, agrees quite satisfactory with available CERN data. It is shown that the influence of multiple scattering on radiation process is suppressed due to action of crystal field.

  16. Hydrodynamic sweepout thresholds in BWR Mark III reactor cavity interactions

    SciTech Connect (OSTI)

    Spencer, B.W.; Baronowsky, S.P.; Kilsdonk, D.J.

    1984-04-01T23:59:59.000Z

    Simulant-material experiments and related analysis are described which investigated hydrodynamics aspects of ex-vessel interactions following postulated core meltdown with subsequent meltthrough of the vessel lower head and ejection of molten corium from the vessel into the containment region beneath the vessel. Objectives were to examine the possible sweepout of water and corium from the cavity by the steam/H/sub 2/ flow. The dispersal pathways in this containment design include a single manway and four CRD penetrations in the cylindrical pedestal wall connecting to the drywell with a combined cross-sectional area of approx. 10 m/sup 2/. These openings range from 3.4 to 6.3 m in elevation off the concrete floor of the cavity. The experiments were performed using a 1:34 scale mock-up of the RPV/pedestal region. The first tests were quasi-steady tests. Tests were also performed using molten Wood's metal (WM). Some tests were performed with water on the cavity floor, and one test was performed using steel shot. The test results indicated that threshold gas flowrates existed beyond which dispersal of water and/or corium from the cavity can be expected. The predominant dispersal flow regime observed in the experiments involved fluidization of the water or molten WM by the gas flowrate through the system and sweepout of the fluidized liquid droplets as the gas exited the cavity through the openings in the wall. The superficial gas velocity at the onset of water sweepout ranged from 0.87 to 1.04 m/s in the tests which agrees very closely to the calculated fluidization threshold of 0.96 m/s. Application of the fluidization model for prediction of sweepout for the full-size system suggests that sweepout of water and corium can occur if the breach size in the RPV lower head exceeds approx. 10 and 17 cm dia, respectively, for steam blowdown at a vessel initial pressure of 1000 psi.

  17. Adaptive Liquid Crystal Windows

    SciTech Connect (OSTI)

    Taheri, Bahman; Bodnar, Volodymyr

    2011-12-31T23:59:59.000Z

    Energy consumption by private and commercial sectors in the U.S. has steadily grown over the last decade. The uncertainty in future availability of imported oil, on which the energy consumption relies strongly, resulted in a dramatic increase in the cost of energy. About 20% of this consumption are used to heat and cool houses and commercial buildings. To reduce dependence on the foreign oil and cut down emission of greenhouse gases, it is necessary to eliminate losses and reduce total energy consumption by buildings. To achieve this goal it is necessary to redefine the role of the conventional windows. At a minimum, windows should stop being a source for energy loss. Ideally, windows should become a source of energy, providing net gain to reduce energy used to heat and cool homes. It is possible to have a net energy gain from a window if its light transmission can be dynamically altered, ideally electronically without the need of operator assistance, providing optimal control of the solar gain that varies with season and climate in the U.S. In addition, the window must not require power from the building for operation. Resolution of this problem is a societal challenge and of national interest and will have a broad global impact. For this purpose, the year-round, allclimate window solution to provide an electronically variable solar heat gain coefficient (SHGC) with a wide dynamic range is needed. AlphaMicron, Inc. (AMI) developed and manufactured 1ft × 1ft prototype panels for the world’s first auto-adjusting Adaptive Liquid Crystal Windows (ALCWs) that can operate from sunlight without the need for external power source and demonstrate an electronically adjustable SHGC. This novel windows are based on AlphaMicron’s patented e-Tint® technology, a guesthost liquid crystal system implemented on flexible, optically clear plastic films. This technology is suitable both for OEM and aftermarket (retro-fitting) lamination to new and existing windows. Low level of power consumption by ALCWs allows for on-board power electronics for automatic matching of transmission through windows to varying climate conditions without drawing the power from the power grid. ALCWs are capable of transmitting more sunlight in winters to assist in heating and less sunlight in summers to minimize overheating. As such, they can change the window from being a source of energy loss to a source of energy gain. In addition, the scalable AMI’s roll-to-roll process, proved by making 1ft × 1ftALCW prototype panels, allows for cost-effective production of large-scale window panels along with capability to change easily their color and shape. In addition to architectural glazing in houses and commercial buildings, ALCWs can be used in other applications where control of sunlight is needed, such as green houses, used by commercial produce growers and botanical gardens, cars, aircrafts, etc.

  18. Review of ingot niobium as a material for superconducting radiofrequency accelerating cavities

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kneisel, Peter; Ciovati, Gianluigi; Dhakal, Pashupati; Saito, Kenji; Singer, W; Singer, X; Myneni, Ganapati Rao

    2015-02-01T23:59:59.000Z

    As a result of collaboration between Jefferson Lab and niobium manufacturer Companhia Brasileira de Metalurgia e Mineração (CBMM), ingot niobium was explored as a possible material for superconducting radiofrequency (SRF) cavity fabrication. The first single cell cavity from large-grain high purity niobium was fabricated and successfully tested at Jefferson Lab in 2004. This work triggered research activities in other SRF laboratories around the world. Large-grain (LG) niobium became not only an interesting alternative material for cavity builders, but also material scientists and surface scientists were eager to participate in the development of this technology. Many single cell cavities made frommore »material of different suppliers have been tested successfully and several multi-cell cavities have shown performances comparable to the best cavities made from standard fine-grain niobium. Several 9-cell cavities fabricated by Research Instruments and tested at DESY exceeded the best performing fine grain cavities with a record accelerating gradient of Eacc=45.6 MV/m. The quality factor of those cavities was also higher than that of fine-grain (FG) cavities processed with the same methods. Such performance levels push the state-of-the art of SRF technology and are of great interest for future accelerators. This contribution reviews the development of ingot niobium technology and highlights some of the differences compared to standard FG material and opportunities for further developments.« less

  19. Review of ingot niobium as a material for superconducting radiofrequency accelerating cavities

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kneisel, Peter [JLAB; Ciovati, Gianluigi [JLAB; Dhakal, Pashupati [JLAB; Saito, Kenji; Singer, W; Singer, X; Myneni, Ganapati Rao [JLAB

    2015-02-01T23:59:59.000Z

    As a result of collaboration between Jefferson Lab and niobium manufacturer Companhia Brasileira de Metalurgia e Mineração (CBMM), ingot niobium was explored as a possible material for superconducting radiofrequency (SRF) cavity fabrication. The first single cell cavity from large-grain high purity niobium was fabricated and successfully tested at Jefferson Lab in 2004. This work triggered research activities in other SRF laboratories around the world. Large-grain (LG) niobium became not only an interesting alternative material for cavity builders, but also material scientists and surface scientists were eager to participate in the development of this technology. Many single cell cavities made from material of different suppliers have been tested successfully and several multi-cell cavities have shown performances comparable to the best cavities made from standard fine-grain niobium. Several 9-cell cavities fabricated by Research Instruments and tested at DESY exceeded the best performing fine grain cavities with a record accelerating gradient of Eacc=45.6 MV/m. The quality factor of those cavities was also higher than that of fine-grain (FG) cavities processed with the same methods. Such performance levels push the state-of-the art of SRF technology and are of great interest for future accelerators. This contribution reviews the development of ingot niobium technology and highlights some of the differences compared to standard FG material and opportunities for further developments.

  20. Exploration of material removal rate of srf elliptical cavities as a function of media type and cavity shape on niobium and copper using centrifugal barrel polishing (cbp)

    SciTech Connect (OSTI)

    Palczewski, Ari [JLAB; Ciovati, Gianluigi [JLAB; Li, Yongming [PEKING; Geng, Rongli [JLAB

    2013-09-01T23:59:59.000Z

    Centrifugal barrel polishing (cbp) for SRF application is becoming more wide spread as the technique for cavity surface preparation. CBP is now being used in some form at SRF laboratories around the world including in the US, Europe and Asia. Before the process can become as mature as wet chemistry like eletro-polishing (EP) and buffered chemical polishing (BCP) there are many questions which remain unanswered. One of these topics includes the uniformity of removal as a function of cavity shape and material type. In this presentation we show CBP removal rates for various media types on 1.3 GHz TESLA and 1.5 GHz CEBAF large/fine grain niobium cavities, and 1.3GHz low surface field copper cavity. The data will also include calculated RF frequency shift modeling non-uniform removal as a function of cavity position and comparing them with CBP results.

  1. Radionuclide Partitioning in an Underground Nuclear Test Cavity

    SciTech Connect (OSTI)

    Rose, T P; Hu, Q; Zhao, P; Conrado, C L; Dickerson, R; Eaton, G F; Kersting, A B; Moran, J E; Nimz, G; Powell, B A; Ramon, E C; Ryerson, F J; Williams, R W; Wooddy, P T; Zavarin, M

    2009-01-09T23:59:59.000Z

    In 2004, a borehole was drilled into the 1983 Chancellor underground nuclear test cavity to investigate the distribution of radionuclides within the cavity. Sidewall core samples were collected from a range of depths within the re-entry hole and two sidetrack holes. Upon completion of drilling, casing was installed and a submersible pump was used to collect groundwater samples. Test debris and groundwater samples were analyzed for a variety of radionuclides including the fission products {sup 99}Tc, {sup 125}Sb, {sup 129}I, {sup 137}Cs, and {sup 155}Eu, the activation products {sup 60}Co, {sup 152}Eu, and {sup 154}Eu, and the actinides U, Pu, and Am. In addition, the physical and bulk chemical properties of the test debris were characterized using Scanning Electron Microscopy (SEM) and Electron Microprobe measurements. Analytical results were used to evaluate the partitioning of radionuclides between the melt glass, rubble, and groundwater phases in the Chancellor test cavity. Three comparative approaches were used to calculate partitioning values, though each method could not be applied to every nuclide. These approaches are based on: (1) the average Area 19 inventory from Bowen et al. (2001); (2) melt glass, rubble, and groundwater mass estimates from Zhao et al. (2008); and (3) fission product mass yield data from England and Rider (1994). The U and Pu analyses of the test debris are classified and partitioning estimates for these elements were calculated directly from the classified Miller et al. (2002) inventory for the Chancellor test. The partitioning results from this study were compared to partitioning data that were previously published by the IAEA (1998). Predictions of radionuclide distributions from the two studies are in agreement for a majority of the nuclides under consideration. Substantial differences were noted in the partitioning values for {sup 99}Tc, {sup 125}Sb, {sup 129}I, and uranium. These differences are attributable to two factors: chemical volatility effects that occur during the initial plasma condensation, and groundwater remobilization that occurs over a much longer time frame. Fission product partitioning is very sensitive to the early cooling history of the test cavity because the decay of short-lived (t{sub 1/2} < 1 hour) fission-chain precursors occurs on the same time scale as melt glass condensation. Fission product chains that include both volatile and refractory elements, like the mass 99, 125, and 129 chains, can show large variations in partitioning behavior depending on the cooling history of the cavity. Uranium exhibits similar behavior, though the chemical processes are poorly understood. The water temperature within the Chancellor cavity remains elevated (75 C) more than two decades after the test. Under hydrothermal conditions, high solubility chemical species such as {sup 125}Sb and {sup 129}I are readily dissolved and transported in solution. SEM analyses of melt glass samples show clear evidence of glass dissolution and secondary hydrothermal mineral deposition. Remobilization of {sup 99}Tc is also expected during hydrothermal activity, but moderately reducing conditions within the Chancellor cavity appear to limit the transport of {sup 99}Tc. It is recommended that the results from this study should be used together with the IAEA data to update the range in partitioning values for contaminant transport models at the Nevada National Security Site (formerly known as the Nevada Test Site).

  2. automated crystal screening: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    high crystallization rates and the production of diffraction-quality crystals. microfluidics Quake, Stephen R. 5 Data Mining Crystallization Databases: Knowledge-Based...

  3. Multi-purpose 805 MHz Pillbox RF Cavity for Muon Acceleration Studies

    SciTech Connect (OSTI)

    Kurennoy, Sergey S. [Los Alamos National Laboratory; Chan, Kwok-Chi Dominic [Los Alamos National Laboratory; Jason, Andrew [Los Alamos National Laboratory; Miyadera, Haruo [Los Alamos National Laboratory; Turchi, Peter J. [Los Alamos National Laboratory

    2011-01-01T23:59:59.000Z

    An 805 MHz RF pillbox cavity has been designed and constructed to investigate potential muon beam acceleration and cooling techniques. The cavity can operate at vacuum or under pressure to 100 atmospheres, at room temperature or in a liquid nitrogen bath at 77 K. The cavity is designed for easy assembly and disassembly with bolted construction using aluminum seals. The surfaces of the end walls of the cavity can be replaced with different materials such as copper, aluminum, beryllium, or molybdenum, and with different geometries such as shaped windows or grid structures. Different surface treatments such as electro polished, high-pressure water cleaned, and atomic layer deposition are being considered for testing. The cavity has been designed to fit inside the 5-Tesla solenoid in the MuCool Test Area at Fermilab. Current status of the cavity prepared for initial conditioning and operation in the external magnetic field is discussed.

  4. Preparation and Testing of the SRF Cavities for the CEBAF 12 GeV Upgrade

    SciTech Connect (OSTI)

    Reilly, A. V.; Bass, T.; Burrill, A.; Davis, G. K.; Marhauser, F.; Reece, C. E.; Stirbet, M.

    2011-07-01T23:59:59.000Z

    Eighty new 7-cell, low-loss cell-shaped cavities are required for the CEBAF 12 GeV Upgrade project. In addition to ten pre-production units fabricated at JLab, the full set of commercially-produced cavities have been delivered. An efficient processing routine, which includes a controlled 30 micron electropolish, has been established to transform these cavities into qualified 8-cavity strings. This work began in 2010 and will run through the end of 2011. The realized cavity performance consistently exceeds project requirements and also the maximum useful gradient in CEBAF: 25 MV/m. We will describe the cavity processing and preparation protocols and summarize test results obtained to date.

  5. Optical control of resonant light transmission for an atom-cavity system

    E-Print Network [OSTI]

    Sharma, Arijit; Sawant, Rahul V; Sheikholeslami, G; Budker, D; Rangwala, S A

    2015-01-01T23:59:59.000Z

    We demonstrate the manipulation of transmitted light through an optical Fabry-Perot cavity, built around a spectroscopy cell containing enriched rubidium vapor. Light resonant with the $^{87}$Rb D$_{2}$ ($F=2/F=1$) $\\leftrightarrow F'$ manifold, is controlled by transverse intersection of the cavity mode by another resonant light beam. The cavity transmission can be suppressed or enhanced depending on the coupling of atomic states due to the intersecting beams. The extreme manifestation of cavity mode control is the precipitious destruction (negative logic switching) or buildup (positive logic switching) of the transmitted light intensity, on intersection of the transverse control beam with the cavity mode. Both the steady state and transient response are experimentally investigated. The mechanism behind the change in cavity transmission is discussed in brief.

  6. Cavity nucleation and evolution in He-implanted Si and GaAs

    SciTech Connect (OSTI)

    Follstaedt, D.M.; Myers, S.M.; Petersen, G.A.; Barbour, J.C.

    1995-12-01T23:59:59.000Z

    The criteria for forming stable cavities by He{sup +} implantation and annealing are examined for Si and GaAs. In Si, implanting at room temperature requires a minimum of 1.6 at. % He to form a continuous layer of cavities after annealing at 700{degrees}C. The cavities are located at dislocations and planar defects. Implanting peak He concentrations just above this threshold produces narrow layers of cavities at the projected range. In GaAs, room-temperature implantation followed by annealing results in exfoliation of the surface layer. Cavities were formed instead by implanting Ar followed by overlapping He, both at 400{degrees}C, with additional annealing at 400{degrees}C to outgas the He. This method forms 1.5--3.5 nm cavities that are often on [111] planar defects.

  7. Design, prototyping and testing of a compact superconducting double quarter wave crab cavity

    E-Print Network [OSTI]

    Xiao, Binping; Belomestnykh, Sergey; Ben-Zvi, Ilan; Calaga, Rama; Cullen, Chris; Capatina, Ofelia; Hammons, Lee; Li, Zenghai; Marques, Carlos; Skaritka, John; Verdú-Andres, Silvia; Wu, Qiong

    2015-01-01T23:59:59.000Z

    A novel design of superconducting Crab Cavity was proposed and designed at Brookhaven National Laboratory. The new cavity shape is a Double Quarter Wave or DQWCC. After fabrication and surface treatments, the niobium proof-of-principle cavity was cryogenically tested in a vertical cryostat. The cavity is extremely compact yet has a low frequency of 400 MHz, an essential property for service for the Large Hadron Collider luminosity upgrade. The electromagnetic properties of the cavity are also well matched for this demanding task. The demonstrated deflecting voltage of 4.6 MV is well above the requirement for a crab cavity in the future High Luminosity LHC of 3.34 MV. In this paper we present the design, prototyping and test results of the DQWCC.

  8. Cooling Dynamics Trough Transition Temperature of Niobium SRF Cavities Captured by Temperature Mapping

    E-Print Network [OSTI]

    Martinello, M; Checchin, M; Grassellino, A; Crawford, A C; Melnychuk, A; Sergatskov, D A

    2015-01-01T23:59:59.000Z

    Cool-down dynamics of superconducting accelerating cavities became particularly important for obtaining very high quality factors in SRF cavities. Previous studies proved that when cavity is cooled fast, the quality factor is higher than when cavity is cooled slowly. This has been discovered to derive from the fact that a fast cool-down allows better magnetic field expulsion during the superconducting transition. In this paper we describe the first experiment where the temperature all around the cavity was mapped during the cavity cool-down through transition temperature, proving the existence of two different transition dynamics: a sharp superconducting-normal conducting transition during fast cool-down which favors flux expulsion and nucleation phase transition during slow cool-down, which leads to full flux trapping.

  9. Intra-Cavity Total Reflection For High Sensitivity Measurement Of Optical Properties

    DOE Patents [OSTI]

    Pipino, Andrew C. R. (Gaithersburg, MD); Hudgens, Jeffrey W. (Rockville, MD)

    1999-08-24T23:59:59.000Z

    An optical cavity resonator device is provided for conducting sensitive murement of optical absorption by matter in any state with diffraction-limited spatial resolution through utilization of total internal reflection within a high-Q (high quality, low loss) optical cavity. Intracavity total reflection generates an evanescent wave that decays exponentially in space at a point external to the cavity, thereby providing a localized region where absorbing materials can be sensitively probed through alteration of the Q-factor of the otherwise isolated cavity. When a laser pulse is injected into the cavity and passes through the evanescent state, an amplitude loss resulting from absorption is incurred that reduces the lifetime of the pulse in the cavity. By monitoring the decay of the injected pulse, the absorption coefficient of manner within the evanescent wave region is accurately obtained from the decay time measurement.

  10. Intra-Cavity Total Reflection For High Sensitivity Measurement Of Optical Properties

    DOE Patents [OSTI]

    Pipino, Andrew Charles Rule (Gaithersburg, MD)

    1999-11-16T23:59:59.000Z

    An optical cavity resonator device is provided for conducting sensitive murement of optical absorption by matter in any state with diffraction-limited spatial resolution through utilization of total internal reflection within a high-Q (high quality, low loss) optical cavity. Intracavity total reflection generates an evanescent wave that decays exponentially in space at a point external to the cavity, thereby providing a localized region where absorbing materials can be sensitively probed through alteration of the Q-factor of the otherwise isolated cavity. When a laser pulse is injected into the cavity and passes through the evanescent state, an amplitude loss resulting from absorption is incurred that reduces the lifetime of the pulse in the cavity. By monitoring the decay of the injected pulse, the absorption coefficient of manner within the evanescent wave region is accurately obtained from the decay time measurement.

  11. Selective transfer of superposition of coherent states by exploiting a cavity QED system

    E-Print Network [OSTI]

    N. Behzadi; S. Kazemi Rudsary

    2014-05-15T23:59:59.000Z

    We propose a scheme on the basis of a N+2 identical single-mode coupled-cavity QED system for selective transfer of a qubit constructed from superposition of standard coherent states. The cavities arranged in such way that the intermediate or channel cavity is connected uniformly to the sender and N receiver cavities. We consider N different ternary sets of identical QDs whose QDs have been distributed in the sender, channel and one of the receiver cavities respectively. We demonstrate a situation in which the dynamics of the system is confined selectively in a sub sector belongs to one of the ternary set of QDs. This selective dynamics is able to transfer the coherent state-constructed qubit (CSCQ) from the sender party to the desired receiver one reliably. Also, we illustrate that the scheme is optimally robust due to dissipations arises from photon losses in the cavities.

  12. Multiple capillary biochemical analyzer

    DOE Patents [OSTI]

    Dovichi, N.J.; Zhang, J.Z.

    1995-08-08T23:59:59.000Z

    A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibers to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands. 21 figs.

  13. Precision Crystal Calorimeters in High Energy Physics

    ScienceCinema (OSTI)

    Ren-Yuan Zhu

    2010-01-08T23:59:59.000Z

    Precision crystal calorimeters traditionally play an important role in high energy physics experiments. In the last two decades, it faces a challenge to maintain its precision in a hostile radiation environment. This paper reviews the performance of crystal calorimeters constructed for high energy physics experiments and the progress achieved in understanding crystal?s radiation damage as well as in developing high quality scintillating crystals for particle physics. Potential applications of new generation scintillating crystals of high density and high light yield, such as LSO and LYSO, in particle physics experiments is also discussed.

  14. Results of Cavity Series Fabrication at Jefferson Laboratory for the Cryomodule “R100”

    SciTech Connect (OSTI)

    F. Marhauser, W.A. Clemens, M.A. Drury, D. Forehand, J. Henry, S. Manning, R.B. Overton, R.S. Williams

    2011-09-01T23:59:59.000Z

    A series production of eight superconducting RF cavities for the cryomodule R100 was conducted at JLab in 2010. The cavities underwent chemical post-processing prior to vertical high power testing and routinely exceeded the envisaged performance specifications. After cryomodule assembly, cavities were successfully high power acceptance tested. In this paper, we present the achievements paving the way for the first demonstration of 100 MV (and beyond) in a single cryomodule to be operated at CEBAF.

  15. Crystal-field effects in fluoride crystals for optical refrigeration

    SciTech Connect (OSTI)

    Hehlen, Markus P [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    The field of optical refrigeration of rare-earth-doped solids has recently seen an important breakthrough. The cooling of a YLiF{sub 4} (YLF) crystal doped with 5 mol% Yb3+ to 155 K by Seletskiy et al [NPhot] has surpassed the lowest temperatures ({approx}170 K for {approx}100 mW cooling capacity) that are practical with commercial multi-stage thermoelectric coolers (TEC) [Glaister]. This record performance has advanced laser cooling into an application relevant regime and has put first practical optical cryocoolers within reach. The result is also relevant from a material perspective since for the first time, an Yb3+-doped crystal has outperformed an Yb3+-doped glass. The record temperature of 208 K was held by the Yb3+-doped fluorozirconate glass ZBLAN. Advanced purification and glass fabrication methods currently under development are expected to also advance ZBLAN:Yb3+ to sub-TEC temperatures. However, recent achievements with YLF:Yb3+ illustrate that crystalline materials may have two potentially game-changing advantajes over glassy materials. First, the crystalline environment reduces the inhomogeneous broadening of the Yb3+ electronic transitions as compared to a glassy matrix. The respective sharpening of the crystal-field transitions increases the peak absorption cross section at the laser excitation wavelength and allows for more efficient pumping of the Yb3+ ions, particularly at low temperatures. Second, many detrimental impurities present in the starting materials tend to be excluded from the crystal during its slow growth process, in contrast to a glass where all impurities present in the starting materials are included in the glass when it is formed by temperature quenching a melt. The ultra high purity required for laser cooling materials [PRB] therefore may be easier to realize in crystals than in glasses. Laser cooling occurs by laser excitation of a rare-earth ion followed by anti-Stokes luminescence. Each such laser-cooling cycle extracts thermal energy from the solid and carries it away as high-entropy light, thereby cooling the material. In the ideal case, the respective laser-cooling power is given by the pump wavelength ({lambda}{sub p}), the mean fluorescence wavelength ({bar {lambda}}{sub L}), and the absorption coefficient (a{sub r}) of the pumped transition. These quantities are solely determined by crystal field interactions. On one hand, a large crystal-field splitting offers a favorably large difference of {lambda}{sub p} - {bar {lambda}}{sub L} and thus a high cooling efficiency {eta}{sub cool} = ({lambda}{sub p} - {bar {lambda}}{sub L})/{bar {lambda}}{sub L}. On the other hand, a small crystal-field splitting offers a high thermal population (n{sub i}) of the initial state of the pumped transition, giving a high pump absorption coefficient and thus high laser cooling power, particularly at low temperatures. A quantitative description of crystal-field interactions is therefore critical to the understanding and optimization of optical refrigeration. In the case of Yb3+ as the laser cooling ion, however, development of a crystal-field model is met with substantial difficulties. First, Yb3+ has only two 4/multiplets, {sup 2}F{sub 7/2} and {sup 2}F{sub 5/2}, which lead to at most 7 crystal-field levels. This makes it difficult, and in some cases impossible, to evaluate the crystal-field Hamiltonian, which has at least 4 parameters for any Yb3+ point symmety lower than cubic. Second, {sup 2}F{sub 7/2}{leftrightarrow}{sup 2}F{sub 5/2} transitions exhibit an exceptionally strong electron-phonon coupling compared to 4f transitions of other rare earths. This makes it difficult to distinguish electronic from vibronic transitions in the absorption and luminescence spectra and to reliably identify the crystal-field levels. Yb3+ crystal-field splittings reported in the literature should thus generally be viewed with caution. This paper explores the effects of crystal-field interactions on the laser cooling performance of Yb3+-doped fluoride crystals. It is shown that the total crystal-field splitting o

  16. axisymmetric-fold-combination cavity adapting: Topics by E-print...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to the same pseudo-temperature''. Nathaniel Obadia 2007-02-07 18 The Superconducting TESLA Cavities CERN Preprints Summary: The conceptional design of the proposed linear...

  17. Energy Recovery Linac cavity at BNL | U.S. DOE Office of Science...

    Office of Science (SC) Website

    Energy Recovery Linac cavity at BNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Applications of Nuclear Science Applications of Nuclear...

  18. Resonant cavity mode dependence of anomalous and inverse spin Hall effect

    SciTech Connect (OSTI)

    Kim, Sang-Il; Seo, Min-Su; Park, Seung-young, E-mail: parksy@kbsi.re.kr [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-806 (Korea, Republic of)

    2014-05-07T23:59:59.000Z

    The direct current electric voltage induced by the Inverse Spin Hall Effect (ISHE) and Anomalous Hall Effect (AHE) was investigated in the TE{sub 011} and TE{sub 102} cavities. The ISHE and AHE components were distinguishable through the fitting of the voltage spectrum. The unwanted AHE was minimized by placing the DUT (Device Under Test) at the center of both the TE{sub 011} and TE{sub 102} cavities. The voltage of ISHE in the TE{sub 011} cavity was larger than that in the TE{sub 102} cavity due to the higher quality factor of the former. Despite optimized centering, AHE voltage from TE{sub 011} cavity was also higher. The reason was attributed to the E-field distribution inside the cavity. In the case of the TE{sub 011} cavity, the DUT was easily exposed to the E-field in all directions. Therefore, the parasitic AHE voltage in the TE{sub 102} cavity was less sensitive than that in the TE{sub 011} cavity to decentering problem.

  19. Environment assisted speed-up of the field evolution in cavity QED

    E-Print Network [OSTI]

    A. D. Cimmarusti; Z. Yan; B. D. Patterson; L. P. Corcos; L. A. Orozco; S. Deffner

    2015-03-09T23:59:59.000Z

    We measure the quantum speed of the state evolution of the field in a weakly-driven optical cavity QED system. To this end, the mode of the electromagnetic field is considered as a quantum system of interest with a preferential coupling to a tunable environment: the atoms. By controlling the environment, i.e., changing the number of atoms coupled to the optical cavity mode, an environment assisted speed-up is realized: the quantum speed of the state re-population in the optical cavity increases with the coupling strength between the optical cavity mode and this non-Markovian environment (the number of atoms).

  20. Single Spoke Cavities for Low-energy Part of CW Linac of Project X.

    SciTech Connect (OSTI)

    Gonin, Ivan; Champion, Mark; Khabiboulline, Timergali; Lunin, Andrei; Perunov, Nikolay; Solyak, Nikolay; Yakovlev, Vyacheslav; /Fermilab

    2010-05-01T23:59:59.000Z

    In the low-energy part of the Project X H-linac three families of 325 MHz SC single spoke cavities will be used, having {beta} = 0.11, 0.21 and 0.4. Single spoke cavity was selected for the linac because of higher r/Q. Results of optimization of all cavities are presented. Results of the beam dynamics optimization for initial stage of the linac with beta=0.11 single spoke cavity are presented at poster MOPEC082 (this conference).

  1. DESIGN AND FABRICATION OF SCRF CAVITIES FOR THE APT CONTINUOUS-WAVE PROTON LINAC.

    SciTech Connect (OSTI)

    Gentzlinger, R.C. (Robert C.); Haynes, W. B. (William B.); Chan, K. D. (Kwok-Chi D.); Kelley, J. P. (John Patrick); Krawczyk, F. L. (Frank L.); Kuzminski, J. (Jozef); Mitchell R.; Montoya, D. I. (Debbie I.); Rusnak, B. (Brian); Safa, H. (Henri); Schrage, D. L. (Dale L.); Tajima, T. (Tsuyoshi)

    2001-01-01T23:59:59.000Z

    At Los Alamos National Laboratory, a prototype design of proton superconducting cavities has been developed for the Accelerator Production of Tritium (APT) project. These cavities are designed for b=0.64. They have five cells and operate at 700 MHz. They will operate at 2.15 K in a liquid-helium bath contained in an unalloyed, Grade 2 titanium vessel. Six cavities were manufactured with RRR-250 niobium, one by Los Alamos and five by industry. This paper discusses both the design and fabrication of the cavity and helium vessel, and the experience gained during the fabrication process.

  2. Vertical and horizontal test results of 3.9-GHz accelerating cavities at FNAL

    SciTech Connect (OSTI)

    Khabiboulline, T.; Edwards, H.; Foley, M.; Harms, E.; Hocker, James Andrew; Mitchell, D.; Rowe, A.; Solyak, N.; /Fermilab

    2008-06-01T23:59:59.000Z

    The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve the beam performance of the VUV FEL, FLASH. In the frame of a collaborative agreement, Fermilab will provide DESY with a cryomodule containing a string of four cavities. Seven 9-cell Nb cavities were tested and six of them did reach accelerating gradient up to 24 MV/m almost twice more than design value of 14 MV/m. Two of these cavities are with new HOM couplers with improved design. In this paper we present all results of the vertical and horizontal tests.

  3. Quantum information processing and multiatom entanglement engineering with a thermal cavity

    E-Print Network [OSTI]

    Shi-Biao Zheng

    2012-02-24T23:59:59.000Z

    We propose a scheme for realizing two-qubit quantum phase gates with atoms in a thermal cavity. The photon-number dependent parts in the evolution operator are canceled with the assistant of a strong classical field. Thus the scheme is insensitive to the thermal field. In the scheme the detuning between the atoms and the cavity is equal to the atom-cavity coupling strength and thus the gates operate at a high speed, which is also important in view of decoherence. The scheme can be generalized to generate multiatom entangled states with a thermal cavity.

  4. Photovoltaic Probe of Cavity Polaritons in a Quantum Cascade Structure

    E-Print Network [OSTI]

    Luca Sapienza; Raffaele Colombelli; Angela Vasanelli; Cristiano Ciuti; Christophe Manquest; Ulf Gennser; Carlo Sirtori

    2007-03-07T23:59:59.000Z

    The strong coupling between an intersubband excitation in a quantum cascade structure and a photonic mode of a planar microcavity has been detected by angle-resolved photovoltaic measurements. A typical anticrossing behavior, with a vacuum-field Rabi splitting of 16 meV at 78K, has been measured, for an intersubband transition at 163 meV. These results show that the strong coupling regime between photons and intersubband excitations can be engineered in a quantum cascade opto-electronic device. They also demonstrate the possibility to perform angle-resolved mid-infrared photodetection and to develop active devices based on intersubband cavity polaritons.

  5. Doped H(2)-Filled RF Cavities for Muon Beam Cooling

    SciTech Connect (OSTI)

    Yonehara, K.; Chung, M.; Jansson, A.; Hu, M.; Moretti, A.; Popovic, M.; /Fermilab; Alsharo'a, M.; Johnson, R.P.; Neubauer, M.; Sah, R.; /Muons Inc., Batavia; Rose, D.V.; /Voss Sci., Albuquerque

    2009-05-01T23:59:59.000Z

    RF cavities pressurized with hydrogen gas may provide effective muon beam ionization cooling needed for muon colliders. Recent 805 MHz test cell studies reported below include the first use of SF{sub 6} dopant to reduce the effects of the electrons that will be produced by the ionization cooling process in hydrogen or helium. Measurements of maximum gradient in the Paschen region are compared to a simulation model for a 0.01% SF{sub 6} doping of hydrogen. The observed good agreement of the model with the measurements is a prerequisite to the investigation of other dopants.

  6. Entanglement accumulation, retrieval, and concentration in cavity QED

    E-Print Network [OSTI]

    Daniel Ballester

    2009-06-02T23:59:59.000Z

    The ability to accumulate and retrieve entanglement in the fields of two remote cavities with pairs of two-level atoms is discussed. It is shown that this transfer and retrieval can be indeed ideal with a resonant interaction. The case of initial non-maximally entangled atomic pairs is also considered. This leads to the possibility of concentrating entanglement into a single pair at the retrieval stage. A teleportation protocol based on the same setup is presented. This makes possible teleportation with built-in entanglement concentration.

  7. Phonon mediated electromagnetically induced absorption in cavity optomechanics

    E-Print Network [OSTI]

    Qu, Kenan

    2013-01-01T23:59:59.000Z

    We predict the existence of the electromagnetically induced absorption (EIA) in the double cavity configurations of the optomechanical systems (OMS). We discuss the origin of the EIA in OMS which exhibit the existence of an absorption peak within the transparency window. We provide analytical results for the width and the height of the EIA peak. The combination of the EIT and EIA is especially useful for photon switching applications. The EIA that we discuss is different from the one originally discovered by Lezama et al in atomic systems and can be understood in terms of the dynamics of three coupled oscillators (rather than two) under different conditions on the relaxation parameters.

  8. Ingot Niobium RF Cavity Design and Development at BARC

    SciTech Connect (OSTI)

    Mittal, K. C.; Mondal, J.; Ghatak, S.; Dhavale, A. S.; Ghodke, S. R. [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Vohra, R. S.; Jawale, S. B. [Centre for Design and Manufacture, Bhabha Atomic Research Centre, Mumbai 400085 (India); Dutta, D.; Pujari, P. K.; Saha, T. K.; Bapat, A. V. [Radiation Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2011-03-31T23:59:59.000Z

    This article presents the different activity of Ingot niobium in BARC. BARC is developing a technology for the accelerator driven subcritical system (ADSS) that will be mainly utilized for the transmutation of nuclear waste and enrichment of U{sup 233}. Design and development of superconducting medium velocity cavity has been taken up as a part of the ADSS project. The design and fabrication of f = 1050 MHz, {beta} = 0.49 with Ingot niobium will be presented. Positron annihilation studies are conducted on small samples of ingot niobium to understand the defect depth profile of the niobium surface. The results are presented here.

  9. A CAVITY RING-DOWN SPECTROSCOPY MERCURY CONTINUOUS EMISSION MONITOR

    SciTech Connect (OSTI)

    Christopher C. Carter, Ph.D.

    2003-06-30T23:59:59.000Z

    Previous work on the detection of mercury using the cavity ring-down (CRD) technique has concentrated on the detection and characterization of the desired mercury transition. Interferent species present in flue gas emissions have been tested as well as a simulated flue gas stream. Additionally, work has been done on different mercury species such as the elemental and oxidized forms. The next phase of the effort deals with the actual sampling system. This sampling system will be responsible for acquiring a sample stream from the flue gas stack, taking it to the CRD cavity where it will be analyzed and returning the gas stream to the stack. In the process of transporting the sample gas stream every effort must be taken to minimize any losses of mercury to the walls of the sampling system as well as maintaining the mercury in its specific state (i.e. elemental, oxidized, or other mercury compounds). SRD first evaluated a number of commercially available sampling systems. These systems ranged from a complete sampling system to a number of individual components for specific tasks. SRD engineers used some commercially available components and designed a sampling system suited to the needs of the CRD instrument. This included components such as a pyrolysis oven to convert all forms of mercury to elemental mercury, a calibration air source to ensure mirror alignment and quality of the mirror surfaces, and a pumping system to maintain the CRD cavity pressure from atmospheric pressure (760 torr) down to about 50 torr. SRD also began evaluating methods for the CRD instrument to automatically find the center of a mercury transition. This procedure is necessary as the instrument must periodically measure the baseline losses of the cavity off of the mercury resonance and then return to the center of the transition to accurately measure the mercury concentration. This procedure is somewhat complicated due to the isotopic structure of the 254 nm mercury transition. As a result of 6 isotopes and hyperfine splittings there are 5 individual peaks that can be resolved by the CRD instrument. SRD tested a derivative method with both simulated data and actual data taken with the CRD apparatus. Initial tests indicate that this method is successful in automatically finding the center of the mercury transitions.

  10. Radiative heat transfer in a parallelogram shaped cavity

    E-Print Network [OSTI]

    Dez, V Le

    2015-01-01T23:59:59.000Z

    An exact analytical description of the internal radiative field inside an emitting-absorbing gray semi-transparent medium enclosed in a two-dimensional parallelogram cavity is proposed. The expressions of the incident radiation and the radiative flux field are angularly and spatially discretized with a double Gauss quadrature, and the temperature field is obtained by using an iterative process. Some numerical solutions are tabulated and graphically presented as the benchmark solutions. Temperature and two components of the radiative flux are finally sketched on the whole domain. It is shown that the proposed method gives perfectly smooth results.

  11. SRF Cavities for High Current ERLs Rama Calaga

    E-Print Network [OSTI]

    ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ SRF GUN Beam Dump Stretcher RHIC BeamRHIC Beam 4 x 5 cell cavities - 703.75 MHz Compressor Cooling

  12. Microfluidic and Nanofluidic Cavities for Quantum Fluids Experiments

    E-Print Network [OSTI]

    Duh, A; Hauer, B D; Saeedi, R; Kim, P H; Biswas, T S; Davis, J P

    2011-01-01T23:59:59.000Z

    Many areas of science are taking advantage of the advances made possible using microfabrication and nanofabrication. But research into quantum fluids in confined geometries has largely focused on macroscopic devices, like carefully separated plates, or porous media. This is unfortunate since the relevant length scales in quantum fluids, 3He in particular, are comparable to those possible using microfluidic and nanofluidic devices. Here we present devices fabricated specifically for quantum fluids research, with cavity sizes ranging from 30 nm to 11 microns deep. We present characterization of these devices and their usefulness for quantum fluids experiments.

  13. Manufacturing method of photonic crystal

    DOE Patents [OSTI]

    Park, In Sung; Lee, Tae Ho; Ahn, Jin Ho; Biswas, Rana; Constant, Kristen P.; Ho, Kai-Ming; Lee, Jae-Hwang

    2013-01-29T23:59:59.000Z

    A manufacturing method of a photonic crystal is provided. In the method, a high-refractive-index material is conformally deposited on an exposed portion of a periodic template composed of a low-refractive-index material by an atomic layer deposition process so that a difference in refractive indices or dielectric constants between the template and adjacent air becomes greater, which makes it possible to form a three-dimensional photonic crystal having a superior photonic bandgap. Herein, the three-dimensional structure may be prepared by a layer-by-layer method.

  14. Quasiresonant excitation of InP/InGaP quantum dots using second harmonic generated in a photonic crystal cavity

    E-Print Network [OSTI]

    Vuckovic, Jelena

    Quasiresonant excitation of InP/InGaP quantum dots using second harmonic generated in a photonic://apl.aip.org/about/rights_and_permissions #12;Quasiresonant excitation of InP/InGaP quantum dots using second harmonic generated in a photonic signal to noise quasiresonant excitation of InP/InGaP quantum dots. The excitation is provided via second

  15. Multiple layer insulation cover

    DOE Patents [OSTI]

    Farrell, James J. (Livingston Manor, NY); Donohoe, Anthony J. (Ovid, NY)

    1981-11-03T23:59:59.000Z

    A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

  16. On Multiple Einstein Rings

    E-Print Network [OSTI]

    M. C. Werner; J. An; N. W. Evans

    2008-07-30T23:59:59.000Z

    A number of recent surveys for gravitational lenses have found examples of double Einstein rings. Here, we investigate analytically the occurrence of multiple Einstein rings. We prove, under very general assumptions, that at most one Einstein ring can arise from a mass distribution in a single plane lensing a single background source. Two or more Einstein rings can therefore only occur in multi-plane lensing. Surprisingly, we show that it is possible for a single source to produce more than one Einstein ring. If two point masses (or two isothermal spheres) in different planes are aligned with observer and source on the optical axis, we show that there are up to three Einstein rings. We also discuss the image morphologies for these two models if axisymmetry is broken, and give the first instances of magnification invariants in the case of two lens planes.

  17. Mixed Mode Matrix Multiplication

    SciTech Connect (OSTI)

    Meng-Shiou Wu; Srinivas Aluru; Ricky A. Kendall

    2004-09-30T23:59:59.000Z

    In modern clustering environments where the memory hierarchy has many layers (distributed memory, shared memory layer, cache,...), an important question is how to fully utilize all available resources and identify the most dominant layer in certain computations. When combining algorithms on all layers together, what would be the best method to get the best performance out of all the resources we have? Mixed mode programming model that uses thread programming on the shared memory layer and message passing programming on the distributed memory layer is a method that many researchers are using to utilize the memory resources. In this paper, they take an algorithmic approach that uses matrix multiplication as a tool to show how cache algorithms affect the performance of both shared memory and distributed memory algorithms. They show that with good underlying cache algorithm, overall performance is stable. When underlying cache algorithm is bad, superlinear speedup may occur, and an increasing number of threads may also improve performance.

  18. AM with Multiple Merlins

    E-Print Network [OSTI]

    Scott Aaronson; Russell Impagliazzo; Dana Moshkovitz

    2014-01-27T23:59:59.000Z

    We introduce and study a new model of interactive proofs: AM(k), or Arthur-Merlin with k non-communicating Merlins. Unlike with the better-known MIP, here the assumption is that each Merlin receives an independent random challenge from Arthur. One motivation for this model (which we explore in detail) comes from the close analogies between it and the quantum complexity class QMA(k), but the AM(k) model is also natural in its own right. We illustrate the power of multiple Merlins by giving an AM(2) protocol for 3SAT, in which the Merlins' challenges and responses consist of only n^{1/2+o(1)} bits each. Our protocol has the consequence that, assuming the Exponential Time Hypothesis (ETH), any algorithm for approximating a dense CSP with a polynomial-size alphabet must take n^{(log n)^{1-o(1)}} time. Algorithms nearly matching this lower bound are known, but their running times had never been previously explained. Brandao and Harrow have also recently used our 3SAT protocol to show quasipolynomial hardness for approximating the values of certain entangled games. In the other direction, we give a simple quasipolynomial-time approximation algorithm for free games, and use it to prove that, assuming the ETH, our 3SAT protocol is essentially optimal. More generally, we show that multiple Merlins never provide more than a polynomial advantage over one: that is, AM(k)=AM for all k=poly(n). The key to this result is a subsampling theorem for free games, which follows from powerful results by Alon et al. and Barak et al. on subsampling dense CSPs, and which says that the value of any free game can be closely approximated by the value of a logarithmic-sized random subgame.

  19. Crystallization in High-Level Waste Glasses

    SciTech Connect (OSTI)

    Hrma, Pavel R. (BATTELLE (PACIFIC NW LAB)); Dane R Spearing, Gary L Smith, SK Sundaram

    2002-01-01T23:59:59.000Z

    This review outlines important aspects of crystallization in HLW glasses, such as equilibrium, nucleation, growth, and dissolution. The impact of crystallization on continuous melters and the chemical durability of high-level waste glass are briefly discussed.

  20. Generation of vector beams with liquid crystal disclination lines

    E-Print Network [OSTI]

    Miha ?an?ula; Miha Ravnik; Slobodan Žumer

    2014-08-12T23:59:59.000Z

    We report that guiding light beams, ranging from continuous beams to femtosecond pulses, along liquid crystal defect lines can transform them into vector beams with various polarization profiles. Using Finite Difference Time Domain numerical solving of Maxwell equations, we confirm that the defect in the orientational order of the liquid crystal induces a defect in the light field with twice the winding number of the liquid crystal defect, coupling the topological invariants of both fields. For example, it is possible to transform uniformly-polarized light into light with a radial polarization profile. Our approach also correctly yields a zero-intensity region near the defect core, which is always present in areas of discontinuous light polarization or phase. Using circularly polarized incident light, we show that defects with non-integer winding numbers can be obtained, where topological constants are preserved by phase vortices, demonstrating coupling between the light's spin, orbital angular momentum and polarization profile. Further, we find an ultrafast femtosecond laser pulse travelling along a defect line splits into multiple intensity regions, again depending on the defect's winding number, allowing applications in beam steering and filtering. Finally, our approach describing generation of complex optical fields via coupling with topological defect lines in optically birefringent nematic fluids can be easily extended to high-intensity beams that affect nematic ordering.

  1. Visible light emitting vertical cavity surface emitting lasers

    DOE Patents [OSTI]

    Bryan, R.P.; Olbright, G.R.; Lott, J.A.; Schneider, R.P. Jr.

    1995-06-27T23:59:59.000Z

    A vertical cavity surface emitting laser that emits visible radiation is built upon a substrate, then having mirrors, the first mirror on top of the substrate; both sets of mirrors being a distributed Bragg reflector of either dielectrics or other materials which affect the resistivity or of semiconductors, such that the structure within the mirror comprises a plurality of sets, each having a thickness of {lambda}/2n where n is the index of refraction of each of the sets; each of the mirrors adjacent to spacers which are on either side of an optically active bulk or quantum well layer; and the spacers and the optically active layer are from one of the following material systems: In{sub z}(Al{sub y}Ga{sub 1{minus}y}){sub 1{minus}z}P, InAlGaAs, AlGaAs, InGaAs, or AlGaP/GaP, wherein the optically active region having a length equal to m {lambda}/2n{sub eff} where m is an integer and n{sub eff} is the effective index of refraction of the laser cavity, and the spacer layer and one of the mirrors being transmissive to radiation having a wavelength of {lambda}/n, typically within the green to red portion of the visible spectrum. 10 figs.

  2. Resolution of a High Performance Cavity Beam Position Monitor System

    SciTech Connect (OSTI)

    Walston, S; Chung, C; Fitsos, P; Gronberg, J; Ross, M; Khainovski, O; Kolomensky, Y; Loscutoff, P; Slater, M; Thomson, M; Ward, D; Boogert, S; Vogel, V; Meller, R; Lyapin, A; Malton, S; Miller, D; Frisch, J; Hinton, S; May, J; McCormick, D; Smith, S; Smith, T; White, G; Orimoto, T; Hayano, H; Honda, Y; Terunuma, N; Urakawa, J

    2005-09-12T23:59:59.000Z

    International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved - ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. A metrology system for the three BPMs was recently installed. This system employed optical encoders to measure each BPM's position and orientation relative to a zero-coefficient of thermal expansion carbon fiber frame and has demonstrated that the three BPMs behave as a rigid-body to less than 5 nm. To date, we have demonstrated a BPM resolution of less than 20 nm over a dynamic range of +/- 20 microns.

  3. EXPERIMENTAL RESULTS FROM A MICROWAVE CAVITY BEAM POSITION MONITOR.

    SciTech Connect (OSTI)

    BALAKIN,V.; BAZHAN,A.; LUNEV,P.; SOLYAK,N.; VOGEL,V.; ZHOGOLEV,P.; LISITSYN,A.; YAKIMENKO,V.

    1999-03-29T23:59:59.000Z

    Future Linear Colliders have hard requirements for the beam transverse position stability in the accelerator. A beam Position Monitor (BPM) with the resolution better than 0.1 micron in the single bunch regime is needed to control the stability of the beam position along the linac. Proposed BPM is based on the measurement of the asymmetrical mode excited by single bunch in the cavity. Four stages of signal processing (space-, time-, frequency- and phase-filtering providing the required signal-to-noise ratio) are used to obtain extremely high resolution. The measurement set-up was designed by BINP and installed at ATF/BNL to test experimentally this concept. The set-up includes three two-coordinates BPM's at the frequency of 13.566 GHz, and reference intensity/phase cavity. BPM's were mounted on support table. The two-coordinates movers allow to move and align BPM's along the straight line, using the signals from the beam. The position of each monitor is controlled by the sensors with the accuracy 0.03 micron. The information from three monitors allows to exclude angle and position jitter of the beam and measure BPM resolution. In the experiments the resolution of about 0.15 micron for 0.25 nC beam intensity was obtained, that is close to the value required.

  4. Three-Dimensional Electromagnetic High Frequency Axisymmetric Cavity Scars.

    SciTech Connect (OSTI)

    Warne, Larry K.; Jorgenson, Roy E.

    2014-10-01T23:59:59.000Z

    This report examines the localization of high frequency electromagnetic fi elds in three-dimensional axisymmetric cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This report treats both the case where the opposing sides, or mirrors, are convex, where there are no interior foci, and the case where they are concave, leading to interior foci. The scalar problem is treated fi rst but the approximations required to treat the vector fi eld components are also examined. Particular att ention is focused on the normalization through the electromagnetic energy theorem. Both projections of the fi eld along the scarred orbit as well as point statistics are examined. Statistical comparisons are m ade with a numerical calculation of the scars run with an axisymmetric simulation. This axisymmetric cas eformstheoppositeextreme(wherethetwomirror radii at each end of the ray orbit are equal) from the two -dimensional solution examined previously (where one mirror radius is vastly di ff erent from the other). The enhancement of the fi eldontheorbitaxiscanbe larger here than in the two-dimensional case. Intentionally Left Blank

  5. Design and test of SX-FEL cavity BPM

    E-Print Network [OSTI]

    Yuan, Renxian; Chen, Zhichu; Yu, Luyang; Wang, Baopen; Leng, Yongbin

    2013-01-01T23:59:59.000Z

    This paper reports the design and cold test of the cavity beam position monitor (CBPM) for SX-FEL to fulfill the requirement of beam position measurement resolution of less than 1{\\mu}m, even 0.1{\\mu}m. The CBPM was optimized by using a coupling slot to damp the TM010 mode in the output signal. The isolation of TM010 mode is about 117dB, and the shunt impedance is about 200{\\Omega}@4.65GHz with the quality factor 80 from MAFIA simulation and test result. A special antenna was designed to load power for reducing excitation of other modes in the cavity. The resulting output power of TM110 mode was about 90mV/mm when the source was 6dBm, and the accomplishable minimum voltage was about 200{\\mu}V. The resolution of the CBPM was about 0.1{\\mu}m from the linear fitting result based on the cold test.

  6. Visible light emitting vertical cavity surface emitting lasers

    DOE Patents [OSTI]

    Bryan, Robert P. (Boulder, CO); Olbright, Gregory R. (Boulder, CO); Lott, James A. (Albuquerque, NM); Schneider, Jr., Richard P. (Albuquerque, NM)

    1995-01-01T23:59:59.000Z

    A vertical cavity surface emitting laser that emits visible radiation is built upon a substrate, then having mirrors, the first mirror on top of the substrate; both sets of mirrors being a distributed Bragg reflector of either dielectrics or other materials which affect the resistivity or of semiconductors, such that the structure within the mirror comprises a plurality of sets, each having a thickness of .lambda./2n where n is the index of refraction of each of the sets; each of the mirrors adjacent to spacers which are on either side of an optically active bulk or quantum well layer; and the spacers and the optically active layer are from one of the following material systems: In.sub.z (Al.sub.y Ga.sub.1-y).sub.1-z P, InAlGaAs, AlGaAs, InGaAs, or AlGaP/GaP, wherein the optically active region having a length equal to m .lambda./2n.sub.eff where m is an integer and n.sub.eff is the effective index of refraction of the laser cavity, and the spacer layer and one of the mirrors being transmissive to radiation having a wavelength of .lambda./n, typically within the green to red portion of the visible spectrum.

  7. Ultracold atoms in a cavity mediated double-well system

    E-Print Network [OSTI]

    Jonas Larson; Jani-Petri Martikainen

    2010-09-13T23:59:59.000Z

    We study ground-state properties and dynamics of a dilute ultracold atomic gas in a double well potential. The Gaussian barrier separating the two wells derives from the interaction between the atoms and a quantized field of a driven Fabry-Perot cavity. Due to intrinsic atom-field nonlinearity, several novel phenomena arise being the focus of this work. For the ground state, there is a critical pumping amplitude in which the atoms self-organize and the intra cavity field amplitude drastically increases. In the dynamical analysis, we show that the Josephson oscillations depend strongly on the atomic density and may be greatly suppressed within certain regimes, reminiscent of self-trapping of Bose-Einstein condensates in double-well setups. This pseudo self-trapping effect is studied within a mean-field treatment valid for large atom numbers. For small numbers of atoms, we consider the analogous many-body problem and demonstrate a collapse-revival structure in the Josephson oscillations.

  8. Potash Crystallization Lynn Batten1

    E-Print Network [OSTI]

    Tsatsomeros, Michael

    fertilizer and industrial chemical, from saturated brines. Typically, hot brine at about 100 C is cooled, knowledge of the spatial distribution of the chemical supersaturation state of the brine would help to improve the process control objectives: · Define conditions for crystal growth · Minimize occluded brine

  9. Robotic CCD microscope for enhanced crystal recognition

    DOE Patents [OSTI]

    Segelke, Brent W. (San Ramon, CA); Toppani, Dominique (Livermore, CA)

    2007-11-06T23:59:59.000Z

    A robotic CCD microscope and procedures to automate crystal recognition. The robotic CCD microscope and procedures enables more accurate crystal recognition, leading to fewer false negative and fewer false positives, and enable detection of smaller crystals compared to other methods available today.

  10. Incoherence and multiple parton interactions

    SciTech Connect (OSTI)

    Calucci, G.; Treleani, D. [Dipartimento di Fisica Teorica dell'Universita di Trieste and INFN, Sezione di Trieste, Strada Costiera 11, Miramare-Grignano, I-34151 Trieste (Italy)

    2009-09-01T23:59:59.000Z

    At the LHC multiple parton interactions will represent an important feature of the minimum bias and of the underlying event, and will give important contributions in many channels of interest in the search for new physics. Different numbers of multiple collisions may contribute to the production of a given final state, and one should expect important interference effects in the regime where different contributions have similar rates. We show, on the contrary, that, once multiple parton interactions are identified by their different topologies, terms with different numbers of multiple parton interactions do not interfere in the final cross section.

  11. Cryogenic spectroscopy of ultra-low density colloidal lead chalcogenide quantum dots on chip-scale optical cavities towards single quantum dot near-infrared cavity QED

    E-Print Network [OSTI]

    Ranojoy Bose; Jie Gao; James F. McMillan; Alex D. Williams; Chee Wei Wong

    2009-11-09T23:59:59.000Z

    We present evidence of cavity quantum electrodynamics from a sparse density of strongly quantum-confined Pb-chalcogenide nanocrystals (between 1 and 10) approaching single-dot levels on moderately high-Q mesoscopic silicon optical cavities. Operating at important near-infrared (1500-nm) wavelengths, large enhancements are observed from devices and strong modifications of the QD emission are achieved. Saturation spectroscopy of coupled QDs is observed at 77K, highlighting the modified nanocrystal dynamics for quantum information processing.

  12. Erbium-doped fiber ring laser tuning using an intra-cavity Fabry-Perot filter

    E-Print Network [OSTI]

    Malik, Bilal Hameed

    2009-06-02T23:59:59.000Z

    A tunable erbium-doped fiber ring laser using an intra-cavity Fabry-Perot filter as the tuning element is investigated. Tuning is achieved by varying the applied voltage which controls the FP cavity length. The laser's wavelength is monitored using...

  13. Achievement of 35 MV/m in the Superconducting Nine-Cell Cavities for TESLA 1

    E-Print Network [OSTI]

    Achievement of 35 MV/m in the Superconducting Nine-Cell Cavities for TESLA 1 L. Lilje2 , D. Kostin Electronvolt Superconducting Linear Accelerator TESLA is the only linear electron-positron collider project reliably achieved in the cavities of the TESLA Test Facility (TTF) accelerator. The upgrade of TESLA to 800

  14. TESLA 2004-14 Test Measurements of a new TESLA Cavity

    E-Print Network [OSTI]

    TESLA 2004-14 Test Measurements of a new TESLA Cavity Beam Position Monitor at the ELBE Linac V Abstract A new type of a cavity BPM proposed for beam position determination along the TESLA linac to TESLA would fulfil the demands for precise bunch-to-bunch position determination. Possible improvements

  15. Electrical axes of TESLA-type cavities (Theoretical background, development of measurement equipment, measurement results)

    E-Print Network [OSTI]

    - 1 - Electrical axes of TESLA-type cavities (Theoretical background, development of measurement equipment, measurement results) Anton Labanc, MHF-SL, DESY, January 2008 Abstract Cells in TESLA cavities. A short overview was already published at the TESLA Report 2007-01. This paper brings more details about

  16. TESLA Report 2003-28 TESLA cavity modeling and digital implementation

    E-Print Network [OSTI]

    TESLA Report 2003-28 TESLA cavity modeling and digital implementation with FPGA technology solution, Warsaw University of Technology Stefan Simrock TESLA, DESY, Hamburg ABSTRACT The cavity resonator modeling for the TESLA - TeV­Energy Superconducting Linear Accelerator project is initially introduced

  17. Bow shocks formed by plasma collisions in laser irradiated semi-cylindrical cavities

    E-Print Network [OSTI]

    Rocca, Jorge J.

    the axis to form a dense bright plasma focus. Later in time a long lasting bow shock is observed to develop a location near the cavity axis, where it collides forming a bright high density plasma focusBow shocks formed by plasma collisions in laser irradiated semi-cylindrical cavities Jorge Filevich

  18. Novel laser machining of optical fibers for long cavities with low birefringence

    E-Print Network [OSTI]

    Hiroki Takahashi; Jack Morphew; Fedja Orucevic; Atsushi Noguchi; Ezra Kassa; Matthias Keller

    2015-01-07T23:59:59.000Z

    We present a novel method of machining optical fiber surfaces with a CO${}_2$ laser for use in Fiber-based Fabry-Perot Cavities (FFPCs). Previously FFPCs were prone to large birefringence and limited to relatively short cavity lengths ($\\le$ 200 $\\mu$m). These characteristics hinder their use in some applications such as cavity quantum electrodynamics with trapped ions. We optimized the laser machining process to produce large, uniform surface structures. This enables the cavities to achieve high finesse even for long cavity lengths. By rotating the fibers around their axis during the laser machining process the asymmetry resulting from the laser's transverse mode profile is eliminated. Consequently we are able to fabricate fiber mirrors with a high degree of rotational symmetry, leading to remarkably low birefringence. Through measurements of the cavity finesse over a range of cavity lengths and the polarization dependence of the cavity linewidth, we confirmed the quality of the produced fiber mirrors for use in low-birefringence FFPCs.

  19. PHYSICAL REVIEW B 88, 195422 (2013) Cavity-enhanced absorption and Fano resonances in graphene nanoribbons

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    PHYSICAL REVIEW B 88, 195422 (2013) Cavity-enhanced absorption and Fano resonances in graphene 2013) We analyze the absorption of a graphene nanoribbon placed into an optical cavity. We demonstrate the existence of strong coupling between the Van-Hove singularities in armchair graphene nanoribbons

  20. THERMAL PROPERTIES OF A SOLAR CORONAL CAVITY OBSERVED WITH THE X-RAY TELESCOPE ON HINODE

    SciTech Connect (OSTI)

    Reeves, Katharine K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St. MS 58, Cambridge, MA 02138 (United States); Gibson, Sarah E. [HAO/NCAR, P.O. Box 3000, Boulder, CO 80307-3000 (United States); Kucera, Therese A. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States); Hudson, Hugh S. [Space Sciences Laboratories, University of California, Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Kano, Ryouhei, E-mail: kreeves@cfa.harvard.edu [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2012-02-20T23:59:59.000Z

    Coronal cavities are voids in coronal emission often observed above high latitude filament channels. Sometimes, these cavities have areas of bright X-ray emission in their centers. In this study, we use data from the X-ray Telescope (XRT) on the Hinode satellite to examine the thermal emission properties of a cavity observed during 2008 July that contains bright X-ray emission in its center. Using ratios of XRT filters, we find evidence for elevated temperatures in the cavity center. The area of elevated temperature evolves from a ring-shaped structure at the beginning of the observation, to an elongated structure two days later, finally appearing as a compact round source four days after the initial observation. We use a morphological model to fit the cavity emission, and find that a uniform structure running through the cavity does not fit the observations well. Instead, the observations are reproduced by modeling several short cylindrical cavity 'cores' with different parameters on different days. These changing core parameters may be due to some observed activity heating different parts of the cavity core at different times. We find that core temperatures of 1.75 MK, 1.7 MK, and 2.0 MK (for July 19, July 21, and July 23, respectively) in the model lead to structures that are consistent with the data, and that line-of-sight effects serve to lower the effective temperature derived from the filter ratio.