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1

Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers  

SciTech Connect (OSTI)

A neutron source for neutron resonance spectroscopy (NRS) has been developed using high intensity, short pulse lasers. This measurement technique will allow for robust measurements of interior ion temperature of laser-shocked materials and provide insight into equation of state (EOS) measurements. The neutron generation technique uses protons accelerated by lasers off of Cu foils to create neutrons in LiF, through (p,n) reactions with {sup 7}Li and {sup 19}F. The distribution of the incident proton beam has been diagnosed using radiochromic film (RCF). This distribution is used as the input for a (p,n) neturon prediction code which is compared to experimentally measured neutron yields. From this calculation, a total fluence of 1.8 x 10{sup 9} neutrons is infered, which is shown to be a reasonable amount for NRS temperature measurement.

Higginson, D P; McNaney, J M; Swift, D C; Bartal, T; Hey, D S; Pape, S L; Mackinnon, A; Mariscal, D; Nakamura, H; Nakanii, N; Beg, F N

2010-04-22T23:59:59.000Z

2

Intense Pulsed Neutron Source progress report for 1991  

SciTech Connect (OSTI)

The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne's ZING-P and ZING-P' prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and in press'' articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

Not Available

1991-01-01T23:59:59.000Z

3

Pulsed-neutron monochromator  

DOE Patents [OSTI]

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, H.A. Jr.

1984-01-01T23:59:59.000Z

4

Pulsed-neutron monochromator  

DOE Patents [OSTI]

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, Jr., Herbert A. (Oak Ridge, TN)

1985-01-01T23:59:59.000Z

5

Intense Pulsed Neutron Source: Progress report 1991--1996. 15. Anniversary edition -- Volume 1  

SciTech Connect (OSTI)

The 15th Anniversary Edition of the IPNS Progress Report is being published in recognition of the Intense Pulsed Neutron Source`s first 15 years of successful operation as a user facility. To emphasize the importance of this milestone, the authors have made the design and organization of the report significantly different from previous IPNS Progress Reports. This report consists of two volumes. For Volume 1, authors were asked to prepare articles that highlighted recent scientific accomplishments at IPNS, from 1991 to present; to focus on and illustrate the scientific advances achieved through the unique capabilities of neutron studies performed by IPNS users; to report on specific activities or results from an instrument; or to focus on a body of work encompassing different neutron-scattering techniques. Articles were also included on the accelerator system, instrumentation, computing, target, and moderators. A list of published and ``in press` articles in journals, books, and conference proceedings, resulting from work done at IPNS since 1991, was compiled. This list is arranged alphabetically according to first author. Publication references in the articles are listed by last name of first author and year of publication. The IPNS experimental reports received since 1991 are compiled in Volume 2. Experimental reports referenced in the articles are listed by last name of first author, instrument designation, and experiment number.

Marzec, B. [ed.

1996-05-01T23:59:59.000Z

6

Neutron Halo Isomers in Stable Nuclei and their Possible Application for the Production of Low Energy, Pulsed, Polarized Neutron Beams of High Intensity and High Brilliance  

E-Print Network [OSTI]

We propose to search for neutron halo isomers populated via $\\gamma$-capture in stable nuclei with mass numbers of about A=140-180 or A=40-60, where the $4s_{1/2}$ or $3s_{1/2}$ neutron shell model state reaches zero binding energy. These halo nuclei can be produced for the first time with new $\\gamma$-beams of high intensity and small band width ($\\le$ 0.1%) achievable via Compton back-scattering off brilliant electron beams thus offering a promising perspective to selectively populate these isomers with small separation energies of 1 eV to a few keV. Similar to single-neutron halo states for very light, extremely neutron-rich, radioactive nuclei \\cite{hansen95,tanihata96,aumann00}, the low neutron separation energy and short-range nuclear force allows the neutron to tunnel far out into free space much beyond the nuclear core radius. This results in prolonged half lives of the isomers for the $\\gamma$-decay back to the ground state in the 100 ps-$\\mu$s range. Similar to the treatment of photodisintegration of the deuteron, the neutron release from the neutron halo isomer via a second, low-energy, intense photon beam has a known much larger cross section with a typical energy threshold behavior. In the second step, the neutrons can be released as a low-energy, pulsed, polarized neutron beam of high intensity and high brilliance, possibly being much superior to presently existing beams from reactors or spallation neutron sources.

D. Habs; M. Gross; P. G. Thirolf; P. B鰊i

2010-09-30T23:59:59.000Z

7

Neutron production from interactions of high-intensity ultrashort pulse laser with a planar deuterated polyethylene target  

SciTech Connect (OSTI)

The deuteron acceleration from a planar uniform deuterated polyethylene (CD{sub 2}) target was studied with a two-dimensional electromagnetic particle-in-cell method in the ultrarelativistic regime for peak laser intensities between 10{sup 23} and 10{sup 25} W/m{sup 2}. Under identical conditions the deuteron energy and angular distributions are very different when compared to that produced from a double-layer target. The neutron production from D(d,n)-{sup 3}He nuclear fusion reactions was also investigated with a three-dimensional Monte Carlo ion beam-target deposition model. The neutron yield and its angular distribution were studied as a function of peak laser intensity and laser pulse duration. A neutron yield of 10{sup 4}-10{sup 6} neutrons per Joule laser energy is inferred from simulations of a 4 {mu}m thick planar uniform CD{sub 2} target. The angular scattering of neutrons is found to be nonisotropic and has a significant component in the forward (laser propagation) direction.

Petrov, G. M.; Davis, J. [Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Avenue SW, Washington, D.C. 20375 (United States)

2008-07-15T23:59:59.000Z

8

Fast neutron emission from a deuterated polystyrene solid target irradiated by a high-intensity laser pulse  

Science Journals Connector (OSTI)

Fast neutrons were generated from a deuterated polystyrene (C8D8) solid-target irradiated by a high-intensity laser. A TOF neutron signal is analyzed in detail. A...

Lee, Sungman; Kwon, Sungok; Lee, Kitae; Cha, Yong-Ho; Yea, Kwon-hae; Lee, Yong Woo; Lee, Ji Young; Jeong, Young Uk; Rhee, Yong Joo; Cha, Hyungki

9

Fast neutron emission from a deuterated polystyrene solid target irradiated by a high-intensity laser pulse  

Science Journals Connector (OSTI)

Fast neutrons were generated from a deuterated polystyrene (C8D8) solid-target irradiated by a high-intensity laser. A TOF neutron signal is analyzed in detail....

Lee, Sungman; Kwon, Sungok; Lee, Kitae; Cha, Yong-Ho; Yea, Kwon-hae; Lee, Yong Woo; Lee, Ji Young; Jeong, Young Uk; Rhee, Yong Joo; Cha, Hyungki

10

Production of neutrons up to 18 MeV in high-intensity, short-pulse laser matter interactions  

E-Print Network [OSTI]

was 0.5%, an order of magnitude greater than into deuterons. Maximum neutron energy was shown-intensity, petawatt class lasers may provide an attractive alternate with rela- tively lower costs,

11

Pulsed Neutron Powder Diffraction  

Science Journals Connector (OSTI)

The nature and scope of powder diffraction with a white, pulsed beam of neutrons is discussed. Analysis of the data by the Rietveld profile technique is described in brief, and a range of applications in solid...

A. K. Cheetham

1988-01-01T23:59:59.000Z

12

E-Print Network 3.0 - argonne intense pulsed Sample Search Results  

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

laboratory with both types of facilities: the Intense Pulsed Neutron Source (IPNS) for neutron scattering... Argonne Update 1 Hardest, strongest materials combined UPDATE The...

13

Fast Pulsing Neutron Generators for Security Application  

E-Print Network [OSTI]

FAST PULSING NEUTRON GENERATORS FOR SECURITY APPLICATION* Q.time/fast pulsing neutron generator is needed primarily forA compact neutron generator, currently being developed in

Ji, Q.

2010-01-01T23:59:59.000Z

14

Design, production, and evaluation of a zircaloy-clad uranium target for an intense pulsed neutron source application  

SciTech Connect (OSTI)

The design of a Zircaloy-2-clad uranium alloy (450 ppm carbon, 250 ppm iron, 350 ppm silicon) target that can function as a pulsed spallation neutron source on interaction of a pulsed 500-MeV proton beam with the uranium nuclei is determined by consideration of irradiation damage, energy deposition, and thermal cycling effects in the target. The designed target is comprised of eight watercooled Zircaloy-2-clad uranium alloy disks, 10 cm in diameter and 2.7 cm thick operating at a maximum uranium alloy centerline temperature of 330/sup 0/C. The production of the Zircaloy-2-clad uranium alloy disks involves remelting of the cast uranium alloy by the consumable electrode technique and bonding of the Zircaloy-2 to the uranium alloy by subjecting the composite to an isostatic-helium pressure at 840/sup 0/C. The lifetime of the disks in the target before cracking of the Zircaloy-2 cladding owing to lowfrequency thermal cycling fatigue is estimated from stress calculations to be about 500 days. The results of thermal cycling tests on a disk tend to confirm the results of the stress calculations.

Loomis, B.A.; Fogle, G.L.; Gerber, S.B.; Thresh, H.R.

1981-12-01T23:59:59.000Z

15

Device for Writing the Time Tail from Spallation Neutron Pulses  

SciTech Connect (OSTI)

Recent work at Los Alamos Neutron Science Center (LANSCE), has shown that there are large gains in neutron beam intensity to be made by using coupled moderators at spallation neutron sources. Most of these gains result from broadening the pulse-width in time. However the accompanying longer exponential tail at large emission times can be a problem in that it introduces relatively large beam-related backgrounds at high resolutions. We have designed a device that can reshape the moderated neutron beam by cutting the time-tail so that a sharp time resolution can be re-established without a significant loss in intensity. In this work the basic principles behind the tail-cutter and some initial results of Monte Carlo simulations are described. Unwanted neutrons in the long time-tail are diffracted out of the transmitted neutron beam by a nested stack of aperiodic multi-layers, rocking at the same frequency as the source. Nested aperiodic multi-layers have recently been used at X-ray sources and as band-pass filters in quasi-Laue neutron experiments at reactor neutron sources. Optical devices that rock in synchronization with a pulsed neutron beam are relatively new but are already under construction at LANSCE. The tail-cutter described here is a novel concept that uses existing multi-layer technology in a new way for spallation neutrons. Coupled moderators in combination with beam shaping devices offer the means of increasing flux whilst maintaining a sharp time distribution. A prototype device is being constructed for the protein crystallography station at LANSCE. The protein crystallography station incorporates a water moderator that has been judiciously coupled in order to increase the flux over neutron energies that are important to structural biology (3-80meV). This development in moderator design is particularly important because protein crystallography is flux limited and because conventional ambient water and cold hydrogen moderators do not provide relatively large neutron fluxes over this neutron energy range.

Langan, P. (Paul); Schoenborn, Benno P.; Langan, P. (Paul); Schoenborn, Benno P.; Daemen, L. L. (Luc L.)

2001-01-01T23:59:59.000Z

16

Methodology for the use of proportional counters in pulsed fast neutron yield measurements  

E-Print Network [OSTI]

This paper introduces in full detail a methodology for the measurement of neutron yield and the necessary efficiency calibration, to be applied to the intensity measurement of neutron bursts where individual neutrons are not resolved in time, for any given moderated neutron proportional counter array. The method allows efficiency calibration employing the detection neutrons arising from an isotopic neutron source. Full statistical study of the procedure is descripted, taking into account contributions arising from counting statistics, piling-up statistics of real detector pulse-height spectra and background fluctuations. The useful information is extracted from the net waveform area of the signal arising from the electric charge accumulated inside the detector tube. Improvement of detection limit is gained, therefore this detection system can be used in detection of low emission neutron pulsed sources with pulses of duration from nanoseconds to up. The application of the methodology to detection systems to be...

Tarife駉-Saldivia, Ariel; Pavez, Cristian; Soto, Leopoldo

2011-01-01T23:59:59.000Z

17

Commissioning of intensity modulated neutron radiotherapy (IMNRT)  

SciTech Connect (OSTI)

Purpose: Intensity modulated neutron radiotherapy (IMNRT) has been developed using inhouse treatment planning and delivery systems at the Karmanos Cancer Center/Wayne State University Fast Neutron Therapy facility. The process of commissioning IMNRT for clinical use is presented here. Results of commissioning tests are provided including validation measurements using representative patient plans as well as those from the TG-119 test suite. Methods: IMNRT plans were created using the Varian Eclipse optimization algorithm and an inhouse planning system for calculation of neutron dose distributions. Tissue equivalent ionization chambers and an ionization chamber array were used for point dose and planar dose distribution comparisons with calculated values. Validation plans were delivered to water and virtual water phantoms using TG-119 measurement points and evaluation techniques. Photon and neutron doses were evaluated both inside and outside the target volume for a typical IMNRT plan to determine effects of intensity modulation on the photon dose component. Monitor unit linearity and effects of beam current and gantry angle on output were investigated, and an independent validation of neutron dosimetry was obtained. Results: While IMNRT plan quality is superior to conventional fast neutron therapy plans for clinical sites such as prostate and head and neck, it is inferior to photon IMRT for most TG-119 planning goals, particularly for complex cases. This results significantly from current limitations on the number of segments. Measured and calculated doses for 11 representative plans (six prostate/five head and neck) agreed to within -0.8 {+-} 1.4% and 5.0 {+-} 6.0% within and outside the target, respectively. Nearly all (22/24) ion chamber point measurements in the two phantom arrangements were within the respective confidence intervals for the quantity [(measured-planned)/prescription dose] derived in TG-119. Mean differences for all measurements were 0.5% (max = 7.0%) and 1.4% (max = 4.1%) in water and virtual water, respectively. The mean gamma pass rate for all cases was 92.8% (min = 88.6%). These pass rates are lower than typically achieved with photon IMRT, warranting development of a planar dosimetry system designed specifically for IMNRT and/or the improvement of neutron beam modeling in the penumbral region. The fractional photon dose component did not change significantly in a typical IMNRT plan versus a conventional fast neutron therapy plan, and IMNRT delivery is not expected to significantly alter the RBE. All other commissioning results were considered satisfactory for clinical implementation of IMNRT, including the external neutron dose validation, which agreed with the predicted neutron dose to within 1%. Conclusions: IMNRT has been successfully commissioned for clinical use. While current plan quality is inferior to photon IMRT, it is superior to conventional fast neutron therapy. Ion chamber validation results for IMNRT commissioning are also comparable to those typically achieved with photon IMRT. Gamma pass rates for planar dose distributions are lower than typically observed for photon IMRT but may be improved with improved planar dosimetry equipment and beam modeling techniques. In the meantime, patient-specific quality assurance measurements should rely more heavily on point dose measurements with tissue equivalent ionization chambers. No significant technical impediments are anticipated in the clinical implementation of IMNRT as described here.

Burmeister, Jay; Snyder, Michael [Karmanos Cancer Center, Wayne State University School of Medicine, Detroit, Michigan 48201 (United States); Spink, Robyn; Liang Liang; Bossenberger, Todd; Halford, Robert [Karmanos Cancer Center, Detroit, Michigan 48201 (United States); Brandon, John [Michigan State University, East Lansing, Michigan 48201 (United States); Delauter, Jonathan [Wayne State University School of Medicine, Detroit, Michigan 48201 (United States)

2013-02-15T23:59:59.000Z

18

Polarized neutron reflectometry at the IBR-2 pulsed reactor  

SciTech Connect (OSTI)

Polarized neutron reflectometry as a method for investigating layered nanostructures and its implementation at the IBR-2 pulsed reactor (Dubna, Russia) are described. The experimental data illustrating the studies of magnetic layered nanostructures and the development of the method of polarized neutron reflectometry on the polarized neutron spectrometer are presented. The directions of further development of the method of polarized neutron reflectometry are analyzed.

Aksenov, V. L. [Russian Research Centre 'Kurchatov Institute' (Russian Federation); Nikitenko, Yu. V. [Joint Institute for Nuclear Research (Russian Federation)], E-mail: nikiten@nf.jinr.ru

2007-05-15T23:59:59.000Z

19

Supergiant Pulses from Extragalactic Neutron Stars  

E-Print Network [OSTI]

We evaluate the hypothesis that extragalactic radio bursts originate from neutron stars. These could be active pulsars or dormant, slowly spinning objects, but the different population distances for these two classes require correspondingly different contributions to burst dispersion measures from any host or intervening galaxies combined with the intergalactic medium. The large, apparent burst rate $\\sim 10^4~$ sky$^{-1}~$ day$^{-1}$ is comparable to the core-collapse supernova rate in a Hubble volume and can be accommodated by a single burst per object in the resulting large reservoir of $\\sim 10^{17}~$ neutron stars. A smaller population distance requires more bursts per object but the likelihood of seeing repeated bursts from any single object is extremely low on human timescales. Gravitational microlensing could play a role for high redshift sources. Extrapolation of the Crab pulsar's giant pulses --- exemplars of coherent, high brightness temperature radiation --- to a rate of one per $10^3~$yr yields a...

Cordes, J M

2015-01-01T23:59:59.000Z

20

Project of Rotating Carbon High-Power Neutron Target. Research of Graphite Properties for Production of High Intensity Neutron Source  

E-Print Network [OSTI]

Project of Rotating Carbon High-Power Neutron Target. Research of Graphite Properties for Production of High Intensity Neutron Source

Gubin, K V; Bak, P A; Kot, N K; Logatchev, P V

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Response of GaAs to fast intense laser pulses  

E-Print Network [OSTI]

Motivated by recent experiments, we have performed simulations which show in detail how the electrons and ions in GaAs respond to fast intense laser pulses (with durations of order 100 fs and intensities of order 1-10 TW/cm(2)). The method of tight...

Graves, JS; Allen, Roland E.

1998-01-01T23:59:59.000Z

22

MATERIAL STUDIES FOR PULSED HIGH-INTENSITY PROTON BEAM TARGETS  

E-Print Network [OSTI]

PLAN MATERIAL STUDIES FOR PULSED HIGH-INTENSITY PROTON BEAM TARGETS Nicholas Simos, Harold Kirk and removal from the target system 路Target thermo-mechanical response from energetic, high intensity protons are: 路Inconel-718 路Aluminum-3000 路Havar 路Ti-6Al-6V 路Graphite (ATJ) 路Carbon-Carbon 路SuperInvar #12

McDonald, Kirk

23

Calculations of population transfer during intense laser pulses  

SciTech Connect (OSTI)

Recent experiments by several groups have examined the question of population transfer to resonantly excited states during intense short laser pulses, in particular the amount of population that remains ``trapped`` in excited states at the end of a laser pulse. In this chapter we present calculations of population transfer and resonant ionization in xenon at both 660 and 620 nm. At the longer wavelength, the seven photon channel closes at 2.5{times}10{sup 13} W/cm{sup 2}. Pulses with peak intensities higher than this result in ``Rydberg trapping``, the resonant transfer of population to a broad range of high-lying states. The amount of population transferred depends on both the peak intensity and pulse duration. At 620 mm there are numerous possible six photon resonances to states with p or f angular momentum. We have done a large number of calculations for 40 fs pulses at different peak intensities and have examined the population transferred to these low-lying resonant states as a function of the peak laser intensity. We do not have room to comment upon the resonantly enhanced ionized electron energy spectra that we also determine in the same calculations. Our calculations involve the direct numerical integration of the time-dependent Schroedinger equation for an atom interacting with a strong laser field. The time-dependent wave function of a given valence electron is calculated on a spatial grid using a one-electron pseudo potential. This single active electron approximation (SAE) has been shown to be a good approximation for the rare gases at the intensities and wavelengths that we will consider. The SAE potential we use has an explicit angular momentum dependence which allows us to reproduce all of the excited state energies for xenon quite well.

Schafer, K.J.; Kulander, K.C.

1993-08-01T23:59:59.000Z

24

Note: Emittance measurements of intense pulsed proton beam for different pulse length and repetition rate  

SciTech Connect (OSTI)

The high intensity ion source (SILHI), in operation at CEA-Saclay, has been used to produce a 90 mA pulsed proton beam with pulse length and repetition rates suitable for the European Spallation Source (ESS) linac. Typical r-r{sup '} rms normalized emittance values smaller than 0.2{pi} mm mrad have been measured for operation in pulsed mode (0.01 < duty cycle < 0.15 and 1 ms < pulse duration < 10 ms) that are relevant for the design update of the Linac to be used at the ESS in Lund.

Miracoli, R. [ESS Bilbao, Vizcaya (Spain); INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Gammino, S.; Celona, L.; Mascali, D. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Castro, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Universita degli studi di Catania, Dipartimento di Fisica e Astronomia, V. S. Sofia 64, 95123 Catania (Italy); Gobin, R.; Delferriere, O.; Adroit, G.; Senee, F. [CEA-IRFU, Gif sur Yvette Cedex (France); Ciavola, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); CNAO, Str. Pr. Campeggi, Pavia (Italy)

2012-05-15T23:59:59.000Z

25

E-Print Network 3.0 - advanced pulsed-neutron research Sample...  

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

Fuels ; Geosciences 13 Major Facilities for Materials Research Summary: Neutron Source: upgrading of the National Magnet Laboratory: and enriched pulsed neutron targets... and...

26

Design trade-off study for a large volume short pulse neutron assembly  

SciTech Connect (OSTI)

There is a continuing need within the radiation effects research community for more intense and larger volume pulsed neutron facilities. To fulfill these requirements a study was performed to examine conceptual designs for a neutron assembly that could produce high-intensity, short pulse neutron environments over a large experimental volume. The desired system characteristics were a cylindrical experimental cavity 60 inches long (152.4 cm) with a 24 inch diameter (60.96 cm), a cavity fluence of {phi}{sub r} = 8{times}10{sup 14} n/cm{sup 2}, and a neutron pulse width of {tau} = 10--20 {mu}s. Attention was focused on booster assemblies which have been studied since the 1950s at Harwell, General Atomic, and at Sandia National Laboratories. Five conceptual designs were developed and evaluated. Only a two-stage coupled core design with a NpO{sub 2} primary core assembly was found to meet the design goals. A program is proposed to refine the design and to construct this nuclear assembly. The proposed three-phase effort represents a conservative approach that will yield large increases in the experiment volume even if the final coupled-core design is not realized.

Griffin, P.J.; Miller, J.D.; Harms, G.A.; Parma, E.J.; Coats, R.L.; Fan, W.C. [Sandia National Labs., Albuquerque, NM (United States); Petraglia, J.P. [Battelle Pantex, Amarillo, TX (United States)

1994-09-01T23:59:59.000Z

27

A neutron imaging device for sample alignment in a pulsed neutron scattering instrument  

Science Journals Connector (OSTI)

A neutron-imaging device for alignment purposes has been tested on the INES beamline at ISIS the pulsed neutron source of Rutherford Appleton Laboratory (U.K.). Its use in conjunction with a set of movable jaws turns out extremely useful for scattering application to complex samples where a precise and well-defined determination of the scattering volume is needed.

F. Grazzi; A. Scherillo; M. Zoppi

2009-01-01T23:59:59.000Z

28

YALINA-booster subcritical assembly pulsed-neutron experiments : data processing and spatial corrections.  

SciTech Connect (OSTI)

The YALINA-Booster experiments and analyses are part of the collaboration between Argonne National Laboratory of USA and the Joint Institute for Power & Nuclear Research - SOSNY of Belarus for studying the physics of accelerator driven systems for nuclear energy applications using low enriched uranium. The YALINA-Booster subcritical assembly is utilized for studying the kinetics of accelerator driven systems with its highly intensive D-T or D-D pulsed neutron source. In particular, the pulsed neutron methods are used to determine the reactivity of the subcritical system. This report examines the pulsed-neutron experiments performed in the YALINA-Booster facility with different configurations for the subcritical assembly. The 1141 configuration with 90% U-235 fuel and the 1185 configuration with 36% or 21% U-235 fuel are examined. The Sjoestrand area-ratio method is utilized to determine the reactivities of the different configurations. The linear regression method is applied to obtain the prompt neutron decay constants from the pulsed-neutron experimental data. The reactivity values obtained from the experimental data are shown to be dependent on the detector locations inside the subcritical assembly and the types of detector used for the measurements. In this report, Bell's spatial correction factors are calculated based on a Monte Carlo model to remove the detector dependences. The large differences between the reactivity values given by the detectors in the fast neutron zone of the YALINA-Booster are reduced after applying the spatial corrections. In addition, the estimated reactivity values after the spatial corrections are much less spatially dependent.

Cao, Y.; Gohar, Y.; Nuclear Engineering Division

2010-10-11T23:59:59.000Z

29

Neutron Imaging of Advanced Engine Technologies  

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

the development process * Spallation Neutron Source (SNS) - Most intense pulsed neutron beams in the world; energy selective - Multi-laboratory effort funded by DOE Office of...

30

Neutron production from 7Li(d,xn) nuclear fusion reactions driven by high-intensity laser杢arget interactions  

Science Journals Connector (OSTI)

Numerical simulations of neutron production from deuterium杔ithium nuclear fusion reactions have been performed. A set of differential cross sections for the 7Li(d,xn) reaction for incident deuteron energies of up to 50?MeV is assembled. The angular distribution of neutrons from a thick lithium target is simulated and benchmarked against experimental data. Two-stage neutron production from laser杢arget experiments has been studied as a function of laser intensity and energy. During the first stage a well collimated deuteron beam is generated using a high-intensity ultrashort pulse laser. During the second stage it is transported through a lithium target using a 3D Monte-Carlo ion beam杢arget deposition model. The neutron yield is estimated to be ~108?neutrons?J?1 laser energy. Some 1010 neutrons can be expected from a ~100?J petawatt-class laser. For incident deuteron energies above 1?MeV the proposed scheme for neutron production from d朙i reactions is superior to that from d杁 reactions, producing a collimated beam of neutrons with higher neutron yield.

J Davis; G M Petrov; Tz Petrova; L Willingale; A Maksimchuk; K Krushelnick

2010-01-01T23:59:59.000Z

31

Physics of neutralization of intense high-energy ion beam pulses by electronsa...  

E-Print Network [OSTI]

Physics of neutralization of intense high-energy ion beam pulses by electronsa... I. D. Kaganovich beams,13 the physics of solar flares,14 high-intensity high- energy particle beam propagation Neutralization and focusing of intense charged particle beam pulses by electrons form the basis for a wide range

Kaganovich, Igor

32

Small plasma focus as neutron pulsed source for nuclides identification  

SciTech Connect (OSTI)

In this paper, we present preliminary results on the feasibility of employing a low energy (2 kJ, 31 kV) plasma focus device as a portable source of pulsed neutron beams (2.45 MeV) generated by nuclear fusion reactions D-D, for the 搃n situ analysis of substances by nuclear activation. This source has the relevant advantage of being pulsed at requirement, transportable, not permanently radioactive, without radioactive waste, cheap, among others. We prove the feasibility of using this source showing several spectra of the characteristic emission line for manganese, gold, lead, and silver.

Milanese, M.; Moroso, R.; Barbaglia, M. [Centro de Investigaciones en F韘ica e Ingenier韆 del Centro de la Provincia de Buenos Aires (CONICET-UNCPBA), Pinto 399, Tandil 7000, Buenos Aires (Argentina) [Centro de Investigaciones en F韘ica e Ingenier韆 del Centro de la Provincia de Buenos Aires (CONICET-UNCPBA), Pinto 399, Tandil 7000, Buenos Aires (Argentina); Universidad del Centro de la Provincia de Buenos Aires (CONICET-UNCPBA), Pinto 399, Tandil 7000, Buenos Aires (Argentina); Niedbalski, J. [CONICET(Consejo Nacional de Investigaciones Cient韋icas y T閏nicas), Rivadavia 1917, Buenos Aires (Argentina)] [CONICET(Consejo Nacional de Investigaciones Cient韋icas y T閏nicas), Rivadavia 1917, Buenos Aires (Argentina); Mayer, R. [CNEA (Comisi髇 Nacional de Energ韆 At髆ica), Av. Bustillo 9500, San Carlos de Bariloche, Rio Negro (Argentina)] [CNEA (Comisi髇 Nacional de Energ韆 At髆ica), Av. Bustillo 9500, San Carlos de Bariloche, Rio Negro (Argentina); Castillo, F. [UNAM (Universidad Nacional Aut髇oma de M閤ico)朇ircuito Exterior s/n, Ciudad Universitaria, Delg. Coyoac醤, P.O. Box 70-543, M閤ico DF (Mexico)] [UNAM (Universidad Nacional Aut髇oma de M閤ico)朇ircuito Exterior s/n, Ciudad Universitaria, Delg. Coyoac醤, P.O. Box 70-543, M閤ico DF (Mexico); Guich髇, S. [Universidad del Centro de la Provincia de Buenos Aires (CONICET-UNCPBA), Pinto 399, Tandil 7000, Buenos Aires (Argentina)] [Universidad del Centro de la Provincia de Buenos Aires (CONICET-UNCPBA), Pinto 399, Tandil 7000, Buenos Aires (Argentina)

2013-10-15T23:59:59.000Z

33

Small plasma focus as neutron pulsed source for nuclides identification  

Science Journals Connector (OSTI)

In this paper we present preliminary results on the feasibility of employing a low energy (2 kJ 31 kV) plasma focus device as a portable source of pulsed neutron beams (2.45 MeV) generated by nuclear fusion reactions D-D for the 搃n situ analysis of substances by nuclear activation. This source has the relevant advantage of being pulsed at requirement transportable not permanently radioactive without radioactive waste cheap among others. We prove the feasibility of using this source showing several spectra of the characteristic emission line for manganese gold lead and silver.

M. Milanese; J. Niedbalski; R. Moroso; M. Barbaglia; R. Mayer; F. Castillo; S. Guich髇

2013-01-01T23:59:59.000Z

34

Advances in 14 MeV neutron activation analysis by means of a new intense neutron source  

Science Journals Connector (OSTI)

A new intense 14 MeV neutron generator with cylindrical acceleration structure has been put in operation at the GKSS Research Center Geesthacht. The sealed neutron tube is combined with...10 n/cm2s. Theoretical s...

R. Pepelnik; H. -U. Fanger; W. Michaelis; B. Anders

1982-01-01T23:59:59.000Z

35

Intensity modulated neutron radiotherapy optimization by photon proxy  

SciTech Connect (OSTI)

Purpose: Introducing intensity modulation into neutron radiotherapy (IMNRT) planning has the potential to mitigate some normal tissue complications seen in past neutron trials. While the hardware to deliver IMNRT plans has been in use for several years, until recently the IMNRT planning process has been cumbersome and of lower fidelity than conventional photon plans. Our in-house planning system used to calculate neutron therapy plans allows beam weight optimization of forward planned segments, but does not provide inverse optimization capabilities. Commercial treatment planning systems provide inverse optimization capabilities, but currently cannot model our neutron beam. Methods: We have developed a methodology and software suite to make use of the robust optimization in our commercial planning system while still using our in-house planning system to calculate final neutron dose distributions. Optimized multileaf collimator (MLC) leaf positions for segments designed in the commercial system using a 4 MV photon proxy beam are translated into static neutron ports that can be represented within our in-house treatment planning system. The true neutron dose distribution is calculated in the in-house system and then exported back through the MATLAB software into the commercial treatment planning system for evaluation. Results: The planning process produces optimized IMNRT plans that reduce dose to normal tissue structures as compared to 3D conformal plans using static MLC apertures. The process involves standard planning techniques using a commercially available treatment planning system, and is not significantly more complex than conventional IMRT planning. Using a photon proxy in a commercial optimization algorithm produces IMNRT plans that are more conformal than those previously designed at our center and take much less time to create. Conclusions: The planning process presented here allows for the optimization of IMNRT plans by a commercial treatment planning optimization algorithm, potentially allowing IMNRT to achieve similar conformality in treatment as photon IMRT. The only remaining requirements for the delivery of very highly modulated neutron treatments are incremental improvements upon already implemented hardware systems that should be readily achievable.

Snyder, Michael; Hammoud, Ahmad; Bossenberger, Todd; Spink, Robyn; Burmeister, Jay [Karmanos Cancer Center, Wayne State University School of Medicine, Detroit, Michigan 48201 (United States)

2012-08-15T23:59:59.000Z

36

5 MW pulsed spallation neutron source, Preconceptual design study  

SciTech Connect (OSTI)

This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in {approx} 1 {mu}sec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs.

Not Available

1994-06-01T23:59:59.000Z

37

Ultracold-neutron production in a pulsed-neutron beam line  

Science Journals Connector (OSTI)

We present the results of an ultracold neutron (UCN) production experiment in a pulsed-neutron beam line at the Los Alamos Neutron Scattering Center. The experimental apparatus allows for a comprehensive set of measurements of UCN production as a function of target temperature, incident neutron energy, target volume, and applied magnetic field. However, the low counting statistics of the UCN signal can be overwhelmed by the large background associated with the scattering of the primary cold-neutron flux that is required for UCN production. We have developed a background subtraction technique that takes advantage of the very different time-of-flight profiles between the UCN and the cold neutrons, in the pulsed beam. Using the unique timing structure, we can reliably extract the UCN signal. Solid ortho-H22 is used to calibrate UCN transmission through the apparatus, which is designed primarily for studies of UCN production in solid O2. In addition to setting the overall detection efficiency in the apparatus, UCN production data using solid H22 suggest that the UCN upscattering cross section is smaller than previous estimates, indicating the deficiency of the incoherent approximation widely used to estimate inelastic cross sections in the thermal and cold regimes.

C. M. Lavelle; C.-Y. Liu; W. Fox; G. Manus; P. M. McChesney; D. J. Salvat; Y. Shin; M. Makela; C. Morris; A. Saunders; A. Couture; A. R. Young

2010-07-19T23:59:59.000Z

38

Fabrication of nano-structural arrays by channeling pulsed atomic beams through an intensity-modulated  

E-Print Network [OSTI]

Fabrication of nano-structural arrays by channeling pulsed atomic beams through an intensity-dimensional nano-structure arrays by passing a pulsed atomic beam through an intensity-modulated continuous of ``cooling'' along the longitudinal direction. This enables fabrication of vertically heterogeneous nano

Zhu, Xiangdong

39

Dopant induced ignition of helium nanodroplets in intense few-cycle laser pulses  

E-Print Network [OSTI]

We demonstrate ultrafast resonant energy absorption of rare-gas doped He nanodroplets from intense few-cycle (~10 fs) laser pulses. We find that less than 10 dopant atoms "ignite" the droplet to generate a non-spherical electronic nanoplasma resulting ultimately in complete ionization and disintegration of all atoms, although the pristine He droplet is transparent for the laser intensities applied. Our calculations at those intensities reveal that the minimal pulse length required for ignition is about 9 fs.

Krishnan, S R; Kremer, M; Sharma, V; Fischer, B; Camus, N; Jha, J; Krishnamurthy, M; Pfeifer, T; Moshammer, R; Ullrich, J; Stienkemeier, F; Mudrich, M; Mikaberidze, A; Saalmann, U; Rost, J -M

2011-01-01T23:59:59.000Z

40

Effect of Nuclear Motion on Molecular High-Order Harmonics and on Generation of Attosecond Pulses in Intense Laser Pulses  

SciTech Connect (OSTI)

We calculate harmonic spectra and shapes of attosecond-pulse trains using numerical solutions of Non-Born-Oppenheimer time-dependent Shroedinger equation for 1D H{sub 2} molecules in an intense laser pulse. A very strong signature of nuclear motion is seen in the time profiles of high-order harmonics. In general the nuclear motion shortens the part of the attosecond-pulse train originating from the first electron contribution, but it may enhance the second electron contribution for longer pulses. The shape of time profiles of harmonics can thus be used for monitoring the nuclear motion.

Bandrauk, Andre D.; Chelkowski, Szczepan; Kawai, Shinnosuke; Lu, Huizhong [Departement de Chimie, Universite de Sherbrooke, Sherbrooke, Qc, J1K 2R1 (Canada)

2008-10-10T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

CUDA and MPI performances on the computation of Rossi-? distribution from pulsed neutron sources  

Science Journals Connector (OSTI)

Abstract This study presents the methodology to calculate the Rossi-? distribution for a subcritical assembly driven by an external pulsed neutron source through MCNP6 computer simulations. The Rossi-? distribution is obtained from the signal (e.g., 3He(n,p) reactions) of a neutron detector placed in one experimental channel of the subcritical assembly. The detector signal is obtained from MCNP6 computer simulations modeling a single pulse of the external neutron source. The MCNP6 output data for a single pulse of the external neutron source must be processed to take into account the effect of delayed neutrons born in all previous source pulses. The calculation of the Rossi-? distribution from a pulsed neutron source is time consuming because of the huge amount of processed data. Consequently, the algorithms introduced in this work use parallel computing platforms, e.g., CUDA or MPI, to reduce the computing time.

Alberto Talamo

2015-01-01T23:59:59.000Z

42

Neutron production from ultrashort pulse lasers using linear and circular polarization  

SciTech Connect (OSTI)

An implicit 2D3V particle-in-cell code is used to study proton and deuteron acceleration from an ultrathin CD foil with thickness between 20 and 200 nm using linear and circular polarization. The proton and deuteron beams drive nuclear fusion reactions from converter foils in a pitcher-catcher set-up. The neutron yield for three representative reactions d - d, d - Li, and p - Li has been calculated analytically using the total neutron production cross section and ion stopping power. For linear polarization, maximum normalized neutron yield of Y{sub d-d}=3.4x10{sup 6}, Y{sub d-Li}=3.2x10{sup 7}, and Y{sub p-Li}=6.8x10{sup 6} neutrons/J laser energy has been calculated at the optimum foil thickness of 50 nm. For circular polarization, the optimum foil thickness is 20 nm, for which the corresponding neutron yields are Y{sub d-d}=1.9x10{sup 6}, Y{sub d-Li}=2.0x10{sup 7}, and Y{sub p-Li}=2.7x10{sup 6}, respectively. The laser polarization strongly affects the neutron production; for our regime, i.e., intensity I=1x10{sup 21} W/cm{sup 2}, pulse duration {tau}{sub FWHM}=30 fs, and laser energy {epsilon}{sub laser}=3.8 J, both the conversion efficiency of laser energy into ion kinetic energy and neutron yield are higher for linear polarization. Only for ultrathin ({approx}20 nm) foils in the radiation pressure acceleration regime, circular and linear polarizations yield comparable results.

Davis, J.; Petrov, G. M. [Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Ave. SW, Washington, DC 20375 (United States)

2011-07-15T23:59:59.000Z

43

Effect of pulse intensity distributions on fragment internal energy in the infrared multiphoton dissociation of vinyl  

E-Print Network [OSTI]

Effect of pulse intensity distributions on fragment internal energy in the infrared multiphoton of laser intensity on the production of fragment energy distribu- tions. Laser induced fluorescence (LIF pumping is pro- portional to the light intensity, the final energy of the parent molecule

Zare, Richard N.

44

Investigation of laser-driven proton acceleration using ultra-short, ultra-intense laser pulses  

SciTech Connect (OSTI)

We report optimization of laser-driven proton acceleration, for a range of experimental parameters available from a single ultrafast Ti:sapphire laser system. We have characterized laser-generated protons produced at the rear and front target surfaces of thin solid targets (15 nm to 90 {mu}m thicknesses) irradiated with an ultra-intense laser pulse (up to 10{sup 20} W Dot-Operator cm{sup -2}, pulse duration 30 to 500 fs, and pulse energy 0.1 to 1.8 J). We find an almost symmetric behaviour for protons accelerated from rear and front sides, and a linear scaling of proton energy cut-off with increasing pulse energy. At constant laser intensity, we observe that the proton cut-off energy increases with increasing laser pulse duration, then roughly constant for pulses longer than 300 fs. Finally, we demonstrate that there is an optimum target thickness and pulse duration.

Fourmaux, S.; Gnedyuk, S.; Lassonde, P.; Payeur, S.; Pepin, H.; Kieffer, J. C. [INRS-EMT, Universite du Quebec, 1650 Lionel Boulet, Varennes, Quebec J3X 1S2 (Canada); Buffechoux, S.; Albertazzi, B. [INRS-EMT, Universite du Quebec, 1650 Lionel Boulet, Varennes, Quebec J3X 1S2 (Canada); LULI, UMR 7605, CNRS - CEA - Universite Paris 6 - Ecole Polytechnique, 91128 Palaiseau (France); Capelli, D.; Antici, P. [LULI, UMR 7605, CNRS - CEA - Universite Paris 6 - Ecole Polytechnique, 91128 Palaiseau (France); Dipartimento SBAI, Sapienza, Universita di Roma, Via Scarpa 16, 00161 Roma (Italy); Levy, A.; Fuchs, J. [LULI, UMR 7605, CNRS - CEA - Universite Paris 6 - Ecole Polytechnique, 91128 Palaiseau (France); Lecherbourg, L.; Marjoribanks, R. S. [Department of Physics and Institute for Optical Sciences, University of Toronto, Toronto, Ontario M5S 1A7 (Canada)

2013-01-15T23:59:59.000Z

45

Neutron-scattering study of the magnon energies and intensities in iron  

Science Journals Connector (OSTI)

The magnetic inelastic neutron scattering at low temperatures has been measured from a large single crystal of Fe54(12 at.% Si) up to energy transfers of 100 meV using the constant-Q spectrometer at the Los Alamos pulsed neutron source. The spin-wave energies and intensities were obtained from the data by using a multichannel maximum-entropy technique, and we show that much more detailed information can be obtained from the maximum-entropy analysis. The observed spin-wave dispersion relations obtained in the present experiment are in excellent agreement with earlier data, and we observe a sharp falloff of the (001) magnon intensity at approximately 80 meV, which is in accord with previous experimental measurements and multiband theoretical calculations of the dynamic susceptibility of iron. We also compare the data rate obtained with the constant-Q spectrometer to a triple-axis instrument and find that the spectrometer is competitive for this type of measurement.

M. Yethiraj; R. A. Robinson; D. S. Sivia; J. W. Lynn; H. A. Mook

1991-02-01T23:59:59.000Z

46

Generation of high intensity rf pulses in the ionosphere by means of in situ compression  

SciTech Connect (OSTI)

We demonstrate, using a simple model, that high intensity pulses can be generated from a frequency-chirped modifier of much lower intensity by making use of the dispersive properties of the ionosphere. We show that a frequency-chirped pulse can be constructed so that its various components overtake each other at a prescribed height, resulting in large (up to one hundred times) transient intensity enhancements as compared to those achievable from a steady modifier operating at the same power. We examine briefly one possible application: the enhancement of plasma wave amplitudes which occurs as a result of the interaction of such a compressed pulse with pre-generated turbulence.

Cowley, S.C.; Perkins, F.W.; Valeo, E.J.

1993-04-01T23:59:59.000Z

47

Pulsed spallation neutron source with an induction linac and a fixed-field alternating-gradient accelerator  

SciTech Connect (OSTI)

The paper describes an accelerator scenario of a Pulsed Spallation Neutron Source made of an Induction Linac injecting into a Fixed-Field Alternating-Gradient Accelerator (FFAG). The motivations underlying the proposal deal with the concern of removing technical risks peculiar to other scenarios involving RF Linacs, Synchrotrons and Accumulator Rings, which originate, for example, from the need of developing intense negative-ion sources and of multi-turn injection into the Compressor Rings. The system proposed here makes use of a positive-ion source of very short pulse duration, and of single-turn transfer into the circular accelerator.

Ruggiero, A.G. [Brookhaven National Lab., Upton, NY (United States); Bauer, G. [Paul Scherrer Institute, Villigen (Switzerland); Faltens, A. [Lawrence Berkeley National Lab., CA (United States)] [and others

1995-12-01T23:59:59.000Z

48

Polarized neutron reflectometry at the IBR-2 pulsed reactor  

Science Journals Connector (OSTI)

Polarized neutron reflectometry as a method for investigating layered nanostructures ... and the development of the method of polarized neutron reflectometry on the polarized neutron spectrometer are presented. T...

V. L. Aksenov; Yu. V. Nikitenko

2007-05-01T23:59:59.000Z

49

Pulsed D-D Neutron Generator Measurements of HEU Oxide Fuel Pins  

SciTech Connect (OSTI)

Pulsed neutron interrogation measurements have been performed on highly enriched uranium (HEU) oxide fuel pins and depleted uranium (DU) metal using a D-D neutron generator (2x10{sup 6} neutrons-s{sup -1}) and moderated {sup 3}He tubes at the Idaho National Laboratory Power Burst Facility. These measurements demonstrate the ability to distinguish HEU from DU by coincidence counting using a pulsed source. The amount of HEU measured was 8 kg in a sealed 55-gallon drum compared to 31 kg of DU. Neutron events were counted during and after the pulse with the Nuclear Materials Identification System (NMIS) and used to calculate the neutron coincidence time distributions. Passive measurements were also performed for comparison with the pulsed measurements. This paper presents the neutron coincidence time distribution and Feynman variance results from the measurements.

McConchie, Seth; Hausladen, Paul; Mihalczo, John [Oak Ridge National Laboratory, 1 Bethel Valley Road, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Blackburn, Brandon; Chichester, David [Idaho National Laboratory, 2525 North Fremont Avenue, P.O. Box 1625, Idaho Falls, ID 83415 (United States)

2009-03-10T23:59:59.000Z

50

Pulsed D-D Neutron Generator Measurements of HEU Oxide Fuel Pins  

SciTech Connect (OSTI)

Pulsed neutron interrogation measurements have been performed on highly enriched uranium (HEU) oxide fuel pins and depleted uranium (DU) metal using a D-D neutron generator (2 x 10{sup 6} neutrons-s{sup -1}) and moderated {sup 3}He tubes at the Idaho National Laboratory Power Burst Facility. These measurements demonstrate the ability to distinguish HEU from DU by coincidence counting using a pulsed source. The amount of HEU measured was 8 kg in a sealed 55-gallon drum compared to 31 kg of DU. Neutron events were counted during and after the pulse with the Nuclear Materials Identification System (NMIS) and used to calculate the neutron coincidence time distributions. Passive measurements were also performed for comparison with the pulsed measurements. This paper presents the neutron coincidence distribution and Feynman variance results from the measurements.

McConchie, Seth M [ORNL] [ORNL; Hausladen, Paul [ORNL] [ORNL; Mihalczo, John T [ORNL] [ORNL; Blackburn, Brandon [Idaho National Laboratory (INL)] [Idaho National Laboratory (INL); Chichester, David [Idaho National Laboratory (INL)] [Idaho National Laboratory (INL)

2009-01-01T23:59:59.000Z

51

Molecular-bond hardening and dynamics of molecular stabilization and trapping in intense laser pulses  

E-Print Network [OSTI]

stabilization and population trapping of high-lying vibrational states and chemical bond hardening are predicted for both continuous-wave (cw) lasers and short laser pulses. While the intensity dependences of the laser-induced stabilization are essentially...

Yao, Guanhua; Chu, Shih-I

1993-07-01T23:59:59.000Z

52

Electron acceleration by a self-diverging intense laser pulse K. P. Singh,1,  

E-Print Network [OSTI]

Electron acceleration by a self-diverging intense laser pulse K. P. Singh,1, * D. N. Gupta,1 V. K, India 2 Department of Electronic Science, University of Delhi, New Delhi-110021, India (Received 23 October 2003; published 28 April 2004) Electron acceleration by a laser pulse having a Gaussian radial

Singh, Kunwar Pal

53

Generation of mega-electron-volt electron beams by an ultrafast intense laser pulse  

E-Print Network [OSTI]

Generation of mega-electron-volt electron beams by an ultrafast intense laser pulse Xiaofang Wang filamentation and beam breakup. These results suggest an approach for generating a beam of femtosecond, Me-intensity lasers has made it pos- sible to study extreme physics on a tabletop. Among the studies, the generation

Umstadter, Donald

54

Turbulence intensity pulse propagation with self-consistent nonlinear noise  

SciTech Connect (OSTI)

A model of turbulence intensity spreading with self-consistent nonlinear noise is derived systematically for the simple dynamical model of resistivity gradient driven turbulence. Local effective drive, thermal conduction damping, nonlinear coupling, and spatial scattering effects are included. As a consequence of nonlinear mode coupling processes (i.e., triad mode interactions), turbulence energy can be spatially scattered, leading to turbulence propagation and spreading. However, the range of any nonlinear mode interactions of the background with a test mode is restricted to within a few mode scale widths from the test mode rational surface. The speed of a turbulent spreading front is calculated. This front speed is effectively constant on macroscopic scales. We show that the effect of self-consistent nonlinear noise on the intensity front speed is modest, as a consequence of the ordering {Delta}{sub c}

Wang, Z. H. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Department of Physics and Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, California 92093-0424 (United States); Diamond, P. H. [Department of Physics and Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, California 92093-0424 (United States); WCI Center for Fusion Theory, National Fusion Research Institute, Gwahangno 113, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Guercan, Oe. D. [Laboratoire de Physique des Plasmas, Ecole Polytechnique-CNRS, 91128 Palaiseau Cedex (France); Garbet, X. [CEA, IRFM, F-13108 Saint Paul Lez Durance (France); Wang, X. G. [School of Physics, Peking University, Beijing 100871 (China)

2011-03-15T23:59:59.000Z

55

Intensity-resolved Above Threshold Ionization Yields of Atoms with Ultrashort Laser Pulses  

E-Print Network [OSTI]

. Electron ionization yields of xenon were measured for a set of laser pulse intensities using a time of flight (TOF) setup. Horizontally polarized, unchirped, pulses were used in the ionization process. All laser parameters other than the radiation... Tiezer, I am grateful for all their time and help. I would like to thank Dr. James Strohaber for detailed discussions and assistance related to this experiment. I acknowledge the Department of Physics at Texas A&M and the US Air Force...

Hart, Nathan Andrew

2012-10-19T23:59:59.000Z

56

X-ray spectroscopy of buried layer foils irradiated with an ultra high intensity short pulse laser  

E-Print Network [OSTI]

the intensity of the ignition laser pulse is be at least 10fuel [19, 22]. Current ignition laser requirements mandatesShort pulse laser produced plasmas Fast Ignition guides much

Chen, Sophia Nan

2009-01-01T23:59:59.000Z

57

Design and optimization of 6li neutron-capture pulse mode ion chamber  

E-Print Network [OSTI]

The purpose of this research is to design and optimize the performance of a unique, inexpensive 6Li neutron-capture pulse-mode ion chamber (LiPMIC) for neutron detection that overcomes the fill-gas contamination stemming from outgas of detector...

Chung, Kiwhan

2009-05-15T23:59:59.000Z

58

The performance of reflectometers at continuous wave and pulsed-neutron sources  

SciTech Connect (OSTI)

To quantify gains from time-of-flight (TOF) methods, identical reflectometers viewing a continuous wave (CW) neutron source and a variety of pulsed-neutron sources were simulated using a Monte Carlo technique. Reflectivity profiles obtained for a simple thin-film, reflecting,sample were nearly identical in all simulations, and models fitted to the simulated data yielded parameters (film thickness, surface roughness, and scattering length density) that were equally accurate and precise in all cases. The simulations confirm the power of the TOF method and demonstrate that the performance of pulsed sources for reflectometry does not scale simply as the inverse duty factor of the source. In the case of long-pulse sources, the simulations suggest that pulse tails have little effect on results obtained from specular reflectometry and that maximum brightness of the neutron source should be the primary design criterion.

Fritzsimmons, M.R.; Pynn, R.

1995-12-01T23:59:59.000Z

59

Ignition of Doped Helium Nanodroplets in Intense Few-Cycle Laser Pulses  

Science Journals Connector (OSTI)

The ultra-fast dynamics of He nanodroplets (103105 atoms) in intense (17 1014 W/cm2...), few-cycle (?10 fs), infrared (?790 nm) laser pulses has been investigated as a function ... number of dopant rare-gas at...

S. R. Krishnan; L. Fechner; M. Kremer

2012-01-01T23:59:59.000Z

60

Origin of the intensity deficit in neutron Compton scattering  

SciTech Connect (OSTI)

Neutron Compton scattering measurements in a variety of materials have shown a relative deficit in the total signal from hydrogen compared to deuterium and heavier ions. We show here that a breakdown in the Born-Oppenheimer approximation in the final states of the scattering process leads to such a deficit and may be responsible for the effect.

Reiter, G.F.; Platzman, P.M. [Physics Department, University of Houston, Houston, Texas 77204-5506 (United States); Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974-0636 (United States)

2005-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Analytical Calculation of the Neutrons Spectrum for Direct Measurement of N-N Scattering at Pulsed Reactor Yaguar  

E-Print Network [OSTI]

Analytical calculation of a single neutron detector counts per YAGUAR reactor pulse is presented and comparison with coincidence scheme is given.

V. K. Ignatovich

2008-06-23T23:59:59.000Z

62

Analytical Calculation of the Neutrons Spectrum for Direct Measurement of N-N Scattering at Pulsed Reactor Yaguar  

E-Print Network [OSTI]

Analytical calculation of a single neutron detector counts per YAGUAR reactor pulse is presented and comparison with coincidence scheme is given.

Ignatovich, V K

2008-01-01T23:59:59.000Z

63

Characterization of a novel, short pulse laser-driven neutron source  

SciTech Connect (OSTI)

We present a full characterization of a short pulse laser-driven neutron source. Neutrons are produced by nuclear reactions of laser-driven ions deposited in a secondary target. The emission of neutrons is a superposition of an isotropic component into 4? and a forward directed, jet-like contribution, with energies ranging up to 80 MeV. A maximum flux of 4.4 10{sup 9} neutrons/sr has been observed and used for fast neutron radiography. On-shot characterization of the ion driver and neutron beam has been done with a variety of different diagnostics, including particle detectors, nuclear reaction, and time-of-flight methods. The results are of great value for future optimization of this novel technique and implementation in advanced applications.

Jung, D.; Falk, K.; Guler, N.; Devlin, M.; Favalli, A.; Fernandez, J. C.; Gautier, D. C.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Merrill, F.; Schoenberg, K.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wender, S. A.; Wilde, C. H.; Wurden, G. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Deppert, O. [Technische Universit鋞 Darmstadt, 64289 Darmstadt (Germany)] [Technische Universit鋞 Darmstadt, 64289 Darmstadt (Germany); and others

2013-05-15T23:59:59.000Z

64

Apparatus and process for active pulse intensity control of laser beam  

DOE Patents [OSTI]

An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means.

Wilcox, Russell B. (Oakland, CA)

1992-01-01T23:59:59.000Z

65

Systematic Advantages of Pulsed Beams for Measurements of Correlation Coefficients in Neutron Decay  

Science Journals Connector (OSTI)

AbstractMeasurements of correlation coefficients in neutron beta decay probe the structure of the weak interaction and serve to search for new physics beyond the standard model of particle physics. In this article we describe how pulsed cold neutron beams can be employed to effectively eliminate or control leading sources of systematic uncertainty. As two examples we introduce the existing instrument PERKEO III and the new instrument PERC.

Bastian M鋜kisch

2014-01-01T23:59:59.000Z

66

Hole boring in a DT pellet and fast ion ignition with ultra-intense laser pulses  

E-Print Network [OSTI]

Recently achieved high intensities of short laser pulses open new prospects in their application to hole boring in inhomogeneous overdense plasmas and for ignition in precompressed DT fusion targets. A simple analytical model and numerical simulations demonstrate that pulses with intensities exceeding 1022 W/cm2 may penetrate deeply into the plasma as a result of efficient ponderomotive acceleration of ions in the forward direction. The penetration depth as big as hundreds of microns depends on the laser fluence, which has to exceed a few tens of GJ/cm2. The fast ions, accelerated at the bottom of the channel with an efficiency of more than 20%, show a high directionality and may heat the precompressed target core to fusion conditions.

Naumova, N; Tikhonchuk, V T; Labaune, C; Sokolov, I V; Mourou, G; 10.1103/PhysRevLett.102.025002

2009-01-01T23:59:59.000Z

67

The effect of pulse reactivity for stochastic neutron point kinetic equation in nuclear reactor dynamics  

Science Journals Connector (OSTI)

In this present analysis, the numerical simulation methods are applied to calculate the solution for Stochastic Neutron Point Kinetic Equations (SNPKE) with pulse reactivity in dynamical system of a nuclear reactor. The resulting systems of differential equations are solved for each time step-size. Using experimental data, the methods are investigated with pulse reactivity. The computational results designate that these numerical approximation methods are straightforward, effective and easy for solving stochastic point kinetic equations.

A. Patra; S. Saha Ray

2014-01-01T23:59:59.000Z

68

A search for the sulphur hexafluoride cation with intense, few cycle laser pulses  

SciTech Connect (OSTI)

It is well established that upon ionization of sulphur hexafluoride, the SF{sub 6}{sup +} ion is never observed in mass spectra. Recent work with ultrashort intense laser pulses has offered indications that when strong optical field are used, the resulting 揵ond hardening can induce changes in the potential energy surfaces of molecular cations such that molecular ions that are normally unstable may, indeed, become metastable enough to enable their detection by mass spectrometry. Do intense, ultrashort laser pulses permit formation of SF{sub 6}{sup +}? We have utilized intense pulses of 5 fs, 11 fs, and 22 fs to explore this possibility. Our results are negative: no evidence is discovered for SF{sub 6}{sup +}. However, multiply charged sulphur and fluorine ions from highly charged SF{sub 6}{sup q+} ions are observed that enable us to resolve the controversy regarding the kinetic energy release accompanying formation of F{sup +} fragment ions. Quantum chemical computations of field-distorted potential energy curves of SF{sub 6} and its molecular ion enable us to rationalize our non-observation of SF{sub 6}{sup +}. Our findings have implications for high harmonic generation from SF{sub 6} in the few-cycle regime.

Dota, Krithika; Mathur, Deepak, E-mail: atmol1@tifr.res.in [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India) [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India); Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India); Dharmadhikari, Aditya K. [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India)] [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India); Dharmadhikari, Jayashree A. [Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India)] [Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104 (India); Patra, Kaustuv; Tiwari, Ashwani K. [Indian Institute of Science Education and Research - Kolkata, Mohanpur 741 252 (India)] [Indian Institute of Science Education and Research - Kolkata, Mohanpur 741 252 (India)

2013-11-21T23:59:59.000Z

69

Role of laser-pulse duration in the neutron yield of deuterium cluster targets K. W. Madison,1  

E-Print Network [OSTI]

laser pulses. We find that the cluster explosion energy and resultant fusion yield are sensitive the achievement of high neutron yield but would provide a cost effective pure DD or DT fusion neutron source [9 study of the ion and fusion neutron yields from explosions of deuterium clusters irradiated with 100-TW

Ditmire, Todd

70

Quantitative interpretation of pulsed neutron capture logs: Part 1 --Fast numerical simulation  

E-Print Network [OSTI]

Jordan G. Mimoun1 , Carlos Torres-Verdi麓n2 , and William E. Preeg3 ABSTRACT Pulsed neutron capture (PNC for shoulder-bed effects on R logs acquired in sand- shale laminated reservoirs. Because of diffusion effects responses of pure-sand and pure- shale end members of the sedimentary sequence. We have developed a new

Torres-Verd铆n, Carlos

71

Electron acceleration by an intense short pulse laser in a static magnetic field in vacuum K. P. Singh*  

E-Print Network [OSTI]

Electron acceleration by an intense short pulse laser in a static magnetic field in vacuum K. P 2003; revised manuscript received 22 December 2003; published 28 May 2004) Electron acceleration the peak of the pulse interacts with the electron and the direction of the static magnetic field is taken

Roy, Subrata

72

Instrument performance study on the short and long pulse options of the second Spallation Neutron Source target station  

SciTech Connect (OSTI)

The Spallation Neutron Source (SNS) facility at the Oak Ridge National Laboratory is designed with an upgrade option for a future low repetition rate, long wavelength second target station. This second target station is intended to complement the scientific capabilities of the 1.4 MW, 60 Hz high power first target station. Two upgrade possibilities have been considered, the short and the long pulse options. In the short pulse mode, proton extraction occurs after the pulse compression in the accumulator ring. The proton pulse structure is thus the same as that for the first target station with a pulse width of ?0.7 ?s. In the long pulse mode, protons are extracted as they are produced by the linac, with no compression in the accumulator ring. The time width of the uncompressed proton pulse is ?1 ms. This difference in proton pulse structure means that neutron pulses will also be different. Neutron scattering instruments thus have to be designed and optimized very differently for these two source options which will directly impact the overall scientific capabilities of the SNS facility. In order to assess the merits of the short and long pulse target stations, we investigated a representative suit of neutron scattering instruments and evaluated their performance under each option. Our results indicate that the short pulse option will offer significantly better performance for the instruments and is the preferred choice for the SNS facility.

Zhao, J. K.; Herwig, Kenneth W.; Robertson, J. L.; Gallmeier, Franz X.; Riemer, Bernard W. [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2013-10-15T23:59:59.000Z

73

Tomographic analysis of neutron and gamma pulse shape distributions from liquid scintillation detectors at Joint European Torus  

SciTech Connect (OSTI)

The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world devoted to nuclear fusion experiments of magnetic confined Deuterium (D)/Deuterium-Tritium (DT) plasmas. Neutrons produced in these plasmas are measured using various types of neutron detectors and spectrometers. Two of these instruments on JET make use of organic liquid scintillator detectors. The neutron emission profile monitor implements 19 liquid scintillation counters to detect the 2.45 MeV neutron emission from D plasmas. A new compact neutron spectrometer is operational at JET since 2010 to measure the neutron energy spectra from both D and DT plasmas. Liquid scintillation detectors are sensitive to both neutron and gamma radiation but give light responses of different decay time such that pulse shape discrimination techniques can be applied to identify the neutron contribution of interest from the data. The most common technique consists of integrating the radiation pulse shapes within different ranges of their rising and/or trailing edges. In this article, a step forward in this type of analysis is presented. The method applies a tomographic analysis of the 3-dimensional neutron and gamma pulse shape and pulse height distribution data obtained from liquid scintillation detectors such that n/? discrimination can be improved to lower energies and additional information can be gained on neutron contributions to the gamma events and vice versa.

Giacomelli, L. [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom) [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Department of Physics, Universit degli Studi di Milano-Bicocca, Milano (Italy); Conroy, S. [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom) [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Department of Physics and Astronomy, Uppsala University, Uppsala (Sweden); Gorini, G. [Department of Physics, Universit degli Studi di Milano-Bicocca, Milano (Italy)] [Department of Physics, Universit degli Studi di Milano-Bicocca, Milano (Italy); Horton, L.; Murari, A.; Popovichev, S.; Syme, D. B. [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)] [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)

2014-02-15T23:59:59.000Z

74

Development and testing of neutron pulse time stamping data acquisition system for neutron noise experiment  

Science Journals Connector (OSTI)

Abstract Statistical correlation techniques find applications in the analysis of zero power reactor noise and in passive neutron assay (PNA). A large number of apparently different techniques have been in use in these application areas and traditionally the electronics modules used for data acquisition and analysis is specific to the method used. In this paper we describe a data acquisition scheme developed by us, which is independent of the specific analysis method and can therefore be used for all of them. This is a neutron time stamping data acquisition system based on a timer card and an interface software to acquire and store the data in the required format. The system has been successfully tested with two statistically different types of neutron sources, namely a random Poisson source (Pu朆e) and a correlated source (a nuclear reactor).

Rajeev Kumar; M Yakub Ali; S.B. Degweker; S.C. Vishwasrao; R.T. Jadhav

2015-01-01T23:59:59.000Z

75

Ion heating dynamics in solid buried layer targets irradiated by ultra-short intense laser pulses  

SciTech Connect (OSTI)

We investigate bulk ion heating in solid buried layer targets irradiated by ultra-short laser pulses of relativistic intensities using particle-in-cell simulations. Our study focuses on a CD{sub 2}-Al-CD{sub 2} sandwich target geometry. We find enhanced deuteron ion heating in a layer compressed by the expanding aluminium layer. A pressure gradient created at the Al-CD{sub 2} interface pushes this layer of deuteron ions towards the outer regions of the target. During its passage through the target, deuteron ions are constantly injected into this layer. Our simulations suggest that the directed collective outward motion of the layer is converted into thermal motion inside the layer, leading to deuteron temperatures higher than those found in the rest of the target. This enhanced heating can already be observed at laser pulse durations as low as 100 fs. Thus, detailed experimental surveys at repetition rates of several ten laser shots per minute are in reach at current high-power laser systems, which would allow for probing and optimizing the heating dynamics.

Huang, L. G. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, 201800 Shanghai (China) [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, 201800 Shanghai (China); Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany) [Germany; University of Chinese Academy of Sciences, 100049 Beijing (China); Bussmann, M.; Kluge, T. [Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany)] [Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Lei, A. L. [Shanghai Institute of Laser Plasma, 201800 Shanghai (China)] [Shanghai Institute of Laser Plasma, 201800 Shanghai (China); Yu, W. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, 201800 Shanghai (China)] [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, 201800 Shanghai (China); Cowan, T. E. [Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany) [Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Technische Universit鋞 Dresden, 01062 Dresden (Germany)

2013-09-15T23:59:59.000Z

76

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux  

DOE Patents [OSTI]

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

Bowman, C.D.

1992-11-03T23:59:59.000Z

77

Fast Scintillation Probes For Investigation Of Pulsed Neutron Radiation From Small Fusion Devices  

SciTech Connect (OSTI)

This paper presents the design as well as laboratory/performance tests results taken by means of the fast scintillation probes. The design of each scintillation probe is based on photomultiplier tube hybrid assembly, which--besides photomultiplier itself--also includes high-voltage divider optimized for recording of fast radiation bursts. Plastic scintillators with short-time response are applied as hard X-ray and neutron radiation detectors. Heavy-duty probe's housing provides efficient shielding against electromagnetic interference and allows carrying out pulsed neutron measurements in a harsh electromagnetic environment. The crucial parameters of scintillation probes have been examined during laboratory tests in which our investigations have been aimed mainly to determine: a time response, an anode radiant sensitivity and an electron transit time dependence on high-voltage supply. During the performance tests, the relative calibration of probes set has been done. It allowed to carry out very accurate measurements of neutron emission anisotropy and investigations of neutron radiation scattering by different materials. The usefulness of presented scintillation probes - embedded in the neutron time-of-flight diagnostic system was proven during experimental campaigns conducted on the plasma-focus PF1000 device.

Tomaszewski, Krzysztof J. [ACS Ltd., Advanced Diagnostics Laboratory, Hery 23 St., 01-497 Warsaw (Poland)

2008-04-07T23:59:59.000Z

78

Phase control of the photofragment branching ratio of the HI molecule in two intense few-cycle laser pulses  

Science Journals Connector (OSTI)

A time-dependent quantum wave packet method is used to calculate the branching ratio of photodissociation products of the HI molecule in two-color intense few-cycle laser pulses with varying relative phase. It is demonstrated that the relative phase between two intense few-cycle pulses (? and 2?) can be used for controlling the branching ratio of the photodissociation products I(P3?22) and I(P1?22) of the HI molecule. The nonadiabatic effect of the crossing potential energy curves on the photodissociation product yields of the HI molecule is also discussed.

Sen-Ming Wang; Kai-Jun Yuan; Ying-Yu Niu; Yong-Chang Han; Shu-Lin Cong

2006-10-11T23:59:59.000Z

79

Highly efficient second-harmonic generation of intense femtosecond pulses with a significant effect of cubic nonlinearity  

SciTech Connect (OSTI)

A highly efficient (73%) second-harmonic generation of femtosecond pulses in a 1-mm-thick KDP crystal at a fundamentalharmonic peak intensity of 2 TW cm{sup -2} has been demonstrated experimentally. In a 0.5-mm-thick KDP crystal, a 50% efficiency has been reached at a peak intensity of 3.5 TW cm{sup -2}. We examine the key factors that limit the conversion efficiency and present numerical simulation results on further temporal compression of second-harmonic pulses.

Mironov, S Yu; Ginzburg, V N; Lozhkarev, V V; Luchinin, G A; Kirsanov, Aleksei V; Yakovlev, I V; Khazanov, Efim A; Shaykin, A A [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation)

2011-11-30T23:59:59.000Z

80

Mitigation of Electromagnetic Pulse (EMP) Effects from Short-Pulse Lasers and Fusion Neutrons  

SciTech Connect (OSTI)

Our research focused on obtaining a fundamental understanding of the source and properties of EMP at the Titan PW(petawatt)-class laser facility. The project was motivated by data loss and damage to components due to EMP, which can limit diagnostic techniques that can be used reliably at short-pulse PW-class laser facilities. Our measurements of the electromagnetic fields, using a variety of probes, provide information on the strength, time duration, and frequency dependence of the EMP. We measure electric field strengths in the 100's of kV/m range, durations up to 100 ns, and very broad frequency response extending out to 5 GHz and possibly beyond. This information is being used to design shielding to mitigate the effects of EMP on components at various laser facilities. We showed the need for well-shielded cables and oscilloscopes to obtain high quality data. Significant work was invested in data analysis techniques to process this data. This work is now being transferred to data analysis procedures for the EMP diagnostics being fielded on the National Ignition Facility (NIF). In addition to electromagnetic field measurements, we measured the spatial and energy distribution of electrons escaping from targets. This information is used as input into the 3D electromagnetic code, EMSolve, which calculates time dependent electromagnetic fields. The simulation results compare reasonably well with data for both the strength and broad frequency bandwidth of the EMP. This modeling work required significant improvements in EMSolve to model the fields in the Titan chamber generated by electrons escaping the target. During dedicated Titan shots, we studied the effects of varying laser energy, target size, and pulse duration on EMP properties. We also studied the effect of surrounding the target with a thick conducting sphere and cube as a potential mitigation approach. System generated EMP (SGEMP) in coaxial cables does not appear to be a significant at Titan. Our results are directly relevant to planned short-pulse ARC (advanced radiographic capability) operation on NIF.

Eder, D C; Throop, A; Brown, Jr., C G; Kimbrough, J; Stowell, M L; White, D A; Song, P; Back, N; MacPhee, A; Chen, H; DeHope, W; Ping, Y; Maddox, B; Lister, J; Pratt, G; Ma, T; Tsui, Y; Perkins, M; O'Brien, D; Patel, P

2009-03-06T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

HiRadMat at CERN/SPS - A dedicated facility providing high intensity beam pulses to material samples  

E-Print Network [OSTI]

HiRadMat (High Radiation to Materials), constructed in 2011, is a facility at CERN designed to provide high?intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, high power beam targets, collimators) can be tested. The facility uses a 440 GeV proton beam extracted from the CERN SPS with a pulse length of up to 7.2 us, and with a maximum pulse energy of 3.4 MJ (3xE13 proton/pulse). In addition to protons, ion beams with energy of 440 GeV/charge and total pulse energy of 21 kJ can be provided. The beam parameters can be tuned to match the needs of each experiment. HiRadMat is not an irradiation facility where large doses on equipment can be accumulated. It is rather a test area designed to perform single pulse experiments to evaluate the effect of high?intensity pulsed beams on materials or accelerator component assemblies in a controlled environment. The fa? cility is designed for a maximum of 1E16 protons per year, dist...

Charitonidis, N; Efthymiopoulos, I

2014-01-01T23:59:59.000Z

82

YALINA-booster subcritical assembly pulsed-neutron e xperiments: detector dead time and apatial corrections.  

SciTech Connect (OSTI)

In almost every detector counting system, a minimal dead time is required to record two successive events as two separated pulses. Due to the random nature of neutron interactions in the subcritical assembly, there is always some probability that a true neutron event will not be recorded because it occurs too close to the preceding event. These losses may become rather severe for counting systems with high counting rates, and should be corrected before any utilization of the experimental data. This report examines the dead time effects for the pulsed neutron experiments of the YALINA-Booster subcritical assembly. The nonparalyzable model is utilized to correct the experimental data due to dead time. Overall, the reactivity values are increased by 0.19$ and 0.32$ after the spatial corrections for the YALINA-Booster 36% and 21% configurations respectively. The differences of the reactivities obtained with He-3 long or short detectors at the same detector channel diminish after the dead time corrections of the experimental data for the 36% YALINA-Booster configuration. In addition, better agreements between reactivities obtained from different experimental data sets are also observed after the dead time corrections for the 21% YALINA-Booster configuration.

Cao, Y.; Gohar, Y.; Nuclear Engineering Division

2010-10-11T23:59:59.000Z

83

High-Efficiency Resonant RF Spin Rotator with Broad Phase Space Acceptance for Pulsed Polarized Cold Neutron Beams  

E-Print Network [OSTI]

We have developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5 cm x 9.5 cm pulsed cold neutron beam with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared qualitatively to RF neutron spin flippers based on adiabatic fast passage. The spin rotator does not change the kinetic energy of the neutrons and leaves the neutron beam phase space unchanged to high precision. We discuss the design of the spin rotator and describe two types of transmission-based neutron spin-flip efficiency measurements where the neutron beam was both polarized and analyzed by optically-polarized 3He neutron spin filters. The efficiency of the spin rotator was measured to be 98.0+/-0.8% on resonance for neutron energies from 3.3 to 18.4 meV over the full phase space of the beam. As an example of the application of this device to an experiment we describe the integration of the RF spin rotator into an apparatus to search for the small parity-violating asymmetry A_gamma in polarized cold neutron capture on para-hydrogen by the NPDGamma collaboration at LANSCE.

P. -N. Seo; L. Barron-Palos; J. D. Bowman; T. E. Chupp; C. Crawford; M. Dabaghyan; M. Dawkins; S. J. Freedman; T. Gentile; M. T. Gericke; R. C. Gillis; G. L. Greene; F. W. Hersman; G. L. Jones; M. Kandes; S. Lamoreaux; B. Lauss; M. B. Leuschner; R. Mahurin; M. Mason; J. Mei; G. S. Mitchell; H. Nann; S. A. Page; S. I. Penttila; W. D. Ramsay; A. Salas Bacci; S. Santra; M. Sharma; T. B. Smith; W. M. Snow; W. S. Wilburn; H. Zhu

2007-10-15T23:59:59.000Z

84

Palm top plasma focus device as a portable pulsed neutron source  

Science Journals Connector (OSTI)

Development of a palm top plasma focus device generating (5.2 0.8) 104 neutrons/pulse into 4? steradians with a pulse width of 15 3 ns is reported for the first time. The weight of the system is less than 1.5 kg. The system comprises a compact capacitor bank a triggered open air spark gap switch and a sealed type miniature plasma focus tube. The setup is around 14 cm in diameter and 12.5 cm in length. The energy driver for the unit is a capacitor bank of four cylindrical commercially available electrolytic capacitors. Each capacitor is of 2 ?F capacity 4.5 cm in diameter and 9.8 cm in length. The cost of each capacitor is less than US$ 10. The internal diameter and the effective length of the plasma focus unit are 2.9 cm and 5 cm respectively. A DC to DC converter power supply powered by two rechargeable batteries charges the capacitor bank to the desired voltage and also provides a trigger pulse of ?15 kV to the spark gap. The maximum energy of operation of the device is 100 J (8 ?F 5 kV 59 kA) with deuterium gas filling pressure of 3 mbar. The neutrons have also been produced at energy as low as 36 J (3 kV) of operation. The neutron diagnostics are carried out with a bank of 3He detectors and with a plastic scintillator detector. The device is portable reusable and can be operated for multiple shots with a single gas filling.

2013-01-01T23:59:59.000Z

85

Time dependence of X-ray polarizability of a crystal induced by an intense femtosecond X-ray pulse  

Science Journals Connector (OSTI)

The time evolution of the electron density and the resulting time dependence of the X-ray polarizability of a crystal irradiated by highly intense XFEL femtosecond pulses is investigated theoretically. Rate equations for bound electrons and the Boltzmann equation for the unbound electron gas are used in calculations.

Leonov, A.

2014-10-23T23:59:59.000Z

86

Line X-ray emission from Al targets irradiated by high-intensity, variable-length laser pulses  

E-Print Network [OSTI]

Line X-ray emission from Al targets irradiated by high-intensity, variable-length laser pulses J; the scaling rules for the conversion efficiency of the laser radiation into the line X-ray emission are discussed. Keywords: Laser-produced plasma; Line X-ray emission; X-ray sources; X-ray spectroscopy 1

Limpouch, Jiri

87

Pulse neutron subcritical K/sub EFF/ measurements on water flooded arrays of fuel rods  

SciTech Connect (OSTI)

The pulsed neutron source technique has been utilized at the Pacific Northwest Laboratory for some twenty years for measurement of subcritical reactivities of a variety of fuel systems. One area of application has included measurements of subcritical reactivities of water flooded arrays of fuel rods. This report summarizes these measurements. The theory behind the measurement process is reviewed and the instrumentation of the measurement system discussed. Also, four experiment programs are described in detail, illustrating system use and flexibility. Some changes are suggested for system improvements to speed up data collection and data reduction, and some possible areas of future application of the method are described.

Durst, B.M.; Bierman, S.R.; Clayton, E.D.

1980-07-01T23:59:59.000Z

88

Spallation Neutron Source  

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

D/gim D/gim Spallation Neutron Source SNS is an accelerator-based neutron source. This one-of-a-kind facility pro- vides the most intense pulsed neutron beams in the world. When ramped up to its full beam power of 1.4 MW, SNS will be eight times more powerful than today's best facility. It will give researchers more detailed snapshots of the smallest samples of physical and biological materials than ever before

89

Non-filamentated ultra-intense and ultra-short pulse fronts in three-dimensional Raman seed amplification  

SciTech Connect (OSTI)

Ultra-intense and ultra-short laser pulses may be generated up to the exawatt-zetawatt regime due to parametric processes in plasmas. The minimization of unwanted plasma processes leads to operational limits which are discussed here with respect to filamentation. Transverse filamentation, which originally was derived for plane waves, is being investigated for seed pulse propagation in the so called ?-pulse limit. A three-dimensional (3D) three-wave-interaction model is the basis of the present investigation. To demonstrate the applicability of the three-wave-interaction model, the 1D pulse forms are compared with those obtained from 1D particle in cell and Vlasov simulations. Although wave-breaking may occur, the kinetic simulations show that the leading pumped pulse develops a form similar to that obtained from the three-wave-interaction model. In the main part, 2D and 3D filamentation processes of (localized) pulses are investigated with the three-wave-interaction model. It is shown that the leading pulse front can stay filamentation-free, whereas the rear parts show transverse modulations.

Lehmann, G.; Spatschek, K. H. [Institut f黵 Theoretische Physik, Heinrich-Heine-Universit鋞 D黶seldorf, D-40225 D黶seldorf (Germany)] [Institut f黵 Theoretische Physik, Heinrich-Heine-Universit鋞 D黶seldorf, D-40225 D黶seldorf (Germany)

2014-05-15T23:59:59.000Z

90

Analysis of two-dimensional high-energy photoelectron momentum distributions in the single ionization of atoms by intense laser pulses  

E-Print Network [OSTI]

, using longer pulses at lower intensities. The energy spectra above 4Up, where Up is the ponderomotive energy, have been found to vary rapidly with small changes in laser intensities 10,11 when laser pulseAnalysis of two-dimensional high-energy photoelectron momentum distributions in the single

Lin, Chii-Dong

91

The determination of neutron flux in the Texas A & M triga reactor during pulse and steady-state operations  

E-Print Network [OSTI]

-state operation. Neutron flux measurement during a pulse presents an additional problem in that the flux levels vary during the rapid rise and fall in reactor power. The power level transient of the reactor was followed, using the current output of a boron-10... as a flux monitor only at low power. levels or neutron fluxes. The antimony flux monitor in the steady-state flux measurement showed the same type of increase in flux magni- tude as that of the pulse measurement. The high flux values at steady...

O'Donnell, John Joseph

2012-06-07T23:59:59.000Z

92

Detailed studies of Minor Actinide transmutation-incineration in high-intensity neutron fluxes  

SciTech Connect (OSTI)

The Mini-INCA project is dedicated to the measurement of incineration-transmutation chains and potentials of minor actinides in high-intensity thermal neutron fluxes. In this context, new types of detectors and methods of analysis have been developed. The {sup 241}Am and {sup 232}Th transmutation-incineration chains have been studied and several capture and fission cross sections measured very precisely, showing some discrepancies with existing data or evaluated data. An impact study was made on different based-like GEN-IV reactors. It underlines the necessity to proceed to precise measurements for a large number of minor-actinides that contribute to these future incineration scenarios. (authors)

Bringer, O. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France); Al Mahamid, I. [Lawrence Berkeley National Laboratory, E.H. and S. Div., CA (United States); Blandin, C. [CEA/Cadarache/DEN/DER/SPEX, Saint-Paul-lez-Durances (France); Chabod, S. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France); Chartier, F. [CEA/Cadarache/DEN/DPC/SECR, Gif-sur-Yvette (France); Dupont, E.; Fioni, G. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France); Isnard, H. [CEA/Cadarache/DEN/DPC/SECR, Gif-sur-Yvette (France); Letourneau, A.; Marie, F. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France); Mutti, P. [Institut Laue-Langevin, Grenoble (France); Oriol, L. [CEA/Cadarache/DEN/DER/SPEX, Saint-Paul-lez-Durances (France); Panebianco, S.; Veyssiere, C. [CEA/Saclay/DSM/DAPNIA, Gif-sur-Yvette (France)

2006-07-01T23:59:59.000Z

93

A self-consistent regime of generation of terahertz radiation by an optical pulse with a tilted intensity front  

SciTech Connect (OSTI)

We derived a self-consistent system of nonlinear wave equations describing the terahertz generation in dielectric uniaxial crystals by optical pulsed radiation with a tilted wavefront. The numerical analysis of the system of equations showed that the generation of a broadband one-period terahertz signal is accompanied by a red shift of the carrier frequency of the optical pulse, the magnitude of the shift being proportional to the pulse intensity. The generation efficiency with respect to energy reached a maximum at a certain distance of propagation in the crystal, after which the efficiency decreased. A satisfactory agreement was obtained between theoretical calculations and experimental data of other investigations. (generation of terahertz radiation)

Bugai, A N; Sazonov, S V; Shashkov, Andrei Yu

2012-11-30T23:59:59.000Z

94

Non-invasive field measurements of soil water content using a pulsed 14 MeV neutron generator  

E-Print Network [OSTI]

Non-invasive field measurements of soil water content using a pulsed 14 MeV neutron generator S to the atmosphere. Soil water sensors routinely are used in applications such as research on crop production, water-3120, United States 1. Introduction Knowledge of soil water content is critical to agricultural, hydrological

Johnson, Peter D.

95

Self-focusing, channel formation, and high-energy ion generation in interaction of an intense short laser pulse with a He jet  

E-Print Network [OSTI]

Self-focusing, channel formation, and high-energy ion generation in interaction of an intense short of interaction of a relativistically intense 4-TW, 400-fs laser pulse with a He gas jet. We observe a stable data, we reconstructed the axial profile of laser channel and on-axis laser intensity. The estimated

Umstadter, Donald

96

Benchmark validation comparisons of measured and calculated delayed neutron detector responses for a pulsed photonuclear assessment technique  

SciTech Connect (OSTI)

An MCNPX-based calculational methodology has been developed to numerically simulate the complex electron杙hotonneutron transport problem for the active interrogation system known as the pulsed photonuclear assessment (PPA) technique. The PPA technique uses a pulsed electron accelerator to generate bremsstrahlung photons in order to fission nuclear materials. Delayed neutron radiation is then detected with helium-3 neutron detectors as evidence of the nuclear material presence. Two experimental tests were designed, setup and run to generate experimental data for benchmarking purposes. The first test irradiated depleted uranium in air, and the second test, depleted uranium in a simulated cargo container (plywood pallet), using 10 MeV electron pulses. Time-integrated, post-flash, delayed neutron counts were measured and compared to calculated count predictions in order to benchmark the calculational methodology and computer models. Comparisons between the experimental measurements and numerical predictions of the delayed neutron detector responses resulted in reasonable experiment/calculated ratios of 1.42 and 1.06 for the two tests. High-enriched uranium (HEU) predictions were also made with the benchmarked models.

J. W. Sterbentz; J. L. Jones; W. Y. Yoon; D. R. Norman; K. J. Haskell

2007-08-01T23:59:59.000Z

97

Initial increase, ''peaking effect'', in the internal friction of copper following pulsed neutron and electron irradiation  

SciTech Connect (OSTI)

Under certain experimental conditions the internal friction in metals can first increase and following prolonged irradiation decrease. Many models have been proposed to account for this ''peaking effect''; however, in many of the cases, no effort is made to distinguish between the influence of interstitials and/or vacancies. To determine the nature of the point defect responsible for the peaking effect in high purity copper, we have performed a series of pulsed irradiations using neutrons and electrons. In all of the experiments an initial very rapid rise in the internal friction and Young's modulus was observed. These data show that a fast diffusing defect is responsible for the peaking effect: i.e. the interstitial.

Simpson, H.M.; Parkin, D.M.; Goldstone, J.A.; Hemsky, J.W.

1985-01-01T23:59:59.000Z

98

Structure of Al-Mn-Cr-Si quasicrystals studied by pulsed neutron scattering  

Science Journals Connector (OSTI)

The atomic structure of rapidly quenched quasicrystals, Al80Mn20, Al75Mn20Si5, and Al75Mn15Cr5Si5, was studied by pulsed neutron scattering. The pair distribution function was obtained by a direct Fourier transformation of the structure factor, and by assuming isomorphous substitution of Cr for Mn the differential distribution function (DDF) was determined. The addition of Si was found to increase the medium-range order significantly. The DDF from Mn atoms indicates the presence of a quasicrystalline substructure which is occupied both by Mn and Al atoms. The atomic structure of these solids, therefore, is significantly different from that of quasicrystalline Pd58.8U20.6Si20.6.

S. Nanao; W. Dmowski; T. Egami; J. W. Richardson; Jr.; J. D. Jorgensen

1987-01-15T23:59:59.000Z

99

Selective Dissociation of Sulfur Hexafluoride by Intense CO2 Laser Radiation in Pulsed Gas Dynamic Flow  

Science Journals Connector (OSTI)

Isotopically selective IR multiphoton dissociation (MPD) of SF6 in a pulsed gas dynamic flow was studied. The dependence of the yield of the product SF4 on the frequency of CO2 laser radiation exciting SF6 molecu...

G. N. Makarov; A. N. Petin

2000-11-01T23:59:59.000Z

100

H{sub 2}{sup +} photodissociation by an intense pulsed photonic Fock state  

SciTech Connect (OSTI)

We study the photodissociation of the H{sub 2}{sup +} molecule by ultrashort Fock-state electromagnetic pulses (EMPs). We use the Born-Oppenheimer treatment combined with an explicit photon number representation via diabatic electrophoton potential surfaces for simplification of the basic equations. We discuss the issue of the number of photon states required and show that six photon states enable good accuracy for photoproduct kinetic energies of up to 3 eV. We calculate photodissociation probabilities and nuclear kinetic-energy (KE) distributions of the photodissociation products for 800-nm, 50-TW/cm{sup 2} pulses. We show that KE distributions depend on three pulse durations of 10, 20, and 45 fs and on various initial vibrational states of the molecule. We compare the Fock-state results to those obtained by 'conventional', i.e., coherent-state, laser pulses of equivalent electric fields and durations. The effects of the quantum state of EMPs on the photodissociation dynamics are especially strong for high initial vibrational states of H{sub 2}{sup +}. While coherent-state pulses suppress photodissociation for the high initial vibrational states of H{sub 2}{sup +}, the Fock-state pulses enhance it.

Paul, Amit K.; Adhikari, Satrajit [Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Baer, Michael [Fritz Haber Research Center for Molecular Dynamics, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Baer, Roi [Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

2010-01-15T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Spallation Neutron Source, SNS  

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

Spallation Neutron Source Spallation Neutron Source Providing the most intense pulsed neutron beams in the world... Accumulator Ring Commissioning Latest Step for Spallation Neutron Source The Spallation Neutron Source, located at Oak Ridge National Laboratory, has passed another milestone on the way to completion this year--the commissioning of the proton accumulator ring. Brookhaven led the design and construction of the accumulator ring, which will allow an order of magnitude more beam power than any other facility in the world. The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Oak Ridge, Tennessee, by the U.S. Department of Energy. The figure on the right shows a schematic of the accumulator ring and transport beam lines that are being designed and built by Brookhaven

102

Generation and focusing of pulsed intense ion beams. Final progress report, April 1, 1979-September 30, 1979  

SciTech Connect (OSTI)

Theoretical calculations suggest that an intense pulsed approx. 1 MeV proton beam can be used to simulate the characteristics of approx. 1 GeV heavy ion beam propagation in an inertial confinement fusion reactor chamber. Given the present availability of the former beams and the high projected cost for obtaining the latter ones, such experimental simulations appear appropriate. Work was undertaken under the cited contract to apply the technology of intense proton beams to this end. The first task was the development of a high brightness pulsed proton source which could produce a weakly convergent approx. 10 kA proton beam in a field free drift region. This was accomplished at approx. 250 keV, and preliminary beam propagation experiments were performed. It was concluded that a proper simulation experiment would require a higher voltage beam. An upgraded version of the existing generator, which would have produced a 30 kA beam at about 500 keV, and further propagation experiments were proposed as part of our unsuccessful renewal proposal dated October 15, 1979.

Sudan, R.N.; Hammer, D.A.

1981-04-01T23:59:59.000Z

103

Electron-nuclear dynamics of the one-electron nonlinear polyatomic molecule H32+ in ultrashort intense laser pulses  

Science Journals Connector (OSTI)

A quantum description of the one-electron triangular H32+ molecular ion, beyond the Born-Oppenheimer approximation, is used to study the full influence of the nuclear motion on the high-intensity photoionization and harmonic generation processes. A detailed analysis of electron and proton motions and their time-dependent acceleration allows for identification of the main electron recollision events as a function of time-dependent configuration of the protons. High-order-harmonic generation photons are shown to be produced by single-electron recollision in the second half of the pulse envelope, which also induces a redshift in the harmonics, due to the rapid few-femtosecond motions of protons. Perpendicular harmonics are produced, in general, with a linearly polarized laser pulse parallel to a bond of the triangular molecule, and, in particular, the harmonics in the cutoff region are elliptically polarized. When the laser-pulse polarization is parallel to a symmetry axis of the triangular molecular ion, creation and destruction of the chemical bond perpendicular to the polarization is predicted on a near-femtosecond time scale.

C. Lefebvre; H. Z. Lu; S. Chelkowski; A. D. Bandrauk

2014-02-06T23:59:59.000Z

104

Gamma/neutron analysis for SNM signatures at high-data rates(greater than 107 cps) for single-pulse active interrogation  

SciTech Connect (OSTI)

We are developing a high data gamma/neutron spectrometer suitable for active interrogation of special nuclear materials (SNM) activated by a single burst from an intense source. We have tested the system at Naval Research Laboratory's (NRL) Mercury pulsed-power facility at distances approaching 10 meters from a depleted uranium (DU) target. We have found that the gamma-ray field in the target room 'disappears' 10 milliseconds after the x-ray flash, and that gamma ray spectroscopy will then be dominated by isomeric states/beta decay of fission products. When a polyethylene moderator is added to the DU target, a time-dependent signature of the DU is produced by thermalized neutrons. We observe this signature in gamma-spectra measured consecutively in the 0.1-1.0 ms time range. These spectra contain the Compton edge line (2.2 MeV) from capture in hydrogen, and a continuous high energy gamma-spectrum from capture or fission in minority constituents of the DU.

Forman L.; Dioszegi, I.; Salwen, C.

2011-04-26T23:59:59.000Z

105

Dynamical ionization ignition of clusters in intense and short laser pulses  

E-Print Network [OSTI]

The electron dynamics of rare gas clusters in laser fields is investigated quantum mechanically by means of time-dependent density functional theory. The mechanism of early inner and outer ionization is revealed. The formation of an electron wave packet inside the cluster shortly after the first removal of a small amount of electron density is observed. By collisions with the cluster boundary the wave packet oscillation is driven into resonance with the laser field, hence leading to higher absorption and ionization. Although the mechanism is sensitive to the laser frequency, any plasma resonances are found to be insignificant for the cluster sizes, the short pulse durations, and the modest charge states under consideration.

Bauer, D

2003-01-01T23:59:59.000Z

106

KORONA; An intense sealed-tube 14-MeV neutron generator  

SciTech Connect (OSTI)

This paper describes a sealed-tube, high-current, low-energy accelerator (190 kV, 150 mA) in operation at the GKSS Research Center since 1981. The deuterium-tritium reaction yields a total source strength of 3 {times} 10 {sup 12} n/s. The neutron flux in the center of the hollow cylinder target is {approx} 3 {times} 10 n/cm{sup 2} {center dot} s in a 4-cm{sup 3} volume. Numerous 14-MeV neutron reaction cross sections have been determined with satisfactory accuracy; however, the system has been mainly used for neutron activation analysis. To predict the gamma-ray activity of any element after short-term irradiation with 14-MeV neutrons, a sensitivity study was performed, which proved to be a useful tool for analyzing complex spectra.

Pepelnik, R.; Fanger, H.U.; Michaelis, W. (GKSS-Forschungszentrum Geesthacht GmbH, Inst. fur Physik, Postfach 1160, D-2054 Geesthacht (DE))

1990-11-01T23:59:59.000Z

107

Momentum distributions of sequential ionization generated by an intense laser pulse  

E-Print Network [OSTI]

beam is produced in an EBIT (electron beam ion trap) that is kept at a potential of approximately 5 kV, and which can produce xenon ions with charges ranging from Xe1+ to around Xe20+. Selecting the desired initial charge state with a Wienfilter... that is on the order of its rest energy. Taking into account that the oscillation energy of a free electron is F 2/4?2, one can easily find that relativistic effects occur for radiation of the Ti:Sa laser at the intensity greater than 5? 1018 W/cm2 (see Ref. [2...

Shvetsov-Shilovski, N. I.; Sayler, A. M.; Rathje, T.; Paulus, Gerhard G.

2011-01-01T23:59:59.000Z

108

A proton?driven, intense, subcritical, fission neutron source for radioisotope production  

Science Journals Connector (OSTI)

99mTc the most frequently used radioisotope in nuclear medicine is distributed as 99Mo?99mTc generators. 99 Mo is a fission product of 235U. To replace the aging nuclear reactors used today for this production we propose to use a spallation neutron source with neutron multiplication by fission. A 150 MeV H? cyclotron can produce a 225 kW proton beam with 50% total system energy efficiency. The proton beam would hit a molten lead target surrounded by a water moderator and a graphite reflector producing around 0.96 primary neutron per proton. The primary spallation neutrons moderated would strike secondary targets containing a subcritical amount of 235U. The assembly would show a keff of 0.8 yielding a fivefold neutron multiplication. The thermal neutron flux at the targets location would be 2 1014 n/cm2.s resulting in a fission power of 500 to 750 kW. One such system could supply the world demand in 99 Mo as well as other radioisotopes. Preliminary indications show that the cost would be lower than the cost of a commercial 10 MW isotope production reactor. The cost of operation of disposal of radiowaste and of decommissioning should be significantly lower as well. Finally the non?critical nature of the system would make it more acceptable for the public than a nuclear reactor and should simplify the licensing process.

Yves Jongen

1995-01-01T23:59:59.000Z

109

Study on neutron emission from 2.2?kJ plasma focus device  

SciTech Connect (OSTI)

The neutron emission from a low energy (2.2?kJ) plasma focus device operated in deuterium medium has been investigated by employing photo-multiplier tube (PMT) and bubble dosimeter. The neutron emission is found to be pressure dependent and anisotropic in nature. In most cases of plasma focus shots, the PMT signal shows double pulses of neutron emission with different intensities and widths. An interesting relation between intensity of hard X-ray and neutron emission is also observed.

Talukdar, N.; Neog, N. K.; Borthakur, T. K., E-mail: tkborthakur@yahoo.co.uk [Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782402, Kamrup, Assam (India)

2014-06-15T23:59:59.000Z

110

Broadband colored-crescent generation in a single {beta}-barium-borate crystal by intense femtosecond pulses  

SciTech Connect (OSTI)

A visible colored crescent with a bandwidth broader than 220 nm is observed experimentally by loosely focused femtosecond pulses in a bulk quadratic nonlinear crystal ({beta}-BBO crystal) at certain incident angles. Through the analysis based on a simple collinear phase-matching model, we suggest that the colored crescent might be the coexistence of spontaneous parametric down-conversions (SPDCs) in the infrared range and the corresponding efficient second-order harmonic generations (SHGs) that occur in a wide spectrum. We further provide a possible mechanism for the SHG process in which the phase-mismatching angles of the frequency doubling of SPDCs in {beta}-BBO crystal are assumed to be compensated by the strong diffraction effect during the self-focusing process of the generated intense SPDC signals.

Wang, L.; Fan, Y. X.; Zhu, H.; Yan, Z. D.; Zhu, S. N.; Wang, Z. L. [Department of Physics and National Laboratory of Solid State Microstructures, Nanjing University, 210093 Nanjing (China); Zeng, H. [State Key Laboratory of Precision Spectroscopy, East China Normal University, 200062 Shanghai (China); Wang, H.-T. [Department of Physics and National Laboratory of Solid State Microstructures, Nanjing University, 210093 Nanjing (China); School of Physics, Nankai University, 300071 Tianjin (China)

2011-12-15T23:59:59.000Z

111

Voluminous D2 source for intense cold neutron beam production at the ESS  

E-Print Network [OSTI]

The development of the flat moderator concept at ESS recently opened up the possibility that a single flat moderator above the target could serve all the scattering instruments, that rely on high brightness. This would allow for the introduction of a fundamentally different moderator below the target for the complementary needs of certain fundamental physics experiments. To facilitate experiments depending on the total number of neutrons in a sizable beam, the option of a voluminous D2 moderator, in a large cross-section extraction guide is discussed and its neutronic performance is assessed.

Klinkby, Esben; Mezei, Ferenc; Sch鴑feldt, Troels; Takibayev, Alan; Zanini, Luca

2014-01-01T23:59:59.000Z

112

Voluminous D2 source for intense cold neutron beam production at the ESS  

E-Print Network [OSTI]

The development of the flat moderator concept at ESS recently opened up the possibility that a single flat moderator above the target could serve all the scattering instruments, that rely on high brightness. This would allow for the introduction of a fundamentally different moderator below the target for the complementary needs of certain fundamental physics experiments. To facilitate experiments depending on the total number of neutrons in a sizable beam, the option of a voluminous D2 moderator, in a large cross-section extraction guide is discussed and its neutronic performance is assessed.

Esben Klinkby; Konstantin Batkov; Ferenc Mezei; Troels Sch鴑feldt; Alan Takibayev; Luca Zanini

2014-01-23T23:59:59.000Z

113

E-Print Network 3.0 - advanced pulsed neutron Sample Search Results  

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

... Source: Controlled Fusion Atomic Data Center (CFADC) Collection: Plasma Physics and Fusion 5 Spallation-Driven Cold Neutron Sources Dr. Bradley J. Micklich Summary: probe the...

114

The Transmutation of Nuclear Waste in the Two-Zone Subcritical System Driven by High- Intensity Neutron Generator - 12098  

SciTech Connect (OSTI)

The main problems of transmutation of high-level radioactive waste (minor actinides and long-lived fission products) are considered in our work. The range of radioactive waste of nuclear power is analyzed. The conditions under which the transmutation of radioactive waste will be most effective are analyzed too. The modeling results of a transmutation of the main radioactive isotopes are presented and discussed. The transmutation of minor actinides and long-lived fission products are modeled in our work (minor actinides - Np-237, Am-241, Am-242, Am-243, Cm-244, Cm-245; long-lived fission products - I-129, Tc-99). The two-zone subcritical system is calculated with help of different neutron-physical codes (MCNP, Scale, Montebarn, Origen). The ENDF/B-VI nuclear data library used in above calculations. Thus, radioactive wastes can be divided into two main groups that need to be transmuted. The minor actinides form the first group and the long-lived fission products form the second one. For the purpose of effective transmutation these isotopes must be extracted from the spent nuclear fuel with the help of either PUREX technology or pyrometallurgical technology. The two-zone reactor system with fast and thermal regions is more effective for nuclear waste transmutation than the one-zone reactor. Modeling results show that nearly all radioactive wastes can be transmuted in the two-zone subcritical system driven by a high-intensity neutron generator with the external neutron source strength of 1.10{sup 13} n/sec. Obviously, transmutation rate will increase with a rise of the external neutron source strength. From the results above we can also see that the initial loading of radioactive isotopes into the reactor system should exceed by mass those isotopes that are finally produced. (authors)

Babenko, V.O. [Bogolyubov Institute for Theoretical Physics, Metrolohichna str. 14-b, Kiev, 03680 (Ukraine); Gulik, V.I.; Pavlovych, V.M. [Institute for Nuclear Research, pr. Nauky 47, Kyiv, 03680 (Ukraine)

2012-07-01T23:59:59.000Z

115

Specific features of microheterogeneous plasma produced by irradiation of a polymer aerogel target with an intense 500-ps-long laser pulse  

Science Journals Connector (OSTI)

The properties of microheterogeneous plasma produced by irradiation of a polymer aerogel target with an intense (1014 W/cm3) short (0.5 ps) 1.064-?m laser pulse were studied. It is found that, even at plasma dens...

N. G. Borisenko; Yu. A. Merkul抏v; A. S. Orekhov; S. Chaurasia

2013-08-01T23:59:59.000Z

116

SNS | Spallation Neutron Source | ORNL  

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

SNS SNS Instruments Working with SNS Contact Us User Program Manager Laura Morris Edwards 865.574.2966 Spallation Neutron Source Home | User Facilities | SNS SNS | Spallation Neutron Source SHARE SNS is an accelerator-based neutron source in Oak Ridge, Tennessee, USA. This one-of-a-kind facility provides the most intense pulsed neutron beams in the world for scientific research and industrial development. The 80-acre SNS site is located on Chestnut Ridge and is part of Oak Ridge National Laboratory. Although most people don't know it, neutron scattering research has a lot to do with our everyday lives. For example, things like medicine, food, electronics, and cars and airplanes have all been improved by neutron scattering research. Neutron research also helps scientists improve materials used in a

117

Investigating Correlated Neutrons from Pulsed Photonuclear Interrogation for Treaty Verification Applications  

E-Print Network [OSTI]

systems, and 2D gamma imaging technology.3 More modern efforts have again returned to singles neutron and gamma counting techniques, but have more specifically focused on adapting portal monitoring technology to fill roles in potential treaty...

Stewart, Scott

2013-06-03T23:59:59.000Z

118

Dead-time effects of neutron detectors due to pulsed radiation  

Science Journals Connector (OSTI)

......distance from the accelerator. If electrons are lost in the vacuum system, they...neutrons by nuclear reactions...materials used in vacuum systems of accelerators. Because the...at electron accelerators. For both nuclear reactions......

K. Ott; M. Helmecke; M. Luszik-Bhadra; M. Martin; A. Weber

2013-07-01T23:59:59.000Z

119

The extraction of a mono-energetic neutron beam of maximum intensity from a nuclear reactor  

E-Print Network [OSTI]

all aluminum was taken because Mn has a high capture cross section for thermal neutrons and becomes highly radioactive Mn . Mn has a long half life and gives off 56 FIa 6 SHIELDING PLUG WITH CO I. LIMA TOR TUSE RVNNERS END VIEW POSITION I NS... the horizontal plane. Rather than try to construct a cylindrical boral liner for the tube, it was decided that a rectangular one would be much simpler to construct and would suit the purpose just as well. The rectangular liner was constructed to fit just...

Snow, Edward Clark

1965-01-01T23:59:59.000Z

120

First time nuclear material detection by one short-pulse-laser-driven neutron  

E-Print Network [OSTI]

counters; one detector containing a 2 kg sample of depleted uranium, and the other one empty for background comparison. A single shot interrogation of the depleted uranium sample, showed a clear signal from the delayed neutrons in the detector with uranium, compared with the background, and with the typical time

Kurien, Susan

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

A PC-PCL-based control system for the high-voltage pulsed-power operation of the Intense Diagnostic Neutral Beam (IDNB) Experiment  

SciTech Connect (OSTI)

A stand-alone, semiautomated control system for the high-voltage pulsed-power energy sources on the Intense Diagnostic Neutral Beam Experiment at Los Alamos National Laboratory using personal computer (PC) and programmable logic controller (PLC) technology has been developed and implemented. The control system, consisting of a PC with the graphic operator interface, the network connecting the PC to the PLC, the PLC, the PLC I/O modules, fiber-optic interfaces and software, is described.

Gribble, R.

1993-06-01T23:59:59.000Z

122

Laser-Energy Transfer and Enhancement of Plasma Waves and Electron Beams by Interfering High-Intensity Laser Pulses  

E-Print Network [OSTI]

Laser-Energy Transfer and Enhancement of Plasma Waves and Electron Beams by Interfering High-Intensity) The effects of interference due to crossed laser beams were studied experimentally in the high- intensity regime. Two ultrashort (400 fs), high-intensity (4 1017 and 1:6 1018 W=cm2) and 1 m wavelength laser

Umstadter, Donald

123

EIS-0247: Construction and Operation of the Spallation Neutron Source |  

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

247: Construction and Operation of the Spallation Neutron 247: Construction and Operation of the Spallation Neutron Source EIS-0247: Construction and Operation of the Spallation Neutron Source SUMMARY The United States needs a high-flux, short- pulsed neutron source to provide its scientific and industrial research communities with a much more intense source of pulsed neutrons for neutron scattering research than is currently available. This source would assure the availability of a state-of-the-art neutron research facility in the United States in the decades ahead. This facility would be used to conduct research in areas such as materials science, condensed matter physics, the molecular structure of biological materials, properties of polymers and complex fluids, and magnetism. In addition to creating new scientific and

124

Impact of pulsed irradiation upon neutron activation calculations for inertial and magnetic fusion energy power plants  

SciTech Connect (OSTI)

Sisolak et al. defined two methods for the approximation of pulsed irradiation: the steady-state (SS) and the equivalent steady-state (ESS) methods. Both methods have been shown to greatly simplify the process of calculating radionuclide inventories. However, they are not accurate when applied to magnetic fusion energy (MFF) and inertial fusion energy (IFE) experimental facilities. In the work reported here, an attempt has been made to evaluate the accuracy of the SS and ESS methods as they might be applied to typical MFE and IFE power plants. 18 refs., 6 figs.

Latkowski, J.F. [Lawrence Livermore National Lab., CA (United States); Sanz, J. [Universidad Politecnica de Madrid (Spain); Vujic, J.L. [Univ. of California, Berkeley, CA (United States)

1996-12-31T23:59:59.000Z

125

SINGLE CRYSTAL NEUTRON DIFFRACTION.  

SciTech Connect (OSTI)

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.

KOETZLE,T.F.

2001-03-13T23:59:59.000Z

126

Slow neutron leakage spectra from spallation neutron sources  

SciTech Connect (OSTI)

An efficient technique is described for Monte Carlo simulation of neutron beam spectra from target-moderator-reflector assemblies typical of pulsed spallation neutron sources. The technique involves the scoring of the transport-theoretical probability that a neutron will emerge from the moderator surface in the direction of interest, at each collision. An angle-biasing probability is also introduced which further enhances efficiency in simple problems. These modifications were introduced into the VIM low energy neutron transport code, representing the spatial and energy distributions of the source neutrons approximately as those of evaporation neutrons generated through the spallation process by protons of various energies. The intensity of slow neutrons leaking from various reflected moderators was studied for various neutron source arrangements. These include computations relating to early measurements on a mockup-assembly, a brief survey of moderator materials and sizes, and a survey of the effects of varying source and moderator configurations with a practical, liquid metal cooled uranium source Wing and slab, i.e., tangential and radial moderator arrangements, and Be vs CH/sub 2/ reflectors are compared. Results are also presented for several complicated geometries which more closely represent realistic arrangements for a practical source, and for a subcritical fission multiplier such as might be driven by an electron linac. An adaptation of the code was developed to enable time dependent calculations, and investigated the effects of the reflector, decoupling and void liner materials on the pulse shape.

Das, S.G.; Carpenter, J.M.; Prael, R.E.

1980-02-01T23:59:59.000Z

127

Spallation Neutron Source The Spallation Neutron Source (SNS)  

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

F/gim F/gim Spallation Neutron Source The Spallation Neutron Source (SNS) gives researchers more detailed informa- tion on the structure and dynamics of physical and biological materials than ever before possible. This accelerator- based facility provides the most intense pulsed neutron beams in the world. Scien- tists are able to count scattered neutrons, measure their energies and the angles at which they scatter, and map their final positions. SNS enables measurements of greater sensitivity, higher speed, higher resolution, and in more complex sample environments than have been possible at existing neutron facilities. Future Growth SNS was designed from the outset to accommodate a second target station, effectively doubling the capacity of the

128

High-resolution measurements of the spatial and temporal evolution of megagauss magnetic fields created in intense short-pulse laser-plasma interactions  

SciTech Connect (OSTI)

A pump-probe polarimetric technique is demonstrated, which provides a complete, temporally and spatially resolved mapping of the megagauss magnetic fields generated in intense short-pulse laser-plasma interactions. A normally incident time-delayed probe pulse reflected from its critical surface undergoes a change in its ellipticity according to the magneto-optic Cotton-Mouton effect due to the azimuthal nature of the ambient self-generated megagauss magnetic fields. The temporal resolution of the magnetic field mapping is typically of the order of the pulsewidth, limited by the laser intensity contrast, whereas a spatial resolution of a few ?m is achieved by this optical technique. High-harmonics of the probe can be employed to penetrate deeper into the plasma to even near-solid densities. The spatial and temporal evolution of the megagauss magnetic fields at the target front as well as at the target rear are presented. The ?m-scale resolution of the magnetic field mapping provides valuable information on the filamentary instabilities at the target front, whereas probing the target rear mirrors the highly complex fast electron transport in intense laser-plasma interactions.

Chatterjee, Gourab, E-mail: gourab@tifr.res.in; Singh, Prashant Kumar; Adak, Amitava; Lad, Amit D.; Kumar, G. Ravindra, E-mail: grk@tifr.res.in [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India)

2014-01-15T23:59:59.000Z

129

Electronic and structural response of InSb to ultra-short and ultra-intense laser pulses  

E-Print Network [OSTI]

intensity of Ac 2. 00 gauss. cm. lrn(&(l'1)) for lnSb for a field intensity of A&i ? 2. 23 gauss cm. Im(e(E)) for InSb for a field intensity of A&i -- 2. 40 gauss cm. hn(e(E)) for InSb for a field intensity of A&i 2. 82 gauss cm. Im(&(E)) for InSb for a...-correlation function for InSb for a field intcnsit, y of Ac ? 2. 00 gauss cin. 21 Tiiiic. cvoluti&m of thc pair-correlation function for lnSb for a field intensity of As = 2. 46 gauss cm. 44 Time evolution of the pair-correlation function for InSb for a field...

Burzo, Andrea Mihaela

2001-01-01T23:59:59.000Z

130

Generation of periodic ultrashort electron bunches and strongly asymmetric ion Coulomb explosion in nanometer foils interacting with ultra-intense laser pulse  

SciTech Connect (OSTI)

The interaction of a linearly polarized intense laser pulse with an ultrathin nanometer plasma layer is investigated to understand the physics of the ion acceleration. It is shown by the computer simulation that the plasma response to the laser pulse comprises two steps. First, due to the vxB effect, electrons in the plasma layer are extracted and periodic ultrashort relativistic electron bunches are generated every half of a laser period. Second, strongly asymmetric Coulomb explosion of ions in the foil occurs due to the strong electrostatic charge separation, once the foil is burnt through. Followed by the laser accelerated electron bunch, the ion expansion in the forward direction occurs along the laser beam that is much stronger as compared to the backward direction.

Tian Youwei [College of Mathematics and Physics, Nanjing University of Posts and Telecommunications, Nanjing 210003 (China); Yu Wei; Xu Han; Lei Anle; Shen Baifei; Wang Xin [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Lu Peixiang [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan 430070 (China); Senecha, Vinod [Raja Ramanna Centre for Advanced Technology, Indore-452 013 (India)

2008-05-15T23:59:59.000Z

131

Rapid sintering of TiO{sub 2} photoelectrodes using intense pulsed white light for flexible dye-sensitized solar cells  

SciTech Connect (OSTI)

Intense pulsed white light (IPWL) sintering was carried out at room temperature, which is suitable dye-sensitized solar cells (DSSCs) fabrication process on plastic substrates for the mass production. Five seconds irradiation of IPWL on TiO{sub 2} electrode significantly improves the photocurrent density and power conversion efficiency of DSSCs by more than 110% and 115%, respectively, compared to the DSSCs without IPWL treatment. These improvements were mainly attributed to the enhanced interconnection between the TiO{sub 2} nanoparticles induced by IPWL illumination, which is confirmed by the impedance spectra analysis.

Jin, Hwa-Young [Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Kim, Jae-Yup; Ah Lee, Jin; Lee, Kwangsoo; Yoo, Kicheon; Lee, Doh-Kwon; Kim, BongSoo; Young Kim, Jin; Kim, Honggon; Jung Son, Hae [Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Kim, Jihyun [Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Ah Lim, Jung, E-mail: jalim@kist.re.kr, E-mail: mjko@kist.re.kr [Interface Control Research Center, Future Convergence Research Division, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Jae Ko, Min, E-mail: jalim@kist.re.kr, E-mail: mjko@kist.re.kr [Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Green School, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of)

2014-04-07T23:59:59.000Z

132

Note: Characterization of the plasma parameters of a capillary discharge-produced plasma channel waveguide to guide an intense laser pulse  

SciTech Connect (OSTI)

We demonstrated the production of an optical waveguide in a capillary discharge-produced plasma using a cylindrical capillary. Plasma parameters of its waveguide were characterized by use of both a Nomarski laser interferometer and a hydrogen plasma line spectrum. A space-averaged maximum temperature of 3.3 eV with electron densities of the order of 10{sup 17} cm{sup -3} was observed at a discharge time of 150 ns and a maximum discharge current of 400 A. An ultrashort, intense laser pulse was guided by use of this plasma channel.

Higashiguchi, Takeshi; Yugami, Noboru [Department of Advanced Interdisciplinary Sciences and Center for Optical Research and Education (CORE), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Hikida, Masafumi; Terauchi, Hiromitsu; Bai Jinxiang [Department of Advanced Interdisciplinary Sciences and Center for Optical Research and Education (CORE), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Kikuchi, Takashi [Department of Electrical Engineering, Nagaoka University of Technology, Kami-tomiokamachi 1603-1, Nagaoka, Niigata 940-2188 (Japan); Tao Yezheng [Center for Energy Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0438 (United States)

2010-04-15T23:59:59.000Z

133

Magnetically insulated diode for generating pulsed neutron and gamma ray emissions  

DOE Patents [OSTI]

A magnetically insulated diode employs a permanent magnet to generate a magnetic insulating field between a spaced anode and cathode in a vacuum. An ion source is provided in the vicinity of the anode and used to liberate ions for acceleration toward the cathode. The ions are virtually unaffected by the magnetic field and are accelerated into a target for generating an nuclear reaction. The ions and target material may be selected to generate either neutrons or gamma ray emissions from the reaction of the accelerated ions and the target. In another aspect of the invention, a field coil is employed as part of one of the electrodes. A plasma prefill is provided between the electrodes prior to the application of a pulsating potential to one of the electrodes. The field coil multiplies the applied voltage for high diode voltage applications. The diode may be used to generate a .sup.7 Li(p,.gamma.).sup.8 Be reaction to produce 16.5 MeV gamma emission.

Kuswa, Glenn W. (Albuquerque, NM); Leeper, Ramon J. (Albuquerque, NM)

1987-01-01T23:59:59.000Z

134

Specific features of microheterogeneous plasma produced by irradiation of a polymer aerogel target with an intense 500-ps-long laser pulse  

SciTech Connect (OSTI)

The properties of microheterogeneous plasma produced by irradiation of a polymer aerogel target with an intense (10{sup 14} W/cm{sup 3}) short (0.5 ps) 1.064-?m laser pulse were studied. It is found that, even at plasma densities exceeding the critical density, a small fraction of the incident laser radiation penetrates through the plasma in which the processes of density and temperature equalization still take place. The intensification (as compared to plasmas produced from denser foams and solid films) of transport processes in such plasma along and across the laser beam can be caused by the initial microheterogeneity of the solid target. The replacement of a small (10% by mass) part of the polymer with copper nanoparticles leads to a nearly twofold increase in the intensity of the plasma X-ray emission.

Borisenko, N. G.; Merkul抏v, Yu. A.; Orekhov, A. S., E-mail: orekhov@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Chaurasia, S.; Tripathi, S.; Munda, D. S.; Dhareshwar, L. J. [Bhabha Atomic Research Centre, High-Pressure and Synchrotron Radiation Physics Division (India)] [Bhabha Atomic Research Centre, High-Pressure and Synchrotron Radiation Physics Division (India); Pimenov, V. G.; Sheveleva, E. E. [Russian Academy of Sciences, Zelinksy Institute of Organic Chemistry (Russian Federation)] [Russian Academy of Sciences, Zelinksy Institute of Organic Chemistry (Russian Federation)

2013-08-15T23:59:59.000Z

135

Enhancement of x-ray line emission from plasmas produced by short high-intensity laser double pulses  

E-Print Network [OSTI]

Enhancement of x-ray line emission from plasmas produced by short high-intensity laser double laser-produced plasmas are bright ultrafast line x-ray sources potentially suitable for different onto a solid target into the x-ray emission is significantly enhanced when a laser prepulse precedes

Limpouch, Jiri

136

Software realization of real-time neutrons and {gamma}-rays pulse shape discrimination using CUDA platform  

SciTech Connect (OSTI)

The two pulse shape discrimination methods were implemented in real-time. The pulse gradient analysis method was implemented programmatically on PC. The method based on artificial neural network was programmatically implemented using CUDA platform. It is shown that both implementations can provide up to 10{sup 6} pulses per second processing performance. The results for pulse shape discrimination using polycrystalline stilbene and LiF detectors were shown. (authors)

Kolbasin, V. A.; Ivanov, A. I.; Pedash, V. Y. [Inst. for Scintillation Materials NAS of Ukraine, Kharkov (Ukraine)

2011-07-01T23:59:59.000Z

137

Generation of Initial Kinetic Distributions for Simulation of Long-Pulse Charged Particle Beams with High Space-Charge intensity  

SciTech Connect (OSTI)

Self-consistent Vlasov-Poisson simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel--both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of kinetic distributions commonly in use as initial Vlasov distributions in simulations of unbunched or weakly bunched beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial kinetic distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

Lund, Steven M.; Kikuchi, Takashi; Davidson, Ronald C.

2007-04-03T23:59:59.000Z

138

Use of delayed gamma rays for active non-destructive assay of 235U irradiated by pulsed neutron source (plasma focus)  

Science Journals Connector (OSTI)

Abstract A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of 235U by monitoring its delayed high energy ?-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl)) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100爏 while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50爉s. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10燤eV. The lower limit of detection of 235U in the oxide samples with this set-up is estimated to be 14爉g.

Sanjay Andola; Ram Niranjan; T.C. Kaushik; R.K. Rout; Ashwani Kumar; D.B. Paranjape; Pradeep Kumar; B.S. Tomar; K.L. Ramakumar; S.C. Gupta

2014-01-01T23:59:59.000Z

139

Compression and acceleration of electron bunches to high energies in the interference field of intense laser pulses with tilted amplitude fronts: concept and modelling  

SciTech Connect (OSTI)

A new concept of accelerating electrons by laser radiation is proposed, namely, direct acceleration by a laser field under the conditions of interference of several relativistic-intensity laser pulses with amplitude fronts tilted by the angle 45 Degree-Sign with respect to the phase fronts. Due to such interference the traps moving with the speed of light arise that capture the electrons, produced in the process of ionisation of low-density gas by the same laser radiation. The modelling on the basis of solving the relativistic Newton equation with the appropriate Lorenz force shows that these traps, moving in space, successively collect electrons from the target, compress the resulting electron ensemble in all directions up to the dimensions smaller than the wavelength of the laser radiation and accelerate it up to the energies of the order of a few GeV per electron. (extreme light fields and their applications)

Korobkin, V V; Romanovsky, Mikhail Yu; Trofimov, V A; Shiryaev, O B [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2013-03-31T23:59:59.000Z

140

Effect of the change in the load resistance on the high voltage pulse transformer of the intense electron-beam accelerators  

SciTech Connect (OSTI)

A high voltage pulse transformer (HVPT) is usually used as a charging device for the pulse forming line (PFL) of intense electron-beam accelerators (IEBAs). Insulation of the HVPT is one of the important factors that restrict the development of the HVPT. Until now, considerable effort has been focused on minimizing high field regions to avoid insulation breakdown between windings. Characteristics of the HVPT have been widely discussed to achieve these goals, but the effects of the PFL and load resistance on HVPT are usually neglected. In this paper, a HVPT is used as a charging device for the PFL of an IEBA and the effect of the change in the load resistance on the HVPT of the IEBA is presented. When the load resistance does not match the wave impedance of the PFL, a high-frequency bipolar oscillating voltage will occur, and the amplitude of the oscillating voltage will increase with the decrease in the load resistance. The load resistance approximates to zero and the amplitude of the oscillating voltage is much higher. This makes it easier for surface flashover along the insulation materials to form and decrease the lifetime of the HVPT.

Cheng Xinbing; Liu Jinliang; Qian Baoliang; Zhang Yu; Zhang Hongbo [College of Photoelectrical Science and Engineering, National University of Defense Technology, Hunan 410073 (China)

2009-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
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141

Monte Carlo determination of the neutron-gamma spectrum behind cadmium loaded polyethylene slabs irradiated by the Sandia Pulse Reactor III  

E-Print Network [OSTI]

(Horizontal View) the other ha 1 f the oppos 1 te s 1 de of the reactor from the test conf fguration. These sub-divisions el low greater eff 1 c iency by increasing the biasing parameters in the regions farther from the detector. The floor was mode) led... the neutron ? gamma spectrum behind slabs with different thicknesses, different cadmium loadings within the poly- ethylene, and various detector geometries. This work is being done for the Sandia Pulse Reactor I I I because one of the uses for the SPR-3...

Sartor, Raymond Francis

2012-06-07T23:59:59.000Z

142

Criticality and Characteristic Neutronic Analysis of a Transient-State Shockwave in a Pulsed Spherical Gaseous Uranium-Hexafluoride Reactor.  

E-Print Network [OSTI]

??The purpose of this study is to analyze the theoretical criticality of a spherical uranium-hexafluoride reactor with a transient, pulsed shockwave emanating from the center (more)

Boles, Jeremiah

2013-01-01T23:59:59.000Z

143

Neutron skins and neutron stars  

SciTech Connect (OSTI)

The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ('PREX') at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in {sup 208}Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron beams may impact the physics of neutron stars.

Piekarewicz, J. [Department of Physics, Florida State University, Tallahassee, FL 32306-4350 (United States)

2013-11-07T23:59:59.000Z

144

Simulation of a suite of generic long-pulse neutron instruments to optimize the time structure of the European Spallation Source  

SciTech Connect (OSTI)

We here describe the result of simulations of 15 generic neutron instruments for the long-pulsed European Spallation Source. All instruments have been simulated for 20 different settings of the source time structure, corresponding to pulse lengths between 1 ms and 2 ms; and repetition frequencies between 10 Hz and 25 Hz. The relative change in performance with time structure is given for each instrument, and an unweighted average is calculated. The performance of the instrument suite is proportional to (a) the peak flux and (b) the duty cycle to a power of approximately 0.3. This information is an important input to determining the best accelerator parameters. In addition, we find that in our simple guide systems, most neutrons reaching the sample originate from the central 3-5 cm of the moderator. This result can be used as an input in later optimization of the moderator design. We discuss the relevance and validity of defining a single figure-of-merit for a full facility and compare with evaluations of the individual instrument classes.

Lefmann, Kim; Kleno, Kaspar H.; Holm, Sonja L.; Sales, Morten [Nanoscience and eScience Centers, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen O (Denmark); Danish Workpackage for the ESS Design Update Phase, Universitetsparken 5, 2100 Copenhagen O (Denmark); Birk, Jonas Okkels [Nanoscience and eScience Centers, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen O (Denmark); Danish Workpackage for the ESS Design Update Phase, Universitetsparken 5, 2100 Copenhagen O (Denmark); Laboratory for Quantum Magnetism, Ecole Polytecnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Hansen, Britt R.; Knudsen, Erik; Willendrup, Peter K. [Institute of Physics, Technical University of Denmark, 2800 Lyngby (Denmark); Danish Workpackage for the ESS Design Update Phase, 2800 Lyngby (Denmark); Lieutenant, Klaus [Institute for Energy Technology, Instituttveien 18, 2007 Kjeller (Norway); Helmholtz Center for Energy and Materials, Hahn-Meitner Platz, 14109 Berlin (Germany); German Work Package for the ESS Design Update, Hahn-Meitner Platz, 14109 Berlin (Germany); Moos, Lars von [Department of Energy Conversion and Storage, Technical University of Denmark, 4000 Roskilde (Denmark); Danish Workpackage for the ESS Design Update Phase, 2800 Lyngby (Denmark); Institute for Energy Conversion, Technical University of Denmark, 4000 Roskilde (Denmark); Andersen, Ken H. [European Spallation Source ESS AB, 22100 Lund (Sweden)

2013-05-15T23:59:59.000Z

145

VOLUME 88, NUMBER 7 P H Y S I C A L R E V I E W L E T T E R S 18 FEBRUARY 2002 Boosting Sonoluminescence with a High-Intensity Ultrasonic Pulse Focused  

E-Print Network [OSTI]

. Therefore, they are seriously limited by the narrow stability domain of the bubble, which results from Sonoluminescence with a High-Intensity Ultrasonic Pulse Focused on the Bubble by an Adaptive Array Jean Diderot, 10 rue Vauquelin, 75231 Paris, France (Received 29 June 2001; published 1 February 2002) Single-bubble

Forterre, Yo毛l

146

Pulse combustion  

Science Journals Connector (OSTI)

Pulse combustion has been gaining increased interest because of its potential for higher combustion efficiency greater combustion intensity and lower pollutant emissions. Unsteady combustion causes increased mass momentum and heat transfer. As a result reactants mix faster heat release is accelerated and heat transfer is enhanced in unsteady reacting flows. Many of these phenomena were discovered long ago by engineers looking for the cause of often detrimental combustion instabilities. Much more recently some of these enhanced transfer properties have been used to design efficient and compact pulse combustors. Although to date successful commercialization on a large scale has been limited to home heating units (e.g. the Lenox Pulse Furnace) highly efficient pulse spray dryers (Bepex Unison Dryer) pulse calciners and pulse waste incinerators have been designed. Pulsations have also been applied to carbon black fluidized bed gasifiers. Not all these designs will become economically viable. However the development of tunable pulse combustors that can be acoustically matched to the changing resonance frequency of these pulse processes have made many of them more promising. Recent findings that pulsation can enhance burning even in turbulent flows lend further encouragement to the developers of novel pulse combustion devices.

Jechiel I. Jagoda

2000-01-01T23:59:59.000Z

147

LANSCE | Lujan Neutron Scattering Center  

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

Department of Energy, National Office of Science Department of Energy, National Office of Science science.energy.gov Department of Energy, National Nuclear Security Administration nnsa.energy.gov Lujan Neutron Scattering Center Logo Lujan Center Mission The Lujan Center delivers science by exploiting the unique characteristics of intense beams of pulsed neutrons for academia, national security, and industry. Lujan Center Vision The Lujan Center will operate a world class user program in the service of the nation. Lujan Center scientists will be recognized for their leadership and innovation in neutron scattering. Lujan Center at LANSCE The Lujan Center is one of five user facilities supported by the LANSCE accelerator which is stewarded. Funding to operate 10 instruments in a national user program is provided by the Department of Energy's Office of

148

Neutron Scattering Facilities 1982  

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

NEUTRON SOURCES NEUTRON SOURCES 飦琓ypes of Sources 飦琔.S. Sources Available for Users 飦琍lans for the Future 飦琓he Neutron Scattering Society of America (NSSA) SNS/ANL School on Neutron and x-Ray Scattering, June 2011 Jim Rhyne Lujan Neutron Scattering Center Los Alamos National Lab. What do we need to do neutron scattering? * Neutron Source - produces neutrons * Diffractometer or Spectrometer - Allows neutrons to interact with sample - Sorts out discrete wavelengths by monochromator (reactor) or by time of flight (pulse source) - Detectors pick up neutrons scattered from sample * Analysis methods to determine material properties * Brain power to interpret results Sources of neutrons for scattering * Nuclear Reactor - Neutrons produced from fission of 235 U - Fission spectrum neutrons

149

Neutron Microscope  

Science Journals Connector (OSTI)

We report successful operation of a neutron microscope using ultracold neutrons at the high-flux reactor at Grenoble. A sharp, achromatic image of an object slit was obtained at a magnification of 50. The measured resolution of 0.1 mm was limited mainly by the available beam intensity, not by aberrations.

P. Herrmann; K. -A. Steinhauser; R. G鋒ler; A. Steyerl; W. Mampe

1985-05-06T23:59:59.000Z

150

The impact of pulsed irradiation upon neutron activation calculations for inertial and magnetic fusion energy power plants  

SciTech Connect (OSTI)

Inertial fusion energy (IFE) and magnetic fusion energy (MFE) power plants will probably operate in a pulsed mode. The two different schemes, however, will have quite different time periods. Typical repetition rates for IFE power plants will be 1-5 Hz. MFE power plants will ramp up in current for about 1 hour, shut down for several minutes, and repeat the process. Traditionally, activation calculations for IFE and MFE power plants have assumed continuous operation and used either the ``steady state`` (SS) or ``equivalent steady state`` (ESS) approximations. It has been suggested recently that the SS and ESS methods may not yield accurate results for all radionuclides of interest. The present work expands that of Sisolak, et al. by applying their formulae to conditions which might be experienced in typical IFE and MFE power plants. In addition, complicated, multi-step reaction/decay chains are analyzed using an upgraded version of the ACAB radionuclide generation/depletion code. Our results indicate that the SS method is suitable for application to MFE power plant conditions. We also find that the ESS method generates acceptable results for radionuclides with half-lives more than a factor of three greater than the time between pulses. For components that are subject to 0.05 Hz (or more frequent) irradiation (such as coolant), use of the ESS method is recommended. For components or materials that are subject to less frequent irradiation (such as high-Z target materials), pulsed irradiation calculations should be used.

Latkowski, J.F. [Lawrence Livermore National Lab., CA (United States); Sanz, J. [Universidad Politecnica de Madrid (Spain); Vujic, J.L. [California Univ., Berkeley, CA (United States)

1996-06-26T23:59:59.000Z

151

The Spallation Neutron Source (SNS) project: a fertile ground for radiation protection and shielding challenges  

Science Journals Connector (OSTI)

......pulse intensity(18). A heavy water-cooled beryllium and...outer plug, which is a heavy water-cooled steel reflector...experience at modern research reactors, neutron beam lines at...International Conference on Advanced Monte Carlo for Radiation......

F. X. Gallmeier; P. D. Ferguson; I. I. Popova; E. B. Iverson

2005-12-20T23:59:59.000Z

152

Neutron-deuteron breakup and quasielastic scattering  

E-Print Network [OSTI]

Quasielastic scattering and deuteron breakup in the 200 MeV region is studied by impinging a pulsed neutron beam on a deuterium target at the Weapons Neutron Research facility at the Los Alamos Neutron Science Center. The ...

Ohlson, Alice Elisabeth

2009-01-01T23:59:59.000Z

153

A High Count Rate Neutron Beam Monitor for Neutron Scattering Facilities  

SciTech Connect (OSTI)

Abstract Beam monitors are an important diagnostic tool in neutron science facilities. Present beam monitors use either ionization chambers in integration mode, which are slow and have no timing information, or pulse counters which can easily be saturated by high beam intensities. At high flux neutron scattering facilities, neutron beam monitors with very low intrinsic efficiency (10-5) are presently selected to keep the counting rate within a feasible range, even when a higher efficiency would improve the counting statistics and yield a better measurement of the incident beam. In this work, we report on a high count rate neutron beam monitor. This beam monitor offers good timing with an intrinsic efficiency of 10-3 and a counting rate capability of over 1,000,000 cps without saturation.

Barnett, Amanda [University of Tennessee, Knoxville (UTK); Crow, Lowell [ORNL; Diawara, Yacouba [ORNL; Hayward, J P [University of Tennessee, Knoxville (UTK); Hayward, Jason P [ORNL; Menhard, Kocsis [European Synchrotron Radiation Facility (ESRF); Sedov, Vladislav N [ORNL; Funk, Loren L [ORNL

2013-01-01T23:59:59.000Z

154

Core Vessel Insert Handling Robot for the Spallation Neutron Source  

SciTech Connect (OSTI)

The Spallation Neutron Source provides the world's most intense pulsed neutron beams for scientific research and industrial development. Its eighteen neutron beam lines will eventually support up to twenty-four simultaneous experiments. Each beam line consists of various optical components which guide the neutrons to a particular instrument. The optical components nearest the neutron moderators are the core vessel inserts. Located approximately 9 m below the high bay floor, these inserts are bolted to the core vessel chamber and are part of the vacuum boundary. They are in a highly radioactive environment and must periodically be replaced. During initial SNS construction, four of the beam lines received Core Vessel Insert plugs rather than functional inserts. Remote replacement of the first Core Vessel Insert plug was recently completed using several pieces of custom-designed tooling, including a highly complicated Core Vessel Insert Robot. The design of this tool are discussed.

Graves, Van B [ORNL; Dayton, Michael J [ORNL

2011-01-01T23:59:59.000Z

155

Active beam position stabilization of pulsed lasers for long-distance ion profile diagnostics at the Spallation Neutron Source (SNS)  

SciTech Connect (OSTI)

A high peak-power Q-switched laser has been used to monitor the ion beam profiles in the superconducting linac at the Spallation Neutron Source (SNS). The laser beam suffers from position drift due to movement, vibration, or thermal effects on the optical components in the 250-meter long laser beam transport line. We have designed, bench-tested, and implemented a beam position stabilization system by using an Ethernet CMOS camera, computer image processing and analysis, and a piezo-driven mirror platform. The system can respond at frequencies up to 30 Hz with a high position detection accuracy. With the beam stabilization system, we have achieved a laser beam pointing stability within a range of 2 rad (horizontal) to 4 rad (vertical), corresponding to beam drifts of only 0.5 mm 1 mm at the furthest measurement station located 250 meters away from the light source.

Hardin, Robert A [ORNL; Liu, Yun [ORNL; Long, Cary D [ORNL; Aleksandrov, Alexander V [ORNL; Blokland, Willem [ORNL

2011-01-01T23:59:59.000Z

156

How the Spallation Neutron Source Works | ORNL Neutron Sciences  

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

high-energy proton pulses strike a heavy-metal target, which is a container of liquid mercury. Corresponding pulses of neutrons freed by the spallation process are slowed down in...

157

Crystal Driven Neutron Source: A New Paradigm for Miniature Neutron Sources  

SciTech Connect (OSTI)

Neutron interrogation techniques have specific advantages for detection of hidden, shielded, or buried threats over other detection modalities in that neutrons readily penetrate most materials providing backscattered gammas indicative of the elemental composition of the potential threat. Such techniques have broad application to military and homeland security needs. Present neutron sources and interrogation systems are expensive and relatively bulky, thereby making widespread use of this technique impractical. Development of a compact, high intensity crystal driven neutron source is described. The crystal driven neutron source approach has been previously demonstrated using pyroelectric crystals that generate extremely high voltages when thermal cycled [1-4]. Placement of a sharpened needle on the positively polarized surface of the pyroelectric crystal results in sufficient field intensification to field ionize background deuterium molecules in a test chamber, and subsequently accelerate the ions to energies in excess of {approx}100 keV, sufficient for either D-D or D-T fusion reactions with appropriate target materials. Further increase in ion beam current can be achieved through optimization of crystal thermal ramping, ion source and crystal accelerator configuration. The advantage of such a system is the compact size along with elimination of large, high voltage power supplies. A novel implementation discussed incorporates an independently controlled ion source in order to provide pulsed neutron operation having microsecond pulse width.

Tang, V; Morse, J; Meyer, G; Falabella, S; Guethlein, G; Kerr, P; Park, H G; Rusnak, B; Sampayan, S; Schmid, G; Spadaccini, C; Wang, L

2008-08-08T23:59:59.000Z

158

LANSCE | Lujan Neutron Scattering Center  

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

Lujan Center Data Management Lujan Neutron Scattering Center Logo The Lujan Center within LANSCE utilizes a pulsed source and has a complement of 15 instruments. It maintains a...

159

Gamma ray emission from spheres pulsed with D-T neutrons: Results of May 1987 experiments at RTNS-1  

SciTech Connect (OSTI)

Subsequent to the analysis of the June 1986 series of experiments at RTNS-1, we thought it sensible to repeat some of the experiments with greater care given to the high energy portions of the effluent gamma ray spectra. In addition, some new materials were recommended for study, such as silicon. And since among our earlier experiments we observed data which was not highly reproducible, repeated runs would provide a quantitative assessment of the precision of the experiments. Accordingly, we followed the procedure outlined in UCID-20884. First, we calibrated the NE-213 detector with standard gamma ray sources and checked for linearity of pulse height with energy deposited by electrons. We then conducted experiments at RTNS-1, using spherical configurations of C, Si, Al, H/sub 2/O, N/sub 2/,Ti, Fe, and C/sub 2/F/sub 4/. The H/sub 2/O was contained in a modified glass flask, while the liquid nitrogen was held in a double-walled steel dewar. 25 refs., 17 figs., 9 tabs.

Goldberg, E.; Hansen, L.F.; Howerton, R.J.; Komoto, T.T.; Pohl, B.A.

1987-11-01T23:59:59.000Z

160

The Intense Radiation Gas  

E-Print Network [OSTI]

We present a new dispersion relation for photons that are nonlinearly interacting with a radiation gas of arbitrary intensity due to photon-photon scattering. It is found that the photon phase velocity decreases with increasing radiation intensity, it and attains a minimum value in the limit of super-intense fields. By using Hamilton's ray equations, a self-consistent kinetic theory for interacting photons is formulated. The interaction between an electromagnetic pulse and the radiation gas is shown to produce pulse self-compression and nonlinear saturation. Implications of our new results are discussed.

M. Marklund; P. K. Shukla; B. Eliasson

2005-03-08T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Personnel electronic neutron dosimeter  

DOE Patents [OSTI]

A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

Falk, Roger B. (Lafayette, CO); Tyree, William H. (Boulder, CO)

1984-12-18T23:59:59.000Z

162

Personnel electronic neutron dosimeter  

DOE Patents [OSTI]

A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

Falk, R.B.; Tyree, W.H.

1982-03-03T23:59:59.000Z

163

January 16, 2009: Expansion of Spallation Neutron Source | Department...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

the Spallation Neutron Source, expanding what is already the world's most powerful pulsed neutron scattering facility. The new station, which will cost approximately 1 billion,...

164

Neutron Polarization  

Science Journals Connector (OSTI)

The production of polarized neutrons in magnetized iron has been studied, using the intense neutron beams available at the Argonne heavy water pile. The theoretical work of Halpern et al., used as a guide in the experiments, has been checked in many respects, with the exception that the polarization cross section p has a measured value of 3.15 barns compared to the theoretical 1 barn. The application of neutron polarization to the measurement of the approach to saturation in ferromagnets is described and preliminary results are reported.

D. J. Hughes; J. R. Wallace; R. H. Holtzman

1948-06-01T23:59:59.000Z

165

Fast neutron imaging device and method  

DOE Patents [OSTI]

A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.

Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.

2014-02-11T23:59:59.000Z

166

Overcoming High Energy Backgrounds at Pulsed Spallation Sources  

E-Print Network [OSTI]

Instrument backgrounds at neutron scattering facilities directly affect the quality and the efficiency of the scientific measurements that users perform. Part of the background at pulsed spallation neutron sources is caused by, and time-correlated with, the emission of high energy particles when the proton beam strikes the spallation target. This prompt pulse ultimately produces a signal, which can be highly problematic for a subset of instruments and measurements due to the time-correlated properties, and different to that from reactor sources. Measurements of this background have been made at both SNS (ORNL, Oak Ridge, TN, USA) and SINQ (PSI, Villigen, Switzerland). The background levels were generally found to be low compared to natural background. However, very low intensities of high-energy particles have been found to be detrimental to instrument performance in some conditions. Given that instrument performance is typically characterised by S/N, improvements in backgrounds can both improve instrument pe...

Cherkashyna, Nataliia; DiJulio, Douglas D; Khaplanov, Anton; Pfeiffer, Dorothea; Scherzinger, Julius; Cooper-Jensen, Carsten P; Fissum, Kevin G; Ansell, Stuart; Iverson, Erik B; Ehlers, Georg; Gallmeier, Franz X; Panzner, Tobias; Rantsiou, Emmanouela; Kanaki, Kalliopi; Filges, Uwe; Kittelmann, Thomas; Extegarai, Maddi; Santoro, Valentina; Kirstein, Oliver; Bentley, Phillip M

2015-01-01T23:59:59.000Z

167

Strongest Pulsed Muon Source at J-PARC MUSE  

SciTech Connect (OSTI)

The muon science facility (MUSE, abbreviation of MUon Science Establishment), along with the neutron, hadron, and neutrino facilities, is located in the Materials and Life Science Facility (MLF), which is a building integrated to include both neutron and muon science programs. On the November, 2009 beam cycle, we achieved extraction of the world's strongest pulsed muon beam at J-PARC MUSE by beam tuning at the Decay-Surface muon beam line (D-line). Surface muons ({mu}{sup +}) as much as 1.8x10{sup 6}/s were extracted with the use of 120 kW of protons from the Rapid Cycle Synchrotron (RCS), which corresponds to 1.5x10{sup 7}/s surface muons when a future proton beam reached at the intensity of 1MW. These intensities, at the future 1 MW operation, will correspond to more than ten times those at the RIKEN-RAL Muon facility.

Miyake, Y.; Shimomura, K.; Kawamura, N.; Strasser, P.; Koda, A.; Fujimori, H.; Makimura, S.; Nakahara, K.; Kato, M.; Takeshita, S.; Nishiyama, K.; Kobayashi, Y.; Kojima, K.; Kadono, R. [Meson Science Laboratory, High Energy Accelerator Research Organization, Ibaraki 305-0801 (Japan); Muon Section, Materials and Life Science Division, J-PARC Center, Ibaraki 319-1195 (Japan); Higemoto, W.; Ito, T.; Ninomiya, K. [Muon Section, Materials and Life Science Division, J-PARC Center, Ibaraki 319-1195 (Japan); Japan Atomic Energy Research Center (JAEA), Ibaraki 319-1195 (Japan); Hiraishi, M.; Miyazaki, M. [Department of Materials Structure Science, Graduate University for Advanced Studies (Japan); Kubo, K. [Graduate School Division of Natural Sciences, International Christian University, Mitaka, Tokyo (Japan)

2011-10-06T23:59:59.000Z

168

Neutron scattering effects on fusion ion temperature measurements.  

SciTech Connect (OSTI)

To support the nuclear fusion program at Sandia National Laboratories (SNL), a consistent and verifiable method to determine fusion ion temperatures needs to be developed. Since the fusion temperature directly affects the width in the spread of neutron energies produced, a measurement of the neutron energy width can yield the fusion temperature. Traditionally, the spread in neutron energies is measured by using time-of-flight to convert a spread in neutron energies at the source to a spread in time at detector. One potential obstacle to using this technique at the Z facility at SNL is the need to shield the neutron detectors from the intense bremsstrahlung produced. The shielding consists of eight inches of lead and the concern is that neutrons will scatter in the lead, artificially broaden the neutron pulse width and lead to an erroneous measurement. To address this issue, experiments were performed at the University of Rochester's Laboratory for Laser Energetics, which demonstrated that a reliable ion temperature measurement can be achieved behind eight inches of lead shielding. To further expand upon this finding, Monte Carlo N-Particle eXtended (MCNPX) was used to simulate the experimental geometric conditions and perform the neutron transport. MCNPX was able to confidently estimate results observed at the University of Rochester.

Ziegler, Lee (Bechtel/Nevada, Las Vegas, NV); Starner, Jason R.; Cooper, Gary Wayne; Ruiz, Carlos L.; Franklin, James Kenneth (Ktech Corporation, Albuquerque, NM); Casey, Daniel T.

2006-06-01T23:59:59.000Z

169

Calculations of neutron spectra after neutron杗eutron scattering  

Science Journals Connector (OSTI)

A direct neutron杗eutron scattering length, ann, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of ann will not only help resolve conflicting results of ann by indirect means, but also in comparison to the proton杙roton scattering length, app, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum桵axwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal杢hermal and thermal杄pithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

B E Crawford; S L Stephenson; C R Howell; G E Mitchell; W Tornow; W I Furman; E V Lychagin; A Yu Muzichka; G V Nekhaev; A V Strelkov; E I Sharapov; V N Shvetsov

2004-01-01T23:59:59.000Z

170

HOTSPUR: gamma ray emission from spheres pulsed with D-T neutrons. I. Calibration of improved NE213 detector assembly. II. Comparison of TART/SANDYL electron recoil spectra to experiment; preliminary results  

SciTech Connect (OSTI)

The NE213 scintillator detector was modified so that the pulse height would be linear with electron energy over the full range of interest - up to 7.1 MeV. Absolute calibration was done with four different calibrated gamma sources. An average correction factor is obtained which normalizes SANDYL calculations with respect to the calibration experiments. The procedure for calculating neutron-induced gamma-ray output and electron recoil spectra is described, and experimental data from a number of spherical assemblies are given and compared to TART/SANDYL calculations. (LEW)

Goldberg, E.; Hansen, L.F.; Komoto, T.T.; Pohl, B.A.

1986-09-01T23:59:59.000Z

171

E-Print Network 3.0 - actinide neutron cross Sample Search Results  

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

gain 30 Max. neutron intensity 6... the spectra of the neutrons leaving the subcritical assembly, we propose to use a spectrometrical method... of neutrons slowing down...

172

High-power radio frequency pulse generation and extration based on wakefield excited by an intense charged particle beam in dielectric-loaded waveguides.  

SciTech Connect (OSTI)

Power extraction using a dielectric-loaded (DL) waveguide is a way to generate high-power radio frequency (RF) waves for future particle accelerators, especially for two-beam-acceleration. In a two-beam-acceleration scheme, a low-energy, high-current particle beam is passed through a deceleration section of waveguide (decelerator), where the power from the beam is partially transferred to trailing electromagnetic waves (wakefields); then with a properly designed RF output coupler, the power generated in the decelerator is extracted to an output waveguide, where finally the power can be transmitted and used to accelerate another usually high-energy low-current beam. The decelerator, together with the RF output coupler, is called a power extractor. At Argonne Wakefield Accelerator (AWA), we designed a 7.8GHz power extractor with a circular DL waveguide and tested it with single electron bunches and bunch trains. The output RF frequency (7.8GHz) is the sixth harmonic of the operational frequency (1.3GHz) of the electron gun and the linac at AWA. In single bunch excitation, a 1.7ns RF pulse with 30MW of power was generated by a single 66nC electron bunch passing through the decelerator. In subsequent experiments, by employing different splitting-recombining optics for the photoinjector laser, electron bunch trains were generated and thus longer RF pulses could be successfully generated and extracted. In 16-bunch experiments, 10ns and 22ns RF pulses have been generated and extracted; and in 4-bunch experiments, the maximum power generated was 44MW with 40MW extracted. A 26GHz DL power extractor has also been designed to test this technique in the millimeter-wave range. A power level of 148MW is expected to be generated by a bunch train with a bunch spacing of 769ps and bunch charges of 20nC each. The arrangement for the experiment is illustrated in a diagram. Higher-order-mode (HOM) power extraction has also been explored in a dual-frequency design. By using a bunch train with a bunch spacing of 769ps and bunch charges of 50nC each, 90.4MW and 8.68MW of extracted power levels are expected to be reached at 20.8GHz and 35.1GHz, respectively. In order to improve efficiency in HOM power extraction, a novel technique has been proposed to suppress unintended modes.

Gao, F.; High Energy Physics; Illinois Inst. of Tech

2009-07-24T23:59:59.000Z

173

Neutron Bombardment of Counting Diamonds  

Science Journals Connector (OSTI)

21 February 1956 research-article Neutron Bombardment of Counting Diamonds A. H...Examination was also made of the effect of neutron bombardment on pulse-height distribution...additional charge traps produced by the neutrons. The layered crystal texture disclosed...

1956-01-01T23:59:59.000Z

174

World record neutron beam at Los Alamos National Laboratory  

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

World record neutron beam at LANL World record neutron beam at Los Alamos National Laboratory Scientists have created the largest neutron beam ever made by a short-pulse laser,...

175

Fast fall-time ion beam in neutron generators  

E-Print Network [OSTI]

ion beam in neutron generators Q. Ji, J. Kwan, M. Regis, Y.useful in building neutron generators for the application offall-time pulsed neutron generator using an array of 2020

Ji, Q.

2009-01-01T23:59:59.000Z

176

E-Print Network 3.0 - accelerator neutron source Sample Search...  

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

driven by a powerful particle accelerator. This intense neutron source... . In subcritical systems driven by an intense external source of neutrons - in ADS. An external...

177

26 Tesla DC Magnet for Neutron Scattering  

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

Previously, DC Magnets located at Neutron-Scattering Beamlines were commercially-manufactured superconducting magnets and limited to 17 T. A few pulsed magnet systems have been...

178

Neutron-deuteron breakup and quasielastic scattering .  

E-Print Network [OSTI]

??Quasielastic scattering and deuteron breakup in the 200 MeV region is studied by impinging a pulsed neutron beam on a deuterium target at the Weapons (more)

Ohlson, Alice Elisabeth

2009-01-01T23:59:59.000Z

179

Moderators - Instrument Support | ORNL Neutron Sciences  

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

Moderators Moderators Detailed design of scattering instruments requires detailed knowledge of the neutron beam emitted from the moderator in question. We are currently providing moderator performance estimates based on the result of detailed Monte Carlo simulations of the entire target system. These simulations are being performed for both the High Power Target Station (HPTS) and the Long Wavelength Target Station (LWTS), and have been performed for the Intense Pulsed Neutron Source (IPNS) in the same manner. We make the IPNS source files available as a means to benchmark instrument simulation codes. These files follow a particular "source file format" which will adapt to the changing needs of instrument simulation as necessary. We also provide worked examples showing how to use the information in the source files

180

Data Intensive  

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

Data Intensive Data Intensive Computing Pilot Program In 2014 NERSC is conducting its second and last round of allocations to projects in data intensive science. This pilot aims to...

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Scientific opportunities with advanced facilities for neutron scattering  

SciTech Connect (OSTI)

The present report documents deliberations of a large group of experts in neutron scattering and fundamental physics on the need for new neutron sources of greater intensity and more sophisticated instrumentation than those currently available. An additional aspect of the Workshop was a comparison between steady-state (reactor) and pulsed (spallation) sources. The main conclusions were: (1) the case for a new higher flux neutron source is extremely strong and such a facility will lead to qualitatively new advances in condensed matter science and fundamental physics; (2) to a large extent the future needs of the scientific community could be met with either a 5 x 10/sup 15/ n cm/sup -2/s/sup -1/ steady state source or a 10/sup 17/ n cm/sup -2/s/sup -1/ peak flux spallation source; and (3) the findings of this Workshop are consistent with the recommendations of the Major Materials Facilities Committee.

Lander, G.H.; Emery, V.J. (eds.)

1984-01-01T23:59:59.000Z

182

The World Neutron Monitor Network as a tool for the study of solar neutrons  

E-Print Network [OSTI]

The World Neutron Monitor Network as a tool for the study of solar neutrons I. G. Usoskin1 , G. A Neutron Monitor Network to detect high-energy solar neutrons is dis- cussed in detail. It is shown that the existing network can be used for the routine detection of intense sporadic solar-neutron events whenever

Paris-Sud XI, Universit茅 de

183

Coherent Scattering Investigations at the Spallation Neutron Source: a Snowmass White Paper  

SciTech Connect (OSTI)

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Tennessee, provides an intense flux of neutrinos in the few tens-of-MeV range, with a sharply-pulsed timing structure that is beneficial for background rejection. In this white paper, we describe how the SNS source can be used for a measurement of coherent elastic neutrino-nucleus scattering (CENNS), and the physics reach of different phases of such an experimental program (CSI: Coherent Scattering Investigations at the SNS).

Akimov, D. [Moscow Engineering Physics Institute (MEPhI), Russia] Moscow Engineering Physics Institute (MEPhI), Russia; Bernstein, A. [Lawrence Livermore National Laboratory (LLNL)] Lawrence Livermore National Laboratory (LLNL); BarbeauP., [Duke University; Barton, P. J. [Lawrence Berkeley National Laboratory (LBNL)] Lawrence Berkeley National Laboratory (LBNL); Bolozdynya, A. [Moscow Engineering Physics Institute (MEPhI), Russia] Moscow Engineering Physics Institute (MEPhI), Russia; Cabrera-Palmer, B. [Sandia National Laboratories (SNL)] Sandia National Laboratories (SNL); Cavanna, F. [Yale University] Yale University; Cianciolo, Vince [ORNL] ORNL; Collar, J. [University of Chicago, Enrico Fermi Institute] University of Chicago, Enrico Fermi Institute; Cooper, R. J. [Indiana University] Indiana University; Dean, D. J. [Oak Ridge National Laboratory (ORNL)] Oak Ridge National Laboratory (ORNL); Efremenko, Yuri [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)] University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Etenko, A. [Moscow Engineering Physics Institute (MEPhI), Russia] Moscow Engineering Physics Institute (MEPhI), Russia; Fields, N. [University of Chicago, Enrico Fermi Institute] University of Chicago, Enrico Fermi Institute; Foxe, M. [Pennsylvania State University, University Park, PA] Pennsylvania State University, University Park, PA; Figueroa-Feliciano, E. [Massachusetts Institute of Technology (MIT)] Massachusetts Institute of Technology (MIT); Fomin, N. [University of Tennessee, Knoxville (UTK)] University of Tennessee, Knoxville (UTK); Gallmeier, F. [Oak Ridge National Laboratory (ORNL)] Oak Ridge National Laboratory (ORNL); Garishvili, I. [University of Tennessee, Knoxville (UTK)] University of Tennessee, Knoxville (UTK); Gerling, M. [Sandia National Laboratories (SNL)] Sandia National Laboratories (SNL); Green, M. [University of North Carolina, Chapel Hill] University of North Carolina, Chapel Hill; Greene, Geoffrey [University of Tennessee, Knoxville (UTK)] University of Tennessee, Knoxville (UTK); Hatzikoutelis, A. [University of Tennessee, Knoxville (UTK)] University of Tennessee, Knoxville (UTK); Henning, Reyco [University of North Carolina, Chapel Hill] University of North Carolina, Chapel Hill; Hix, R. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)] University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Hogan, D. [University of California-Berkeley] University of California-Berkeley; Hornback, D. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)] University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Jovanovic, I. [Pennsylvania State University, University Park, PA] Pennsylvania State University, University Park, PA; Hossbach, T. [Pacific Northwest National Laboratory (PNNL)] Pacific Northwest National Laboratory (PNNL); Iverson, Erik B [ORNL] ORNL; Klein, S. R. [Lawrence Berkeley National Laboratory (LBNL)] Lawrence Berkeley National Laboratory (LBNL); Khromov, A. [Moscow Engineering Physics Institute (MEPhI), Russia] Moscow Engineering Physics Institute (MEPhI), Russia; Link, J. [Virginia Polytechnic Institute and State University] Virginia Polytechnic Institute and State University; Louis, W. [Los Alamos National Laboratory (LANL)] Los Alamos National Laboratory (LANL); Lu, W. [Oak Ridge National Laboratory (ORNL)] Oak Ridge National Laboratory (ORNL); Mauger, C. [Los Alamos National Laboratory (LANL)] Los Alamos National Laboratory (LANL); Marleau, P. [Sandia National Laboratories (SNL)] Sandia National Laboratories (SNL); Markoff, D. [North Carolina Central University, Durham] North Carolina Central University, Durham; Martin, R. D. [University of South Dakota] University of South Dakota; Mueller, Paul Edward [ORNL] ORNL; Newby, J. [Oak Ridge National Laboratory (ORNL)] Oak Ridge National Laboratory (ORNL); Orrell, John L. [Pacific Northwest National Laboratory (PNNL)] Pacific Northwest National Laboratory (PNNL); O'Shaughnessy, C. [University of North Carolina, Chapel Hill] University of North Carolina, Chapel Hill

2013-01-01T23:59:59.000Z

184

Neutron calibration facilities  

Science Journals Connector (OSTI)

......shut down. A recent development for a thermal neutron calibration field is a neutron guide used at the research reactor GKSS Geesthacht(35). The result is a high-intensity thermal beam providing a flux of up to 106 s1 with a field size of about 2.5 2......

H. Schuhmacher

2004-08-01T23:59:59.000Z

185

A water-based neutron detector as a well multiplicity counter  

Science Journals Connector (OSTI)

Abstract We report the performance characteristics of a water-based neutron detecting multiplicity counter for the non-destructive assay of fissile sources. This technique could replace or supplement existing 3He-based multiplicity counters. The counter is a 1.02爉3 tank containing pure deionized water doped with 0.5% GdCl3. It has highly reflective walls and eight 10-in. \\{PMTs\\} mounted at the top. An unshielded source well of 19燾m diameter, mounted at the top and center, extends 73燾m down into the detector. The counter was evaluated using low intensity 252Cf and 60Co sources, and a fast pulsing LED to simulate higher intensity backgrounds. At low gamma ray intensities (~200爇Bq or less) we report an absolute neutron detection efficiency of 28% and a 60Co rejection/suppression factor of ~108 to 1. For sources with high gamma ray intensities, the neutron efficiency was 22%1% up to a 60Co equivalent activity of 4燤Bq. The detector background event rate, primarily due to muons and other cosmogenic particles, was found to be stable over a period of almost three months. The minimum detectable neutron source intensity above background was 3.1爊/s, assuming a one-hour data acquisition.

S. Dazeley; A. Asghari; A. Bernstein; N.S. Bowden; V. Mozin

2015-01-01T23:59:59.000Z

186

Ramsey Experiments Using Neutron Beams  

Science Journals Connector (OSTI)

Abstract Ramsey's technique of separated oscillatory fields adapted to cold neutron beams is a very sensitive method to probe for spin- dependent interactions of neutrons with magnetic and pseudomagnetic fields. In the last couple of years several distinctive experiments using this technique have been performed, e.g. to determine the incoherent neutron scattering length of the deuteron, to perform polarized neutron imaging of magnetic fields and samples, and lately, to search for new light spin-1 bosons. Here, some of these results are reviewed and possible future measurements with respect to a pulsed neutron source are presented.

Florian M. Piegsa

2014-01-01T23:59:59.000Z

187

HYSPEC : A CRYSTAL TIME OF FLIGHT HYBRID SPECTROMETER FOR THE SPALLATION NEUTRON SOURCE.  

SciTech Connect (OSTI)

This document lays out a proposal by the Instrument Development Team (IDT) composed of scientists from leading Universities and National Laboratories to design and build a conceptually new high-flux inelastic neutron spectrometer at the pulsed Spallation Neutron Source (SNS) at Oak Ridge. This instrument is intended to supply users of the SNS and scientific community, of which the IDT is an integral part, with a platform for ground-breaking investigations of the low-energy atomic-scale dynamical properties of crystalline solids. It is also planned that the proposed instrument will be equipped with a polarization analysis capability, therefore becoming the first polarized beam inelastic spectrometer in the SNS instrument suite, and the first successful polarized beam inelastic instrument at a pulsed spallation source worldwide. The proposed instrument is designed primarily for inelastic and elastic neutron spectroscopy of single crystals. In fact, the most informative neutron scattering studies of the dynamical properties of solids nearly always require single crystal samples, and they are almost invariably flux-limited. In addition, in measurements with polarization analysis the available flux is reduced through selection of the particular neutron polarization, which puts even more stringent limits on the feasibility of a particular experiment. To date, these investigations have mostly been carried out on crystal spectrometers at high-flux reactors, which usually employ focusing Bragg optics to concentrate the neutron beam on a typically small sample. Construction at Oak Ridge of the high-luminosity spallation neutron source, which will provide intense pulsed neutron beams with time-averaged fluxes equal to those at medium-flux reactors, opens entirely new opportunities for single crystal neutron spectroscopy. Drawing upon experience acquired during decades of studies with both crystal and time-of-flight (TOF) spectrometers, the IDT has developed a conceptual design for a focused-beam, hybrid time-of-flight instrument with a crystal monochromator for the SNS called HYSPEC (an acronym for hybrid spectrometer). The proposed instrument has a potential to collect data more than an order of magnitude faster than existing steady-source spectrometers over a wide range of energy transfer ({h_bar}{omega}) and momentum transfer (Q) space, and will transform the way that data in elastic and inelastic single-crystal spectroscopy are collected. HYSPEC is optimized to provide the highest neutron flux on sample in the thermal and epithermal neutron energy ranges at a good-to-moderate energy resolution. By providing a flux on sample several times higher than other inelastic instruments currently planned for the SNS, the proposed instrument will indeed allow unique ground-breaking measurements, and will ultimately make polarized beam studies at a pulsed spallation source a realistic possibility.

SHAPIRO,S.M.; ZALIZNYAK,I.A.

2002-12-30T23:59:59.000Z

188

THERMAL NEUTRON BACKSCATTER IMAGING.  

SciTech Connect (OSTI)

Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

2004-10-16T23:59:59.000Z

189

Experimental evidence of thermonuclear neutrons in a modified plasma focus  

Science Journals Connector (OSTI)

The PF-1000 plasma focus was modified by adding the cathode disk 3 cm in front of the anode. This modification facilitated the evaluation of neutron energy spectra. Two neutron pulses were distinguishable. As regards the first neutron pulse it lasted 40 ns during the plasma stagnation and it demonstrated high isotropy of neutron emission. A peak neutronenergydetected upstream was 2.46 0.02 ? MeV . The full width of neutron energy spectra of 90 20 ? keV enabled to calculate an ion temperature of 1.2 keV. These parameters and a neutron yield of 10 9 corresponded to theoretical predictions for thermonuclear neutrons.

D. Klir; P. Kubes; M. Paduch; T. Pisarczyk; T. Chodukowski; M. Scholz; Z. Kalinowska; E. Zielinska; B. Bienkowska; J. Hitschfel; S. Jednorog; L. Karpinski; J. Kortanek; J. Kravarik; K. Rezac; I. Ivanova-Stanik; K. Tomaszewski

2011-01-01T23:59:59.000Z

190

Neutron reflectometry  

Science Journals Connector (OSTI)

Neutron reflectivity is a powerful tool for the ... chapter include: the theory of elastic specular neutron diffraction; polarized neutron reflectivity; surface roughness; experimental methodology; resolution in ...

G. S. Smith; C. F. Majkrzak

2004-01-01T23:59:59.000Z

191

Injection locked oscillator system for pulsed metal vapor lasers  

DOE Patents [OSTI]

An injection locked oscillator system for pulsed metal vapor lasers is disclosed. The invention includes the combination of a seeding oscillator with an injection locked oscillator (ILO) for improving the quality, particularly the intensity, of an output laser beam pulse. The present invention includes means for matching the first seeder laser pulses from the seeding oscillator to second laser pulses of a metal vapor laser to improve the quality, and particularly the intensity, of the output laser beam pulse.

Warner, Bruce E. (Livermore, CA); Ault, Earl R. (Dublin, CA)

1988-01-01T23:59:59.000Z

192

Neutron-Neutron Interaction  

Science Journals Connector (OSTI)

The present status of the problem of charge dependence is discussed. The information about the neutron-neutron interaction derived from the two-neutron system, three-nucleon systems, final-state interactions in multiparticle reactions, and peripheral processes is critically evaluated. The experimental data indicate the breakdown of charge independence by about 3-5%. Evidence concerning the violation of charge symmetry is inconclusive, but it seems that most of the data are consistent with the assumption that charge symmetry is satisfied within 0.5-1%. The most suitable studies which might improve the knowledge of the neutron-neutron forces are indicated.

IVO 奓AUS

1967-07-01T23:59:59.000Z

193

A scintillating-fiber 14-MeV neutron detector on TFTR during DT operation  

SciTech Connect (OSTI)

A compact 14-MeV neutron detector using an array of scintillating fibers has been tested on the TFTR tokamak under conditions of a high gamma background. This detector uses a fiber-matrix geometry, a magnetic field-insensitive phototube with an active HV base and pulse-height discrimination to reject low-level pulses from 2.5 MeV neutron and intense gammas. Laboratory calibrations have been performed at EG&G Las Vegas using a pulsed DT neutron generator and a 30 kCi {sup 60}Co source as background, at PPPL using DT neutron sources, and at LANL using an energetic deuterium beam and target at a tandem Van de Graaff accelerator. During the first high power DT shots on TFTR in December 1993, the detector was 15.5 meters from the torus in a large collimator. For a rate of 1 {times} 10{sup 18} n/sec from the tokamak, it operated in an equivalent background of 1 {times} 10{sup 10} gammas/cm{sup 2}/sec ({approximately}4 mA current drain) at a DT count rate of 200 kHz.

Wurden, G.A.; Chrien, R.E.; Barnes, C.W.; Sailor, W.C. [Los Alamos National Lab., NM (United States); Roquemore, A.L. [Princeton Plasma Physics Lab., NJ (United States); Lavelle, M.J.; O`Gara, P.M.; Jordan, R.J. [EG& G Energy Measurements, Las Vegas, NV (United States)

1994-07-01T23:59:59.000Z

194

Ultrafast neutron detector  

DOE Patents [OSTI]

The invention comprises a neutron detector (50) of very high temporal resolution that is particularly well suited for measuring the fusion reaction neutrons produced by laser-driven inertial confinement fusion targets. The detector comprises a biased two-conductor traveling-wave transmission line (54, 56, 58, 68) having a uranium cathode (60) and a phosphor anode (62) as respective parts of the two conductors. A charge line and Auston switch assembly (70, 72, 74) launch an electric field pulse along the transmission line. Neutrons striking the uranium cathode at a location where the field pulse is passing, are enabled to strike the phosphor anode and produce light that is recorded on photographic film (64). The transmission line may be variously configured to achieve specific experimental goals.

Wang, Ching L. (Livermore, CA)

1987-01-01T23:59:59.000Z

195

Neutron beam imaging at neutron spectrometers at Dhruva  

SciTech Connect (OSTI)

A low efficiency, 2-Dimensional Position Sensitive Neutron Detector based on delay line position encoding is developed. It is designed to handle beam flux of 10{sup 6}-10{sup 7} n/cm{sup 2}/s and for monitoring intensity profiles of neutron beams. The present detector can be mounted in transmission mode, as the hardware allows maximum neutron transmission in sensitive region. Position resolution of 1.2 mm in X and Y directions, is obtained. Online monitoring of beam images and intensity profile of various neutron scattering spectrometers at Dhruva are presented. It shows better dynamic range of intensity over commercial neutron camera and is also time effective over the traditionally used photographic method.

Desai, Shraddha S.; Rao, Mala N. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2012-06-05T23:59:59.000Z

196

Portable neutron spectrometer and dosimeter  

DOE Patents [OSTI]

The disclosure relates to a battery operated neutron spectrometer/dosimeter utilizing a microprocessor, a built-in tissue equivalent LET neutron detector, and a 128-channel pulse height analyzer with integral liquid crystal display. The apparatus calculates doses and dose rates from neutrons incident on the detector and displays a spectrum of rad or rem as a function of keV per micron of equivalent tissue and also calculates and displays accumulated dose in millirads and millirem as well as neutron dose rates in millirads per hour and millirem per hour.

Waechter, David A. (Los Alamos, NM); Erkkila, Bruce H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM)

1985-01-01T23:59:59.000Z

197

Neutron energy spectrum from 120 GeV protons on a thick copper target  

E-Print Network [OSTI]

Neutron energy spectrum from 120 GeV protons on a thick copper target was measured at the Meson Test Beam Facility (MTBF) at Fermi National Accelerator Laboratory. The data allows for evaluation of neutron production process implemented in theoretical simulation codes. It also helps exploring the reasons for some disagreement between calculation results and shielding benchmark data taken at high energy accelerator facilities, since it is evaluated separately from neutron transport. The experiment was carried out using a 120 GeV proton beam of 3E5 protons/spill. Since the spill duration was 4 seconds, proton-induced events were counted pulse by pulse. The intensity was maintained using diffusers and collimators installed in the beam line to MTBF. The protons hit a copper block target the size of which is 5cm x 5cm x 60 cm long. The neutrons produced in the target were measured using NE213 liquid scintillator detectors, placed about 5.5 m away from the target at 30^{\\circ} and 5 m 90^{\\circ} with respect to the proton beam axis. The neutron energy was determined by time-of-flight technique using timing difference between the NE213 and a plastic scintillator located just before the target. Neutron detection efficiency of NE213 was determined on basis of experimental data from the high energy neutron beam line at Los Alamos National Laboratory. The neutron spectrum was compared with the results of multi-particle transport codes to validate the implemented theoretical models. The apparatus would be applied to future measurements to obtain a systematic data set for secondary particle production on various target materials.

Nobuhiro Shigyo; Toshiya Sanami; Tsuyoshi Kajimoto; Yosuke Iwamoto; Masayuki Hagiwara; Kiwamu Saito; Kenji Ishibashi; Hiroshi Nakashima; Yukio Sakamoto; Hee-Seock Lee; Erik Ramberg; Aria A. Meyhoefer; Rick Coleman; Doug Jensen; Anthony F. Leveling; David J. Boehnlein; Nikolai V. Mokhov

2012-02-07T23:59:59.000Z

198

Scattered neutron tomography based on a neutron transport problem  

E-Print Network [OSTI]

scattering objects because it does not adequately account for the scattering component of the neutron beam intensity exiting the sample. We proposed a new method of computed tomography which employs an inverse problem analysis of both the transmitted...

Scipolo, Vittorio

2005-11-01T23:59:59.000Z

199

Use of metal organic fluors for spectral discrimination of neutrons and gammas.  

SciTech Connect (OSTI)

A new method for spectral shape discrimination (SSD) of fast neutrons and gamma rays has been investigated. Gammas interfere with neutron detection, making efficient discrimination necessary for practical applications. Pulse shape discrimination (PSD) in liquid organic scintillators is currently the most effective means of gamma rejection. The hazardous liquids, restrictions on volume, and the need for fast timing are drawbacks to traditional PSD scintillators. In this project we investigated harvesting excited triplet states to increase scintillation yield and provide distinct spectral signatures for gammas and neutrons. Our novel approach relies on metal-organic phosphors to convert a portion of the energy normally lost to the scintillation process into useful luminescence with sub-microsecond lifetimes. The approach enables independent control over delayed luminescence wavelength, intensity, and timing for the first time. We demonstrated that organic scintillators, including plastics, nanoporous framework materials, and oil-based liquids can be engineered for both PSD and SSD.

Allendorf, Mark D.; Doty, F. Patrick; Feng, Patrick L.

2010-09-01T23:59:59.000Z

200

Laser-Matter Interaction Above the Plasma Ignition Threshold Intensity  

Science Journals Connector (OSTI)

In this chapter we present the process of laser-matter interaction above the plasma ignition threshold intensity. The physics of the pulsed laser ablation process at high intensities is very complex since it invo...

Mihai Stafe; Aurelian Marcu; Niculae N. Puscas

2014-01-01T23:59:59.000Z

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While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Spallation Neutron Source reaches megawatt power  

ScienceCinema (OSTI)

The Department of Energy's Spallation Neutron Source (SNS), already the world's most powerful facility for pulsed neutron scattering science, is now the first pulsed spallation neutron source to break the one-megawatt barrier. "Advances in the materials sciences are fundamental to the development of clean and sustainable energy technologies. In reaching this milestone of operating power, the Spallation Neutron Source is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said Dr. William F. Brinkman, Director of DOE's Office of Science.

Dr. William F. Brinkman

2010-01-08T23:59:59.000Z

202

Neutron capture therapies  

DOE Patents [OSTI]

In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

Yanch, Jacquelyn C. (Cambridge, MA); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

1999-01-01T23:59:59.000Z

203

HydroPulse Drilling  

SciTech Connect (OSTI)

Tempress HydroPulse{trademark} tool increases overbalanced drilling rates by generating intense suction pulses at the drill bit. This report describes the operation of the tool; results of pressure drilling tests, wear tests and downhole drilling tests; and the business case for field applications. The HydroPulse{trademark} tool is designed to operate on weighted drilling mud at conventional flow rates and pressures. Pressure drilling tests confirm that the HydroPulse{trademark} tool provides 33% to 200% increased rate of penetration. Field tests demonstrated conventional rotary and mud motor drilling operations. The tool has been operated continuous for 50 hours on weighted mud in a wear test stand. This level of reliability is the threshold for commercial application. A seismic-while-drilling version of the tool was also developed and tested. This tool was used to demonstrate reverse vertical seismic profiling while drilling an inclined test well with a PDC bit. The primary applications for the HydroPulse{trademark} tool are deep onshore and offshore drilling where rate of penetration drives costs. The application of the seismic tool is vertical seismic profiling-while-drilling and look-ahead seismic imaging while drilling.

J.J. Kolle

2004-04-01T23:59:59.000Z

204

Neutron Polarimetry  

Science Journals Connector (OSTI)

8 July 1993 research-article Neutron Polarimetry P. Jane Brown J. Bruce Forsyth Francis Tasset Zero-field neutron polarimetry is a technique which has...polarization analysis to be carried out in a neutron scattering experiment. The incident...

1993-01-01T23:59:59.000Z

205

Influence of prepulse plasma formation on neutron production from the laser-target interaction  

SciTech Connect (OSTI)

The interaction of an intense ultrashort pulse laser with a planar uniform target was studied with a two-dimensional relativistic electromagnetic particle-in-cell method to determine the acceleration of deuterons and production of neutrons. A Au-CD{sub 2} double-layer planar target with thickness of {approx}1 {mu}m and a preplasma of variable length was used to generate high-energy deuterons as a precursor for neutron production. The deuteron energy and angular distributions and the neutron production from D(d,n)-{sup 3}He nuclear fusion reactions were studied as a function of the preplasma scale length and target thickness. For very thin (submicron) targets the preplasma increases the neutron yield only marginally, but for realistic targets with thickness of a few microns the preplasma enhances the neutron yield by two orders of magnitude. Both the average deuteron energy and neutron yield peak at an optimum preplasma scale length L{sub p}{sup opt}{approx_equal}1/k{sub 0} (k{sub 0} laser wave vector), which is of the order of one inverse laser wave vector.

Davis, J.; Petrov, G. M. [Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Avenue SW, Washington, DC 20375 (United States)

2008-08-15T23:59:59.000Z

206

Ion Acceleration by Short Chirped Laser Pulses  

E-Print Network [OSTI]

Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

Li, Jian-Xing; Keitel, Christoph H; Harman, Zolt醤

2015-01-01T23:59:59.000Z

207

Cosmic ray neutron background reduction using localized coincidence veto neutron counting  

DOE Patents [OSTI]

This invention relates to both the apparatus and method for increasing the sensitivity of measuring the amount of radioactive material in waste by reducing the interference caused by cosmic ray generated neutrons. The apparatus includes: (a) a plurality of neutron detectors, each of the detectors including means for generating a pulse in response to the detection of a neutron; and (b) means, coupled to each of the neutrons detectors, for counting only some of the pulses from each of the detectors, whether cosmic ray or fission generated. The means for counting includes a means that, after counting one of the pulses, vetos the counting of additional pulses for a prescribed period of time. The prescribed period of time is between 50 and 200 .mu.s. In the preferred embodiment the prescribed period of time is 128 .mu.s. The veto means can be an electronic circuit which includes a leading edge pulse generator which passes a pulse but blocks any subsequent pulse for a period of between 50 and 200 .mu.s. Alternately, the veto means is a software program which includes means for tagging each of the pulses from each of the detectors for both time and position, means for counting one of the pulses from a particular position, and means for rejecting those of the pulses which originate from the particular position and in a time interval on the order of the neutron die-away time in polyethylene or other shield material. The neutron detectors are grouped in pods, preferably at least 10. The apparatus also includes means for vetoing the counting of coincidence pulses from all of the detectors included in each of the pods which are adjacent to the pod which includes the detector which produced the pulse which was counted.

Menlove, Howard O. (Los Alamos, NM); Bourret, Steven C. (Los Alamos, NM); Krick, Merlyn S. (Los Alamos, NM)

2002-01-01T23:59:59.000Z

208

Neutron sources and transmutation of nuclear waste  

Science Journals Connector (OSTI)

Intense neutron sources with different energy spectra are of interest for a variety of applications. In my presentation, after briefly touching on the situation of radioactive waste in Italy, I will try to give a broad picture of Italian existing or proposed neutron sources based on accelerators, ranging from thermal to fast neutrons. I will also describe a specific project for a low-power ADS, aimed at studying neutron spectra as well as at demonstrating incineration and transmutation of nuclear waste.

M. Ripani

2013-01-01T23:59:59.000Z

209

The Manuel Lujan, Jr. Neutron Scattering Center (LANSCE) experiment reports 1992 run cycle. Progress report  

SciTech Connect (OSTI)

This year was the fifth in which LANSCE ran a formal user program. A call for proposals was issued before the scheduled run cycles, and experiment proposals were submitted by scientists from universities, industry, and other research facilities around the world. An external program advisory committee, which LANSCE shares with the Intense Pulsed Neutron Source (IPNS), Argonne National Laboratory, examined the proposals and made recommendations. At LANSCE, neutrons are produced by spallation when a pulsed, 800-MeV proton beam impinges on a tungsten target. The proton pulses are provided by the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator and an associated Proton Storage Ring (PSR), which can alter the intensity, time structure, and repetition rate of the pulses. The LAMPF protons of Line D are shared between the LANSCE target and the Weapons Neutron Research (WNR) facility, which results in LANSCE spectrometers being available to external users for unclassified research about 80% of each annual LAMPF run cycle. Measurements of interest to the Los Alamos National Laboratory may also be performed and may occupy up to an additional 20% of the available beam time. These experiments are reviewed by an internal program advisory committee. One hundred sixty-seven proposals were submitted for unclassified research and twelve proposals for research of a programmatic interest to the Laboratory; six experiments in support of the LANSCE research program were accomplished during the discretionary periods. Oversubscription for instrument beam time by a factor of three was evident with 839 total days requested and only 371 available for allocation.

DiStravolo, M.A. [comp.

1993-09-01T23:59:59.000Z

210

Neutron Production, Neutron Facilities and Neutron Instrumentation  

Science Journals Connector (OSTI)

...Mexico, 87545, U.S.A, e-mail: sven@lanl.gov Hans-Georg Priesmeyer Geesthacht Neutron Scattering Facility, GKSS Research Center, 21502 Geesthacht, Germany, e-mail: hans-georg.priesmeyer@gkss.de NEUTRON GENERATION The...

Sven C. Vogel; Hans-Georg Priesmeyer

211

Neutron coincidence detectors employing heterogeneous materials  

DOE Patents [OSTI]

A neutron detector relies upon optical separation of different scintillators to measure the total energy and/or number of neutrons from a neutron source. In pulse mode embodiments of the invention, neutrons are detected in a first detector which surrounds the neutron source and in a second detector surrounding the first detector. An electronic circuit insures that only events are measured which correspond to neutrons first detected in the first detector followed by subsequent detection in the second detector. In spectrometer embodiments of the invention, neutrons are thermalized in the second detector which is formed by a scintillator-moderator and neutron energy is measured from the summed signals from the first and second detectors.

Czirr, J. Bartley (Mapleton, UT); Jensen, Gary L. (Orem, UT)

1993-07-27T23:59:59.000Z

212

Design of the Small Angle Neutron Scattering instrument at the Indiana University Low Energy Neutron Source| Applications to the study of nanostructured materials.  

E-Print Network [OSTI]

?? The Low Energy Neutron Source (LENS) located at the Indiana University Cyclotron Facility (IUCF) is a prototypical long-pulse accelerator-based neutron source. The Small Angle (more)

Remmes, Nicholas B.

2008-01-01T23:59:59.000Z

213

Spatial and spectral effects in subcritical system pulsed experiments  

SciTech Connect (OSTI)

Accurate neutronic models are needed for the interpretation of pulsed experiments in subcritical systems. In this work, the extent of spatial and spectral effects in the pulse propagation phenomena is investigated and the analysis is applied to the GUINEVERE experiment. The multigroup cross section data is generated by the Monte Carlo SERPENT code and the neutronic evolution following the source pulse is simulated by a kinetic diffusion code. The results presented show that important spatial and spectral aspects need to be properly accounted for and that a detailed energy approach may be needed to adequately capture the physical features of the system to the pulse injection. (authors)

Dulla, S.; Nervo, M.; Ravetto, P. [Politecnico di Torino, Dipartimento Energia, Corso Duca degli Abruzzi, 24, 10129 Torino (Italy); Carta, M. [ENEA - C.R. CASACCIA, UTFISSM-PRONOC, Via Anguillarese, 301, 00123 S. Maria di Galeria (Italy)

2013-07-01T23:59:59.000Z

214

Pulse stretcher  

DOE Patents [OSTI]

Apparatus (20) for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse. The apparatus (20) uses a White cell (10) having a plurality of optical delay paths (18a-18d) of successively increasing number of passes between the field mirror (13) and the objective mirrors (11 and 12). A pulse (26) from a laser (27) travels through a multi-leg reflective path (28) between a beam splitter (21) and a totally reflective mirror (24) to the laser output (37). The laser pulse (26) is also simultaneously injected through the beam splitter (21) to the input mirrors (14a-14d) of the optical delay paths (18a-18d). The pulses from the output mirrors (16a-16d) of the optical delay paths (18a-18d) go simultaneously to the laser output (37) and to the input mirrors ( 14b-14d) of the longer optical delay paths. The beam splitter (21) is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output (37).

Horton, James A. (Livermore, CA)

1994-01-01T23:59:59.000Z

215

Neutron Reflectivity  

Science Journals Connector (OSTI)

Neutron Reflectivity ... This article is part of the Neutron Reflectivity special issue. ... The articles in this special issue on neutron reflectivity cover a broad range of the applications of this technique and the related X-ray and neutron scattering experiments of SAXS, SANS, GISAXS, and GISANS. ...

Jeffrey Penfold

2009-03-31T23:59:59.000Z

216

Neutron scattering at high pressure D. B. McWhan  

E-Print Network [OSTI]

715 Neutron scattering at high pressure D. B. McWhan Room 1D-234, Murray Hill, New Jersey 07974, U scattering at steady-state and pulsed sources are reviewed. The pressure cells available at most neutron 10 GPa have been made. For elastic scattering, a comparison is made between neutron scattering and X

Paris-Sud XI, Universit茅 de

217

About Neutrons  

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

Neutron Basics Neutron Basics A neutron is one of the fundamental particles that make up matter. This uncharged particle exists in the nucleus of a typical atom, along with its positively charged counterpart, the proton. Protons and neutrons each have about the same mass, and both can exist as free particles away from the nucleus. In the universe, neutrons are abundant, making up more than half of all visible matter. Find Out What a Neutron Is Youtube icon Properties of Neutrons How Can Neutrons Be Used for Research? Image of glucose movement in plants Neutron imaging techniques have been able to determine the precise movement of glucose in plants. This knowledge can help scientists better understand how biomass can be efficiently converted into fuel. Neutrons have many properties that make them ideal for certain types of

218

Coherence as ultrashort pulse train generator  

E-Print Network [OSTI]

Intense, well-controlled regular light pulse trains start to play a crucial role in many fields of physics. We theoretically demonstrate a very simple and robust technique for generating such periodic ultrashort pulses from a continuous probe wave which propagates in a dispersive thermal gas media.

Gevorg Muradyan; Mariam Hovhannisyan

2010-07-08T23:59:59.000Z

219

Energetic proton generation from intense Coulomb explosion of large-size ethane clusters  

Science Journals Connector (OSTI)

An experimental investigation is performed on the interaction of intense femtosecond laser pulses at the intensity of 6??1017?W/cm2 (55 fs 160?mJ at 800?nm) with ethane cluster (C2H6) N jets prepared under the backing pressure of 30 bars at room temperature (298?K). The experiment results indicate the generation of energetic protons whose average and maximum kinetic energies are 12.2 and 138.1?keV respectively by Coulomb explosion of (C2H6) N clusters. (C2H6) N clusters of 5?nm in radius are generated in the experiment which are 1.7 times larger than that of (CH4) N clusters prepared in the same conditions. Empirical estimation suggests that (C2H6) N clusters with radius of about 9.6?nm can be prepared at 80-bars backing pressure at 308?K. While (C2H6) N clusters of so large size are irradiated by sufficiently intense laser pulses the average energy of protons will be increased up to 50?keV. It is inferred that such large-size deuterated ethane clusters (C2D6) N will favor more efficient neutron generation due to the significant increase of the D-D nuclear reaction cross section in laser-driven cluster nuclear fusion.

Song Li; Zili Zhou; Ye Tian; Haiyang Lu; Wentao Wang; Jingjing Ju; Hongyu Li; Yi Xu; Yuxin Leng; Guoquan Ni; Cheng Wang; Jiansheng Liu

2013-01-01T23:59:59.000Z

220

2011 Intensity -1 INTENSITY OF SOUND  

E-Print Network [OSTI]

the rate at which energy is passing a certain point. This concept involves sound intensity. Consider the sound intensity. Recall the time rate of energy transfer is called "power". Thus, sound intensity2011 Intensity - 1 INTENSITY OF SOUND The objectives of this experiment are: 路 To understand

Glashausser, Charles

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Infrared pulse characterization using four-wave mixing inside a few cycle pulse filament in air  

SciTech Connect (OSTI)

We demonstrate a four-wave mixing (FWM) technique to measure near- and mid-infrared (IR) laser pulse shapes in time domain. Few cycle 800?nm laser pulses were synchronized with the IR pulse and focused colinearly to generate a plasma filament in air. Second harmonic radiation around 400?nm was generated through FWM, with a yield proportional to the IR pulse intensity. Excellent signal to noise ratio was observed from 2.1??m to 18??m. With proper phase stabilization of the IR beam, this technique is a promising step toward direct electric field sensing of near-IR pulses in air.

Marceau, Claude, E-mail: claude.marceau.2@ulaval.ca; Thomas, Steven; Kassimi, Yacine; Gingras, Guillaume; Witzel, Bernd [Centre d'Optique, Photonique et Laser, Pavillon d'optique-photonique Qu閎ec (Qu閎ec), Universit Laval, Qu閎ec G1V 0A6 (Canada)

2014-02-03T23:59:59.000Z

222

Neutron Scattering at 2.2 Mev by Time of Flight  

Science Journals Connector (OSTI)

A millimicrosecond time-of-flight technique has been applied to a study of the scattering of 2.2-Mev neutrons from targets of Fe, Pb206, and Y. The 3-Mev phase-focused proton beam from the BNL 18-inch cyclotron was used to produce high-intensity neutron pulses in the T(p,爊)He3 reaction. The angular distributions of the elastically scattered neutrons have been measured for the above targets. The angular distributions of the inelastically scattered neutrons from the 0.845-Mev level in Fe56 and from the 0.803-Mev level in Pb206 have been carefully studied, and were found to be symmetric about ?c.m.=90. The angular distributions of the inelastically scattered neutrons from levels at 1.34 and 1.43 Mev in Pb206 and from levels at 0.913 and 1.53 Mev in Y have been measured, and also appear to be symmetric about ?c.m.=90. The inelastic scattering from Pb206 shows evidence for a new level at 1.15 Mev.

H. H. Landon; A. J. Elwyn; G. N. Glasoe; S. Oleksa

1958-11-15T23:59:59.000Z

223

Neutron-Neutron Scattering Length  

Science Journals Connector (OSTI)

The final-state interaction of the two neutrons from the reaction ?-+d?2n+? has a pronounced and distinctive effect on the momentum spectrum of the outgoing particles. In particular, the neutron spectrum is sharply peaked in the neighborhood of 2 Mev, with a shape that is quite sensitive to the strength of the nn interaction. In the region of this peak, the relative neutron-neutron momentum is so small that the nn interaction is completely characterized by its scattering length. Hence it is proposed that a measurement of the shape of the neutron spectrum from this reaction may provide a convenient means of measuring the neutron-neutron scattering length. Neutron spectra are calculated in an impulse approximation, for several assumed values of the scattering length. It appears from their shapes that, in this way, present neutron-detection techniques should be capable of determining the scattering length to within 25%.

Kirk W. McVoy

1961-03-01T23:59:59.000Z

224

Pulsed Laser Deposition | EMSL  

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

Pulsed Laser Deposition Pulsed Laser Deposition EMSL's pulsed laser deposition (PLD) system is designed for epitaxial growth of oxide, ceramic, or synthetic mineral thin films and...

225

Fundamental Neutron Physics Beamline at the Spallation Neutron Source at ORNL  

E-Print Network [OSTI]

We describe the Fundamental Neutron Physics Beamline (FnPB) facility located at the Spallation Neutron Source at Oak Ridge National Laboratory. The FnPB was designed for the conduct of experiments that investigate scientific issues in nuclear physics, particle physics, astrophysics and cosmology using a pulsed slow neutron beam. We present a detailed description of the design philosophy, beamline components, and measured fluxes of the polychromatic and monochromatic beams.

N. Fomin; G. L. Greene; R. Allen; V. Cianciolo; C. Crawford; T. Ito; P. R. Huffman; E. B. Iverson; R. Mahurin; W. M. Snow

2014-08-04T23:59:59.000Z

226

Neutron scattering  

Science Journals Connector (OSTI)

... likely to be able to contribute to many different branches of chemistry and secondly because neutron ...neutronscattering ...

A. J. Leadbetter

1977-12-01T23:59:59.000Z

227

Neutron guide  

DOE Patents [OSTI]

A neutron guide in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art.

Greene, Geoffrey L. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

228

Neutron Diffraction  

Science Journals Connector (OSTI)

22 February 1949 research-article Neutron Diffraction G. E. Bacon J. Thewlis The problem of neutron diffraction by crystals is treated by analogy...deals with a comparison between X-ray and neutron diffraction and it is shown that quantitatively...

1949-01-01T23:59:59.000Z

229

First time nuclear material detection by one short-pulse-laser-driven  

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

Articles 禄 Articles 禄 First time nuclear material detection by one short-pulse-laser-driven neutron source First time nuclear material detection by one short-pulse-laser-driven neutron source The results obtained are the first experimental demonstration of active interrogation of nuclear material by a short pulse laser driven neutron source. April 3, 2013 TRIDENT pulse The results obtained are the first experimental demonstration of active interrogation of nuclear material by a short pulse laser driven neutron source. Contact James Rickman Communications Specialist (505) 665-9203 Email A single shot interrogation of the depleted uranium sample, showed a clear signal from the delayed neutrons in the detector with uranium, compared with the background, and with the typical time behavior of delayed

230

Pulsed hydrojet  

DOE Patents [OSTI]

An underwater pulsed hydrojet propulsion system is provided for accelerating and propelling a projectile or other vessel. A reactant, such as lithium, is fluidized and injected into a water volume. The resulting reaction produces an energy density in a time effective to form a steam pocket. Thrust flaps or baffles direct the pressure from the steam pocket toward an exit nozzle for accelerating a water volume to create thrust. A control system regulates the dispersion of reactant to control thrust characteristics.

Bohachevsky, I.O.; Torrey, M.D.

1986-06-10T23:59:59.000Z

231

Combined neutron reflectometry and rheology  

E-Print Network [OSTI]

We have combined neutron reflectometry with rheology in order to investigate the solid boundary of liquids and polymers under shear deformation. Our approach allows one to apply a controlled stress to a material while resolving the structural arrangements on the sub nanometer length scale with neutron reflectivity, off-specular and small angle scattering at the same time. The specularly reflected neutron intensity of a 20 % by weight solution of the Pluronic F127 in deuterated water is evaluated. We find pronounced changes in the near interface structure under applied deformation for surfaces with different surface energies, which are correlated with changes in the storage and loss modulus.

Max Wolff; Peter Kuhns; Georg Liesche; John F. Ankner; Jim F. Browning; Philipp Gutfreund

2013-04-18T23:59:59.000Z

232

Control of XeF laser output by pulse injecton  

SciTech Connect (OSTI)

Injection locking is investigated as a means for control of optical pulse duration and polarization in a XeF laser. Intense short-pulse generation in the ultraviolet is achieved by injection of a low-level 1-ns optical pulse into a XeF oscillator. Control of laser output polarization by injection locking is demonstrated and studied as a function of injected signal level. Enhancement of XeF electric-discharge laser efficiency by injection pulse ''priming'' is observed.

Pacala, T.J.; Christensen, C.P.

1980-04-15T23:59:59.000Z

233

VULCAN: the Engineering Materials Diffractometer at SNS | ORNL Neutron  

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

Engineering Materials Diffractometer at SNS Engineering Materials Diffractometer at SNS VULCAN with the multiaxial loadframe on the sample stage. VULCAN with the multiaxial loadframe on the sample stage. VULCAN is designed for deformation, phase transformation, residual stress, texture, and microstructure studies. Load frames, furnaces, battery chargers, and other auxiliary equipment for in situ and time-resolved measurements are integrated in the instrument. As a time-of-flight diffractometer at the world's most intense pulsed, accelerator-based neutron source, VULCAN provides rapid volumetric mapping with a sampling volume of 1 mm3 and a measurement time of minutes for common engineering materials. In extreme cases, VULCAN has the ability to study kinetic behaviors in sub-second time frames. Applications

234

Lithium batteries for pulse power  

SciTech Connect (OSTI)

New designs of lithium batteries having bipolar construction and thin cell components possess the very low impedance that is necessary to deliver high-intensity current pulses. The R D and understanding of the fundamental properties of these pulse batteries have reached an advanced level. Ranges of 50--300 kW/kg specific power and 80--130 Wh/kg specific energy have been demonstrated with experimental high-temperature lithium alloy/transition-metal disulfide rechargeable bipolar batteries in repeated 1- to 100-ms long pulses. Other versions are designed for repetitive power bursts that may last up to 20 or 30 s and yet may attain high specific power (1--10 kW/kg). Primary high-temperature Li-alloy/FeS{sub 2} pulse batteries (thermal batteries) are already commercially available. Other high-temperature lithium systems may use chlorine or metal-oxide positive electrodes. Also under development are low-temperature pulse batteries: a 50-kW Li/SOCl{sub 2} primary batter and an all solid-state, polymer-electrolyte secondary battery. Such pulse batteries could find use in commercial and military applications in the near future. 21 refs., 8 figs.

Redey, L.

1990-01-01T23:59:59.000Z

235

Neutron skins and neutron stars  

Science Journals Connector (OSTI)

Background: The neutron skin of a heavy nucleus as well as many neutron-star properties are highly sensitive to the poorly constrained density dependence of the symmetry energy.Purpose: To provide for the first time meaningful theoretical errors and to assess the degree of correlation between the neutron-skin thickness of 208Pb and several neutron-star properties.Methods: A proper covariance analysis based on the predictions of an accurately calibrated relativistic functional 揊SUGold is used to quantify theoretical errors and correlation coefficients.Results: We find correlation coefficients of nearly 1 (or ?1) between the neutron-skin thickness of 208Pb and a host of observables of relevance to the structure, dynamics, and composition of neutron stars.Conclusions: We suggest that a follow-up Lead Radius Experiment (PREX) measurement, ideally with a 0.5% accuracy, could significantly constrain the equation of state of neutron-star matter.

F. J. Fattoyev and J. Piekarewicz

2012-07-05T23:59:59.000Z

236

Neutron Scattering Tutorials | Neutron Science | ORNL  

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

Neutron Scattering Tutorials SHARE Neutron Scattering Tutorials The following lectures were presented at the 2011 and 2010 National School on Neutron & X-Ray Scattering. This...

237

Yield of delayed neutrons in the thermal-neutron-induced reaction {sup 245}Cm(n, f)  

SciTech Connect (OSTI)

The yield of delayed neutrons, v{sub d}, from thermal-neutron-induced fission of {sup 245}Cm is measured. Experiments aimed at studying the properties of delayed neutrons from the fission of some reactor isotopes and initiated in 1997 were continued at the upgraded Isomer-M facility by a method according to which a periodic irradiation of a sample with a pulsed neutron beam from the IBR-2 reactor was accompanied by recording emitted neutrons in the intervals between the pulses. The accuracy of the resulting total delayed-neutron yield v{sub d} = (0.64 {+-} 0.02)% is two times higher than that in previous measurements. This work was performed at the Frank Laboratory of Neutron Physics at the Joint Institute for Nuclear Research (JINR, Dubna).

Andrianov, V. R. [Joint Institute for Nuclear Research (Russian Federation); Vyachin, V. N. [All-Russia Scientific Research Institute of Experimental Physics (VNIIEF) (Russian Federation); Gundorin, N. A. [Joint Institute for Nuclear Research (Russian Federation); Druzhinin, A. A. [All-Russia Scientific Research Institute of Experimental Physics (VNIIEF) (Russian Federation); Zhdanova, K. V.; Lihachev, A. N.; Pikelner, L. B.; Rebrova, N. V.; Salamatin, I. M.; Furman, V. I. [Joint Institute for Nuclear Research (Russian Federation)

2008-10-15T23:59:59.000Z

238

Tapered pulse tube for pulse tube refrigerators  

DOE Patents [OSTI]

Thermal insulation of the pulse tube in a pulse-tube refrigerator is maintained by optimally varying the radius of the pulse tube to suppress convective heat loss from mass flux streaming in the pulse tube. A simple cone with an optimum taper angle will often provide sufficient improvement. Alternatively, the pulse tube radius r as a function of axial position x can be shaped with r(x) such that streaming is optimally suppressed at each x.

Swift, Gregory W. (Sante Fe, NM); Olson, Jeffrey R. (San Mateo, CA)

1999-01-01T23:59:59.000Z

239

Neutron detector  

DOE Patents [OSTI]

A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

Stephan, Andrew C. (Knoxville, TN); Jardret; Vincent D. (Powell, TN)

2011-04-05T23:59:59.000Z

240

MAGNETIC NEUTRON SCATTERING  

SciTech Connect (OSTI)

Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern science, ranging from large-scale structures and dynamics of polymers and biological systems, to electronic properties of today's technological materials. Neutron scattering developed into a vast field, encompassing many different experimental techniques aimed at exploring different aspects of matter's atomic structure and dynamics. Modern magnetic neutron scattering includes several specialized techniques designed for specific studies and/or particular classes of materials. Among these are magnetic reflectometry aimed at investigating surfaces, interfaces, and multilayers, small-angle scattering for the large-scale structures, such as a vortex lattice in a superconductor, and neutron spin-echo spectroscopy for glasses and polymers. Each of these techniques and many others offer exciting opportunities for examining magnetism and warrant extensive reviews, but the aim of this chapter is not to survey how different neutron-scattering methods are used to examine magnetic properties of different materials. Here, we concentrate on reviewing the basics of the magnetic neutron scattering, and on the recent developments in applying one of the oldest methods, the triple axis spectroscopy, that still is among the most extensively used ones. The developments discussed here are new and have not been coherently reviewed. Chapter 2 of this book reviews magnetic small-angle scattering, and modern techniques of neutron magnetic reflectometry are discussed in Chapter 3.

ZALIZNYAK,I.A.; LEE,S.H.

2004-07-30T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Neutron Scattering  

Science Journals Connector (OSTI)

... Magnetic Neutron Diffraction By Yurii A. Izyumov and Ruslan P. Ozerov. Translated from the Russian. ... York; Heydon: London, June 1970.) 350s; $37.50; 150 DM.

G. L. SQUIRES

1970-12-05T23:59:59.000Z

242

Nonlinear Phenomena Induced by Millijoule Femtosecond Laser Pulses at an Air-water Interface  

E-Print Network [OSTI]

transformation in water. We find that nonlinear femtosecond pulse propagation begins at a peak pulse intensity of about 1010 W/cm2. This experiment provides a convenient segway into the discussion and investigation of femtosecond laser filaments. We describe...

Strycker, Benjamin

2013-11-04T23:59:59.000Z

243

Neutron activation analysis  

Science Journals Connector (OSTI)

Neutron activation analysis ... Describes the science and techniques of neutron activation analysis. ...

H. R. Lukens

1967-01-01T23:59:59.000Z

244

Validation of neutron emission profiles in MAST with a collimated neutron S. Sangaroon, M. Cecconello, S. Conroy, M. Weiszflog, M. Turnyanskiy et al.  

E-Print Network [OSTI]

as well as the detector's response function. The contribution of scattered neutrons to the pulse heightValidation of neutron emission profiles in MAST with a collimated neutron monitor S. Sangaroon, M) Prospects for the Thomson scattering system on NSTX-Upgrade Rev. Sci. Instrum. 83, 10D532 (2012) Swinging

245

Fast pulsed excitation wiggler or undulator  

DOE Patents [OSTI]

A fast pulsed excitation, electromagnetic undulator or wiggler, employing geometrically alternating substacks of thin laminations of ferromagnetic material, together with a single turn current loop excitation of the composite assembly, of such shape and configuration that intense, spatially alternating, magnetic fields are generated; for use as a pulsed mode undulator or wiggler radiator, for use in a Free Electron Laser (FEL) type radiation source or, for use in an Inverse Free Electron Laser (IFEL) charged particle accelerator.

van Steenbergen, Arie (Shoreham, NY)

1990-01-01T23:59:59.000Z

246

POWDER: The Neutron Powder Diffractometer at HFIR | ORNL Neutron Sciences  

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

Neutron Powder Diffractometer Neutron Powder Diffractometer Neutron Powder Diffractometer. Neutron Powder Diffractometer. The HB-2A diffractometer is a workhorse instrument used to conduct crystal structural and magnetic structural studies of powdered and ceramic samples, particularly as a function of intensive conditions (T, P, H, etc.). Powder diffraction data collected on this instrument are ideally suited for the Rietveld method. A full range of ancillary sample environments can be used, including cryofurnaces (4-800 K), furnaces (to 1800 K), cryostats (to 0.3 K), and cryomagnets (to 7 T). The Powder Diffractometer has a Debye-Scherrer geometry. The detector bank has 44 3He tubes, each with 6' Soller collimators. A germanium wafer-stack monochromator is vertically focusing and provides one of three principal

247

Neutron scattering  

Science Journals Connector (OSTI)

... statements that the EMBL outstation in Grenoble "[has an] uncertain future" and that "neutrons have not turned out to be particularly useful for biologists" in Peter Newmark's ... on the European Molecular Biology Laboratory (Nature 338, 724; 1989) require some comment.Neutron ...

S. CUSACK; B. JACROT; R. LEBERMAN; R. MAY; P. TlMMINS; G. ZACCAI

1989-06-01T23:59:59.000Z

248

Effect of pulse duration on resonant heating of laser-irradiated argon and deuterium clusters  

Science Journals Connector (OSTI)

We study the effect of pulse duration on the heating of single van der Waals bound argon and deuterium clusters by a strong laser field using a two-dimensional (2D) electrostatic particle-in-cell (PIC) code in the range of laser-cluster parameters such that kinetic as well as hydrodynamic effects are active. Heating is dominated by a collisionless resonant absorption process that involves energetic electrons transiting through the cluster. A size-dependent intensity threshold defines the onset of this resonance [T. Taguchi et al., Physical Review Letters, 92, 20 (2004)]. It is seen that increasing the laser pulse duration lowers this intensity threshold and the energetic electrons take multiple laser periods to transit the cluster instead of one laser period. Our simulations also show that strong electron heating is accompanied by the generation of a high-energy peak in the ion energy distribution function. We also calculate the yield of thermonuclear fusion neutrons from exploding deuterium clusters using the PIC model with periodic boundary conditions that allows for the interaction of ions from neighboring clusters.

Ayush Gupta; T. M. Antonsen; T. Taguchi; J. Palastro

2006-10-25T23:59:59.000Z

249

Vibration intensity difference thresholds.  

E-Print Network [OSTI]

??The intensity difference threshold is defined as 憈he difference in the intensity of two stimuli which is just sufficient for their difference to be detected. (more)

Forta, Nazim Gizem

2009-01-01T23:59:59.000Z

250

Isolated trigger pulse generator  

DOE Patents [OSTI]

A trigger pulse generation system capable of delivering a multiplicity of isolated 100 kV trigger pulses with picosecond simultaneity. 2 figs.

Aaland, K.

1980-02-19T23:59:59.000Z

251

Thermal neutron detection system  

DOE Patents [OSTI]

According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

Peurrung, Anthony J. (Richland, WA); Stromswold, David C. (West Richland, WA)

2000-01-01T23:59:59.000Z

252

System for generating shaped optical pulses and measuring optical pulses using spectral beam deflection (SBD)  

DOE Patents [OSTI]

A temporally shaped or modified optical output pulse is generated from a bandwidth-encoded optical input pulse in a system in which the input pulse is in the form of a beam which is spectrally spread into components contained within the bandwidth, followed by deflection of the spectrally spread beam (SBD) thereby spatially mapping the components in correspondence with the temporal input pulse profile in the focal plane of a lens, and by spatially selective attenuation of selected components in that focal plane. The shaped or modified optical output pulse is then reconstructed from the attenuated spectral components. The pulse-shaping system is particularly useful for generating optical pulses of selected temporal shape over a wide range of pulse duration, such pulses finding application in the fields of optical communication, optical recording and data storage, atomic and molecular spectroscopy and laser fusion. An optical streak camera is also provided which uses SBD to display the beam intensity in the focal plane as a function of time during the input pulse. 10 figures.

Skupsky, S.; Kessler, T.J.; Letzring, S.A.

1993-11-16T23:59:59.000Z

253

Compact neutron imaging system using axisymmetric mirrors  

DOE Patents [OSTI]

A dispersed release of neutrons is generated from a source. A portion of this dispersed neutron release is reflected by surfaces of a plurality of nested, axisymmetric mirrors in at least an inner mirror layer and an outer mirror layer, wherein the neutrons reflected by the inner mirror layer are incident on at least one mirror surface of the inner mirror layer N times, wherein N is an integer, and wherein neutrons reflected by the outer mirror are incident on a plurality of mirror surfaces of the outer layer N+i times, where i is a positive integer, to redirect the neutrons toward a target. The mirrors can be formed by a periodically reversed pulsed-plating process.

Khaykovich, Boris; Moncton, David E; Gubarev, Mikhail V; Ramsey, Brian D; Engelhaupt, Darell E

2014-05-27T23:59:59.000Z

254

Energetic proton generation from intense Coulomb explosion of large-size ethane clusters  

SciTech Connect (OSTI)

An experimental investigation is performed on the interaction of intense femtosecond laser pulses at the intensity of 6 Multiplication-Sign 10{sup 17} W/cm{sup 2} (55 fs, 160 mJ at 800 nm) with ethane cluster (C{sub 2}H{sub 6}){sub N} jets prepared under the backing pressure of 30 bars at room temperature (298 K). The experiment results indicate the generation of energetic protons, whose average and maximum kinetic energies are 12.2 and 138.1 keV, respectively, by Coulomb explosion of (C{sub 2}H{sub 6}){sub N} clusters. (C{sub 2}H{sub 6}){sub N} clusters of 5 nm in radius are generated in the experiment, which are 1.7 times larger than that of (CH{sub 4}){sub N} clusters prepared in the same conditions. Empirical estimation suggests that (C{sub 2}H{sub 6}){sub N} clusters with radius of about 9.6 nm can be prepared at 80-bars backing pressure at 308 K. While (C{sub 2}H{sub 6}){sub N} clusters of so large size are irradiated by sufficiently intense laser pulses, the average energy of protons will be increased up to 50 keV. It is inferred that such large-size deuterated ethane clusters (C{sub 2}D{sub 6}){sub N} will favor more efficient neutron generation due to the significant increase of the D-D nuclear reaction cross section in laser-driven cluster nuclear fusion.

Li Song; Zhou Zili; Tian Ye; Lu Haiyang; Wang Wentao; Ju Jingjing; Xu Yi; Leng Yuxin; Ni Guoquan; Wang Cheng; Liu Jiansheng [State Key Laboratory of High Filed Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Li Hongyu [College of Physics and Electronic Information, Tianjin Normal University, Tianjin 300387 (China)

2013-04-15T23:59:59.000Z

255

New measurement of the scattering cross section of slow neutrons on liquid parahydrogen from neutron transmission  

E-Print Network [OSTI]

Slow neutron scattering provides quantitative information on the structure and dynamics of materials of interest in physics, chemistry, materials science, biology, geology, and other fields. Liquid hydrogen is a widely-used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. In particular the rapid drop of the slow neutron scattering cross section of liquid parahydrogen below 14.5~meV is especially interesting and important. We have measured the total cross section and the scattering cross section for slow neutrons with energies between 0.43~meV and 16.1~meV on liquid hydrogen at 15.6~K using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge National Laboratory. At 1~meV this measurement is a factor of 3 below the data from previous work which has been used in the design of liquid hydrogen moderators at slow neutron sources. We describe our measurements, compare them with previous work, and discuss the implications for designing more intense slow neutron sources.

K. B. Grammer; R. Alarcon; L. Barr髇-Palos; D. Blyth; J. D. Bowman; J. Calarco; C. Crawford; K. Craycraft; D. Evans; N. Fomin; J. Fry; M. Gericke; R. C. Gillis; G. L. Greene; J. Hamblen; C. Hayes; S. Kucuker; R. Mahurin; M. Maldonado-Vel醶quez; E. Martin; M. McCrea; P. E. Mueller; M. Musgrave; H. Nann; S. I. Penttil; W. M. Snow; Z. Tang; W. S. Wilburn

2014-12-12T23:59:59.000Z

256

Neutron Checkup  

Science Journals Connector (OSTI)

Neutron activation analysis is yet another technique in the arsenal of diagnostic methods that physicians can draw on to examine the health of their patients. The University of Washington's school of medicine in Seattle is the first facility in the ...

1969-11-10T23:59:59.000Z

257

Neutron Reflectometry  

Science Journals Connector (OSTI)

Neutron reflectometry is a relatively new technique [1,2]. In the last years, it has been extensively used for solving soft matter problems like polymer mixing [3,4] or the structure of liquids at the surface [5,

Claude Fermon; Fr閐閞ic Ott; Alain Menelle

1999-01-01T23:59:59.000Z

258

Neutron-Neutron Correlations in the Dissociation of Halo Nuclei  

E-Print Network [OSTI]

Studies attempting to probe the spatial configuration of the valence neutrons in two-neutron halo nuclei using the technique of intensity interferometry are described. Following a brief review of the method and its application to earlier measurements of the breakup of 6He, 11Li and 14Be, the results of the analysis of a high statistics data set for 6He are presented. The limitations of the technique, including the assumption of incoherent emission in the breakup and the sensitivity to the continuum states populated in the dissociation rather than the ground state, are discussed.

N. A. Orr

2008-03-06T23:59:59.000Z

259

Neutron Tomography and Space  

E-Print Network [OSTI]

Kevin Shields, 揙ptimization of neutron tomography for rapidNEUTRON TOMOGRAPHY AND SPACE Hal Egbert, Ronald Walker, R.industrial applications[1]. Neutron Computed Tomography was

Egbert, Hal; Walker, Ronald; Flocchini, R.

2007-01-01T23:59:59.000Z

260

Neutron range spectrometer  

DOE Patents [OSTI]

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.

Manglos, S.H.

1988-03-10T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Raman Amplification of Laser Pulses in Microcapillary Plasmas  

E-Print Network [OSTI]

of overcoming the power limit of current chirped-pulse-amplification (CPA) CP641, X-Ray Lasers 2002: 8th International Conference on X-Ray Lasers, edited by J. J. Rocca et al. > 2002American Institute of Physics 0 of the optics. Such Raman amplifiers can be useful to produce ultra-intense laser pulses for pumping soft x-ray

262

Dual Gamma Neutron Directional Elpasolite Detector  

SciTech Connect (OSTI)

Some applications, particularly in homeland security, require detection of both neutron and gamma radiation. Typically, this is accomplished with a combination of two detectors registering neutrons and gammas separately. We have investigated a new type of neutron/gamma (n/?) directional detection capability. We explored a new class of scintillator, cerium (Ce)-doped Elpasolites such as Cs2LiYCl6:Ce (CLYC), Cs2LiLaCl6 (CLLC), Cs2LiLaBr6:Ce (CLLB), or Cs2LiYBr6:Ce (CLYB). These materials are capable of providing energy resolution as good as 2.9% at 662 keV (FWHM), which is better than that of NaI:Tl. Because they contain 6Li, Elpasolites can also detect thermal neutrons. In the energy spectra, the full energy thermal neutron peak appears near or above 3 GEEn MeV. Thus, very effective pulse height discrimination is possible. In addition, the core-to-valence luminescence (CVL) provides Elpasolites with different temporal responses under gamma and neutron excitation, and, therefore, may be exploited for effective pulse shape discrimination. For instance, the CLLC emission consists of two main components: (1) CVL spanning from 220 nm to 320 nm and (2) Ce emission found in the range of 350 to 500 nm. The former emission is of particular interest because it appears only under gamma excitation. It is also very fast, decaying with a 2 ns time constant. The n/? discrimination capability of Elpasolite detectors may be optimized by tuning the cerium doping content for maximum effect on n/? pulse shape differences. The resulting Elpasolite detectors have the ability to collect neutron and gamma data simultaneously, with excellent discrimination. Further, an array of four of these Elpasolites detectors will perform directional detection in both the neutron and gamma channels simultaneously.

Guss, P. P.; Mukhopadhyay, S.

2013-09-01T23:59:59.000Z

263

Neutron apparatus for measuring strain in composites  

DOE Patents [OSTI]

A method and apparatus for orienting a pulsed neutron source and a multi-angle diffractometer toward a sample of a ceramic-matrix or metal-matrix composite so that the measurement of internal strain (from which stress is calculated) is reduced to uncomplicated time-of-flight measurements.

Kupperman, David S. (Oak Park, IL); Majumdar, Saurindranath (Naperville, IL); Faber, Jr., John F. (Downers Grove, IL); Singh, J. P. (Bolingbrook, IL)

1990-01-01T23:59:59.000Z

264

Development of a fast neutron therapy beam placement film technique  

E-Print Network [OSTI]

the treatment dose is delivered. It was requested by those radiotherapists who will hopefully utilize the TAMVEC fast-neutron therapy beam, however, that sn "on-line" placement check film be made to doubly insure proper tumor positioning. The research... is achieved, the measured intensity, I(x, E) of the unscat- tered neutrons is given by Equation 1. I(x, E) I (x, E) exp [-u(E)x] Equation 1 0 where I (x, E) = INCIDENT NEUTRON INTENSITY, neutrons/cm /sec 2 p(E) = LINEAR ATTENUATION COEFFICIENT, cm x...

Baron, Robert Layton

2012-06-07T23:59:59.000Z

265

Excimer emission from pulsed microhollow cathode discharges in xenon  

SciTech Connect (OSTI)

Direct current (dc) microhollow cathode discharge (MHCD) is an intense source for excimer radiation in vacuum ultraviolet at a wavelength of 172 nm in a high pressure xenon (Xe) gas. The concentration of precursors for the excimer formation, i.e., excited and ionized gas atoms, increases significantly by applying high voltage pulse onto the dc MHCD over the pulse duration range from 20 to 100 ns. The intensity of the excimer emission for the voltage pulse of 20 ns duration exceeds that of the emission intensity obtained from the same MHCD operated only in the dc mode, by one order of magnitude. In addition, the emission intensity increases by one order of magnitude over the pulse duration range from 20 to 100 ns. It can be assumed that the emission intensity of the MHCD source increases as long as the duration of the high voltage pulse is shorter than the electron relaxation time. For the high voltage pulse of 100 ns duration, the emission intensity has been found to be further enhanced by a factor of three when the gas pressure is increased from 200 to 800 mbar.

Lee, B.-J.; Nam, S. H. [Pohang Accelerator Laboratory, Pohang, Kyungbuk 790-784 (Korea, Republic of)] [Pohang Accelerator Laboratory, Pohang, Kyungbuk 790-784 (Korea, Republic of); Rahaman, H. [CSIR朇EERI Pilani, Rajasthan 333031 (India)] [CSIR朇EERI Pilani, Rajasthan 333031 (India); Iberler, M.; Jacoby, J. [Institute of Applied Physics, Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany)] [Institute of Applied Physics, Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Frank, K. [Physics Department 1, University of Erlangen Nuremberg, 91058 Erlangen (Germany)] [Physics Department 1, University of Erlangen Nuremberg, 91058 Erlangen (Germany)

2013-12-15T23:59:59.000Z

266

LANSCE | News & Media | The Pulse  

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

Rosen Prize First neutron diffraction study of a stoichiometric oxide compound of gold Neutron scattering provides insight into enzymatic degradation of cellulose Neutron total...

267

Intense pulsed light sintering of copper nanoink for printed electronics  

E-Print Network [OSTI]

During the arc plasma generation, the ?ash lamp emits anusing an arc plasma phenomenon in the xenon ?ash lamp [7].

Kim, Hak-Sung; Dhage, Sanjay R.; Shim, Dong-Eun; Hahn, H. Thomas

2009-01-01T23:59:59.000Z

268

Ultra- high pulse intensity amplification and compression in plasma  

Science Journals Connector (OSTI)

This talk provides the summary of experimental research at Princeton on Raman Backscattering (RBS) amplification and compression in plasma [1]. The main subject of the talk is about...

Morozov, Anatoli; Li, Shuanglei; Turnbull, David; Suckewer, Szymon

269

Neutron Repulsion  

E-Print Network [OSTI]

Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding how: a.) The Sun generates and releases neutrinos, energy and solar-wind hydrogen and helium; b.) An inhabitable planet formed and life evolved around an ordinary-looking star; c.) Continuous climate change - induced by cyclic changes in gravitational interactions of the Sun's energetic core with planets - has favored survival by adaptation.

Oliver K. Manuel

2011-02-08T23:59:59.000Z

270

Fast-Neutron Handbook  

Science Journals Connector (OSTI)

... FAST neutron physics, in the present context, concerns the study of interactions of atomic nuclei with neutrons ...

J. H. MONTAGUE

1961-06-10T23:59:59.000Z

271

Characterisation of mixed neutron杙hoton workplace fields at nuclear facilities by spectrometry (energy and direction) within the EVIDOS project  

Science Journals Connector (OSTI)

......starting spectrum (initial...NUBAY, the neutron spectrum was approximated...components: a thermal peak, a high-energy peak and...modelled with a fission Maxwellian...pulse height spectra of all 24...depends on the energy and direction...incoming neutron radiation...ranging from thermal up to 15...pulse height induced by photon......

M. Luszik-Bhadra; D. Bartlett; T. Bolognese-Milsztajn; M. Boschung; M. Coeck; G. Curzio; F. d'Errico; A. Fiechtner; V. Lacoste; L. Lindborg; M. Reginatto; H. Schuhmacher; R. Tanner; F. Vanhavere

2007-04-01T23:59:59.000Z

272

Neutron Compound Refractive Prisms - DOE SBIR Phase II Final Report  

SciTech Connect (OSTI)

The results of the research led to a pulsed electromagnetic periodic magnetic field array (PMF), which coupled with a pair of collimation slits, and a mechanical chopper slit, were able to deflect spin-up neutrons to a band of line-fused neutrons a focal plane heights that correspond to the time-varying magnetic field amplitude. The electromagnetic field PMF produced 5.4 pulses per minute in which each pulse was 50 msec in duration with a full width half maximum (FWHM) of 7.5 msec. The calculated 7.7 mm vertical height of the band of focused spin-up neutrons corresponded closely to the measured 7.5 mm height of the center line of the imaged band of neutrons. The band of deflected spin-up neutrons was 5 mm in vertical width and the bottom of the band was 5 mm above the surface of the PMF pole. The limited exposure time of 3 hours and the smaller 0.78 T magnetic field allowed focused and near focused neutrons of 1.8 ???? to 2.6 ???? neutrons, which were in the tails of the McClellan Nuclear Radiation Center Bay 4 Maxwell Boltzmann distribution of neutrons with peak flux at 1.1-1.2 ????. The electromagnetic PMF was expected to produces a 2.0 T peak magnetic field amplitude, which would be operational at a higher duty factor, rather than the as built 7.5 msec FWHM with pulse repetition frequency of 5.4 pulses per minute. The fabricated pulsed electromagnetic PMF with chopper is expected to perform well on a cold, very cold or ultra cold beam line as a spectrometer or monochromator source of spin-up polarized neutron. In fact there may be a possible use of the PMF to do ultra-cold neutron trapping, see paper by A. I. Frank1, V. G. Nosov, Quantum Effects in a One-Dimensional Magnetic Gravitational Trap for Ultracold Neutrons, JETP Letters, Vol. 79, No. 7, 2004, pp. 313?垄????315. The next step is to find a cold or very cold neutron facility, where further testing or use of the pulsed magnetic field PMF can be pursued.

Dr. Jay Theodore Cremer, Jr

2011-06-25T23:59:59.000Z

273

Neutron Scattering User Program | Neutron Science | ORNL  

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

User Program SHARE Neutron Scattering Can Benefit Your Research Neutron scattering has applications in almost every technical and scientific field, from biology and chemistry to...

274

First Neutron Spectrometry Measurement at the HL-2A Tokamak  

E-Print Network [OSTI]

A compact neutron spectrometer based on the liquid scintillator is presented for the neutron energy spectrum measurement at the HL-2A tokamak. The spectrometer has been well characterized and a fast digital pulse shape discrimination software has been developed using the charge comparison method. A digitizer data acquisition system with the maximum frequency of 1 MHz can work under the high count rate environment at HL-2A. Specific radiation shielding and magnetic shielding for the spectrometerhas been designed for the neutron spectrum measurement at the HL-2A Tokamak. For the analysis of the pulse height spectrum, dedicated numerical simulation utilizing NUBEAM combining with GENESIS has been made to obtain the neutron energy spectrum, following which the transportation process from the plasma to the detector has been evaluated with Monte Carlo calculations. The distorted neutron energy spectrum has been folded with response matrix of the liquid scintillation spectrometer, and good consistency has been found...

Xi, Yuan; Xufei, Xie; Zhongjing, Chen; Xingyu, Peng; Tieshuan, Fan; Jinxiang, Chen; Xiangqing, Li; Guoliang, Yuan; Jinwei, Yang; Qingwei, Yang

2013-01-01T23:59:59.000Z

275

Neutron Polarization  

Science Journals Connector (OSTI)

Experiments for the determination of the polarization cross section p of iron with monochromatic and non-monochromatic neutrons are described. The absolute value of p as well as its dependence on the neutron velocity is found to be in good agreement with the recent calculations of Steinberger and Wick and also with other experiments. For a complex neutron spectrum originating from a paraffin moderator p is found to be (2.350.1)10-24 cm2 in agreement with previous investigations. It is shown that the larger value of 3.1510-24 cm2 found by Hughes, Wallace, and Holtzman must be due to spectral differences. The approach of the magnetization of iron towards saturation is also investigated.

J. Fleeman; D. B. Nicodemus; H. H. Staub

1949-12-15T23:59:59.000Z

276

Utilization of Monte Carlo Calculations in Radiation Transport Analyses to Support the Design of the U.S. Spallation Neutron Source (SNS)  

SciTech Connect (OSTI)

The Department of Energy (DOE) has given the Spallation Neutron Source (SNS) project approval to begin Title I design of the proposed facility to be built at Oak Ridge National Laboratory (ORNL) and construction is scheduled to commence in FY01 . The SNS initially will consist of an accelerator system capable of delivering an {approximately}0.5 microsecond pulse of 1 GeV protons, at a 60 Hz frequency, with 1 MW of beam power, into a single target station. The SNS will eventually be upgraded to a 2 MW facility with two target stations (a 60 Hz station and a 10 Hz station). The radiation transport analysis, which includes the neutronic, shielding, activation, and safety analyses, is critical to the design of an intense high-energy accelerator facility like the proposed SNS, and the Monte Carlo method is the cornerstone of the radiation transport analyses.

Johnson, J.O.

2000-10-23T23:59:59.000Z

277

Neutron Imaging Explored as Complementary Technique for Improving Cancer  

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

Neutron Imaging Explored as Complementary Technique for Improving Cancer Neutron Imaging Explored as Complementary Technique for Improving Cancer Detection August 05, 2013 Researcher Maria Cekanova analyzes the neutron radiographs of a canine breast tumor (black color in top image of monitor screen) using the software to visualize in color the various intensities of neutron transmissions through the breast tissue. ORNL and University of Tennessee collaboration now analyzing first results from neutron radiographs of cancerous tissue samples Today's range of techniques for detection of breast and other cancers include mammography, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, positron emission tomography (PET), and optical imaging. Each technology has advantages and disadvantages, with limitations either

278

A compact stilbene crystal neutron spectrometer for EAST D-D plasma neutron diagnostics  

SciTech Connect (OSTI)

A new compact stilbene crystal neutron spectrometer has been investigated and applied in the neutron emission spectroscopy on the EAST tokamak. A new components analysis method is presented to study the anisotropic light output in the stilbene crystal detector. A Geant4 code was developed to simulate the neutron responses in the spectrometer. Based on both the optimal light output function and the fitted pulse height resolution function, a reliable neutron response matrix was obtained by Geant4 simulations and validated by 2.5 MeV and 14 MeV neutron measurements at a 4.5 MV Van de Graaff accelerator. The spectrometer was used to diagnose the ion temperature in plasma discharges with lower hybrid wave injection and ion cyclotron resonance heating on the EAST tokamak.

Zhang Xing; Yuan Xi; Xie Xufei; Chen Zhongjing; Peng Xingyu; Chen Jinxiang; Zhang Guohui; Li Xiangqing; Fan Tieshuan [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Chengfu Road 201, 100871 Beijing (China); Zhong Guoqiang; Hu Liqun; Wan Baonian [Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, 230031 Hefei, Anhui (China)

2013-03-15T23:59:59.000Z

279

The neutron long counter NERO for studies of beta-delayed neutron emission in the r-process  

E-Print Network [OSTI]

The neutron long counter NERO was built at the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, for measuring beta-delayed neutron-emission probabilities. The detector was designed to work in conjunction with a beta-decay implantation station, so that beta decays and beta-delayed neutrons emitted from implanted nuclei can be measured simultaneously. The high efficiency of about 40%, for the range of energies of interest, along with the small background, are crucial for measuring beta-delayed neutron emission branchings for neutron-rich r-process nuclei produced as low intensity fragmentation beams in in-flight separator facilities.

J. Pereira; P. Hosmer; G. Lorusso; P. Santi; A. Couture; J. Daly; M. Del Santo; T. Elliot; J. Goerres; C. Herlitzius; K. -L. Kratz; L. O. Lamm; H. Y. Lee; F. Montes; M. Ouellette; E. Pellegrini; P. Reeder; H. Schatz; F. Schertz; L. Schnorrenberger; K. Smith; E. Stech; E. Strandberg; C. Ugalde; M. Wiescher; A. Woehr

2010-07-28T23:59:59.000Z

280

Neutron scattering-modern techniques and their scientific impact  

E-Print Network [OSTI]

The sustained interest in the neutron and its use as a probe of the structure and dynamics of condensed matter is examined against the background of neutron availabil-ity. An analysis is made of developments in neutron source brightness, instrument physics and experimental methodology which have been or are likely to be of outstand-ing value in physics, chemistry, biology and materials technology studies. The role of pulsed sources as the next step ahead in neutron source brightness, their need for extensive instrument development to realise this potential and their complementarity with steady-state reactors is analysed using newly available experimental results. This review was received in December 1983.

J W White; C G Windsor; J W White; C G Windsor

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281

Neutron total cross section measurements of gold and tantalum at the nELBE photoneutron source  

E-Print Network [OSTI]

Neutron total cross sections of 197 Au and nat Ta have been measured at the nELBE photoneutron source in the energy range from 0.1 - 10 MeV with a statistical uncertainty of up to 2 % and a total systematic uncertainty of 1 %. This facility is optimized for the fast neutron energy range and combines an excellent t ime structure of the neutron pulses (electron bunch width 5 ps) with a short flight path of 7 m. Because of the low instantaneous neutron flux transmission measurements of neutron total cross sections are possible, that exhibit very different beam and back ground conditions than found at other neutron sources.

Hannaske, Roland; Beyer, Roland; Junghans, Arnd; Bemmerer, Daniel; Birgersson, Evert; Ferrari, Anna; Grosse, Eckart; Kempe, Mathias; K鰃ler, Toni; Marta, Michele; Massarczyk, Ralph; Matic, Andrija; Schramm, Georg; Schwengner, Ronald; Wagner, Andreas

2014-01-01T23:59:59.000Z

282

Relativistic Doppler Effect: Universal Spectra and Zeptosecond Pulses  

Science Journals Connector (OSTI)

We report on a numerical observation of the train of zeptosecond pulses produced by the reflection of a relativistically intense femtosecond laser pulse from the oscillating boundary of an overdense plasma because of the Doppler effect. These pulses promise to become unique experimental and technological tools since their length is of the order of the Bohr radius and the intensity is extremely high ?1019??W/cm2. We present the physical mechanism, analytical theory, and direct particle-in-cell simulations. We show that the harmonic spectrum is universal: the intensity of nth harmonic scales as 1/np for n<4?2, where ? is the largest ? factor of the electron fluid boundary, and p=3 and p=5/2 for the broadband and quasimonochromatic laser pulses, respectively.

S. Gordienko; A. Pukhov; O. Shorokhov; T. Baeva

2004-09-10T23:59:59.000Z

283

Relativistic Doppler effect: universal spectra and zeptosecond pulses  

E-Print Network [OSTI]

We report on a numerical observation of the train of zeptosecond pulses produced by reflection of a relativistically intense femtosecond laser pulse from the oscillating boundary of an overdense plasma because of the Doppler effect. These pulses promise to become a unique experimental and technological tool since their length is of the order of the Bohr radius and the intensity is extremely high $\\propto 10^{19}$ W/cm$^2$. We present the physical mechanism, analytical theory, and direct particle-in-cell simulations. We show that the harmonic spectrum is universal: the intensity of $n$th harmonic scales as $1/n^{p}$ for $n < 4\\gamma^2$, where $\\gamma$ is the largest $\\gamma$--factor of the electron fluid boundary, $p=3$ and $p=5/2$ for the broadband and quasimonochromatic laser pulses respectively.

S. Gordienko; A. Pukhov; O. Shorokhov; T. Baeva

2004-05-10T23:59:59.000Z

284

A Neutron Generator Utilizing the Deuteron-Deuteron Reaction  

Science Journals Connector (OSTI)

A simple accelerating tube for the production of neutrons by the deuteron-deuteron reaction is described. The neutron intensity from a heavy water ice target is compared with the neutron intensity from a strong Rn桞e source. The yield is found to be 6 mC per microampere of positive ions at 100 kv, and 9 mC per microampere of positive ions at 124 kv. Positive ion currents at the target in excess of one milliampere are obtained. With a beam of deuterons resolved by means of a magnetic field, a constant neutron intensity equivalent to that from a Rn桞e source of 4 curies has been obtained at 100 kv, and 6.5 curies at 124 kv. The neutron yield in the former case is 22 mC per microampere of deuterons and in the latter case is 37 mC per microampere.

Walter H. Zinn and Samuel Seely

1937-11-01T23:59:59.000Z

285

The Neutron  

Science Journals Connector (OSTI)

The writers point out that the postulation of the existence of the "neutron," a combination of an electron and a proton, of small size and low energy would be very useful in explaining a number of atomic and cosmic phenomena. They find that a mathematical treatment based on existing theory leads to indications of such a state but no definite proof.

R. M. Langer and N. Rosen

1931-06-15T23:59:59.000Z

286

Optically pulsed electron accelerator  

DOE Patents [OSTI]

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Fraser, J.S.; Sheffield, R.L.

1985-05-20T23:59:59.000Z

287

Optically pulsed electron accelerator  

DOE Patents [OSTI]

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Fraser, John S. (Los Alamos, NM); Sheffield, Richard L. (Los Alamos, NM)

1987-01-01T23:59:59.000Z

288

Fast neutron background measurements at shallow depths  

SciTech Connect (OSTI)

We report on measurements of the neutron backgrounds for neutrino experiments at shallow depth (such as the proposed San Onofre neutrino oscillation experiment). A detector capable of pulse-shape discrimination measured the flux of fast neutrons at 20 mwe depth in the Stanford Underground Facility to be (1.07 {+-} 0.30) X 10{sup -6} cm{sup -2} s{sup -1}. An experiment, situated in the Tendon Gallery of the San Onofre Unit 2 reactor. studied spallation neutrons from muons traversing Pb and Cu. An underground experiment in the SUF, employing a detector filled with Gd-loaded liquid scintillator, is measuring the neutron production rate and multiplicity for muon spallation in low-A material (hydrocarbon-based liquid scintillator).

Chen, M.; Hertenberger, R.; Novikov, V. [Inst. of Nuclear Research, Moscow (Russian Federation); Dougherty, B.

1993-10-01T23:59:59.000Z

289

NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS  

E-Print Network [OSTI]

NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS AND POLARIZED 3He R. GOLUB~and Steve K REPORTS (Review Section of Physics Letters) 237, No. 1(1994)1--62. PHYSICS REPORTS North-Holland Neutron electric-dipole moment, ultracold neutrons and polarized 3He R. Goluba and Steve K. Lamoreauxb a

290

Neutron reflecting supermirror structure  

DOE Patents [OSTI]

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

Wood, J.L.

1992-12-01T23:59:59.000Z

291

Neutron reflecting supermirror structure  

DOE Patents [OSTI]

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

292

Deuterium-Tritium Pulse Propulsion with Hydrogen as Propellant and the Entire Spacecraft as a Gigavolt Capacitor for Ignition  

E-Print Network [OSTI]

A deuterium-tritium (DT) nuclear pulse propulsion concept for fast interplanetary transport is proposed utilizing almost all the energy for thrust and without the need for a large radiator: 1. By letting the thermonuclear micro-explosion take place in the center of a liquid hydrogen sphere with the radius of the sphere large enough to slow down and absorb the neutrons of the DT fusion reaction, heating the hydrogen to a fully ionized plasma at a temperature of ~ 105 K. 2. By using the entire spacecraft as a magnetically insulated gigavolt capacitor, igniting the DT micro-explosion with an intense GeV ion beam discharging the gigavolt capacitor, possible if the space craft has the topology of a torus.

Friedwardt Winterberg

2012-07-31T23:59:59.000Z

293

Additive Manufacturing: Technology and Applications  

Energy Savers [EERE]

name Neutron scattering: SNS and HFIR * World's most intense pulsed neutron beams * World's highest flux reactor-based neutron source Leadership-class computing: Titan...

294

Characterization of Metallurgical Chars by Small Angle Neutron Scattering  

Science Journals Connector (OSTI)

Characterization of Metallurgical Chars by Small Angle Neutron Scattering ... Small angle scattering measures the intensity I(q) of scattered neutrons as a function of scattering angle ? from the input beam, or alternatively, as a function of the scattering vector q:? q = |q| = (4?/?) sin(?/2), where ? is the wavelength of the incident wave. ...

I. Snook; I. Yarovsky; H. J. M. Hanley; M. Y. Lin; D. Mainwaring; H. Rogers; P. Zulli

2002-08-06T23:59:59.000Z

295

High-voltage supply for neutron tubes in well-logging applications  

DOE Patents [OSTI]

A high voltage supply is provided for a neutron tube used in well logging. The biased pulse supply of the invention combines DC and full pulse techniques and produces a target voltage comprising a substantial negative DC bias component on which is superimposed a pulse whose negative peak provides the desired negative voltage level for the neutron tube. The target voltage is preferably generated using voltage doubling techniques and employing a voltage source which generates bipolar pulse pairs having an amplitude corresponding to the DC bias level.

Humphreys, D.R.

1982-09-15T23:59:59.000Z

296

Neutron resonance spin echo, bootstrap method for increasing the effective magnetic field  

E-Print Network [OSTI]

1195 Neutron resonance spin echo, bootstrap method for increasing the effective magnetic field R donn茅 en spectrom茅trie d'echos de spins de neutrons. Les limites th茅oriques et techniques 脿 l field intensity in Neutron Resonance Spin Echo (NRSE) spectrometry. The limits, theoretical as well

Paris-Sud XI, Universit茅 de

297

Effective Long-Range Attraction between Protein Molecules in Solutions Studied by Small Angle Neutron Scattering  

E-Print Network [OSTI]

Neutron Scattering Yun Liu,1 Emiliano Fratini,2 Piero Baglioni,1,2 Wei-Ren Chen,1 and Sow-Hsin Chen1,* 1, Italy (Received 8 February 2005; published 8 September 2005) Small angle neutron scattering intensity neutron and x-ray scattering investigations of proteins suggest the presence of a short-range attractive

Chen, Sow-Hsin

298

SUPPLEMENTARY MATERIAL Lipid bilayer structure determined by the simultaneous analysis of neutron  

E-Print Network [OSTI]

scattering intensities I(q) for both neutrons and x-rays using )()()()( qPqPqIqF TSLC= , (1.) where PLC in structure between oriented and spherical bilayers experimentally using both neutron and x-ray scattering in (2). Our study concluded no difference between the two for x-ray and neutron scattering data

Nagle, John F.

299

Europhysics Letters PREPRINT Lipid membranes on a surface grating studied by neutron  

E-Print Network [OSTI]

Europhysics Letters PREPRINT Lipid membranes on a surface grating studied by neutron reflectometry by neutron reflectometry, we determine the smectic penetration length = K/B from the relative intensity 37073 Goettingen, Germany PACS. 87.16.Dg 颅 Membranes, bilayers, and vesicles. PACS. 61.12.Ha 颅 Neutron

Paris-Sud XI, Universit茅 de

300

Neutron Star Superfluidity, Dynamics and Precession  

E-Print Network [OSTI]

Basic rotational and magnetic properties of neutron superfluids and proton superconductors in neutron stars are reviewed. The modes of precession of the neutron superfluid are discussed in detail. We emphasize that at finite temperature, pinning of superfluid vortices does not offer any constraint on the precession. Any pinning energies can be surmounted by thermal activation and there exists a dynamical steady state in which the superfluid follows the precession of the crust at a small lag angle between the crust and superfluid rotation velocity vectors. At this small lag the system is far from the critical conditions for unpinning, even if the observed precession of the crust may entail a large angle between the figure axis and the crust's rotation velocity vector. We conclude that if long period modulations of pulse arrival times and pulse shapes observed in a pulsar like the PSR B1828-11 are due to the precession of the neutron star, this does not have any binding implications about the existence of pinning by flux lines or the existence of Type II superconductivity in the neutron star.

M. Ali Alpar

2005-05-04T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Neutron Polarization  

Science Journals Connector (OSTI)

The neutron polarization cross section of iron has been measured as a function of energy from 0.7 to 3.3A by two methods: using the single transmission effect in a block of polycrystalline iron at energies selected by a quartz crystal monochromator; and using a single crystal of magnetized magnetite to analyze the beam emerging from the iron polarizer, the magnetite crystal itself serving as monochromator. The measured values are compared with those of other observers and the theoretically expected values. These are found to agree fairly well within the limits of accuracy of the measurements and existing knowledge of the wave function of the iron 3d shell. The two techniques were used also to determine the average polarization (32 percent) as seen by a 1v detector in a beam of reactor neutrons emerging from a 4-cm thick polarizing block of iron. Problems and techniques associated with the measurement of the average polarization of a continuous spectrum are discussed. A simplified experimental treatment of the problem of beam "hardening" is described. A description is given of the use of the magnetic resonance method in conjunction with a single-crystal magnetite analyzer for the measurement of neutron polarization.

C. P. Stanford; T. E. Stephenson; L. W. Cochran; S. Bernstein

1954-04-15T23:59:59.000Z

302

Neutron Gas  

Science Journals Connector (OSTI)

We assume that the neutron-neutron potential is well-behaved and velocity-dependent. We can then apply perturbation theory to find the energy per particle of a neutron gas, in the range of Fermi wave numbers 0.5

J. S. Levinger and L. M. Simmons

1961-11-01T23:59:59.000Z

303

Evidence for Neutron Production Via Enhanced Resistivity in a Plasma Focus  

Science Journals Connector (OSTI)

Intense neutron production in a plasma-focus discharge begins when the visible plasma light fades abruptly. This correlation is interpreted in terms of enhanced plasma resistivity that causes Ohmic heating and permits a rapid constriction of the discharge current distribution; the latter phenomenon leads to deuteron acceleration resulting in intense neutron production.

M. J. Bernstein and F. Hai

1970-09-07T23:59:59.000Z

304

Light intensity compressor  

DOE Patents [OSTI]

In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

Rushford, Michael C. (Livermore, CA)

1990-01-01T23:59:59.000Z

305

Transverse spreading of electrons in high-intensity laser fields  

E-Print Network [OSTI]

We show that for collisions of electrons with a high-intensity laser, discrete photon emissions introduce a transverse beam spread which is distinct from that due to classical (or beam shape) effects. Via numerical simulations, we show that this quantum induced transverse momentum gain of the electron is manifest in collisions with a realistic laser pulse of intensity within reach of current technology, and we propose it as a measurable signature of strong-field quantum electrodynamics.

D. G. Green; C. N. Harvey

2014-03-18T23:59:59.000Z

306

Double pulse laser induced breakdown spectroscopy; experimental study of  

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

Double pulse laser induced breakdown spectroscopy; experimental study of Double pulse laser induced breakdown spectroscopy; experimental study of lead emission intensity dependence on the wavelengths and sample matrix Title Double pulse laser induced breakdown spectroscopy; experimental study of lead emission intensity dependence on the wavelengths and sample matrix Publication Type Journal Article Year of Publication 2009 Authors Piscitelli, Vincent, Mauro A. Martinez, Alberto J. Fernandez, Jhanis J. Gonzalez, Xianglei Mao, and Richard E. Russo Journal Spectrochimica Acta Part B Volume 64 Issue 2 Pagination 147-154 Date Published 02/2009 Keywords Double pulse LIBS, laser induced breakdown spectroscopy, lead Abstract Lead (Pb) emission intensity (atomic line 405.78 nm) dependence on the sample matrix (metal alloy) was studied by means of collinear double pulse (DP)-laser induced breakdown spectroscopy (LIBS). The measurement of the emission intensity produced by three different wavelength combinations (i.e. I:532 nm-II:1064 nm, I:532 nm-II:532 nm, and I:532 nm-II:355 nm) from three series of standard reference materials showed that the lead atomic line 405.78 nm emission intensity was dependent on the sample matrix for all the combination of wavelengths, however reduced dependency was found for the wavelength combination I:532 nm-II:355 nm.

307

Publications | Neutron Science | ORNL  

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

Publications SHARE Publications The Neutron Science publications system contains peer-reviewed publications based on research conducted at ORNL's Neutron Science facilities or...

308

Neutron Scattering Facilities  

Science Journals Connector (OSTI)

The past history, present performance and future prospects for neutron scattering facilities will be discussed. Special features of neutron scattering techniques applicable to biological problems will be ... . Th...

D. L. Price

1996-01-01T23:59:59.000Z

309

High voltage pulse conditioning  

DOE Patents [OSTI]

Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

Springfield, Ray M. (Sante Fe, NM); Wheat, Jr., Robert M. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

310

Accelerated guided atomic pulse  

Science Journals Connector (OSTI)

The deleterious effects of dispersion on a propagating coherent atomic pulse, along the axis of a traveling-wave laser beam, can be ameliorated by the nonlinear self-interacting force due to dipole-dipole coupling between atoms. We show that a wide atomic pulse with a particular profile can retain its shape during propagation and, moreover, the momentum of the pulse increases due to photon absorption. For the wide soliton case, we demonstrate analytically that the self-interacting atomic force scales inversely with the third power of the pulse width.

S. Dyrting; Weiping Zhang; B. C. Sanders

1997-09-01T23:59:59.000Z

311

Spallation Neutron Source | ORNL Neutron Sciences  

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

Spallation Neutron Source SNS site, Spring 2012 The 80-acre SNS site is located on the east end of the ORNL campus and is about a three-minute drive from her sister neutron...

312

Photonic generation of UWB pulses with pulse position modulation  

E-Print Network [OSTI]

Photonic generation of UWB pulses with pulse position modulation H. Mu and J. Yao A novel photonic approach to generating ultra-wideband (UWB) signals with pulse position modulation (PPM) is proposed delay-line filter for UWB monocycle pulse generation, the second subsystem being a pulse

Yao, Jianping

313

Pulsed Power Technology at Sandia National Laboratories  

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

News and Reviews News and Reviews Pulsed Power in the News Nuclear fusion simulation shows high-gain energy output (March 2012) Rapid-fire pulse brings Sandia Z method closer to goal of high-yield fusion reactor (April 2007) Ice created in nanoseconds by Sandia's Z machine (March 2007) Z-Machine Shockwaves Melt Diamond (November 2006) Phase diagram of water revised by Sandia researchers (October 2006) Z fires objects faster than Earth moves through space (June 6, 2005) Sandia imagists view imploding wire arrays on Z (November 10, 2004) Z's $61.7 million refurbishment to advance capabilities (October 21, 2004) Z produces fusion neutrons (April 7, 2003) Former shock physics manager (Asay) elected to NAE (February 20, 2003) Z-Beamlet image shows Z evenly compresses pellet (August 30, 2001)

314

Neutron Absorption Cross Sections of Pa231 and Pa232  

Science Journals Connector (OSTI)

Activation studies of Pa231 in the graphite region of the Materials Testing Reactor have resulted in a value of 20015 barns for the thermal neutron absorption cross section of Pa231. Resonance neutron effects were eliminated by the method of cadmium differences and by conducting the irradiations in a region where the ratio of resonance to thermal neutrons is small.Measurements of the Pa232 and Pa233 activities produced in a highly intense neutron irradiation of Pa231 have resulted in a value of 760100 barns for the absorption cross section of Pa232.

R. R. Smith; N. P. Alley; R. H. Lewis; A. VanderDoes

1956-02-01T23:59:59.000Z

315

Science | ORNL Neutron Sciences  

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

Neutron Science Neutron Science Neutron Scattering Science Neutrons are one of the fundamental particles that make up matter and have properties that make them ideal for certain types of research. In the universe, neutrons are abundant, making up more than half of all visible matter. Neutron scattering provides information about the positions, motions, and magnetic properties of solids. When a beam of neutrons is aimed at a sample, many neutrons will pass through the material. But some will interact directly with atomic nuclei and "bounce" away at an angle, like colliding balls in a game of pool. This behavior is called neutron diffraction, or neutron scattering. Using detectors, scientists can count scattered neutrons, measure their energies and the angles at which they scatter, and map their final position

316

High-power, high-intensity laser propagation and interactions  

SciTech Connect (OSTI)

This paper presents overviews of a number of processes and applications associated with high-power, high-intensity lasers, and their interactions. These processes and applications include: free electron lasers, backward Raman amplification, atmospheric propagation of laser pulses, laser driven acceleration, atmospheric lasing, and remote detection of radioactivity. The interrelated physical mechanisms in the various processes are discussed.

Sprangle, Phillip [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Electrical and Computer Engineering and Physics, University of Maryland, College Park, Maryland 20740 (United States); Hafizi, Bahman [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2014-05-15T23:59:59.000Z

317

Biology and Soft Matter | Neutron Sciences | ORNL  

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

Biology and Soft Matter Biology and Soft Matter SHARE Biology and Soft Matter This is a time of unprecedented opportunity for using neutrons in biological and soft matter research. The US Department of Energy (DOE) has invested in two forefront neutron user facilities, the accelerator-based Spallation Neutron Source (SNS) and the reactor-based High Flux Isotope Reactor (HFIR), at Oak Ridge National Laboratory (ORNL). Researchers have access to new instrumentation on some of the world's most intense neutron beam lines for studying the structure, function, and dynamics of complex systems. We anticipate that soft matter and biological sciences of tomorrow will require understanding, predicting, and manipulating complex systems to produce the new materials and products required to meet our nation's

318

Neutron-driven gamma-ray laser  

DOE Patents [OSTI]

A lasing cylinder emits laser radiation at a gamma-ray wavelength of 0.87 .ANG. when subjected to an intense neutron flux of about 400 eV neutrons. A 250 .ANG. thick layer of Be is provided between two layers of 100 .ANG. thick layer of .sup.57 Co and these layers are supported on a foil substrate. The coated foil is coiled to form the lasing cylinder. Under the neutron flux .sup.57 Co becomes .sup.58 Co by neutron absorption. The .sup.58 Co then decays to .sup.57 Fe by 1.6 MeV proton emission. .sup.57 Fe then transitions by mesne decay to a population inversion for lasing action at 14.4 keV. Recoil from the proton emission separates the .sup.57 Fe from the .sup.57 Co and into the Be, where Mossbauer emission occurs at a gamma-ray wavelength.

Bowman, Charles D. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

319

First Neutron Spectrometry Measurement at the HL-2A Tokamak  

E-Print Network [OSTI]

A compact neutron spectrometer based on the liquid scintillator is presented for neutron energy spectrum measurements at the HL-2A tokamak. The spectrometer was well characterized and a fast digital pulse shape discrimination software was developed using the charge comparison method. A digitizer data acquisition system with a maximum frequency of 1 MHz can work under an environment with a high count rate at HL-2A tokamak. Specific radiation and magnetic shielding for the spectrometer were designed for the neutron spectrum measurement at the HL-2A tokamak. For pulse height spectrum analysis, dedicated numerical simulation utilizing NUBEAM combined with GENESIS was performed to obtain the neutron energy spectrum. Subsequently, the transportation process from the plasma to the detector was evaluated with Monte Carlo calculations. The distorted neutron energy spectrum was folded with the response matrix of the liquid scintillation spectrometer, and good consistency was found between the simulated and measured pulse height spectra. This neutron spectrometer based on a digital acquisition system could be well adopted for the investigation of the auxiliary heating behavior and the fast-ion related phenomenon on different tokamak devices.

Yuan Xi; Zhang Xing; Xie Xufei; Chen Zhongjing; Peng Xingyu; Fan Tieshuan; Chen Jinxiang; Li Xiangqing; Yuan Guoliang; Yang Jinwei; Yang Qingwei

2013-06-17T23:59:59.000Z

320

Neutron lifetime measured with stored ultracold neutrons  

Science Journals Connector (OSTI)

The neutron lifetime has been measured by counting the neutrons remaining in a fluid-walled bottle as a function of the duration of storage. Losses of neutrons caused by the wall reflections are eliminated by varying the bottle volume-to-surface ratio. The result obtained is ??=887.63 s.

W. Mampe; P. Ageron; C. Bates; J. M. Pendlebury; A. Steyerl

1989-08-07T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Nonlinear dynamics of ionization stabilization of atoms in intense laser fields  

E-Print Network [OSTI]

We revisit the stabilization of ionization of atoms subjected to a superintense laser pulse using nonlinear dynamics. We provide an explanation for the lack of complete ionization at high intensity and for the decrease of the ionization probability as intensity is increased. We investigate the role of each part of the laser pulse (ramp-up, plateau, ramp-down) in this process. We emphasize the role of the choice for the ionization criterion, energy versus distance criterion.

Michael Norman; C. Chandre; T. Uzer; Peijie Wang

2014-12-06T23:59:59.000Z

322

Neutron-Neutron Quasifree Scattering  

Science Journals Connector (OSTI)

The reaction D(n ,2n)p has been measured at Einc=14.1 MeV, ?n (3)=?n(4)=30?, ?=180?, and the results are compared with the predictions of two separable-potential models. Neutron-proton and proton-proton quasifree scattering from nucleon + deuteron reactions at 14 MeV are also compared with the predictions of the same models. The upper limit of 2 mb/sr2 is determined for the reaction D(n,n?)d.

Ivo Slaus; J. W. Sunier; G. Thompson; J. C. Young; J. W. Verba; D. J. Margaziotis; P. Doherty; R. T. Cahill

1971-03-29T23:59:59.000Z

323

Neutron Detection with Mercuric Iodide  

SciTech Connect (OSTI)

Mercuric iodide is a high-density, high-Z semiconducting material useful for gamma ray detection. This makes it convertible to a thermal neutron detector by covering it with a boron rich material and detecting the 478 keV gamma rays resulting from the {sup 10}B(n, {alpha}){sup 7}Li* reaction. However, the 374 barn thermal capture cross section of {sup nat}Hg, makes the detector itself an attractive absorber, and this has been exploited previously. Since previous work indicates that there are no low-energy gamma rays emitted in coincidence with the 368 keV capture gamma from the dominant {sup 199}Hg(n, {gamma}){sup 200}Hg reaction, only the 368 keV capture gamma is seen with any efficiency a relatively thin (few mm) detector. In this paper we report preliminary measurements of neutrons via capture reactions in a bare mercuric iodide crystal and a crystal covered in {sup 10}B-loaded epoxy. The covered detector is an improvement over the bare detector because the presence of both the 478 and 368 keV gamma rays removes the ambiguity associated with the observation of only one of them. Pulse height spectra, obtained with and without lead and cadmium absorbers, showed the expected gamma rays and demonstrated that they were caused by neutrons.

Bell, Z.A.

2003-06-17T23:59:59.000Z

324

Chaotic Pulse Trains  

E-Print Network [OSTI]

We study a third-order nonlinear ordinary differential equation whose solutions, under certain specific conditions, are individual pulses. These correspond to homoclinic orbits in the phase space of the equation and we study the possible pulse types in some detail. Sufficiently close to the conditions under which a homoclinic orbit exists, the solutions take the form of trains of well-separated pulses. A measure of closeness to homoclinic conditions provides a small parameter for the development of an asymptotic solution consisting of superposed, isolated pulses. The solvability condition in the resulting singular perturbation theory is a {\\its timing map} relating successive pulse spacings. This map of the real line onto itself, together with the known form of the homoclinic orbit, provides a concise and accurate solution of the equation.

N. J. Balmforth; G. R. Ierley; E. A. Spiegel

1993-09-08T23:59:59.000Z

325

Los Alamos Using Neutrons to Stop Nuclear Smugglers  

SciTech Connect (OSTI)

Los Alamos National Laboratory researchers have successfully demonstrated for the first time that laser-generated neutrons can be enlisted as a useful tool in the War on Terror. The international research team used the short-pulse laser at Los Alamos's TRIDENT facility to generate a neutron beam with novel characteristics that interrogated a closed container to confirm the presence and quantity of nuclear material inside. The successful experiment paves the way for creation of a table-top-sized or truck-mounted neutron generator that could be installed at strategic locations worldwide to thwart smugglers trafficking in nuclear materials.

Favalli, Andrea; Swinhoe, Martyn

2013-06-03T23:59:59.000Z

326

Los Alamos Using Neutrons to Stop Nuclear Smugglers  

ScienceCinema (OSTI)

Los Alamos National Laboratory researchers have successfully demonstrated for the first time that laser-generated neutrons can be enlisted as a useful tool in the War on Terror. The international research team used the short-pulse laser at Los Alamos's TRIDENT facility to generate a neutron beam with novel characteristics that interrogated a closed container to confirm the presence and quantity of nuclear material inside. The successful experiment paves the way for creation of a table-top-sized or truck-mounted neutron generator that could be installed at strategic locations worldwide to thwart smugglers trafficking in nuclear materials.

Favalli, Andrea; Swinhoe, Martyn

2014-06-02T23:59:59.000Z

327

Development of multichannel low-energy neutron spectrometer  

SciTech Connect (OSTI)

A multichannel low-energy neutron spectrometer for down-scattered neutron (DSN) measurements in inertial confinement fusion (ICF) experiments has been developed. Our compact-size 256-channel lithium-glass-scintillator-based spectrometer has been implemented and tested in ICF experiments with the GEKKO XII laser. We have performed time calibration of the 256-channel analog-to-digital convertor system used for DSN measurements via X-ray pulse signals. We have clearly observed the DD-primary fusion neutron signal and have successfully studied the detector's impulse response. Our detector is soon to be implemented in future ICF experiments.

Arikawa, Y., E-mail: arikawa-y@ile.osaka-u.ac.jp; Nagai, T.; Abe, Y.; Kojima, S.; Sakata, S.; Inoue, H.; Utsugi, M.; Iwasa, Y.; Sarukura, N.; Nakai, M.; Shiraga, H.; Fujioka, S.; Azechi, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka (Japan); Murata, T. [Kumamoto University, 2-40-1 Kurokami, Kumamoto 860-8555 (Japan)

2014-11-15T23:59:59.000Z

328

Neutron reflecting supermirror structure  

DOE Patents [OSTI]

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

329

Direct Measurement of Neutron?Neutron Scattering  

Science Journals Connector (OSTI)

In order to resolve long?standing discrepancies in indirect measurements of the neutron?neutron scattering length ann and contribute to solving the problem of the charge symmetry of the nuclear force the collaboration DIANNA (Direct Investigation of ann Association) plans to measure the neutron?neutron scattering cross section ? nn . The key issue of our approach is the use of the through?channel in the Russia reactor YAGUAR with a peak neutron flux of 1018 /cm2/s. The proposed experimental setup is described. Results of calculations are presented to connect ? nn with the nn?collision detector count rate and the neutron flux density in the reactor channel. Measurements of the thermal neutron fields inside polyethylene converters show excellent prospects for the realization of the direct nn?experiment.

E. I. Sharapov; C. D. Bowman; B. E. Crawford; W. I. Furman; C. R. Howell; B. G. Levakov; V. I. Litvin; W. I. Lychagin; A. E. Lyzhin; E. P. Magda; G. E. Mitchell; G. V. Muzichka; G. V. Nekhaev; Yu. V. Safronov; V. N. Shvetsov; S. L. Stephenson; A. V. Strelkov; W. Tornow

2003-01-01T23:59:59.000Z

330

Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method  

DOE Patents [OSTI]

A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0.times.10.sup.9 neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use.

Yoon, Woo Y. (Idaho Falls, ID); Jones, James L. (Idaho Falls, ID); Nigg, David W. (Idaho Falls, ID); Harker, Yale D. (Idaho Falls, ID)

1999-01-01T23:59:59.000Z

331

Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method  

DOE Patents [OSTI]

A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0{times}10{sup 9} neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use. 3 figs.

Yoon, W.Y.; Jones, J.L.; Nigg, D.W.; Harker, Y.D.

1999-05-11T23:59:59.000Z

332

Piecewise Adiabatic Passage with a Series of Femtosecond Pulses  

SciTech Connect (OSTI)

We develop a method of executing complete population transfers between quantum states in a piecewise manner using a series of femtosecond laser pulses. The method can be applied to a large class of problems as it benefits from the high peak powers and large spectral bandwidths afforded by femtosecond pulses. The degree of population transfer is robust to a wide variation in the absolute and relative intensities, durations, and time ordering of the pulses. The method is studied in detail for atomic sodium where piecewise adiabatic population transfer, as well as the induction of Ramsey-type interferences, is demonstrated.

Shapiro, E. A. [Department of Chemistry, University of British Columbia, Vancouver, V6T1Z3 (Canada); Milner, V. [Department of Chemistry, University of British Columbia, Vancouver, V6T1Z3 (Canada); Department of Physics, University of British Columbia, Vancouver, V6T1Z3 (Canada); Menzel-Jones, C. [Department of Physics, University of British Columbia, Vancouver, V6T1Z3 (Canada); Shapiro, M. [Department of Chemistry, University of British Columbia, Vancouver, V6T1Z3 (Canada); Department of Physics, University of British Columbia, Vancouver, V6T1Z3 (Canada); Department of Chemical Physics, Weizmann Institute, Rehovot, 76100 (Israel)

2007-07-20T23:59:59.000Z

333

Neutron-Mirror-Neutron Oscillations in a Trap  

E-Print Network [OSTI]

We calculate the rate of neutron-mirror-neutron oscillations for ultracold neutrons trapped in a storage vessel. Recent experimental bounds on the oscillation time are discussed.

B. Kerbikov; O. Lychkovskiy

2008-04-03T23:59:59.000Z

334

Neutron杕irror-neutron oscillations in a trap  

Science Journals Connector (OSTI)

We calculate the rate of neutron杕irror-neutron oscillations for ultracold neutrons trapped in a storage vessel. Recent experimental bounds on the oscillation time are discussed.

B. Kerbikov and O. Lychkovskiy

2008-06-27T23:59:59.000Z

335

Manuel Lujan Jr. Neutron Scattering Center Los Alamos Neutron...  

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

2013 LANSCE School on Neutron Scattering Geosciences & Materials in Extreme Environments Manuel Lujan Jr. Neutron Scattering Center Los Alamos Neutron Science Center Los Alamos...

336

Nuclear Simulation and Radiation Physics Investigations of the Target Station of the European Spallation Neutron Source  

SciTech Connect (OSTI)

The European Spallation Neutron Source (ESS) delivers high-intensity pulsed particle beams with 5-MW average beam power at 1.3-GeV incident proton energy. This causes sophisticated demands on material and geometry choices and a very careful optimization of the whole target system. Therefore, complex and detailed particle transport models and computer code systems have been developed and used to study the nuclear assessment of the ESS target system. The purpose here is to describe the methods of calculation mainly based on the Monte Carlo code to show the performance of the ESS target station. The interesting results of the simulations of the mercury target system are as follows: time-dependent neutron flux densities, energy deposition and heating, radioactivity and afterheat, materials damage by radiation, and high-energy source shielding. The results are discussed in great detail. The validity of codes and models, further requirements to improve the methods of calculation, and the status of running and planned experiments are given also.

Filges, Detlef; Neef, Ralf-Dieter; Schaal, Hartwig [Forschungszentrum Juelich GmbH (Germany)

2000-10-15T23:59:59.000Z

337

Le Bail Intensity Extraction  

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

Le Bail Intensity Extraction Le Bail Intensity Extraction Presentation Goal Introduce the concepts behind LeBail fitting; why it is useful and how to perform a Le Bail fit with GSAS. Format: PDF slides or a RealPlayer video of the slides with accompanying audio and a demo video that shows how a Le Bail fit is performed. Presentation Outline What is the Le Bail method? Other approaches Why use the Le Bail method? Parameter fitting with Le Bail intensity extraction Le Bail refinement strategies Avoiding problems with background fitting: BKGEDIT Demo: an example Le Bail fit Links Le Bail lecture Slides (as PDF file) FlashMovie presentation with index (best viewed with 1024x768 or better screen resolution) FlashMovie file (800x600 pixels) Le Bail demo FlashMovie presentation with index (best viewed with 1024x768 or

338

Neutron crystallography aids drug design  

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

Neutron crystallography aids drug design Neutron crystallography aids drug design Researchers have used neutron crystallography for the first time to determine the structure of a...

339

Los Alamos Neutron Science Center  

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

LINAC Outreach Affiliations Visiting LANSCE Facilities Isotope Production Facility Lujan Neutron Scattering Center MaRIE Proton Radiography Ultracold Neutrons Weapons Neutron...

340

HELIOS: A high intensity chopper spectrometer at LANSCE  

SciTech Connect (OSTI)

A proposal to construct a high intensity chopper spectrometer at LANSCE as part of the SPSS upgrade project is discussed. HELIOS will be optimized for science requiring high sensitivity neutron spectroscopy. This includes studies of phonon density of states in small polycrystalline samples, magnetic excitations in quantum magnets and highly correlated electron systems, as well as parametric studies (as a function of pressure, temperature, or magnetic field) of S(Q,{omega}). By employing a compact design together with the use of supermirror guide in the incident flight path the neutron flux at HELIOS will be significantly higher than any other comparable instrument now operating.

Mason, T.E. [Oak Ridge National Lab., TN (United States); Broholm, C. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Physics and Astronomy; Fultz, B. [California Inst. of Tech., Pasadena, CA (United States). Dept. of Materials Science] [and others

1998-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Neutron scattering Materials research for modern life Almost all of the major changes in our society, the dramatic  

E-Print Network [OSTI]

Neutron scattering Materials research for modern life #12;Almost all of the major changes in our scattering experiments, materials are exposed to intense beams of neutrons inside specialised instruments that neutron scattering science contributes to our lives. Because of the collaborative nature of modern

Crowther, Paul

342

Energy Intensity Strategy  

E-Print Network [OSTI]

Our presentation will cover how we began the journey of conserving energy at our facility. We抣l discuss a basic layout of our energy intensity plan and the impact our team has had on the process, what tools we抮e using, what goals have been...

Rappolee, D.; Shaw, J.

2008-01-01T23:59:59.000Z

343

Recent advances in neutron capture therapy (NCT)  

SciTech Connect (OSTI)

The application of the /sup 10/B(n,..cap alpha..)/sup 7/Li reaction to cancer radiotherapy (Neutron Capture therapy, or NCT) has intrigued investigators since the discovery of the neutron. This paper briefly summarizes data describing recently developed boronated compounds with evident tumor specificity and extended biological half-lives. The implication of these compounds to NCT is evaluated in terms of Therapeutic Gain (TG). The optimization of NCT using band-pass filtered beams is described, again in terms of TG, and irradiation times with these less intense beams are estimated. 24 refs., 3 figs., 3 tabs.

Fairchild, R.G.

1985-01-01T23:59:59.000Z

344

Pulse measurement apparatus and method  

DOE Patents [OSTI]

An embodiment of the invention is directed to a pulse measuring system that measures a characteristic of an input pulse under test, particularly the pulse shape of a single-shot, nano-second duration, high shape-contrast optical or electrical pulse. An exemplary system includes a multi-stage, passive pulse replicator, wherein each successive stage introduces a fixed time delay to the input pulse under test, a repetitively-gated electronic sampling apparatus that acquires the pulse train including an entire waveform of each replica pulse, a processor that temporally aligns the replicated pulses, and an averager that temporally averages the replicated pulses to generate the pulse shape of the pulse under test. An embodiment of the invention is directed to a method for measuring an optical or an electrical pulse shape. The method includes the steps of passively replicating the pulse under test with a known time delay, temporally stacking the pulses, and temporally averaging the stacked pulses. An embodiment of the invention is directed to a method for increasing the dynamic range of a pulse measurement by a repetitively-gated electronic sampling device having a rated dynamic range capability, beyond the rated dynamic range of the sampling device; e.g., enhancing the dynamic range of an oscilloscope. The embodied technique can improve the SNR from about 300:1 to 1000:1. A dynamic range enhancement of four to seven bits may be achieved.

Marciante, John R. (Webster, NY); Donaldson, William R. (Pittsford, NY); Roides, Richard G. (Scottsville, NY)

2011-10-25T23:59:59.000Z

345

Neutron range spectrometer  

DOE Patents [OSTI]

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are collimnated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

Manglos, Stephen H. (East Syracuse, NY)

1989-06-06T23:59:59.000Z

346

Neutron Generator as a Neutron Source for BNCT  

Science Journals Connector (OSTI)

A neutron generator was investigated for a neutron source for BNCT. Neutron generators have some obvious advantages over nuclear reactors for this purpose. The neutron source is the reaction D(d,n)3He. Moderation...

Gad Shani; Lev Tsvang; Semion Rozin; Michael Quastel

1996-01-01T23:59:59.000Z

347

Pulse-burst  

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

Pulse-burst laser systems for fast Thomson scattering "invited... a... D. J. Den Hartog, 1,2,b J. R. Ambuel, 3 M. T. Borchardt, 1 A. F. Falkowski, 1 W. S. Harris, 1 D. J. Holly,...

348

Pulse charging device  

SciTech Connect (OSTI)

This paper describes a device for pulse charging of capacitor storage devices of high-power nanosecond generators. The charging voltage reaches 30 kV, the charged capacitance is 2-100 nF, the charging time is 5-10 usec, the pulse frequency reaches 10 kHz, and the average power of the device is 15 kW. The device uses two-section oscillatory charging of the capacitors from a dc supply through high-speed thyristors and a pulse transformer. The described device is intended for use as part of a test bench for high-power nanosecond pulse generators for pumping gas lasers and their components.

Butakov, L.D.; Dubich, V.K.; Lashuk, N.A.; Shubkin, N.G.; Vizir', V.A.

1986-03-01T23:59:59.000Z

349

Short-pulse laser interferometric measurement of absolute gas densities from a cooled gas jet  

Science Journals Connector (OSTI)

We report on the use of a novel technique to measure the gas density from a pulsed gas jet. Deuterium gas is fully ionized with an intense picosecond laser, and the resulting...

Ditmire, T; Smith, R A

1998-01-01T23:59:59.000Z

350

Pulse magnetic welder  

DOE Patents [OSTI]

A welder is described for automated closure of fuel pins by a pulsed magnetic process in which the open end of a length of cladding is positioned within a complementary tube surrounded by a pulsed magnetic welder. Seals are provided at each end of the tube, which can be evacuated or can receive tag gas for direct introduction to the cladding interior. Loading of magnetic rings and end caps is accomplished automatically in conjunction with the welding steps carried out within the tube.

Christiansen, D.W.; Brown, W.F.

1984-01-01T23:59:59.000Z

351

Effect of temperature on performance of {sup 3}He filled neutron proportional counters  

SciTech Connect (OSTI)

Neutron detectors used for cosmic neutron monitoring and various other applications are mounted in hostile environment. It is essential for detectors to sustain extreme climatic conditions, such as extreme temperature and humidity. Effort is made to evaluate the performance of detectors in extreme temperature in terms of pulse height distribution and avalanche formation. Neutron detectors filled with {sup 3}He incorporate an additive gas with quantity optimized for a particular application. Measurements are performed on neutron detectors filled with {sup 3}He and stopping gases Kr and CF{sub 4}. Detector performance for these fill gas combinations in terms of pulse height distribution is evaluated. Gas gain and Diethorn gas constants measured and analyzed for the microscopic effect on pulse formation. Results from these investigations are presented.

Desai, Shraddha S., E-mail: ssdesai@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

2014-04-24T23:59:59.000Z

352

Narrowband inverse Compton scattering x-ray sources at high laser intensities  

E-Print Network [OSTI]

Narrowband x- and gamma-ray sources based on the inverse Compton scattering of laser pulses suffer from a limitation of the allowed laser intensity due to the onset of nonlinear effects that increase their bandwidth. It has been suggested that laser pulses with a suitable frequency modulation could compensate this ponderomotive broadening and reduce the bandwidth of the spectral lines, which would allow to operate narrowband Compton sources in the high-intensity regime. In this paper we, therefore, present the theory of nonlinear Compton scattering in a frequency modulated intense laser pulse. We systematically derive the optimal frequency modulation of the laser pulse from the scattering matrix element of nonlinear Compton scattering, taking into account the electron spin and recoil. We show that, for some particular scattering angle, an optimized frequency modulation completely cancels the ponderomotive broadening for all harmonics of the backscattered light. We also explore how sensitive this compensation ...

Seipt, D; Surzhykov, A; Fritzsche, S

2014-01-01T23:59:59.000Z

353

Neutrons from the D-D Reactions  

Science Journals Connector (OSTI)

An investigation has been made of the neutron spectra resulting from D-D reactions for a range of incident deuteron energies of 4.75 to 7.33 Mev, using a pulsed-beam time-of-flight method. In addition to mono-energetic neutrons from the reaction D(d,爊)He3, a continuum of neutrons is observed corresponding to D(d,爊p)D. The yield of the latter reaction has been measured at about 0.5-Mev intervals at zero degrees, and at an energy of 6.3 Mev an angular distribution has been obtained for both reactions. At 6.3-Mev deuteron energy and at zero degrees the yield of the continuum for neutron energies above 0.95 Mev is 17% of the yield of monoenergetic neutrons. The yield from both reactions is strongly forward in the laboratory reference frame, and for the breakup process increases rapidly with increase in energy above threshold.

L. Cranberg; A. H. Armstrong; R. L. Henkel

1956-12-15T23:59:59.000Z

354

Neutron producing target for accelerator based neutron source for  

E-Print Network [OSTI]

247 Neutron producing target for accelerator based neutron source for NCT V. Belov1 , S. Fadeev1, Russia Summary Neutron producing targets for novel accelerator based neutron source [1, 2] are presented Neutron producing target is one of the main elements of proposed accelerator based facility for neutron

Taskaev, Sergey Yur'evich

355

Measurement of the Neutron Spectrum of a DD Electronic Neutron Generator  

SciTech Connect (OSTI)

A Cuttler-Shalev (C-S) 3He proportional counter has been used to measure the energy spectrum of neutrons from a portable deuterium-deuterium electronic neutron generator. To improve the analysis of results from the C-S detector digital pulse shape analysis techniques have been used to eliminate neutron recoil artifacts in the recorded data. Data was collected using a 8-GHz, 10-bit waveform digitizer with its full scale corresponding to approximately 6-MeV neutrons. The measurements were made with the detector axis perpendicular to the direction of ions in the ENG in a plane 0.5-m to the side of the ENG, measuring neutrons emitted at an angle from 87.3? to 92.7? with respect to the path of ions in the ENG. The system demonstrated an energy resolution of approximately 0.040 MeV for the thermal peak and approximately 0.13 MeV at the DD neutron energy. In order to achieve the ultimate resolution capable with this type of detector it is clear that a higher-precision digitizer will be needed.

D. L. Chichester; J. T. Johnson; E. H. Seabury

2010-08-01T23:59:59.000Z

356

Pulse shaping with transmission lines  

DOE Patents [OSTI]

A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

Wilcox, Russell B. (Oakland, CA)

1987-01-01T23:59:59.000Z

357

Nonlinear relativistic interaction of an ultrashort laser pulse with a cold plasma  

E-Print Network [OSTI]

J Fisch. . . . Princeton Plasma Physics Laboratory, Princeton University, Princeton, New JerseyNonlinear relativistic interaction of an ultrashort laser pulse with a cold plasma J M Raxa) and N that results when intense ( 10" W/cm* and above) and ultrashort (one plasma period or shorter) laser pulse

358

Unlocking energy intensive habits  

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

energy intensive habits energy intensive habits Presentation at LBL Oct 10, 2013 by Hal Wilhite Professor and Research Director University of Oslo Centre for Development and the Environment Source: WWF US EIA Outlook 2011 Conventional framing of the energy consumption and savings * Sovereign consumers * Economically rational and persistentely reflexive. * Uninfluenced by social and material conditions of everyday life * Focus on efficiency and not on size and volume which is for the most part treated as an indifferent variable Cognitive reductionism The change of frame * From individual to socio-material * From rational/reflexive experience-based (practical) knowledge * From efficiency to reduction A theory of habit * Acknowledges the role of lived experience (history, both cultural and personal) in forming

359

The intensity of motivation  

E-Print Network [OSTI]

rearranged before they were repeated in reverse sequence. Electrocardiographic T-wave amplitude (TWA) and changes were monitored during a 15-sec anticipatory phase, as well as during each 15-second mental manipulation phase. (This ensured that the measures..., and the subject was surreptitiously observed. The high-self-esteem subjects were observed to do more practice www.annualreviews.org/aronline Annual Reviews INTENSITY OF MOTIVATION 121 problems for the difficult- than for the easy-to-please experimenter...

Brehm, Jack W.; Self, E. A.

1989-01-01T23:59:59.000Z

360

Neutron Log At Alum Area (Moos & Ronne, 2010) | Open Energy Information  

Open Energy Info (EERE)

Neutron Log At Alum Area (Moos & Ronne, 2010) Neutron Log At Alum Area (Moos & Ronne, 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Neutron Log At Alum Geothermal Area (Moos & Ronne, 2010) Exploration Activity Details Location Alum Geothermal Area Exploration Technique Neutron Log Activity Date Usefulness useful DOE-funding Unknown Notes Density, photo-electric factor (PEF), neutron, and gamma ray (GR) logs provided sufficient information to clearly delineate basement lithologic variations, suggesting that pulsed neutron logs may not in many cases be needed, References Daniel Moos, Joel Ronne (2010) Selecting The Optimal Logging Suite For Geothermal Reservoir Evaluation- Results From The Alum 25-29 Well, Nevada Retrieved from "http://en.openei.org/w/index.php?title=Neutron_Log_At_Alum_Area_(Moos_%26_Ronne,_2010)&oldid=511025"

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Laser fusion neutron source employing compression with short pulse lasers  

DOE Patents [OSTI]

A method and system for achieving fusion is provided. The method includes providing laser source that generates a laser beam and a target that includes a capsule embedded in the target and filled with DT gas. The laser beam is directed at the target. The laser beam helps create an electron beam within the target. The electron beam heats the capsule, the DT gas, and the area surrounding the capsule. At a certain point equilibrium is reached. At the equilibrium point, the capsule implodes and generates enough pressure on the DT gas to ignite the DT gas and fuse the DT gas nuclei.

Sefcik, Joseph A; Wilks, Scott C

2013-11-05T23:59:59.000Z

362

Photoconductive circuit element pulse generator  

DOE Patents [OSTI]

A pulse generator for characterizing semiconductor devices at millimeter wavelength frequencies where a photoconductive circuit element (PCE) is biased by a direct current voltage source and produces short electrical pulses when excited into conductance by short laser light pulses. The electrical pulses are electronically conditioned to improve the frequency related amplitude characteristics of the pulses which thereafter propagate along a transmission line to a device under test.

Rauscher, Christen (Alexandria, VA)

1989-01-01T23:59:59.000Z

363

The Theta Laser A Low Noise Chirped Pulse Laser  

E-Print Network [OSTI]

The Theta Laser A Low Noise Chirped Pulse Laser Dimitrios Mandridis dmandrid@creol.ucf.edu April 29, 2011 CREOL Affiliates Day 2011 #12;2 Objective: Frequency Swept (FM) Mode-locked Laser 路 Develop a frequency swept laser, 路 linear f-sweep, 路 uniform-intensity, 路 low noise, 路 with long-term stability

Van Stryland, Eric

364

Single-pulse Raman scattering studies of heterogeneous explosive materials  

SciTech Connect (OSTI)

Raman scattering from ambient and shock-loaded heterogeneous (compressed pure polycrystalline) explosive materials has been examined using single-pulse laser excitation. In the case of triamino-trinitrobenzene (TATB), intense nonlinear scattering at 1170 cm/sup -1/ has been observed.

Trott, W.M.; Renlund, A.M.

1985-05-15T23:59:59.000Z

365

Pulsed-Light Inactivation of Food-Related Microorganisms  

Science Journals Connector (OSTI)

...create a high-peak-power discharge. The generator...impedance, when fired, was 6.25 . A...average peak electrical power, per pulse, of...high-intensity light generation, it was possible...significant levels of peak power in the light source...de-charged high pressure gas switches. . Pennington...

N. J. Rowan; S. J. MacGregor; J. G. Anderson; R. A. Fouracre; L. McIlvaney; O. Farish

1999-03-01T23:59:59.000Z

366

Neutron-Proton Interaction: The Scattering of Neutrons by Protons  

Science Journals Connector (OSTI)

The inadequacy of present theories of proton-neutron interaction is shown in work in which 730 proton tracks produced by collisions of fast neutrons with hydrogen nuclei have been studied and measured to determine the distribution-in-angle. The recoils have been observed in three gaseous media; hydrogen, ethylene and hydrogen sulphide, by the use of a sylphon-type Wilson chamber and two cameras mounted in such a way as to give two views of each recoil, thus enabling a stereoscopic projection and a direct measurement of the angle of scattering to be made for each track. In this way it is found that the intensity distribution of recoil protons shows a maximum in the neighborhood of 25. The distribution referred to unit solid angle in each angle interval exhibits a sharp maximum at 0 in close agreement with the work of Kurie, but in contradiction to those who have believed the scattering to be of the classical type. Various factors, both geometrical and statistical, which may lead to distortion of the angular distribution are cited, and it is shown that their effect is taken into account in these experiments, but not necessarily in those of the other workers. The contradictions in the results reported at present in the literature are assumed to arise from these factors. The bearing of the distribution found in these experiments on the neutron-proton inter-action is considered in the light of the modern nuclear theories and evidence is deduced for an exchange or some other type of interaction at energies lower than predicted on the basis of these theories. The mechanism favored by both the classical and quantum theories, namely elastic collision of like spheres, is inadequate to explain the distribution. The present distribution is found to be consistent with Fermi's explanation for the efficiency of hydrogen nuclei in slowing fast neutrons, but indicates an even higher efficiency.

William D. Harkins; Martin D. Kamen; Henry W. Newson; David M. Gans

1936-12-01T23:59:59.000Z

367

Instruments | Neutron Science | ORNL  

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

NScD Careers NScD Careers Supporting Organizations Neutron Science Home | Science & Discovery | Neutron Science | Instruments SHARE Instruments at SNS and HFIR SNS Instrument Name HFIR Instrument Name 1B NOMAD - Nanoscale-Ordered Materials Diffractometer CG-1 Development Beam Line 2 BASIS - Backscattering Spectrometer CG-1D IMAGING - Neutron Imaging Prototype Facility 3 SNAP - Spallation Neutrons and Pressure Diffractometer CG-2 GP-SANS - General-Purpose Small-Angle Neutron Scattering Diffractometer 4A MR - Magnetism Reflectometer CG-3 Bio-SANS - Biological Small-Angle Neutron Scattering Instrument 4B LR - Liquids Reflectometer CG-4C CTAX - Cold Neutron Triple-Axis Spectrometer 5 CNCS - Cold Neutron Chopper Spectrometer HB-1 PTAX - Polarized Triple-Axis Spectrometer

368

Neutron dose equivalent meter  

DOE Patents [OSTI]

A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

Olsher, Richard H. (Los Alamos, NM); Hsu, Hsiao-Hua (Los Alamos, NM); Casson, William H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM); Kleck, Jeffrey H. (Menlo Park, CA); Beverding, Anthony (Foster City, CA)

1996-01-01T23:59:59.000Z

369

The Harwell Neutron Project  

Science Journals Connector (OSTI)

... 2 cm. thick, placed on three sides of the neutron booster. A layer of boron-10 metal placed between these tanks and the uranium-235 core prevents return of slow neutrons ...

M. J. POOLE; E. R. RAE

1960-01-30T23:59:59.000Z

370

Neutrons - 88-Inch Cyclotron  

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

Neutrons Neutron beams are available at the 88-Inch Cyclotron. Available energies range of from 8 to 30 MeV, with fluxes of up to 1E8 neutronscm2sec. For more information,...

371

Thermal Neutron Scattering  

Science Journals Connector (OSTI)

... of its title. It is not for the nuclear physicist, nor even for the neutron physicist, but for the student of solids and liquids. "Thermal ... physicist, but for the student of solids and liquids. "Thermal neutron ...

G. E. BACON

1968-11-09T23:59:59.000Z

372

Neutron activation analysis  

Science Journals Connector (OSTI)

Neutron activation analysis (NAA) is an that relies on the measurement of ?-rays emitted from a sample that was irradiated by neutrons. The rate at which ?-rays are emitted from an element in a sample is dir...

James R. Budahn

1998-01-01T23:59:59.000Z

373

Ultrafast neutron detector  

DOE Patents [OSTI]

A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

Wang, C.L.

1985-06-19T23:59:59.000Z

374

Cooling neutrons using non-dispersive magnetic excitations  

E-Print Network [OSTI]

A new method is proposed for cooling neutrons by inelastic magnetic scattering in weakly absorbing, cold paramagnetic systems. Kinetic neutron energy is removed in constant decrements determined by the Zeeman energy of paramagnetic atoms or ions in an external magnetic field, or by zero-field level splittings in magnetic molecules. Analytical solutions of the stationary neutron transport equation are given using inelastic neutron scattering cross sections derived in an appendix. They neglect any inelastic process except the paramagnetic scattering and hence still underestimate very-cold neutron densities. Molecular oxygen with its triplet ground state appears particularly promising, notably as a host in fully deuterated oxygen-clathrate hydrate, or more exotically, in dry oxygen-He4 van der Waals clusters. At a neutron temperature about 6 K, for which neutron conversion to ultra-cold neutrons by single-phonon emission in pure superfluid He4 works best, conversion rates due to paramagnetic scattering in the clathrate are found to be a factor 9 larger. While in conversion the neutron imparts only a single energy quantum to the medium, the multi-step paramagnetic cooling cascade leads to further strong enhancements of very-cold neutron densities, e.g., by a factor 14 (57) for an initial neutron temperature of 30 K (100 K), for the moderator held at about 1.3 K. Due to a favorable Bragg cutoff of the oxygen-clathrate the cascade-cooling can take effect in a moderator with linear extensions smaller than a meter. The paramagnetic cooling mechanism may offer benefits in novel intense sources of very cold neutrons and for enhancing production of ultra-cold neutrons.

Oliver Zimmer

2014-06-14T23:59:59.000Z

375

Production of heavy and superheavy neutron-rich nuclei in neutron capture processes  

Science Journals Connector (OSTI)

The neutron capture process is considered as an alternative method for production of superheavy (SH) nuclei. Strong neutron fluxes might be provided by nuclear reactors and nuclear explosions in the laboratory frame and by supernova explosions in nature. All these cases are discussed in the paper. There are two gaps of short-lived nuclei (one is the well-known fermium gap and the other one is located in the region of Z=106108 and N?170) which impede the formation of SH nuclei by rather weak neutron fluxes realized at available nuclear reactors. We find that in the course of multiple (rather 搒oft) nuclear explosions these gaps may be easily bypassed, and thus, a measurable amount of the neutron-rich long-living SH nuclei located at the island of stability may be synthesized. Existing pulsed reactors do not allow one to bypass these gaps. We formulate requirements for the pulsed reactors of the next generation that could be used for production of long-living SH nuclei. Natural formation of SH nuclei (in supernova explosions) is also discussed. The yield of SH nuclei relative to lead is estimated to be about 10?12, which is not beyond the experimental sensitivity for a search of SH elements in cosmic rays.

V. I. Zagrebaev; A. V. Karpov; I. N. Mishustin; Walter Greiner

2011-10-24T23:59:59.000Z

376

Neutron computed tomography  

E-Print Network [OSTI]

to make the Donner Algorithms run. TABLE OF CONTEliiTS CHAPTF. . R I NEI. TRON RADIOGRAPHY . I. 1 Background . I. 2 Theory . l. 3 Neutron Beam Characterization I. 4 Image Detectors . COMPI'TED TOMOGRAPHY . Il I Background . II. 2 Notation II. 3... data which is generated by rays traveling (and being attenuated) in straight lines. However in neutron radiography, what is measured is, to most extents, the levels of neutrons which are not attenuated. Neutrons are particles. They scatter...

Russell, Clifford Marlow

2012-06-07T23:59:59.000Z

377

Neutron scattering and ribosomes  

Science Journals Connector (OSTI)

... the complexity of intra-ribosomal interactions. This is however by no means the case with neutron ...neutronscattering ...

Richard Brimacombe

1977-06-23T23:59:59.000Z

378

The neutron-gamma Feynman variance to mean approach: gamma detection and total neutron-gamma detection (theory and practice)  

E-Print Network [OSTI]

Two versions of the neutron-gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron-gamma detection, respectively, are derived and compared in this paper. The new formulas have a particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron-gamma detection Feynman-Y expression corresponds to a situation where no discrimination is made between neutrons and gamma particles. The gamma variance to mean formulas are useful when a detector of only gamma radiation is used or when working with a combined neutron-gamma detector at high count rates. The theoretical derivation is based on the Chapman-Kolmogorov equation with inclusion of general reactions and passage intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a 252Cf-source enclosed in a steel container. In addition, the variance to mean ratios, neutron, gamma and total neutron-gamma, are evaluated experimentally for a weak 252Cf neutron-gamma source in a steel container, a 137Cs random gamma source and a 22Na correlated gamma source. Due to the focus being on the possibility of using neutron-gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-Y formulas.

Dina Chernikova; K錼e Axell; Senada Avdic; Imre P醶sit; Anders Nordlund

2015-01-23T23:59:59.000Z

379

More about neutron - mirror neutron oscillation  

E-Print Network [OSTI]

It was pointed out recently that oscillation of the neutron $n$ into mirror neutron $n'$, a sterile twin of the neutron with exactly the same mass, could be a very fast process with the the baryon number violation, even faster than the neutron decay itself. This process is sensitive to the magnetic fields and it could be observed by comparing the neutron lose rates in the UCN storage chambers for different magnetic backgrounds. We calculate the probability of $n-n'$ oscillation in the case when a mirror magnetic field $\\vec{B}'$ is non-zero and show that in this case it can be suppressed or resonantly enhanced by applying the ordinary magnetic field $\\vec{B}$, depending on its strength and on its orientation with respect to $\\vec{B}'$. The recent experimental data, under this hypothesis, still allow the $n-n'$ oscillation time order 1 s or even smaller. Moreover, they indicate that the neutron losses are sensitive to the orientation of the magnetic field. %at about $3\\sigma$ level. If these hints will be confirmed in the future experiments, this would point to the presence of the mirror magnetic field on the Earth of the order of 0.1 G, or some equivalent spin-dependent force of the other origin that makes a difference between the neutron and mirror neutron states.

Zurab Berezhiani

2008-04-13T23:59:59.000Z

380

Neutron removal cross section as a measure of neutron skin  

Science Journals Connector (OSTI)

We study the relation between neutron removal cross section (?-N) and neutron skin thickness for finite neutron-rich nuclei using the statistical abrasion ablation model. Different sizes of neutron skin are obtained by adjusting the diffuseness parameter of neutrons in the Fermi distribution. It is demonstrated that there is a good linear correlation between ?-N and the neutron skin thickness for neutron-rich nuclei. Further analysis suggests that the relative increase of neutron removal cross section could be used as a quantitative measure for neutron skin thickness in neutron-rich nuclei.

D. Q. Fang (???); Y. G. Ma (???); X. Z. Cai (???); W. D. Tian (???); H. W. Wang (???)

2010-04-07T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

The neutron warhead decision  

Science Journals Connector (OSTI)

The neutron warhead decision ... Nuclear war moved a step closer last week with the U.S.'s decision to move ahead with production of so-called neutron warheads for use on short-range missiles and in artillery shells. ... And neutron weapons would be almost as effective on ... ...

MICHAEL HEYLIN

1981-08-17T23:59:59.000Z

382

A Single Pulse Sub-Nanosecond Proton RFQ  

SciTech Connect (OSTI)

A Radio Frequency Quadrupole (RFQ) linac system has been developed to provide a single pulse of 2 MeV protons with a beam pulse width of {approx}300 ps and a charge of 30 pC, either for injection into a pulsed Dielectric Wall Accelerator or for bombardment of a target to produce a fast neutron pulse. The 1.2 m long RFQ structure operates at 425 MHz and bunches and accelerates a single 2.35 ns beam pulse injected into it at 35 keV using a parallel plate deflector placed directly in front of the RFQ entrance. The input acceptance properties of the RFQ allow a simple dc bias voltage on the plates to block acceleration of the unwanted beam, with a short rf voltage pulse applied to null the deflection field for the ions within the 8 mm 'kicker' plate length. The use of the RFQ as the accelerating structure allows one to efficiently produce a large charge in a single sub-ns bunch. In addition, the kicker can also be used without the dc bias voltage to produce a 'notch' in the normal RFQ output beam for synchrotron injection.

Hamm, R W; Pearce-Percy, H; Pearson, D; Rougieri, M; Weir, J; Zografos, A; Guethlein, G; Hawkins, S; Falabella, S; Poole, B; Blackfield, D

2011-03-29T23:59:59.000Z

383

Solar Neutron Events of October-November 2003  

E-Print Network [OSTI]

During the period when the Sun was intensely active on October-November 2003, two remarkable solar neutron events were observed by the ground-based neutron monitors. On October 28, 2003, in association with an X17.2 large flare, solar neutrons were detected with high statistical significance (6.4 sigma) by the neutron monitor at Tsumeb, Namibia. On November 4, 2003, in association with an X28 class flare, relativistic solar neutrons were observed by the neutron monitors at Haleakala in Hawaii and Mexico City, and by the solar neutron telescope at Mauna Kea in Hawaii simultaneously. Clear excesses were observed at the same time by these detectors, with the significance calculated as 7.5 sigma for Haleakala, and 5.2 sigma for Mexico City. The detector onboard the INTEGRAL satellite observed a high flux of hard X-rays and gamma-rays at the same time in these events. By using the time profiles of the gamma-ray lines, we can explain the time profile of the neutron monitor. It appears that neutrons were produced at the same time as the gamma-ray emission.

K. Watanabe; M. Gros; P. H. Stoker; K. Kudela; C. Lopate; J. F. Valdes-Galicia; A. Hurtado; O. Musalem; R. Ogasawara; Y. Mizumoto; M. Nakagiri; A. Miyashita; Y. Matsubara; T. Sako; Y. Muraki; T. Sakai; S. Shibata

2005-09-19T23:59:59.000Z

384

Laser pulse sampler  

DOE Patents [OSTI]

The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera. 5 figs.

Vann, C.

1998-03-24T23:59:59.000Z

385

Laser pulse sampler  

DOE Patents [OSTI]

The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera.

Vann, Charles (Fremont, CA)

1998-01-01T23:59:59.000Z

386

Pulse power linac  

DOE Patents [OSTI]

A linear acceleration for charged particles is constructed of a plurality of transmission line sections that extend between a power injection region and an accelerating region. Each line section is constructed of spaced plate-like conductors and is coupled to an accelerating gap located at the accelerating region. Each gap is formed between a pair of apertured electrodes, with all of the electrode apertures being aligned along a particle accelerating path. The accelerating gaps are arranged in series, and at the injection region the line sections are connected in parallel. At the injection region a power pulse is applied simultaneously to all line sections. The line sections are graduated in length so that the pulse reaches the gaps in a coordinated sequence whereby pulse energy is applied to particles as they reach each of the gaps along the accelerating path.

Villa, Francesco (Alameda, CA)

1990-01-01T23:59:59.000Z

387

Calibration of the neutron detectors for the cluster fusion experiment on the Texas Petawatt Laser  

SciTech Connect (OSTI)

Three types of neutron detectors (plastic scintillation detectors, indium activation detectors, and CR-39 track detectors) were calibrated for the measurement of 2.45 MeV DD fusion neutron yields from the deuterium cluster fusion experiment on the Texas Petawatt Laser. A Cf-252 neutron source and 2.45 MeV fusion neutrons generated from laser-cluster interaction were used as neutron sources. The scintillation detectors were calibrated such that they can detect up to 10{sup 8} DD fusion neutrons per shot in current mode under high electromagnetic pulse environments. Indium activation detectors successfully measured neutron yields as low as 10{sup 4} per shot and up to 10{sup 11} neutrons. The use of a Cf-252 neutron source allowed cross calibration of CR-39 and indium activation detectors at high neutron yields ({approx}10{sup 11}). The CR-39 detectors provided consistent measurements of the total neutron yield of Cf-252 when a modified detection efficiency of 4.6 Multiplication-Sign 10{sup -4} was used. The combined use of all three detectors allowed for a detection range of 10{sup 4} to 10{sup 11} neutrons per shot.

Bang, W.; Quevedo, H. J.; Dyer, G.; Rougk, J.; Kim, I.; McCormick, M.; Bernstein, A. C.; Ditmire, T. [Center for High Energy Density Science, Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States)

2012-06-15T23:59:59.000Z

388

Neutron Generators Developed at LBNL for Homeland Security andImaging Applications  

SciTech Connect (OSTI)

The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0-9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration with a sub-surface material characterization on Mars. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Four main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-compact axial neutron generator for elemental analysis applications. Current status of the neutron generator development with experimental data will be presented.

Reijonen, Jani

2006-08-13T23:59:59.000Z

389

Fission signal detection using helium-4 gas fast neutron scintillation detectors  

SciTech Connect (OSTI)

We demonstrate the unambiguous detection of the fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium fusion neutron generator and a high pressure {sup 4}He gas fast neutron scintillation detector. The energy deposition by individual neutrons is quantified, and energy discrimination is used to differentiate the induced fission neutrons from the mono-energetic interrogation neutrons. The detector can discriminate between different incident neutron energies using pulse height discrimination of the slow scintillation component of the elastic scattering interaction between a neutron and the {sup 4}He atom. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. The detector is shown here to detect a unique fission neutron signal from a natural uranium sample during active interrogation with a (d, d) neutron generator. This signal path has a direct application to the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection while greatly minimizing the potential for false alarms.

Lewis, J. M., E-mail: lewisj@ufl.edu; Kelley, R. P.; Jordan, K. A. [Nuclear Engineering Program, University of Florida, Gainesville, Florida 32611 (United States); Murer, D. [Arktis Radiation Detectors Ltd., 8045 Zurich (Switzerland)

2014-07-07T23:59:59.000Z

390

Sandia National Laboratories: Z Pulsed Power Facility: About Z  

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

About Z About Z Picture of Z Machine Sandia's Z machine is Earth's most powerful pulsed-power facility and X-ray generator. Z compresses energy in time and space to achieve extreme powers and intensities, found nowhere else on Earth. In approximately 200 shots Z fires every year, the machine uses currents of about 26 million amps to reach peak X-ray emissions of 350 terawatts and an X-ray output of 2.7 megajoules. The Z machine is located in Albuquerque, N.M., and is part of Sandia's Pulsed Power Program, which began in the 1960s. Pulsed power is a technology that concentrates electrical energy and turns it into short pulses of enormous power, which are then used to generate X-rays and gamma rays. Produced in the laboratory, this controlled radiation creates conditions similar to those caused by the detonation of nuclear weapons,

391

Versatile module for experiments with focussing neutron guides  

E-Print Network [OSTI]

We report the development of a versatile module that permits fast and reliable use of focussing neutron guides under varying scattering angles. A simple procedure for setting up the module and neutron guides is illustrated by typical intensity patterns to highlight operational aspects as well as typical parasitic artefacts. Combining a high-precision alignment table with separate housings for the neutron guides on kinematic mounts, the change-over between neutron guides with different focussing characteristics requires no readjustments of the experimental set-up. Exploiting substantial gain factors, we demonstrate the performance of this versatile neutron scattering module in a study of the effects of uniaxial stress on the domain populations in the transverse spin density wave phase of single crystal Cr.

Adams, T; Chacon, A; Wagner, J N; Rahn, M; M黨lbauer, S; Georgii, R; Pfleiderer, C; B鰊i, P

2014-01-01T23:59:59.000Z

392

High energy neutron dosimeter  

DOE Patents [OSTI]

A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures.

Rai, K.S.F.

1994-01-11T23:59:59.000Z

393

Principles of neutron reflection  

SciTech Connect (OSTI)

Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs.

Felcher, G.P.

1988-08-01T23:59:59.000Z

394

On neutron numbers and atomic masses  

Science Journals Connector (OSTI)

On neutron numbers and atomic masses ... Assigning neutron numbers, correct neutron numbers, and atomic masses and nucleon numbers. ...

R. Heyrovsk

1992-01-01T23:59:59.000Z

395

The Spallation Neutron Source A Powerful Tool for Materials Research  

E-Print Network [OSTI]

The wavelengths and energies of thermal and cold neutrons are ideally matched to the length and energy scales in the materials that underpin technologies of the present and future: ranging from semiconductors to magnetic devices, composites to biomaterials and polymers. The Spallation Neutron Source (SNS) will use an accelerator to produce the most intense beams of neutrons in the world when it is complete at the end of 2005. The project is being built by a collaboration of six U.S. Department of Energy laboratories. It will serve a diverse community of users drawn from academia, industry, and government labs with interests in condensed matter physics, chemistry, engineering materials, biology, and beyond.

Mason, Thomas E; Crawford, R K; Herwig, K W; Klose, F; Ankner, J F

2000-01-01T23:59:59.000Z

396

Probing the Universal Critical-Adsorption Profile by Neutron Reflectometry  

Science Journals Connector (OSTI)

We present the results of a neutron-reflectivity study of the universal critical-adsorption profile near the liquid-vapor interface of a binary-liquid mixture (methanol + deuterated cyclohexane) near criticality. As the critical temperature is approached from the one-phase region, we observed an abrupt decrease in the intensity of the specularly reflected neutron beam near the total-reflection edge. By interpreting the observation as the expected neutron-reflectivity discontinuity associated with a slowly decaying power-law profile, we evaluated the power-law exponent ( ?/?=0.500.05).

Hong Zhao; Anne Penninckx-Sans; Lay-Theng Lee; Daniel Beysens; G閞ard Jannink

1995-09-04T23:59:59.000Z

397

New upper bound on the scattering cross section of slow neutrons on liquid parahydrogen from neutron transmission  

E-Print Network [OSTI]

The scattering of slow neutron beams provides unique, non-destructive, quantitative information on the structure and dynamics of materials of interest in physics, chemistry, materials science, biology, geology, and other fields. Liquid hydrogen is a widely-used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. In particular the rapid drop of the slow neutron scattering cross section of liquid parahydrogen below 15 meV, which renders the moderator volume transparent to the neutron energies of most interest for scattering studies, is therefore especially interesting and important. We have placed an upper bound on the total cross section and the scattering cross section for slow neutrons with energies between 0.43 meV and 16.1 meV on liquid hydrogen at 15.6 K using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge Nati...

Grammer, K B; Barr髇-Palos, L; Blyth, D; Bowman, J D; Calarco, J; Crawford, C; Craycraft, K; Evans, D; Fomin, N; Fry, J; Gericke, M; Gillis, R C; Greene, G L; Hamblen, J; Hayes, C; Kucuker, S; Mahurin, R; Maldonado-Vel醶quez, M; Martin, E; McCrea, M; Mueller, P E; Musgrave, M; Nann, H; Penttil, S I; Snow, W M; Tang, Z; Wilburn, W S

2014-01-01T23:59:59.000Z

398

SNMR pulse sequence phase cycling  

DOE Patents [OSTI]

Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and indesired signals are canceled.

Walsh, David O; Grunewald, Elliot D

2013-11-12T23:59:59.000Z

399

Production of Fast Neutron With Plasma Focus Device  

E-Print Network [OSTI]

Before its demise DIANA Hi-TECH, LLC, demonstrated the use of two 50 kJoule Plasma Focus devices for the copius production of fast neutrons, x-rays and radio-isotopes. Such a device is suitable for fast neutron non invasive interogation of contra-band materials including hidden nuclear materials. It could be particularly useful for a fast and fail safe interogation of large cargo containers, or in merchant marine port of entries. The performance and fast neutron production (2.5 or 14 MeV at 10^11 or 10^13 neutrons per pulse, respectively) of the two PF50 Plasma Focus devices produced by DIANA HiTECH, LLC, are discussed.

Moshe Gai

2006-05-05T23:59:59.000Z

400

Production of Fast Neutron With Plasma Focus Device  

E-Print Network [OSTI]

Before its demise DIANA Hi-TECH, LLC, demonstrated the use of two 50 kJoule Plasma Focus devices for the copius production of fast neutrons, x-rays and radio-isotopes. Such a device is suitable for fast neutron non invasive interogation of contra-band materials including hidden nuclear materials. It could be particularly useful for a fast and fail safe interogation of large cargo containers, or in merchant marine port of entries. The performance and fast neutron production (2.5 or 14 MeV at 10^11 or 10^13 neutrons per pulse, respectively) of the two PF50 Plasma Focus devices produced by DIANA HiTECH, LLC, are discussed.

Gai, M

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

The Neutron Lifetime  

E-Print Network [OSTI]

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

Wietfeldt, F E

2014-01-01T23:59:59.000Z

402

The Neutron Lifetime  

E-Print Network [OSTI]

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

F. E. Wietfeldt

2014-11-13T23:59:59.000Z

403

A microsecond-pulsewidth, intense, light-ion beam accelerator  

SciTech Connect (OSTI)

A relatively long-pulsewidth (0.1-1 {mu}s) intense ion beam accelerator has been built for materials processing applications. An applied-B{sub r}, magnetically-insulated extraction ion diode with dielectric flashover ion source is installed directly onto the output of a 1.2-MV, 300-kJ Marx generator. Initial operation of the accelerator at 0.4 MV indicates satisfactory performance without the need for additional pulse-shaping.

Rej, D.J.; Bartsch, R.R.; Davis, H.A.; Greenly, J.B.; Waganaar, W.J.

1993-07-01T23:59:59.000Z

404

Microsoft Word - ~6521732.doc  

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

during Workshop ... 166 Appendix C: Differential Nuclear Data Measurements at the ANL Intense Pulsed Neutron Source... 171 Appendix D:...

405

CVD Diamond Detectors for Current Mode Neutron Time-of-Flight Spectroscopy at OMEGA/NIF  

SciTech Connect (OSTI)

We have performed pulsed neutron and pulsed laser tests of a CVD diamond detector manufactured from DIAFILM, a commercial grade of CVD diamond. The laser tests were performed at the short pulse UV laser at Bechtel Nevada in Livermore, CA. The pulsed neutrons were provided by DT capsule implosions at the OMEGA laser fusion facility in Rochester, NY. From these tests, we have determined the impulse response to be 250 ps fwhm for an applied E-field of 500 V/mm. Additionally, we have determined the sensitivity to be 2.4 mA/W at 500 V/mm and 4.0 mA/W at 1000 V/mm. These values are approximately 2 to 5x times higher than those reported for natural Type IIa diamond at similar E-field and thickness (1mm). These characteristics allow us to conceive of a neutron time-of-flight current mode spectrometer based on CVD diamond. Such an instrument would sit inside the laser fusion target chamber close to target chamber center (TCC), and would record neutron spectra fast enough such that backscattered neutrons and x-rays from the target chamber wall would not be a concern. The acquired neutron spectra could then be used to extract DD fuel areal density from the downscattered secondary to secondary ratio.

G. J. Schmid; V. Yu. Glebov; A. V. Friensehner; D. R. Hargrove; S. P. Hatchett; N. Izumi; R. A. Lerche; T. W. Phillips; T. C. Sangster; C. Silbernagel; C. Stoecki

2001-07-01T23:59:59.000Z

406

Study on the method with associated particle for measuring the neutron yield of D朌 neutron generator  

Science Journals Connector (OSTI)

Abstract A measuring method with associated particles has been developed and tested to monitor the D朌 neutron yield at a ZF-300 intense neutron generator in Lanzhou University. The experiment has been carried out in an environment of 236爇eV and 0.5爉A of deuteron beam with a thick titanium-filmed target of molybdenum substrate at 135 for proton emission. All correction factors, including anisotropy factors and the yield ratio of neutron and proton, have been calculated, and the uncertainty of calculation result has been discussed.

Yan Yan; Xiaolong Lu; Zheng Wei; Siqi Yan; Changlin Lan; Junrun Wang; Jie Wang; Zeen Yao

2015-01-01T23:59:59.000Z

407

The electron-spin-nuclear-spin interaction studied by polarized neutron scattering  

Science Journals Connector (OSTI)

The directional properties of electron-proton spin interaction in an external magnetic field give rise to an anisotropic distribution of the intensity of polarized neutron scattering from dynamically polarized protons of radical molecules in solution.

Stuhrmann, H.B.

2007-11-01T23:59:59.000Z

408

Parallel Computational Modelling of Inelastic Neutron Scattering in Multi-node and Multi-core Architectures  

E-Print Network [OSTI]

This paper examines the initial parallel implementation of SCATTER, a computationally intensive inelastic neutron scattering routine with polycrystalline averaging capability, for the General Utility Lattice Program (GULP). Of particular importance...

Garba, M.T.; Gonzales-Velez, H.; Roach, D.L.

2010-11-26T23:59:59.000Z

409

High intensity femtosecond enhancement cavities  

E-Print Network [OSTI]

To produce extreme ultraviolet radiation via high harmonic generation (HHG) in rare gases, light intensities in excess of 1014 W/cm 2 are required. Usually such high intensity are obtained by parametric amplification of ...

Abram, Gilberto

2009-01-01T23:59:59.000Z

410

Imaging and Neutrons - IAN 2006 - Neutron Sciences  

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

SNS Home Saturday, January 11, 2014 SNS Home Saturday, January 11, 2014 Go IAN 2006 Imaging and Neutrons 2006 October 23-25, 2006 Iran Thomas Auditorium Central Laboratory and Office Building Spallation Neutron Source Oak Ridge National Laboratory, Oak Ridge, TN Who Should Attend Synopsis Goals and Expected Outcomes Application Areas Techniques International Advisory Committee Local Organizing Committee Agenda with Presentations NEW Confirmed Speakers Frequently Asked Questions - FAQ Satellite Workshop - Progress in Electron Volt Neutron Spectroscopy eV Worshop Agenda presentations NEW Lodging, Transportation, Bus Schedule Location Directions and Map Registration CLOSED Abstracts, Posters, Contributed Talks Scholarships Sponsors Vendors May Attend Relevant Reports Important Dates Weather Attractions

411

Downhole pulse tube refrigerators  

SciTech Connect (OSTI)

This report summarizes a preliminary design study to explore the plausibility of using pulse tube refrigeration to cool instruments in a hot down-hole environment. The original motivation was to maintain Dave Reagor`s high-temperature superconducting electronics at 75 K, but the study has evolved to include three target design criteria: cooling at 30 C in a 300 C environment, cooling at 75 K in a 50 C environment, cooling at both 75 K and 30 C in a 250 C environment. These specific temperatures were chosen arbitrarily, as representative of what is possible. The primary goals are low cost, reliability, and small package diameter. Pulse-tube refrigeration is a rapidly growing sub-field of cryogenic refrigeration. The pulse tube refrigerator has recently become the simplest, cheapest, most rugged and reliable low-power cryocooler. The authors expect this technology will be applicable downhole because of the ratio of hot to cold temperatures (in absolute units, such as Kelvin) of interest in deep drilling is comparable to the ratios routinely achieved with cryogenic pulse-tube refrigerators.

Swift, G.; Gardner, D. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group

1997-12-01T23:59:59.000Z

412

The Neutron Energy Spectrum Study from the Phase II Solid Methane Moderator at the LENS Neutron Source  

E-Print Network [OSTI]

Neutron energy spectrum measurements from a solid methane moderator were performed at the Low Energy Neutron Source (LENS) at Indiana University Cyclotron Facility (IUCF) to verify our neutron scattering model of solid methane. The time-of-flight method was used to measure the energy spectrum of the moderator in the energy range of 0.1$meV\\sim$ 1$eV$. Neutrons were counted with a high efficiency $^{3}{He}$ detector. The solid methane moderator was operated in phase II temperature and the energy spectra were measured at the temperatures of 20K and 4K. We have also tested our newly-developed scattering kernels for phase II solid methane by calculating the neutron spectral intensity expected from the methane moderator at the LENS neutron source using MCNP (Monte Carlo N-particle Transport Code). Within the expected accuracy of our approximate approach, our model predicts both the neutron spectral intensity and the optimal thickness of the moderator at both temperatures. The predictions are compared to the measured energy spectra. The simulations agree with the measurement data at both temperatures.

Yunchang Shin; W. Mike Snow; Christopher M. Lavelle; David V. Baxter; Xin Tong; Haiyang Yan; Mark Leuschner

2007-11-19T23:59:59.000Z

413

Solvent Entrainment in and Flocculation of Asphaltenic Aggregates Probed by Small-Angle Neutron Scattering  

E-Print Network [OSTI]

-Angle Neutron Scattering Keith L. Gawrys, George A. Blankenship, and Peter K. Kilpatrick* Department of ChemicalVed September 14, 2005. In Final Form: January 30, 2006 While small-angle neutron scattering (SANS) has proven to the scattering intensity curves were performed using the Guinier approximation, the Ornstein- Zernike (or Zimm

Kilpatrick, Peter K.

414

Characterisation of a neutron beam available at the RPI using a set of bonner spheres  

Science Journals Connector (OSTI)

......knowledge of the energy and intensity characteristics...polyethylene spheres. The energy range of neutron...Reactor) is a 1 MW swimming pool type reactor of standard...function of the neutron energy. Each Bonner sphere...counter, and so the efficiency is small. Figure......

A. Carrillo de Albornoz; L. Marques; I. F. Gon鏰lves; P. Vaz

2005-12-20T23:59:59.000Z

415

Multi-Pulse SCR Rectifiers.  

E-Print Network [OSTI]

??This thesis presents the introduction, analysis and experimental verification of the six-pulse SCR rectifier and multi-pulse SCR rectifiers. As a fundamental three-phase controllable ac-dc converter, (more)

Li, Mei

2005-01-01T23:59:59.000Z

416

Sequentially pulsed traveling wave accelerator  

DOE Patents [OSTI]

A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

Caporaso, George J. (Livermore, CA); Nelson, Scott D. (Patterson, CA); Poole, Brian R. (Tracy, CA)

2009-08-18T23:59:59.000Z

417

Photo-Neutron Sources and the Energy of the Photo-Neutrons  

Science Journals Connector (OSTI)

In a preliminary study photo-neutrons were observed to be produced by the ?-rays from Na24, Mn56, Ga72, As76, and La140 when these artificially radioactive isotopes were placed in D2O or Be; F20, Al28, Cl38, In116, and Sb124 produced neutrons only in Be. The first group of isotopes must have ?-rays with energy higher than 2.18 Mev, and the second group must have ?-rays greater than 1.63 Mev but less than 2.18 Mev. No photo-neutrons were observed from Co60, Cu64, Ag (225 day -life), Pr142, Eu151, Dy165, Ta182, Re188, Ir (19 hours -life), and Au198 in Be; the intense ?-rays from these isotopes must have energies less than 1.63 Mev. In a second experiment the energy of the photo-neutrons from nine of these sources was determined by measuring the hydrogen scattering cross section of the emitted neutrons. Seven, of the sources seem to emit homogeneous groups of neutrons; they are: Sb+Be, Ga+D2O, La+D2O, Mn+D2O, Na+D2O, La+Be, and Na+Be with neutron energies 0.024, 0.13, 0.13, 0.22, 0.22, 0.62, and 0.83 Mev, respectively, for the particular sized sources studied. Mn+Be emits three groups of neutrons of different energies, but more than 80 percent of the neutrons seem to be in a group at 0.14 Mev. The energy of the ?-rays calculated to produce neutrons of these energies are: for Na24, 2.74 Mev; for Mn56, 1.81 and 2.7 Mev (a third ?-ray is present); for Ga72, 2.50 Mev (at least one other ?-ray is present with an energy between 2.2 and 1.63 Mev); for Sb124, 1.67 Mev; and for La140, 2.49 Mev. The total neutron cross section of carbon is also given for seven of these photo-neutron sources.

A. Wattenberg

1947-04-15T23:59:59.000Z

418

Scattering of 64 eV to 3 keV Neutrons from Polyethylene and Graphite and the Coherence Length Problem  

E-Print Network [OSTI]

Scattering of 64 eV to 3 keV Neutrons from Polyethylene and Graphite and the Coherence Length 12180, USA (Received 31 August 2005; published 8 February 2006) We measured the neutron scattering by the neutron coherence length. The scattered intensity ratios were found to conform to conventional

Danon, Yaron

419

High intensity specular reflectometry - first experiments  

E-Print Network [OSTI]

Selene is the attempt to implement a new scheme for high-intensity specular reflectometry. Instead of a highly collimated beam one uses a convergent beam covering a large angular range. The angular resolution is then performed by a position-sensitive detector. Off-specular scattering in this set-up leads to some background, but for screening of wide parameter ranges (e.g. temperature, electric and magnetic fields) the intensity gain of at least one order of magnitude is essential. If necessary, the high precession measurements (even with off-specular components) then are performed with the conventional set-up. The heart of this new set-up is an elliptically focusing guide element of 2\\,m length. Though this guide is optimised for the use on the TOF reflectometer Amor at SINQ, it can be used as stand-alone device to check the possible application also for other neutron scattering techniques. The first measurements on AMOR confirmed the general concept and the various operation modes. A draw-back occurred due t...

Stahn, J; Panzner, T

2011-01-01T23:59:59.000Z

420

Cold neutron research facility at the Budapest Neutron Centre  

Science Journals Connector (OSTI)

The new cold neutron research facility has been routinely operated at the Budapest Neutron Centre (BNC) since February 2001. This ... of equipment consists of a liquid hydrogen cold neutron source, an optimised s...

L. Rosta

2002-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Measurement of Thermal Neutron Flux in Photo-Neutron Source  

Science Journals Connector (OSTI)

The Photo-Neutron Source (PNS) project is a study ... design, simulation and construction an accelerator based neutron source for Boron Neutron Capture Therapy (BNCT). The system uses ... medical linear accelerat...

A. Taheri; A. Torkamani; A. Pazirandeh

2013-01-01T23:59:59.000Z

422

Enhancing Neutron Beam Production with a Convoluted Moderator  

SciTech Connect (OSTI)

We describe a new concept for a neutron moderating assembly resulting in the more efficient production of slow neutron beams. The Convoluted Moderator, a heterogeneous stack of interleaved moderating material and nearly transparent single-crystal spacers, is a directionally-enhanced neutron beam source, improving beam effectiveness over an angular range comparable to the range accepted by neutron beam lines and guides. We have demonstrated gains of 50% in slow neutron intensity for a given fast neutron production rate while simultaneously reducing the wavelength-dependent emission time dispersion by 25%, both coming from a geometric effect in which the neutron beam lines view a large surface area of moderating material in a relatively small volume. Additionally, we have confirmed a Bragg-enhancement effect arising from coherent scattering within the single-crystal spacers. We have not observed hypothesized refractive effects leading to additional gains at long wavelength. In addition to confirmation of the validity of the Convoluted Moderator concept, our measurements provide a series of benchmark experiments suitable for developing simulation and analysis techniques for practical optimization and eventual implementation at slow neutron source facilities.

Iverson, Erik B [ORNL] [ORNL; Baxter, David V [Center for the Exploration of Energy and Matter, Indiana University] [Center for the Exploration of Energy and Matter, Indiana University; Muhrer, Guenter [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Ansell, Stuart [ISIS Facility, Rutherford Appleton Laboratory (ISIS)] [ISIS Facility, Rutherford Appleton Laboratory (ISIS); Gallmeier, Franz X [ORNL] [ORNL; Dalgliesh, Robert [ISIS Facility, Rutherford Appleton Laboratory (ISIS)] [ISIS Facility, Rutherford Appleton Laboratory (ISIS); Lu, Wei [ORNL] [ORNL; Kaiser, Helmut [Center for the Exploration of Energy and Matter, Indiana University] [Center for the Exploration of Energy and Matter, Indiana University

2014-01-01T23:59:59.000Z

423

Neutron sources and applications  

SciTech Connect (OSTI)

Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1994-01-01T23:59:59.000Z

424

Physics design of a cold neutron source for KIPT neutron source facility.  

SciTech Connect (OSTI)

Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of a neutron source facility. It is based on the use of an electron accelerator driven subcritical (ADS) facility with low enriched uranium fuel, using the existing electron accelerators at KIPT of Ukraine [1]. The neutron source of the subcritical assembly is generated from the interaction of 100-KW electron beam, which has a uniform spatial distribution and the electron energy in the range of 100 to 200 MeV, with a natural uranium target [2]. The main functions of the facility are the production of medical isotopes and the support of the Ukraine nuclear power industry. Neutron beam experiments and material studies are also included. Over the past two-three decades, structures with characteristic lengths of 100 {angstrom} and correspondingly smaller vibrational energies have become increasingly important for both science and technology [3]. The characteristic dimensions of the microstructures can be well matched by neutrons with longer vibrational wavelength and lower energy. In the accelerator-driven subcritical facility, most of the neutrons are generated from fission reactions with energy in the MeV range. They are slowed down to the meV energy range through scattering reactions in the moderator and reflector materials. However, the fraction of neutrons with energies less than 5 meV in a normal moderator spectrum is very low because of up-scattering caused by the thermal motion of moderator or reflector molecules. In order to obtain neutrons with energy less than 5 meV, cryogenically cooled moderators 'cold neutron sources' should be used to slow down the neutrons. These cold moderators shift the neutron energy spectrum down because the thermal motion of moderator molecules as well as the up-scattering is very small, which provides large gains in intensity of low energy neutrons, E < 5 meV. The accelerator driven subcritical facility is designed with a provision to add a cryogenically cooled moderator system. This cold neutron source could provide the neutrons beams with lower energy, which could be utilized in scattering experiment and material structures analysis. This study describes the performed physics analyses to define and characterize the cold neutron source of the KIPT neutron source facility. The cold neutron source is designed to optimize the cold neutron brightness to the experimental instruments outside the radial heavy concrete shield of the facility. Liquid hydrogen or solid methane with 20 K temperature is used as a cold moderator. Monte Carlo computer code MCNPX [4], with ENDF/B-VI nuclear data libraries, is utilized to calculate the cold neutron source performance and estimate the nuclear heat load to the cold moderator. The surface source generation capability of MCNPX code has been used to provide the possibility of analyzing different design configurations and perform design optimization analyses with reasonable computer resources. Several design configurations were analyzed and their performance were characterized and optimized.

Zhong, Z.; Gohar, Y.; Kellogg, R.; Nuclear Engineering Division

2009-02-17T23:59:59.000Z

425

Experimental determination of the neutron channeling length in a planar waveguide  

SciTech Connect (OSTI)

In neutron waveguides, the neutron wave is confined inside the guiding layer of the structure and can escape from the layer edge as a microbeam. The channeling within the guiding layer is accompanied by an exponential decay of the neutron wave function density inside the waveguide. Here, we report direct determination of the corresponding decay constant, termed the neutron channeling length. For this, we measured the microbeam intensity as a function of the length of a neutron absorbing layer of variable length placed onto the surface of a waveguide structure. Such planar neutron waveguides transform a conventional neutron beam into an extremely narrow but slightly divergent microbeam, which can be used for the investigation of nanostructures with submicron spatial resolution.

Kozhevnikov, S. V., E-mail: kozhevn@nf.jinr.ru; Ignatovich, V. K., E-mail: ignatovi@nf.jinr.ru [Joint Institute for Nuclear Research (Russian Federation); Ott, F. [CEA, Iramis, Laboratoire Leon Brillouin Gif sur Yvette (France)] [CEA, Iramis, Laboratoire Leon Brillouin Gif sur Yvette (France); Ruehm, A.; Major, J. [Max-Planck-Institut fuer Intelligente Systeme (formerly Max-Planck-Institut fuer Metallforschung) (Germany)] [Max-Planck-Institut fuer Intelligente Systeme (formerly Max-Planck-Institut fuer Metallforschung) (Germany)

2013-10-15T23:59:59.000Z

426

Neutron science research project in JAERI  

Science Journals Connector (OSTI)

A conception of Neutron Science Research Project (NSRP) has been proposed in Japan Atomic Energy Research Institute (JAERI) since 1994 for its future big science project. The project aims at exploring new basic science and nuclear energy science by using a high-intensity proton accelerator. NSRP is a complex composed of a powerful superconducting proton linac the target systems which convert the proton beam to neutrons or other particles and the facilities for scientific research programs. The proton linac is required to supply a high-intensity proton beam with an energy up to 1.5 GeV and an average current around 10 mA. The scientific research programs are as follows: In the area of basic science structural biology and material science with slow neutron scattering method neutron nuclear physics and spallation radioisotope physics and in the area of nuclear energy science the experimental feasibility studies of incineration for the nuclear waste transmutation and material developments with a neutron irradiation facility. Other scientific research programs are also proposed such as meson science for meson and muon physics radioisotope production for medical use. Research and development (R&D) have been carried out for the components of the injector system of the proton linac; an ion source an RFQ linac and a part of DTL linac. The conceptual design work and R&D activities for NSRP have started in the fiscal year 1996. The first beam of 1.5 GeV and 1 mA is expected to be extracted from the proton linac by 2004 and finally a 10 mA is to be obtained in 2007 by reflecting the results of technological developments.

Y. Suzuki; Y. Oyama; T. Sasa; K. Suzuki; H. Yasuda; T. Tone; T. Takizuka; M. Mizumoto; N. Watanabe; T. Mukaiyama

1997-01-01T23:59:59.000Z

427

Metal reflectivity under high?intensity optical radiation  

Science Journals Connector (OSTI)

Single high?intensity (106?109 W/cm2) pulses of 1.06?? radiation emitted from a Q?switched Nd : YAG laser have been used to study reflectivity behavior of single?crystal copper and tantalum samples. Metalreflectivity during irradiation undergoes a significant drop to values much lower than can be attributed to high?temperature effects. This reflectivity drop under high radiation intensity has two characteristic features. First if vaporization is avoided then during the rising portion of the laser pulse the reflectivity drops continuously until it reaches a constant low value. For copper this occurs at an intensity of 3108 W/cm2 and has a reflectivity value of ?0.64. The corresponding values for tantalum are I?2.5107 W/cm2 and R?0.41. For still higher intensities a further drop in reflectivity beyond the plateau region is observed. This drop in reflectivity is always accompanied by heavy melting and followed by some vaporization. As suggested by Prokhorov e t a l. this further drop in reflectivity could be associated with dielectriclike behavior of the molten zone.

T. E. Zavecz; M. A. Saifi; M. Notis

1975-01-01T23:59:59.000Z

428

NSE: the Neutron Spin Echo Spectrometer at SNS | ORNL Neutron Sciences  

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

Spin Echo Spectrometer at SNS Spin Echo Spectrometer at SNS NSE NSE is funded and operated by the J眉lich Centre for Neutron Science. The SNS NSE instrument provides ultrahigh resolution spectroscopy with a Fourier time range that covers 蟿 = 1 ps to a nominal 350 ns with a high effective neutron flux, aiming to be the best of its class in both resolution and dynamic range (please refer to the instrument fact sheet for a detailed current status). Researchers use this instrument to investigate soft condensed matter and complex fluids applications in a variety of fields. The planned optional ferromagnetic and intensity-modulated modes will allow for detailed investigation of magnetic samples and phenomena. The design of the NSE spectrometer takes full advantage of recent progress in neutron optics and polarizing supermirror microbenders,1,2 resulting in

429

Industry - ORNL Neutron Sciences  

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

Industry banner Industry banner Neutron scattering research has applications in practically every field, and neutron research at ORNL is leading to productive partnerships with the industrial and business communities. We welcome proposals for all types of research, including those involving proprietary work. Recent studies have led to discoveries with potential applications in fields such as medicine, energy, and various metals technologies. For more information, please see our recent research highlights. Research Collaborations Industry-Driven Research Benefits Plastics Manufacturing Corning uses VULCAN to test limits of ceramic material for car emission controls, filtration devices Neutrons Probe Inner Workings of Batteries Industry and Neutron Science: Working To Make a Match

430

Neutron wave packet tomography  

E-Print Network [OSTI]

A tomographic technique is introduced in order to determine the quantum state of the center of mass motion of neutrons. An experiment is proposed and numerically analyzed.

G. Badurek; P. Facchi; Y. Hasegawa; Z. Hradil; S. Pascazio; H. Rauch; J. Rehacek; T. Yoneda

2005-03-29T23:59:59.000Z

431

Neutron Science Forum | ORNL  

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

environment for discussion, innovation, and dissemination of information within the neutron scattering community as well as engaging closely related disciplines through...

432

Neutron Science | ORNL  

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

User Office User Program Manager Laura Morris Edwards 865.574.2966 ORNL study uses neutron scattering, supercomputing to demystify forces at play in biofuel production Full...

433

Polarizability of the Neutron  

Science Journals Connector (OSTI)

Experiments on scattering of low-energy neutrons by heavy elements may give information concerning the electric polarizability of the neutron. The relation of the electric polarizability to the low-energy neutron scattering data is developed. One pertinent experiment is discussed and from this an upper bound on the polarizability is obtained. This upper bound to the polarizability ? is an order of magnitude larger than the meson-theoretic estimate of ?. If the value of ? is as small as is predicted by meson theory, or by an analysis of the pion photoproduction data, then it is unlikely to be observed in neutron scattering experiments of the presently achievable accuracy.

R. M. Thaler

1959-05-01T23:59:59.000Z

434

Resonance Neutron Capture in Nb93  

Science Journals Connector (OSTI)

Spectra from radiative capture in S- and P-wave resonances in Nb93 have been compared. Differences in these spectra are interpreted to indicate the presence of sizable two-particle梠ne-hole components in the capturing states. S-wave intensities show no correlation with (d,p) intensities to the same final states, but P-wave intensities exhibit a significant correlation. Lack of a correlation with the initial-state reduced widths rules out an appreciable channel-capture effect in this experiment. The differences in S- and P-wave total radiation widths are discussed. Seven neutron-resonance spin assignments are made, based on the capture ?-ray spectra, and 11 new final states in Nb94 are observed and tabulated.

R. E. Chrien; K. Rimawi; J. B. Garg

1971-05-01T23:59:59.000Z

435

Neutron superfluidity and unusual nuclear shapes in neutron stars crusts  

Science Journals Connector (OSTI)

We calculate in the frame-work of a semiclassical model the neutron superfluidity in the crust of neutron stars, accounting for the presence of unusual....

G. Lazzari; F. V. De Blasio

1994-01-01T23:59:59.000Z

436

Neutron capture cross sections for neutron-rich isotopes  

Science Journals Connector (OSTI)

Average continuum (Hauser-Feshbach) and resonance (Breit-Wigner) neutron capture rates for neutron-rich isotopes, determined on the basis of...

B. Leist; W. Ziegert; M. Wiescher

1985-01-01T23:59:59.000Z

437

Petawatt pulsed-power accelerator  

DOE Patents [OSTI]

A petawatt pulsed-power accelerator can be driven by various types of electrical-pulse generators, including conventional Marx generators and linear-transformer drivers. The pulsed-power accelerator can be configured to drive an electrical load from one- or two-sides. Various types of loads can be driven; for example, the accelerator can be used to drive a high-current z-pinch load. When driven by slow-pulse generators (e.g., conventional Marx generators), the accelerator comprises an oil section comprising at least one pulse-generator level having a plurality of pulse generators; a water section comprising a pulse-forming circuit for each pulse generator and a level of monolithic triplate radial-transmission-line impedance transformers, that have variable impedance profiles, for each pulse-generator level; and a vacuum section comprising triplate magnetically insulated transmission lines that feed an electrical load. When driven by LTD generators or other fast-pulse generators, the need for the pulse-forming circuits in the water section can be eliminated.

Stygar, William A. (Albuquerque, NM); Cuneo, Michael E. (Albuquerque, NM); Headley, Daniel I. (Albuquerque, NM); Ives, Harry C. (Albuquerque, NM); Ives, legal representative; Berry Cottrell (Albuquerque, NM); Leeper, Ramon J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Olson, Craig L. (Albuquerque, NM); Porter, John L. (Sandia Park, NM); Wagoner; Tim C. (Albuquerque, NM)

2010-03-16T23:59:59.000Z

438

The intense slow positron beam facility at the PULSTAR reactor and applications in nano-materials study  

SciTech Connect (OSTI)

An intense slow positron beam has been established at the PULSTAR nuclear research reactor of North Carolina State University. The slow positrons are generated by pair production in a tungsten moderator from gammarays produced in the reactor core and by neutron capture reactions in cadmium. The moderated positrons are electrostatically extracted and magnetically guided out of the region near the core. Subsequently, the positrons are used in two spectrometers that are capable of performing positron annihilation lifetime spectroscopy (PALS) and positron Doppler broadening spectroscopy (DBS) to probe the defect and free volume properties of materials. One of the spectrometers (e{sup +}-PALS) utilizes an rf buncher to produce a pulsed beam and has a timing resolution of 277 ps. The second spectrometer (Ps-PALS) uses a secondary electron timing technique and is dedicated to positronium lifetime measurements with an approximately 1 ns timing resolution. PALS measurements have been conducted in the e{sup +}-PALS spectrometer on a series of nano-materials including organic photovoltaic thin films, membranes for filtration, and polymeric fibers. These studies have resulted in understanding some critical issues related to the development of the examined nano-materials.

Liu, Ming; Moxom, Jeremy; Hawari, Ayman I. [Nuclear Reactor Program, Department of Nuclear Engineering, North Carolina State University, P.O. Box 7909, Raleigh, NC 27695 (United States); Gidley, David W. [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor MI 48109 (United States)

2013-04-19T23:59:59.000Z

439

Neutron Diffraction Studies of Proteins  

Science Journals Connector (OSTI)

20 November 1980 research-article Neutron Diffraction Studies of Proteins G. A. Bentley S. A. Mason Neutrons interact differently with protein crystals...hydrogen or deuterium atoms diffract neutrons relatively more strongly, but in addition...

1980-01-01T23:59:59.000Z

440

Neutron and Nuclear Science News  

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

News Recent news and events related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science News Links Neutron and Nuclear Science News Media Links Profiles Events at...

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Neutron Scattering Methods in Chemistry  

Science Journals Connector (OSTI)

Starting with basic properties of the neutron, this chapter reviews the most important neutron scattering methods that provide valuable information for a ... wide, from standard methods of crystallography to neutron

L. Pusztai

2011-01-01T23:59:59.000Z

442

Measurements of fast neutrons by bubble detectors  

SciTech Connect (OSTI)

Neutron bubble detectors have been studied using Am-Be and D-D neuron sources, which give limited energy information. The Bubble Detector Spectrometer (BDS) have six different energy thresholds ranging from 10 KeV to 10 Mev. The number of bubbles obtained in each measurement is related to the dose (standardized response R) equivalent neutrons through sensitivity (b / {mu}Sv) and also with the neutron flux (neutrons per unit area) through a relationship that provided by the manufacturer. Bubble detectors were used with six different answers (0.11 b/ {mu}Sv, 0093 b/{mu}Sv, 0.14 b/{mu}Sv, 0.17 b/{mu}Sv, 0051 b/{mu}Sv). To test the response of the detectors (BDS) radiate a set of six of them with different energy threshold, with a source of Am-Be, placing them at a distance of one meter from it for a few minutes. Also, exposed to dense plasma focus Fuego Nuevo II (FN-II FPD) of ICN-UNAM, apparatus which produces fusion plasma, generating neutrons by nuclear reactions of neutrons whose energy emitting is 2.45 MeV. In this case the detectors were placed at a distance of 50 cm from the pinch at 90 Degree-Sign this was done for a certain number of shots. In both cases, the standard response is reported (Dose in {mu}Sv) for each of the six detectors representing an energy range, this response is given by the expression R{sub i}= B{sub i} / S{sub i} where B{sub i} is the number of bubbles formed in each and the detector sensitivity (S{sub i}) is given for each detector in (b / {mu}Sv). Also, reported for both cases, the detected neutron flux (n cm{sup -2}), by a given ratio and the response involves both standardized R, as the average cross section sigma. The results obtained have been compared with the spectrum of Am-Be source. From these measurements it can be concluded that with a combination of bubble detectors, with different responses is possible to measure the equivalent dose in a range of 10 to 100 {mu}Sv fields mixed neutron and gamma, and pulsed generated fusion devices.

Castillo, F.; Martinez, H. [Laboratorio de Espectroscopia, Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62251, Cuernavaca Morelos (Mexico); Leal, B. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510, Ciudad Universitaria, Mexico D. F. (Mexico); Rangel, J. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510, Ciudad Universitaria, Mexico D. F (Mexico); Reyes, P. G. [Facultad de Ciencias, Universidad Autonoma del Estado de Mexico, Instituto Literario 100, Col. Centro, 50000, Toluca Estado de Mexico (Mexico)

2013-07-03T23:59:59.000Z

443

Intense Muon Beams for Experiments at Project X  

SciTech Connect (OSTI)

A coherent approach for providing muon beams to several experiments for the intensity-frontier program at Project X is described. Concepts developed for the front end of a muon collider/neutrino factory facility, such as phase rotation and ionization cooling, are applied, but with significant differences. High-intensity experiments typically require high-duty-factor beams pulsed at a time interval commensurate with the muon lifetime. It is challenging to provide large RF voltages at high duty factor, especially in the presence of intense radiation and strong magnetic fields, which may preclude the use of superconducting RF cavities. As an alternative, cavities made of materials such as ultra-pure Al and Be, which become very good 朾ut not super conductors at cryogenic temperatures, can be used.

C.M. Ankenbrandt, R.P. Johnson, C. Y. Yoshikawa, V.S. Kashikhin, D.V. Neuffer, J. Miller, R.A. Rimmer

2011-03-01T23:59:59.000Z

444

High-speed pulse-shape generator, pulse multiplexer  

DOE Patents [OSTI]

The invention combines arbitrary amplitude high-speed pulses for precision pulse shaping for the National Ignition Facility (NIF). The circuitry combines arbitrary height pulses which are generated by replicating scaled versions of a trigger pulse and summing them delayed in time on a pulse line. The combined electrical pulses are connected to an electro-optic modulator which modulates a laser beam. The circuit can also be adapted to combine multiple channels of high speed data into a single train of electrical pulses which generates the optical pulses for very high speed optical communication. The invention has application in laser pulse shaping for inertial confinement fusion, in optical data links for computers, telecommunications, and in laser pulse shaping for atomic excitation studies. The invention can be used to effect at least a 10.times. increase in all fiber communication lines. It allows a greatly increased data transfer rate between high-performance computers. The invention is inexpensive enough to bring high-speed video and data services to homes through a super modem.

Burkhart, Scott C. (Livermore, CA)

2002-01-01T23:59:59.000Z

445

energy intensity | OpenEI  

Open Energy Info (EERE)

intensity intensity Dataset Summary Description Energy intensity data and documentation published by the U.S. DOE's office of Energy Efficiency and Renewable Energy (EERE). Energy intensity is defined as: amount of energy used in producing a given level of output or activity; expressed as energy per unit of output. This is the energy intensity of the the electricity sector, which is an energy consuming sector that generates electricity. Data are organized to separate electricity-only generators from combined heat and power (CHP) generators. Data is available for the period 1949 - 2004. Source EERE Date Released May 31st, 2006 (8 years ago) Date Updated Unknown Keywords Electricity Energy Consumption energy intensity fossil fuels renewable energy Data application/vnd.ms-excel icon electricity_indicators.xls (xls, 2.1 MiB)

446

Breakdown of the Born-Oppenheimer description explains neutron Compton-scattering anomaly  

SciTech Connect (OSTI)

Several neutron Compton scattering experiments reveal an apparent drop of the proton cross section when the collision time {tau}{sub q} is around 1 fs. Such small {tau}{sub q} corresponds to a large energy spread of the proton wave packet after collision, allowing it to access excited electronic levels. This nonadiabatic excitation of electrons leads to a distortion of the shape of the neutron scattering response function with some redistribution of intensity at energies higher than the nuclear recoil energy and a slight shift of the main neutron intensity peak to lower energies.

Gidopoulos, Nikitas I. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX (United Kingdom)

2005-02-01T23:59:59.000Z

447

Characterization of a Surface-Flashover Ion Source with 10 - 250 ns Pulse Width  

SciTech Connect (OSTI)

As a step towards developing an ultra compact D-D neutron source for various defense and homeland security applications, a compact ion source is needed. Towards that end, we are testing a pulsed, surface flashover source, with deuterated titanium films deposited on alumina substrates as the electrodes. An electrochemically-etched mask was used to define the electrode areas on the substrate during the sputtered deposition of the titanium films. Deuterium loading of the films was performed in an all metal-sealed vacuum chamber containing a heated stage. Deuterium ion current from the source was determined by measuring the neutrons produced when the ions impacted a deuterium-loaded target held at -90 kV. As the duration of the arc current is varied, it was observed that the integrated deuteron current per pulse initially increases rapidly, then reaches a maximum near a pulse length of 100 ns.

Falabella, S; Guethlein, G; Kerr, P L; Meyer, G A; Sampayan, S E; Tang, V; Morse, J D

2008-08-05T23:59:59.000Z

448

Neutron Diffraction @ TOPAZ  

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

Topaz Guide Bender Topaz Guide Bender Neutron Diffraction @ TOPAZ Workshop on Single Crystal Neutron Diffraction picture 2 September 29 - October 1, 2011 * Spallation Neutron Source * Oak Ridge National Laboratory * Oak Ridge TN, USA TOPAZ 2011 Home Contacts Agenda and Important Deadlines Registration and Payment filler Workshop summary and purpose A workshop on single crystal neutron diffraction will be held at the Spallation Neutron Source at the Oak Ridge National Laboratory (ORNL). It will present invited and contributed talks to showcase cutting edge science and examples where neutron diffraction can make significant contributions; and provide training in neutron structure analysis and sample screening for the preparation of instrument beam-time proposals. TOPAZ is a high resolution wavelength-resolved Laue diffractometer with a versatile sample environment. Commissioning user experiments have demonstrated successfully the instrument capability for structural study of a vitamin B12 derivative, ion distribution in Li-ion battery materials, order and disorder in shape memory intermetallics, magnetic phase transition in multiferroic single crystal and functional thin films. The workshop is directed towards experienced neutron diffraction users and new users alike and encourages members to highlight their research and interest in structure analysis and investigation. The workshop will give opportunity to bring your own single crystal and screen sample quality and scattering power on TOPAZ @ room temperature, to evaluate data collection time and quality for an anticipated experiment. Finally, an opportunity to compose a proposal for neutron beam time (http://neutrons.ornl.gov/users/proposals.shtml) with staff will be provided in the framework of the workshop. The workshop format is well suited for researchers to contribute by showcasing their research and bring their research group or graduate student, who would like to test a single crystal sample. User access training for the ORNL neutron scattering facility will be included. It will be valid for future experiments.

449

Ultra hard x rays from krypton clusters heated by intense laser fields R. C. Issac,a)  

E-Print Network [OSTI]

drives a fast ignition wave.15 Prop- erties of the cluster media as well as the incident laser paUltra hard x rays from krypton clusters heated by intense laser fields R. C. Issac,a) G. Vieux, B of ultrashort laser pulses with krypton clusters at intensity up to 1.3 1018 Wcm 2 has been investigated

Strathclyde, University of

450

Glassy Dynamics of Polystyrene by Quasielastic Neutron Scattering  

Science Journals Connector (OSTI)

Glassy Dynamics of Polystyrene by Quasielastic Neutron Scattering ... The ratio of coherent to total scattered intensities(25) has also been included on the rhs-axis of Figure 3 (crosses). ... It is introduced as the long-time limit of the intermediate scattering function and it is related to the region of the space accessible to the scatters. ...

S. Arrese-Igor; A. Arbe; B. Frick; J. Colmenero

2011-03-28T23:59:59.000Z

451

Disposition of fuel elements from the Aberdeen and Sandia pulse reactor (SPR-II) assemblies  

SciTech Connect (OSTI)

We describe the disposition of fuel from the Aberdeen (APR) and the Sandia Pulse Reactors (SPR-II) which were used to provide intense neutron bursts for radiation effects testing. The enriched Uranium - 10% Molybdenum fuel from these reactors was shipped to the Los Alamos National Laboratory (LANL) for size reduction prior to shipment to the Savannah River Site (SRS) for final disposition in the H Canyon facility. The Shipper/Receiver Agreements (SRA), intra-DOE interfaces, criticality safety evaluations, safety and quality requirements and key materials management issues required for the successful completion of this project will be presented. This work is in support of the DOE Consolidation and Disposition program. Sandia National Laboratories (SNL) has operated pulse nuclear reactor research facilities for the Department of Energy since 1961. The Sandia Pulse Reactor (SPR-II) was a bare metal Godiva-type reactor. The reactor facilities have been used for research and development of nuclear and non-nuclear weapon systems, advanced nuclear reactors, reactor safety, simulation sources and energy related programs. The SPR-II was a fast burst reactor, designed and constructed by SNL that became operational in 1967. The SPR-ll core was a solid-metal fuel enriched to 93% {sup 235}U. The uranium was alloyed with 10 weight percent molybdenum to ensure the phase stabilization of the fuel. The core consisted of six fuel plates divided into two assemblies of three plates each. Figure 1 shows a cutaway diagram of the SPR-II Reactor with its decoupling shroud. NNSA charged Sandia with removing its category 1 and 2 special nuclear material by the end of 2008. The main impetus for this activity was based on NNSA Administrator Tom D'Agostino's six focus areas to reenergize NNSA's nuclear material consolidation and disposition efforts. For example, the removal of SPR-II from SNL to DAF was part of this undertaking. This project was in support of NNSA's efforts to consolidate the locations of special nuclear material (SNM) to reduce the cost of securing many SNM facilities. The removal of SPR-II from SNL was a significant accomplishment in SNL's de-inventory efforts and played a key role in reducing the number of locations requiring the expensive security measures required for category 1 and 2 SNM facilities. A similar pulse reactor was fabricated at the Y-12 National Security Complex beginning in the late 1960's. This Aberdeen Pulse Reactor (APR) was operated at the Army Pulse Radiation Facility (APRF) located at the Aberdeen Test Center (ATC) in Maryland. When the APRF was shut down in 2003, a portion of the DOE-owned Special Nuclear Material (SNM) was shipped to an interim facility for storage. Subsequently, the DOE determined that the material from both the SPR-II and the APR would be processed in the H-Canyon at the Savannah River Site (SRS). Because of the SRS receipt requirements some of the material was sent to the Los Alamos National Laboratory (LANL) for size-reduction prior to shipment to the SRS for final disposition.

Mckerley, Bill [Los Alamos National Laboratory; Bustamante, Jacqueline M [Los Alamos National Laboratory; Costa, David A [Los Alamos National Laboratory; Drypolcher, Anthony F [Los Alamos National Laboratory; Hickey, Joseph [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

452

Neutron activation experiments in radiochemistry  

Science Journals Connector (OSTI)

Neutron activation experiments in radiochemistry ... Describes experimentation involving the neutron activation of a variety of samples irradiated in a subcritical reactor and a paraffin-moderated source. ...

Karl S. Vorres

1960-01-01T23:59:59.000Z

453

Neutron Stars and Fractal Dimensionality  

E-Print Network [OSTI]

We argue that the material inside Neutron stars behaves anomalously with fractal statistics and that in principle, we could induce mini Neutron stars, with the release of energy.

Burra G. Sidharth

2008-05-06T23:59:59.000Z

454

A history of the neutron  

Science Journals Connector (OSTI)

A history of the neutron ... Describes some of the individuals and the work they did leading to the discovery of the neutron. ...

Vasilis Lavrakas

1952-01-01T23:59:59.000Z

455

Neutron and Nuclear Science Publications  

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

Publications Recent publications related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science Publications Chi-Nu Publications DANCE Publications GEANIE...

456

Neutron and Nuclear Science News  

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

News Recent news and events related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science News Nuclear science observations and opportunities at the Los Alamos...

457

Neutron Science Research Areas | ORNL  

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

Home | Science & Discovery | Neutron Science | Research Areas SHARE Research Areas Neutron scattering research at ORNL covers four broad research areas: biology and soft...

458

LANSCE School on Neutron Scattering:  

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11 th LANSCE School on Neutron Scattering: Materials at the Mesoscale Lujan Center Los Alamos Neutron Science Center Los Alamos National Laboratory lansce.lanl.govneutronschool...

459

Advances in specular neutron reflectometry  

Science Journals Connector (OSTI)

Specular neutron reflectometry provides a depth profile of the scattering ... material. To date, numerous productive applications of neutron reflectometry have been demonstrated. With the new development ... stil...

C.F. Majkrzak; N.F. Berk

2002-12-01T23:59:59.000Z

460

Category:Neutron Log | Open Energy Information  

Open Energy Info (EERE)

Neutron Log page? For detailed information on Neutron Log, click here. Category:Neutron Log Add.png Add a new Neutron Log Technique Pages in category "Neutron Log" This category...

Note: This page contains sample records for the topic "intense pulsed neutron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Evaluation of two-stage system for neutron measurement aiming at increase in count rate at Japan Atomic Energy Agency-Fusion Neutronics Source  

SciTech Connect (OSTI)

In order to increase the count rate capability of a neutron detection system as a whole, we propose a multi-stage neutron detection system. Experiments to test the effectiveness of this concept were carried out on Fusion Neutronics Source. Comparing four configurations of alignment, it was found that the influence of an anterior stage on a posterior stage was negligible for the pulse height distribution. The two-stage system using 25 mm thickness scintillator was about 1.65 times the count rate capability of a single detector system for d-D neutrons and was about 1.8 times the count rate capability for d-T neutrons. The results suggested that the concept of a multi-stage detection system will work in practice.

Shinohara, K., E-mail: shinohara.koji@jaea.go.jp; Ochiai, K.; Sukegawa, A. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Ishii, K.; Kitajima, S. [Department of Quantum Science and Energy Engineering, Tohoku University, Sendai, Miyagi 980-8579 (Japan); Baba, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Sasao, M. [Organization for Research Initiatives and Development, Doshisha University, Kyoto 602-8580 (Japan)

2014-11-15T23:59:59.000Z

462

Tamper to delay motion and decrease ionization of a sample during short pulse x-ray imaging  

DOE Patents [OSTI]

A system for x-ray imaging of a small sample comprising positioning a tamper so that it is operatively connected to the sample, directing short intense x-ray pulses onto the tamper and the sample, and detecting an image from the sample. The tamper delays the explosive motion of the sample during irradiation by the short intense x-ray pulses, thereby extending the time to obtain an x-ray image of the original structure of the sample.

London, Richard A. (Orinda, CA); Szoke; Abraham (Fremont, CA), Hau-Riege; Stefan P. (Fremont, CA), Chapman; Henry N. (Livermore, CA)

2007-06-26T23:59:59.000Z

463

Innovative high pressure gas MEM's based neutron detector for ICF and active SNM detection.  

SciTech Connect (OSTI)

An innovative helium3 high pressure gas detection system, made possible by utilizing Sandia's expertise in Micro-electrical Mechanical fluidic systems, is proposed which appears to have many beneficial performance characteristics with regards to making these neutron measurements in the high bremsstrahlung and electrical noise environments found in High Energy Density Physics experiments and especially on the very high noise environment generated on the fast pulsed power experiments performed here at Sandia. This same system may dramatically improve active WMD and contraband detection as well when employed with ultrafast (10-50 ns) pulsed neutron sources.

Martin, Shawn Bryan; Derzon, Mark Steven; Renzi, Ronald F.; Chandler, Gordon Andrew

2007-12-01T23:59:59.000Z

464

Time-resolved diffraction profiles and atomic dynamics in short-pulse laser-induced structural transformations: Molecular dynamics study  

E-Print Network [OSTI]

Time-resolved diffraction profiles and atomic dynamics in short-pulse laser-induced structural dynamics simulations of a 20 nm Au film irradiated with 200 fs laser pulses of different intensity in time-resolved x-ray and electron diffraction experiments. Three processes are found to be responsible

Zhigilei, Leonid V.

465

Spectral shifts of the fundamental and third harmonic radiation in air induced by self-focused femtosecond laser pulses  

Science Journals Connector (OSTI)

Abstract The large spectral shifts of the fundamental and third harmonic waves (up to 20爊m and 50爊m, respectively) during femtosecond laser pulse filamentation in air have been demonstrated by using focusing lenses of long focal length. It was shown that in a wide range of laser intensities this process does not saturate and linearly depend on the pump pulse energy.

K. Steponkevi?ius; V. Pyragaite; B. Makauskas; E. 巈imys; V. Vai?aitis

2014-01-01T23:59:59.000Z

466

Coiled transmission line pulse generators  

DOE Patents [OSTI]

Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

McDonald, Kenneth Fox (Columbia, MO)

2010-11-09T23:59:59.000Z

467

Neutron Capture Therapy  

Science Journals Connector (OSTI)

... . Only those elements which have a high thermal-neutron capture cross-section, such as boron-10, lithium-6, and uranium-235, are useful. This suggestion was first put forward ... was first put forward in 1936 by Locher. The utilization of thermal neutron capture by boron-10 for the treatment of human-brain tumours, chiefly glioblastoma multiforme, has been under investigation ...

1961-09-23T23:59:59.000Z

468

LANSCE | News & Media | The Pulse  

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

Beams. In situ characterization of multiphase polymeric materials upon deformation. Neutron scattering reveals the atomic motion in a new class of ceramic-metal materials....

469

LANSCE | News & Media | The Pulse  

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

AOT staff receive distinguished performance awards. Lacerda receives mentoring award. Neutron reflectometry provides first sub-nanometer visualization of live cell adhesion....

470

LANSCE | News & Media | The Pulse  

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

Mentor Award Adam T. Holley wins 24th Rosen Prize Elena Fernandez wins APEX award Neutron reflectometry reveals helium bubble formation in radiation resistive materials...

471

Estimation of low-level neutron dose-equivalent rate by using extrapolation method for a curie level Am朆e neutron source  

Science Journals Connector (OSTI)

Abstract Neutron radiation protection is an important research area because of the strong radiation biological effect of neutron field. The radiation dose of neutron is closely related to the neutron energy, and the connected relationship is a complex function of energy. For the low-level neutron radiation field (e.g. the Am朆e source), the commonly used commercial neutron dosimeter cannot always reflect the low-level dose rate, which is restricted by its own sensitivity limit and measuring range. In this paper, the intensity distribution of neutron field caused by a curie level Am朆e neutron source was investigated by measuring the count rates obtained through a 3He proportional counter at different locations around the source. The results indicate that the count rates outside of the source room are negligible compared with the count rates measured in the source room. In the source room, 3He proportional counter and neutron dosimeter were used to measure the count rates and dose rates respectively at different distances to the source. The results indicate that both the count rates and dose rates decrease exponentially with the increasing distance, and the dose rates measured by a commercial dosimeter are in good agreement with the results calculated by the Geant4 simulation within the inherent errors recommended by ICRP and IEC. Further studies presented in this paper indicate that the low-level neutron dose equivalent rates in the source room increase exponentially with the increasing low-energy neutron count rates when the source is lifted from the shield with different radiation intensities. Based on this relationship as well as the count rates measured at larger distance to the source, the dose rates can be calculated approximately by the extrapolation method. This principle can be used to estimate the low level neutron dose values in the source room which cannot be measured directly by a commercial dosimeter.

Gang Li; Jiayun Xu; Jie Zhang

2015