National Library of Energy BETA

Sample records for time clocks vending

  1. Quantum time-of-flight measurements: Kicked clock versus continuous clock

    SciTech Connect (OSTI)

    Alonso, Daniel; Sala Mayato, R.; Muga, J.G.

    2003-03-01

    The measurement of time durations or instants of occurrence of events has been frequently modeled 'operationally' by coupling the system of interest to a ''clock.'' According to several of these models, the operational approach is limited at low energies because the perturbation of the clock does not allow to reproduce accurately the corresponding ideal time quantity, defined for the system in isolation. We show that, for a time-of-flight measurement model that can be set to measure dwell or arrival times, these limitations may be overcome by extending the range of energies where the clock works properly using pulsed couplings rather than continuous ones.

  2. Clock Controller For Ac Self-Timing Analysis Of Logic System

    DOE Patents [OSTI]

    Lo, Tinchee; Flanagan, John D.

    2004-05-18

    A clock controller and clock generating method are provided for AC self-test timing analysis of a logic system. The controller includes latch circuitry which receives a DC input signal at a data input, and a pair of continuous out-of-phase clock signals at capture and launch clock inputs thereof. The latch circuitry outputs two overlapping pulses responsive to the DC input signal going high. The two overlapping pulses are provided to waveform shaper circuitry which produces therefrom two non-overlapping pulses at clock speed of the logic system to be tested. The two non-overlapping pulses are a single pair of clock pulses which facilitate AC self-test timing analysis of the logic system.

  3. Barrier interaction time and the Salecker-Wigner quantum clock: Wave-packet approach

    SciTech Connect (OSTI)

    Park, Chang-Soo

    2009-07-15

    The time-of-flight measurement approach of Peres based on the Salecker-Wigner quantum clock is applied to the one-dimensional scattering of a wave packet from a rectangular barrier. By directly evaluating the expectation value of the clock-time operator in the asymptotic states of wave packet long after the scattering process, we derive an average wave-packet clock time for the barrier interaction, which is expressed as an average of the stationary-state clock time over all possible initial scattering states of the wave packet. We show that the average wave-packet clock time is identical to the average dwell time of a wave packet.

  4. Seattle City Light- Vending Machine Rebate Program

    Office of Energy Efficiency and Renewable Energy (EERE)

    Seattle City Light offers qualifying customers $80 rebates for the purchase of VendingMiser Energy Efficient Vending Machines. VendingMiser reduces the energy consumption of cold drink vending...

  5. Extended Coherence Time on the Clock Transition of Optically Trapped Rubidium

    SciTech Connect (OSTI)

    Kleine Buening, G.; Will, J.; Ertmer, W.; Rasel, E.; Klempt, C.; Arlt, J.; Ramirez-Martinez, F.; Rosenbusch, P.; Piechon, F.

    2011-06-17

    Optically trapped ensembles are of crucial importance for frequency measurements and quantum memories but generally suffer from strong dephasing due to inhomogeneous density and light shifts. We demonstrate a drastic increase of the coherence time to 21 s on the magnetic field insensitive clock transition of {sup 87}Rb by applying the recently discovered spin self-rephasing [C. Deutsch et al., Phys. Rev. Lett. 105, 020401 (2010)]. This result confirms the general nature of this new mechanism and thus shows its applicability in atom clocks and quantum memories. A systematic investigation of all relevant frequency shifts and noise contributions yields a stability of 2.4x10{sup -11{tau}-1/2}, where {tau} is the integration time in seconds. Based on a set of technical improvements, the presented frequency standard is predicted to rival the stability of microwave fountain clocks in a potentially much more compact setup.

  6. EMCS Modules/intelligent Time Clock (ITC). Final report 1977-1980

    SciTech Connect (OSTI)

    Shiroma, D.

    1980-09-01

    The CEL has developed a microprocessor-based intelligent time clock (ITC) for control of HVAC equipment. The ITC has the capability of operating as a stand-alone controller, or as part of a distributed large-scale Energy Monitoring and Control System (EMCS). The ITC has 'intelligence' to monitor actual environmental conditions and to base actual control functions on these data. Evaluation of the ITC has demonstrated that such 'intelligent' control devices can provide significant energy savings over conventional control devices.

  7. Design and Evaluation of a Clock Multiplexing Circuit for the SSRL Booster Accelerator Timing System - Final Paper

    SciTech Connect (OSTI)

    Araya, Million

    2015-08-21

    SPEAR3 is a 234 m circular storage ring at SLAC’s synchrotron radiation facility (SSRL) in which a 3 GeV electron beam is stored for user access. Typically the electron beam decays with a time constant of approximately 10hr due to electron lose. In order to replenish the lost electrons, a booster synchrotron is used to accelerate fresh electrons up to 3GeV for injection into SPEAR3. In order to maintain a constant electron beam current of 500mA, the injection process occurs at 5 minute intervals. At these times the booster synchrotron accelerates electrons for injection at a 10Hz rate. A 10Hz 'injection ready' clock pulse train is generated when the booster synchrotron is operating. Between injection intervals-where the booster is not running and hence the 10 Hz ‘injection ready’ signal is not present-a 10Hz clock is derived from the power line supplied by Pacific Gas and Electric (PG&E) to keep track of the injection timing. For this project I constructed a multiplexing circuit to 'switch' between the booster synchrotron 'injection ready' clock signal and PG&E based clock signal. The circuit uses digital IC components and is capable of making glitch-free transitions between the two clocks. This report details construction of a prototype multiplexing circuit including test results and suggests improvement opportunities for the final design.

  8. Design and Evaluation of a Clock Multiplexing Circuit for the SSRL Booster Accelerator Timing System - Oral Presentation

    SciTech Connect (OSTI)

    Araya, Million

    2015-08-25

    SPEAR3 is a 234 m circular storage ring at SLAC’s synchrotron radiation facility (SSRL) in which a 3 GeV electron beam is stored for user access. Typically the electron beam decays with a time constant of approximately 10hr due to electron lose. In order to replenish the lost electrons, a booster synchrotron is used to accelerate fresh electrons up to 3GeV for injection into SPEAR3. In order to maintain a constant electron beam current of 500mA, the injection process occurs at 5 minute intervals. At these times the booster synchrotron accelerates electrons for injection at a 10Hz rate. A 10Hz 'injection ready' clock pulse train is generated when the booster synchrotron is operating. Between injection intervalswhere the booster is not running and hence the 10 Hz ‘injection ready’ signal is not present-a 10Hz clock is derived from the power line supplied by Pacific Gas and Electric (PG&E) to keep track of the injection timing. For this project I constructed a multiplexing circuit to 'switch' between the booster synchrotron 'injection ready' clock signal and PG&E based clock signal. The circuit uses digital IC components and is capable of making glitch-free transitions between the two clocks. This report details construction of a prototype multiplexing circuit including test results and suggests improvement opportunities for the final design.

  9. Estimation of the time scale of last chance alpha emission using an atomic clock''

    SciTech Connect (OSTI)

    Gallamore, L.; Sarantites, D.G.; Charity, R.J.; Nicolis, N.G.; Sobotka, L.G. ); Beene, J.R.; Halbert, M.L.; Varner, R.L. )

    1994-02-01

    The probability of filling a [ital K]-vacancy, created on the incoming part of the collision, before [alpha]-particle emission is used to time the decay of Yb compound nuclei. These nuclei were produced in the fusion reaction 250 MeV [sup 60]Ni+[sup 100]Mo. In general the nuclear decays are too fast to be timed by this clock, however, [alpha]-particle emitting compound nucleus states have lifetimes sufficiently long for this technique to work when both the [alpha]-particle has low energy and the compound nucleus spin is large. This supports the existence of last, or near last, chance [alpha]-particle emission in the deexcitation of high spin compound nuclei.

  10. Providing Runtime Clock Synchronization With Minimal Node-to-Node Time Deviation on XT4s and XT5s

    SciTech Connect (OSTI)

    Jones, Terry R; Koenig, Gregory A

    2011-01-01

    We present a new high precision clock synchronization algorithm designed for large XT4 and XT5 leadership-class machines. The algorithm, which is designed to support OS noise reduction through co-scheduling, is suitable for usage cases requiring low overhead and minimal time deviation between nodes. Unlike most high-precision algorithms which reach their precision in a post-mortem analysis after the application has completed, the new ORNL developed algorithm rapidly provides precise results during runtime. Previous to our work, the leading high-precision clock synchronization algorithms that made results available during runtime relied on probabilistic schemes that are not guaranteed to result in an answer.

  11. Product Standards for Vending Equipment (Japan) | Open Energy...

    Open Energy Info (EERE)

    Vending Equipment (Japan) Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Product Standards for Vending Equipment (Japan) Focus Area: Energy Efficiency Topics: Policy...

  12. Radio frequency phototube and optical clock: High resolution, high rate and highly stable single photon timing technique

    SciTech Connect (OSTI)

    Margaryan, Amur

    2011-10-01

    A new timing technique for single photons based on the radio frequency phototube and optical clock or femtosecond optical frequency comb generator is proposed. The technique has a 20 ps resolution for single photons, is capable of operating with MHz frequencies and achieving 10 fs instability level.

  13. Channel Modeling and Time Delay Estimation for Clock Synchronization Among Seaweb Nodes

    SciTech Connect (OSTI)

    Gagnon, P; Rice, J; Clark, G A

    2012-07-08

    From simulations, tracking of the impulse response is feasible. Potential to benefit other functions such as ranging between two nodes. Potential to combine the features of different protocols to create a new and more realistic clock-synchronization protocol.

  14. An integrated CMOS 0.15 ns digital timing generator for TDC`s and clock distribution systems

    SciTech Connect (OSTI)

    Christiansen, J.

    1995-08-01

    This paper describes the architecture and performance of a new high resolution timing generator used as a building block for time to Digital Converters (TDC) and clock alignment functions. The timing generator is implemented as an array of locked loops. This architecture enables a timing generator with sub-gate delay resolution to be implemented in a standard digital CMOS process. The TDC function is implemented by storing the state of the timing generator signals in an asynchronous pipeline buffer when a hit signal is asserted. The clock alignment function is obtained by selecting one of the timing generator signals as an output clock. The proposed timing-generator has been mapped into a 1.0 {micro}m CMOS process a RMS error of the time taps of 48 ps has been measured with a bin size 0.15 ns. Used as a TDC device a RMS error of {minus}6 ps has been obtained. A short overview of the basic principles of major TDC and timing generator architectures is given to compare the merits of the proposed scheme to other alternatives.

  15. Clock asynchrony and mass variation

    SciTech Connect (OSTI)

    Gruber, R.P.; Brahm, D.E.

    1993-04-01

    Many theories have been proposed in which particle masses vary with time. In a world with varying particle masses, clocks become asynchronous and metersticks inconsistent. By combining two or more clocks with different known dependences on mass, one can construct a nearly invariant clock, and measure the rate of mass variation. If the proton and electron masses vary differently, then certain equations must be applied to predict a clock's dependence on each. 8 refs.

  16. A Clock Synchronization Strategy for Minimizing Clock Variance...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: SC USDOE - Office of Science (SC) Country of Publication: United States Language: English Subject: Time service; clock synchronization; MPI; supercomputing; system ...

  17. Covered Product Category: Refrigerated Beverage Vending Machines

    Broader source: Energy.gov [DOE]

    FEMP provides acquisition guidance and Federal efficiency requirements across a variety of product categories, including refrigerated beverage vending machines, which are covered by the ENERGY STAR program. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.

  18. Central Activator Keeps the Circadian Clock Ticking

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

    with each other and working together to keep the clock robust and on time. To gain a fuller understanding of the circadian clock, researchers collected x-ray diffraction data at...

  19. Purchasing Energy-Efficient Refrigerated Beverage Vending Machines |

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

    Department of Energy Refrigerated Beverage Vending Machines Purchasing Energy-Efficient Refrigerated Beverage Vending Machines The Federal Energy Management Program (FEMP) provides acquisition guidance for refrigerated beverage vending machines, a product category covered by ENERGY STAR efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product categories covered by these programs and in any

  20. ISSUANCE 2015-10-20: Energy Conservation Program: Energy Conservation Standards for Refrigerated Beverage Vending Machines

    Broader source: Energy.gov [DOE]

    Energy Conservation Program: Energy Conservation Standards for Refrigerated Beverage Vending Machines

  1. A VMEbus clock system for accelerator control

    SciTech Connect (OSTI)

    Beechy, D.G.; McClure, C.R. )

    1992-04-01

    Because an accelerator has many systems which must operate with a high degree of synchronization, a clock signal is typically generated which carries timing information to the various accelerator components. This paper discusses two VMEbus modules designed to generate and receive this clock signal. Together they implement a clock system which can generate timing markers with 200 nanosecond resolution and can generate timing delays of over one hour with one microsecond resolution. The Clock Generator module contains both a time line generator programmed to produce clock events at specific times and eight programmable input channels to produce clock events when externally triggered. Additional clock events are generated directly from the VMEbus. Generators can be cascaded for added capability. The Clock Timer module receives the signal from the generator. It can be programmed to recognize specific clock events which act as triggers to the eight timing channels on the module. Each timing channel is programmed with a 32-bit delay value. The channels are clocked at 1 MHz. At the end of the delay period, a timer channel produces an output pulse and optionally can generate a bus interrupt.

  2. Orientation-Dependent Entanglement Lifetime in a Squeezed Atomic Clock

    SciTech Connect (OSTI)

    Leroux, Ian D.; Schleier-Smith, Monika H.; Vuletic, Vladan

    2010-06-25

    We study experimentally the application of a class of entangled states, squeezed spin states, to the improvement of atomic-clock precision. In the presence of anisotropic noise, the entanglement lifetime is strongly dependent on squeezing orientation. We measure the Allan deviation spectrum of a clock operated with a phase-squeezed input state. For averaging times up to 50 s the squeezed clock achieves a given precision 2.8(3) times faster than a clock operating at the standard quantum limit.

  3. Einstein’s Clocks

    SciTech Connect (OSTI)

    Lincoln, Don

    2015-09-09

    One of the most non-intuitive physics theories ever devised is Einstein’s Theory of Special Relativity, which claim such crazy-sounding things as two people disagreeing on such familiar concepts as length and time. In this video, Fermilab’s Dr. Don Lincoln shows that every single day particle physicists prove that moving clocks tick more slowly than stationary ones. He uses an easy to understand example of particles that move for far longer distances than you would expect from combining their velocity and stationary lifetime.

  4. ISSUANCE 2015-07-15: Energy Conservation Program: Test Procedure for Refrigerated Bottled or Canned Beverage Vending Machines, Final Rule

    Office of Energy Efficiency and Renewable Energy (EERE)

    Energy Conservation Program: Test Procedure for Refrigerated Bottled or Canned Beverage Vending Machines, Final Rule

  5. ISSUANCE 2015-07-30: Energy Conservation Program: Energy Conservation Standards for Refrigerated Beverage Vending Machines, Notice of Proposed Rulemaking

    Office of Energy Efficiency and Renewable Energy (EERE)

    Energy Conservation Program: Energy Conservation Standards for Refrigerated Beverage Vending Machines, Notice of Proposed Rulemaking

  6. Purchasing Energy-Efficient Refrigerated Beverage Vending Machines

    Broader source: Energy.gov [DOE]

    FEMP provides acquisition guidance and Federal efficiency requirements across a variety of product categories, including refrigerated beverage vending machines, which are covered by the ENERGY STAR® program. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.

  7. A microfabricated atomic clock

    SciTech Connect (OSTI)

    Knappe, Svenja; Shah, Vishal; Schwindt, Peter D.D.; Hollberg, Leo; Kitching, John; Liew, Li-Anne; Moreland, John

    2004-08-30

    Fabrication techniques usually applied to microelectromechanical systems (MEMS) are used to reduce the size and operating power of the core physics assembly of an atomic clock. With a volume of 9.5 mm{sup 3}, a fractional frequency instability of 2.5x10{sup -10} at 1 s of integration, and dissipating less than 75 mW of power, the device has the potential to bring atomically precise timing to hand-held, battery-operated devices. In addition, the design and fabrication process allows for wafer-level assembly of the structures, enabling low-cost mass-production of thousands of identical units with the same process sequence, and easy integration with other electronics.

  8. Method and system for downhole clock synchronization

    DOE Patents [OSTI]

    Hall, David R.; Bartholomew, David B.; Johnson, Monte; Moon, Justin; Koehler, Roger O.

    2006-11-28

    A method and system for use in synchronizing at least two clocks in a downhole network are disclosed. The method comprises determining a total signal latency between a controlling processing element and at least one downhole processing element in a downhole network and sending a synchronizing time over the downhole network to the at least one downhole processing element adjusted for the signal latency. Electronic time stamps may be used to measure latency between processing elements. A system for electrically synchronizing at least two clocks connected to a downhole network comprises a controlling processing element connected to a synchronizing clock in communication over a downhole network with at least one downhole processing element comprising at least one downhole clock. Preferably, the downhole network is integrated into a downhole tool string.

  9. Clock Synchronization in High-end Computing Environments: A Strategy...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: SC USDOE - Office of Science (SC) Country of Publication: United States Language: English Subject: Time service; clock synchronization; MPI; supercomputing; system ...

  10. Conveyor-belt clock synchronization

    SciTech Connect (OSTI)

    Giovannetti, Vittorio; Maccone, Lorenzo; Shapiro, Jeffrey H.; Wong, Franco N.C.; Lloyd, Seth

    2004-10-01

    A protocol for synchronizing distant clocks is proposed that does not rely on the arrival times of the signals which are exchanged, and an optical implementation based on coherent-state pulses is described. This protocol is not limited by any dispersion that may be present in the propagation medium through which the light signals are exchanged. Possible improvements deriving from the use of quantum-mechanical effects are also addressed.

  11. Femtosecond optical clock

    SciTech Connect (OSTI)

    Bagaev, Sergei N; Denisov, Vladimir I; Zakharyash, Valerii F; Kashirsky, Aleksandr V; Klementyev, Vasilii M; Kuznetsov, Sergei A; Korel', I I; Pivtsov, V S

    2004-12-31

    New advances in the field of synthesis of optical frequencies and the development of a new generation of optical clocks are considered. The use of mode-locked femtosecond lasers and fibre emission-spectrum stretchers allows the synthesis of any frequencies (from radio-frequencies to the UV region) and drastically simplifies the structure of an optical clock. The schemes of femtosecond optical clock are presented and the application of tapered optical fibres in them is described. (optical metrology and quantum frequency standards)

  12. Measuring Time to Biochemical Failure in the TROG 96.01 Trial: When Should the Clock Start Ticking?

    SciTech Connect (OSTI)

    Denham, James W.; Steigler, Allison; Kumar, Mahesh; Lamb, David S.; Joseph, David; Spry, Nigel A.; Tai, Keen-Hun; Atkinson, Chris; Turner, Sandra FRANZCR; Greer, Peter B.; Gleeson, Paul S.; D'Este, Catherine

    2009-11-15

    Purpose: We sought to determine whether short-term neoadjuvant androgen deprivation (STAD) duration influences the optimal time point from which Phoenix fail (time to biochemical failure; TTBF) should be measured. Methods and Materials: In the Trans-Tasman Radiation Oncology Group 96.01 trial, men with locally advanced prostate cancer were randomized to 3 or 6 months STAD before and during prostatic irradiation (XRT) or to XRT alone. The prognostic value of TTBF measured from the end of radiation (ERT) and randomization were compared using Cox models. Results: Between 1996 and 2000, 802 eligible patients were randomized. In 436 men with Phoenix failure, TTBF measured from randomization was a powerful predictor of prostate cancer-specific survival and marginally more accurate than TTBF measured from ERT in Cox models. Insufficient data were available to confirm that TTBF measured from testosterone recovery may also be a suitable option. Conclusions: TTBF measured from randomization (commencement of therapy) performed well in this trial dataset and will be a convenient option if this finding holds in other datasets that include long-term androgen deprivation data.

  13. The Fermilab D0 master clock system

    SciTech Connect (OSTI)

    Rotolo, C.; Fachin, M.; Chappa, S.; Rauch, M.; Needles, C.; Dyer, A. )

    1992-08-01

    In this paper the Clock System provides bunch-crossing-related timing signals t various detector subsystems. Accelerator synchronization and monitoring as well as timing signal generation and distribution are discussed. The system is built using three module types implemented in Eurostandard hardware with a VME communications interface. The first two types of modules are used to facilitate synchronization with the accelerator and to generate 23 timing signals that are programmable with one RF bucket (18.8 ns) resolution and 1 ns accuracy. fifty-four of the third module type are used to distribute the timing signals and two synchronous 53 MHz and 106 MHz clocks to various detector subsystems.

  14. A Clock Synchronization Strategy for Minimizing Clock Variance at Runtime in High-end Computing Environments

    SciTech Connect (OSTI)

    Jones, Terry R; Koenig, Gregory A

    2010-01-01

    We present a new software-based clock synchronization scheme designed to provide high precision time agreement among distributed memory nodes. The technique is designed to minimize variance from a reference chimer during runtime and with minimal time-request latency. Our scheme permits initial unbounded variations in time and corrects both slow and fast chimers (clock skew). An implementation developed within the context of the MPI message passing interface is described and time coordination measurements are presented. Among our results, the mean time variance among a set of nodes improved from 20.0 milliseconds under standard Network Time Protocol (NTP) to 2.29 secs under our scheme.

  15. Clock Synchronization in High-end Computing Environments: A Strategy for Minimizing Clock Variance at Runtime

    SciTech Connect (OSTI)

    Jones, Terry R; Koenig, Gregory A

    2013-01-01

    We present a new software-based clock synchronization scheme that provides high precision time agreement among distributed memory nodes. The technique is designed to minimize variance from a reference chimer during runtime and with minimal time-request latency. Our scheme permits initial unbounded variations in time and corrects both slow and fast chimers (clock skew). An implementation developed within the context of the MPI message passing interface is described, and time coordination measurements are presented. Among our results, the mean time variance for a set of nodes improved from 20.0 milliseconds under standard Network Time Protocol (NTP) down to 2.29 secs under our scheme.

  16. Nuclear magnetic resonance implementation of a quantum clock synchronization algorithm

    SciTech Connect (OSTI)

    Zhang Jingfu; Long, G.C; Liu Wenzhang; Deng Zhiwei; Lu Zhiheng

    2004-12-01

    The quantum clock synchronization (QCS) algorithm proposed by Chuang [Phys. Rev. Lett. 85, 2006 (2000)] has been implemented in a three qubit nuclear magnetic resonance quantum system. The time difference between two separated clocks can be determined by measuring the output states. The experimental realization of the QCS algorithm also demonstrates an application of the quantum phase estimation.

  17. Distant clock synchronization using entangled photon pairs

    SciTech Connect (OSTI)

    Valencia, Alejandra; Scarcelli, Giuliano; Shih, Yanhua

    2004-09-27

    We report a proof-of-principle experiment on distant clock synchronization. Besides the achievement of picosecond resolution at 3 km distance, this experiment demonstrated a concept for high-accuracy nonlocal timing and positioning based on the quantum feature of entangled states.

  18. A bunch clock for the Advanced Photon Source

    SciTech Connect (OSTI)

    Lenkszus, F.R.; Laird, R.J.

    1997-06-01

    A bunch clock timing module has been developed for use by Advanced Photon Source beamlines. The module provides bunch pattern and timing information that can be used to trigger beamline data collection equipment. The module is fully integrated into the control system software (EPICS) which automatically loads it with the storage ring fill pattern at injection time. Fast timing outputs (1 ns FWHM) for each stored bunch are generated using the storage ring low-level rf and revolution clock as input references. Fiber-optic-based transmitters and receivers are used to transmit a 352-MHz low-level rf reference to distributed bunch clock modules. The bunch clock module is a single-width VME module and may be installed in a VME crate located near beamline instrumentation. A prototype has been in use on the SRI CAT beamline for over a year. The design and integration into the control system timing software along with measured performance results are presented.

  19. Central Activator Keeps the Circadian Clock Ticking

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

    Central Activator Keeps the Circadian Clock Ticking Print Most living organisms have ... such rhythmic behavior, the details of which-the "circadian clock"-are largely conserved. ...

  20. Central Activator Keeps the Circadian Clock Ticking

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

    Central Activator Keeps the Circadian Clock Ticking Central Activator Keeps the Circadian Clock Ticking Print Wednesday, 31 October 2012 00:00 Most living organisms have adapted ...

  1. Theory of generalized branch and combine clock networks

    SciTech Connect (OSTI)

    El-Amawy, A.; Kulasinghe, P.

    1994-12-31

    In a recent development a new clock distribution scheme, called Branch-and-Combine or BaC, has been introduced. The scheme is the first to guarantee constant skew bound regardless of network size. In this paper we generalize and extend the work on BaC networks. We established some interesting results on clocking paths, node input sequences, node inputs` relative timing, network stability, and skew bound. Furthermore, this study establishes an upper bound on maximum clocking rates for BaC networks which is about double that predicted by earlier studies.

  2. Apparatus and method for compensating for clock drift in downhole drilling components

    SciTech Connect (OSTI)

    Hall, David R.; Pixton, David S.; Johnson, Monte L.; Bartholomew, David B.; Hall, Jr., H. Tracy

    2007-08-07

    A precise downhole clock that compensates for drift includes a prescaler configured to receive electrical pulses from an oscillator. The prescaler is configured to output a series of clock pulses. The prescaler outputs each clock pulse after counting a preloaded number of electrical pulses from the oscillator. The prescaler is operably connected to a compensator module for adjusting the number loaded into the prescaler. By adjusting the number that is loaded into the prescaler, the timing may be advanced or retarded to more accurately synchronize the clock pulses with a reference time source. The compensator module is controlled by a counter-based trigger module configured to trigger the compensator module to load a value into the prescaler. Finally, a time-base logic module is configured to calculate the drift of the downhole clock by comparing the time of the downhole clock with a reference time source.

  3. Clock distribution system for digital computers

    DOE Patents [OSTI]

    Wyman, Robert H.; Loomis, Jr., Herschel H.

    1981-01-01

    Apparatus for eliminating, in each clock distribution amplifier of a clock distribution system, sequential pulse catch-up error due to one pulse "overtaking" a prior clock pulse. The apparatus includes timing means to produce a periodic electromagnetic signal with a fundamental frequency having a fundamental frequency component V'.sub.01 (t); an array of N signal characteristic detector means, with detector means No. 1 receiving the timing means signal and producing a change-of-state signal V.sub.1 (t) in response to receipt of a signal above a predetermined threshold; N substantially identical filter means, one filter means being operatively associated with each detector means, for receiving the change-of-state signal V.sub.n (t) and producing a modified change-of-state signal V'.sub.n (t) (n=1, . . . , N) having a fundamental frequency component that is substantially proportional to V'.sub.01 (t-.theta..sub.n (t) with a cumulative phase shift .theta..sub.n (t) having a time derivative that may be made uniformly and arbitrarily small; and with the detector means n+1 (1.ltoreq.n

  4. Bounds on gravitational wave backgrounds from large distance clock comparisons

    SciTech Connect (OSTI)

    Reynaud, S.; Lamine, B.; Duchayne, L.; Wolf, P.; Jaekel, M.-T.

    2008-06-15

    Our space-time is filled with gravitational wave backgrounds that constitute a fluctuating environment created by astrophysical and cosmological sources. Bounds on these backgrounds are obtained from cosmological and astrophysical data but also by analysis of ranging and Doppler signals from distant spacecraft. We propose here a new way to set bounds on those backgrounds by performing clock comparisons between a ground clock and a remote spacecraft equipped with an ultrastable clock, rather than only ranging to an on-board transponder. This technique can then be optimized as a function of the signal to be measured and the dominant noise sources, leading to significant improvements on present bounds in a promising frequency range where different theoretical models are competing. We illustrate our approach using the SAGAS project which aims to fly an ultrastable optical clock in the outer solar system.

  5. Clocking the Early Universe's Expansion

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

    Clocking the Early Universe's Expansion Calculations Performed at NERSC Help Scientists Close in on the Nature of Dark Energy April 17, 2014 Margie Wylie, mwylie@lbl.gov, +1 510 ...

  6. N+CPT clock resonance

    SciTech Connect (OSTI)

    Crescimanno, M.; Hohensee, M.

    2008-12-15

    In a typical compact atomic time standard a current modulated semiconductor laser is used to create the optical fields that interrogate the atomic hyperfine transition. A pair of optical sidebands created by modulating the diode laser become the coherent population trapping (CPT) fields. At the same time, other pairs of optical sidebands may contribute to other multiphoton resonances, such as three-photon N-resonance [Phys. Rev. A 65, 043817 (2002)]. We analyze the resulting joint CPT and N-resonance (hereafter N+CPT) analytically and numerically. Analytically we solve a four-level quantum optics model for this joint resonance and perturbatively include the leading ac Stark effects from the five largest optical fields in the laser's modulation comb. Numerically we use a truncated Floquet solving routine that first symbolically develops the optical Bloch equations to a prescribed order of perturbation theory before evaluating. This numerical approach has, as input, the complete physical details of the first two excited-state manifolds of {sup 87}Rb. We test these theoretical approaches with experiments by characterizing the optimal clock operating regimes.

  7. Molecular clocks control mutation rate in human cells

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

    Molecular clocks control mutation rate in human cells Molecular clocks control mutation rate in human cells These clock-like mutational processes could ultimately be responsible ...

  8. Three-dimensional optical lattice clock with bosonic {sup 88}Sr atoms

    SciTech Connect (OSTI)

    Akatsuka, Tomoya; Takamoto, Masao; Katori, Hidetoshi

    2010-02-15

    We present detailed analyses of our recent experiment on the three-dimensional (3D) optical lattice clock with bosonic {sup 88}Sr atoms in which the collisional frequency shift was suppressed by applying a single-occupancy lattice. Frequency shifts in magnetically induced spectroscopy on the {sup 1}S{sub 0}-{sup 3}P{sub 0} clock transition ({lambda}=698 nm) of {sup 88}Sr were experimentally investigated by referencing a one-dimensional (1D) lattice clock based on spin-polarized {sup 87}Sr atoms. We discuss that the clock stability is limited by the current laser stability as well as the experimental sequence of the clock operation, which may be improved to {sigma}{sub y}({tau})=2x10{sup -16}/{radical}({tau}) by optimizing the cycle time of the clock operation.

  9. Optical Square-Wave Clock Generation Based on an All-Optical Flip-Flop

    SciTech Connect (OSTI)

    Kaplan, A.M.; Agrawal, G.P.; Maywar, D.N.

    2010-03-10

    We demonstrate optical square-wave clock generation based on an all-optical flip-flop. The bistable output power from a resonant-type semiconductor optical amplifier (SOA) is switched ON and OFF by modulating its input with its output via cross-gain modulation in a traveling-wave SOA. All active components are driven by dc currents, and the wavelength and clock frequency are selectable. A clock frequency of 3.5 MHz is demonstrated, limited by the time of flight between bulk optical components. Optical square-wave clock signals are promising for applications in photonic integrated circuits and all-optical signal processing.

  10. BTime A Clock Synchronization Tool For Linux Clusters

    Energy Science and Technology Software Center (OSTI)

    2004-10-22

    BTime software synchronizes the system clocks on Linux computers that can communicate on a network. Primarily intended for Linux computers that form a cluster, BTime ensures that all computers in the cluster have approximately the same time (usually within microseconds). In operation, a BTime server broadcasts target times every second. All BTime clients filter timing data and apply local time corrections synchronously at multiples of 64 seconds. Bayesian estimation of target time errors feeds amore » Kalman filter which estimates local errors in time, clock drift, and wander rates. Server dock adjustments are detected and compensated, thus reducing filter convergence time. Low probability events (e.g. significant time changes) are handled through heuristics also designed to reduce filter convergence time. Normal BTime corrects dock differences, while another version of BTime that only tracks clock differences can be used for measurements. In authors test lasting four days, BTime delivered estimated dock synchronization within 10 microseconds with 99.75% confidence. Standard deviation of the estimated clock offset is typically 2-3 microseconds, even over busy multi-hop networks. These results are about 100 times better than published results for Network Time Protocol (NTP).« less

  11. BTime A Clock Synchronization Tool For Linux Clusters

    SciTech Connect (OSTI)

    Loncaric, Josip

    2004-10-22

    BTime software synchronizes the system clocks on Linux computers that can communicate on a network. Primarily intended for Linux computers that form a cluster, BTime ensures that all computers in the cluster have approximately the same time (usually within microseconds). In operation, a BTime server broadcasts target times every second. All BTime clients filter timing data and apply local time corrections synchronously at multiples of 64 seconds. Bayesian estimation of target time errors feeds a Kalman filter which estimates local errors in time, clock drift, and wander rates. Server dock adjustments are detected and compensated, thus reducing filter convergence time. Low probability events (e.g. significant time changes) are handled through heuristics also designed to reduce filter convergence time. Normal BTime corrects dock differences, while another version of BTime that only tracks clock differences can be used for measurements. In authors test lasting four days, BTime delivered estimated dock synchronization within 10 microseconds with 99.75% confidence. Standard deviation of the estimated clock offset is typically 2-3 microseconds, even over busy multi-hop networks. These results are about 100 times better than published results for Network Time Protocol (NTP).

  12. Optimized multiparty quantum clock synchronization

    SciTech Connect (OSTI)

    Ben-Av, Radel; Exman, Iaakov

    2011-07-15

    A multiparty protocol for distributed quantum clock synchronization has been claimed to provide universal limits on the clock accuracy, viz., that accuracy monotonically decreases with the number n of party members. But this is only true for synchronization when one limits oneself to W states. This work shows that the usage of Z (Symmetric Dicke) states, a generalization of W states, results in improved accuracy, having a maximum when Left-Floor n/2 Right-Floor of its members have their qubits with a |1> eigenstate.

  13. Single-transistor-clocked flip-flop

    DOE Patents [OSTI]

    Zhao, Peiyi; Darwish, Tarek; Bayoumi, Magdy

    2005-08-30

    The invention provides a low power, high performance flip-flop. The flip-flop uses only one clocked transistor. The single clocked transistor is shared by the first and second branches of the device. A pulse generator produces a clock pulse to trigger the flip-flop. In one preferred embodiment the device can be made as a static explicit pulsed flip-flop which employs only two clocked transistors.

  14. Clock Agreement Among Parallel Supercomputer Nodes

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

    Jones, Terry R.; Koenig, Gregory A.

    2014-04-30

    This dataset presents measurements that quantify the clock synchronization time-agreement characteristics among several high performance computers including the current world's most powerful machine for open science, the U.S. Department of Energy's Titan machine sited at Oak Ridge National Laboratory. These ultra-fast machines derive much of their computational capability from extreme node counts (over 18000 nodes in the case of the Titan machine). Time-agreement is commonly utilized by parallel programming applications and tools, distributed programming application and tools, and system software. Our time-agreement measurements detail the degree of time variance between nodes and how that variance changes over time. The dataset includes empirical measurements and the accompanying spreadsheets.

  15. Clock Agreement Among Parallel Supercomputer Nodes

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

    Jones, Terry R.; Koenig, Gregory A.

    This dataset presents measurements that quantify the clock synchronization time-agreement characteristics among several high performance computers including the current world's most powerful machine for open science, the U.S. Department of Energy's Titan machine sited at Oak Ridge National Laboratory. These ultra-fast machines derive much of their computational capability from extreme node counts (over 18000 nodes in the case of the Titan machine). Time-agreement is commonly utilized by parallel programming applications and tools, distributed programming application and tools, and system software. Our time-agreement measurements detail the degree of time variance between nodes and how that variance changes over time. The dataset includes empirical measurements and the accompanying spreadsheets.

  16. Analysis of a magnetically trapped atom clock

    SciTech Connect (OSTI)

    Kadio, D.; Band, Y. B.

    2006-11-15

    We consider optimization of a rubidium atom clock that uses magnetically trapped Bose condensed atoms in a highly elongated trap, and determine the optimal conditions for minimum Allan variance of the clock using microwave Ramsey fringe spectroscopy. Elimination of magnetic field shifts and collisional shifts are considered. The effects of spin-dipolar relaxation are addressed in the optimization of the clock. We find that for the interstate interaction strength equal to or larger than the intrastate interaction strengths, a modulational instability results in phase separation and symmetry breaking of the two-component condensate composed of the ground and excited hyperfine clock levels, and this mechanism limits the clock accuracy.

  17. Accurate Optical Lattice Clock with {sup 87}Sr Atoms

    SciTech Connect (OSTI)

    Le Targat, Rodolphe; Baillard, Xavier; Fouche, Mathilde; Brusch, Anders; Tcherbakoff, Olivier; Rovera, Giovanni D.; Lemonde, Pierre

    2006-09-29

    We report a frequency measurement of the {sup 1}S{sub 0}-{sup 3}P{sub 0} transition of {sup 87}Sr atoms in an optical lattice clock. The frequency is determined to be 429 228 004 229 879(5) Hz with a fractional uncertainty that is comparable to state-of-the-art optical clocks with neutral atoms in free fall. The two previous measurements of this transition were found to disagree by about 2x10{sup -13}, i.e., almost 4 times the combined error bar and 4 to 5 orders of magnitude larger than the claimed ultimate accuracy of this new type of clocks. Our measurement is in agreement with one of these two values and essentially resolves this discrepancy.

  18. Method and apparatus to debug an integrated circuit chip via synchronous clock stop and scan

    SciTech Connect (OSTI)

    Bellofatto, Ralph E.; Ellavsky, Matthew R.; Gara, Alan G.; Giampapa, Mark E.; Gooding, Thomas M.; Haring, Rudolf A.; Hehenberger, Lance G.; Ohmacht, Martin

    2012-03-20

    An apparatus and method for evaluating a state of an electronic or integrated circuit (IC), each IC including one or more processor elements for controlling operations of IC sub-units, and each the IC supporting multiple frequency clock domains. The method comprises: generating a synchronized set of enable signals in correspondence with one or more IC sub-units for starting operation of one or more IC sub-units according to a determined timing configuration; counting, in response to one signal of the synchronized set of enable signals, a number of main processor IC clock cycles; and, upon attaining a desired clock cycle number, generating a stop signal for each unique frequency clock domain to synchronously stop a functional clock for each respective frequency clock domain; and, upon synchronously stopping all on-chip functional clocks on all frequency clock domains in a deterministic fashion, scanning out data values at a desired IC chip state. The apparatus and methodology enables construction of a cycle-by-cycle view of any part of the state of a running IC chip, using a combination of on-chip circuitry and software.

  19. Clock ambiguity and the emergence of physical laws

    SciTech Connect (OSTI)

    Albrecht, Andreas; Iglesias, Alberto

    2008-03-15

    The process of identifying a time variable in time-reparameterization invariant theories results in great ambiguities about the actual laws of physics described by a given theory. A theory set up to describe one set of physical laws can equally well be interpreted as describing any other laws of physics by making a different choice of time variable or clock. In this article we demonstrate how this 'clock ambiguity' arises and then discuss how one might still hope to extract specific predictions about the laws of physics even when the clock ambiguity is present. We argue that a requirement of quasiseparability should play a critical role in such an analysis. As a step in this direction, we compare the Hamiltonian of a local quantum field theory with a completely random Hamiltonian. We find that any random Hamiltonian (constructed in a sufficiently large space) can yield a 'good enough' approximation to a local field theory. Based on this result we argue that theories that suffer from the clock ambiguity may in the end provide a viable fundamental framework for physics in which locality can be seen as a strongly favored (or predicted) emergent behavior. We also speculate on how other key aspects of known physics such as gauge symmetries and Poincare invariance might be predicted to emerge in this framework.

  20. Generating a fault-tolerant global clock using high-speed control signals for the MetaNet architecture

    SciTech Connect (OSTI)

    Ofek, Y. )

    1994-05-01

    This work describes a new technique, based on exchanging control signals between neighboring nodes, for constructing a stable and fault-tolerant global clock in a distributed system with an arbitrary topology. It is shown that it is possible to construct a global clock reference with time step that is much smaller than the propagation delay over the network's links. The synchronization algorithm ensures that the global clock tick' has a stable periodicity, and therefore, it is possible to tolerate failures of links and clocks that operate faster and/or slower than nominally specified, as well as hard failures. The approach taken in this work is to generate a global clock from the ensemble of the local transmission clocks and not to directly synchronize these high-speed clocks. The steady-state algorithm, which generates the global clock, is executed in hardware by the network interface of each node. At the network interface, it is possible to measure accurately the propagation delay between neighboring nodes with a small error or uncertainty and thereby to achieve global synchronization that is proportional to these error measurements. It is shown that the local clock drift (or rate uncertainty) has only a secondary effect on the maximum global clock rate. The synchronization algorithm can tolerate any physical failure. 18 refs.

  1. Shift Register Clock Rate Effects on Coincidence Collection 50MHz versus 4MHz Comparison Tests

    SciTech Connect (OSTI)

    Newell, Matthew R.; Bourret, Steven C.; Swinhoe, Martyn Thomas

    2015-11-03

    The following report identifies and quantifies the timing differences between the older slower Shift Register Coincidence/Multiplicity modules and today’s modern higher speed devices. Modern high speed Shift Register Coincidence/Multiplicity instruments employ high speed internal clocks that run at frequencies more than ten times the older units, typically 50MHz. These higher speed clocks allow for a finer time resolution when recording input pulses.

  2. Central Activator Keeps the Circadian Clock Ticking

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

    Central Activator Keeps the Circadian Clock Ticking Print Most living organisms have adapted their physiology and behavior to match the daily cycle of light and dark generated by the rotation of the earth, operating with a period of approximately 24 hours. Molecular machines in cells ultimately control such rhythmic behavior, the details of which-the "circadian clock"-are largely conserved. To understand the inner workings of the circadian clock, researchers from the University of

  3. Central Activator Keeps the Circadian Clock Ticking

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

    Central Activator Keeps the Circadian Clock Ticking Print Most living organisms have adapted their physiology and behavior to match the daily cycle of light and dark generated by the rotation of the earth, operating with a period of approximately 24 hours. Molecular machines in cells ultimately control such rhythmic behavior, the details of which-the "circadian clock"-are largely conserved. To understand the inner workings of the circadian clock, researchers from the University of

  4. Collisionally induced atomic clock shifts and correlations

    SciTech Connect (OSTI)

    Band, Y. B.; Osherov, I.

    2011-07-15

    We develop a formalism to incorporate exchange symmetry considerations into the calculation of collisional frequency shifts for atomic clocks using a density-matrix formalism. The formalism is developed for both fermionic and bosonic atomic clocks. Numerical results for a finite-temperature {sup 87}Sr {sup 1}S{sub 0} (F=9/2) atomic clock in a magic wavelength optical lattice are presented.

  5. Central Activator Keeps the Circadian Clock Ticking

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

    Central Activator Keeps the Circadian Clock Ticking Print Most living organisms have adapted their physiology and behavior to match the daily cycle of light and dark generated by the rotation of the earth, operating with a period of approximately 24 hours. Molecular machines in cells ultimately control such rhythmic behavior, the details of which-the "circadian clock"-are largely conserved. To understand the inner workings of the circadian clock, researchers from the University of

  6. Central Activator Keeps the Circadian Clock Ticking

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

    Central Activator Keeps the Circadian Clock Ticking Print Most living organisms have adapted their physiology and behavior to match the daily cycle of light and dark generated by the rotation of the earth, operating with a period of approximately 24 hours. Molecular machines in cells ultimately control such rhythmic behavior, the details of which-the "circadian clock"-are largely conserved. To understand the inner workings of the circadian clock, researchers from the University of

  7. Central Activator Keeps the Circadian Clock Ticking

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

    Central Activator Keeps the Circadian Clock Ticking Print Most living organisms have adapted their physiology and behavior to match the daily cycle of light and dark generated by the rotation of the earth, operating with a period of approximately 24 hours. Molecular machines in cells ultimately control such rhythmic behavior, the details of which-the "circadian clock"-are largely conserved. To understand the inner workings of the circadian clock, researchers from the University of

  8. Central Activator Keeps the Circadian Clock Ticking

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

    Central Activator Keeps the Circadian Clock Ticking Print Most living organisms have adapted their physiology and behavior to match the daily cycle of light and dark generated by the rotation of the earth, operating with a period of approximately 24 hours. Molecular machines in cells ultimately control such rhythmic behavior, the details of which-the "circadian clock"-are largely conserved. To understand the inner workings of the circadian clock, researchers from the University of

  9. Central Activator Keeps the Circadian Clock Ticking

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

    Central Activator Keeps the Circadian Clock Ticking Central Activator Keeps the Circadian Clock Ticking Print Wednesday, 31 October 2012 00:00 Most living organisms have adapted their physiology and behavior to match the daily cycle of light and dark generated by the rotation of the earth, operating with a period of approximately 24 hours. Molecular machines in cells ultimately control such rhythmic behavior, the details of which-the "circadian clock"-are largely conserved. To

  10. The AGS Ggamma Meter and Calibrating the Gauss Clock

    SciTech Connect (OSTI)

    Ahrens, Leif

    2014-03-31

    During AGS Polarized Proton acceleration periods, one output from the AGS Ggamma Meter, namely the energy (or Ggamma) calculated from the magnetic field in the AGS main magnets and the beam radius- both measured in particular instant, is used to figure out the times in the AGS magnet acceleration cycle when the beam passes through a particular set of depolarizing resonances. The resonance set occur whenever a particle’s Ggamma (energy*(G/m) becomes nearly equal to n*Qx (i.e. any integer multiplied by the horizontal betatron tune). This deliverable is why the machinery is referred to as the ''Ggamma Meter'' rather than the AGS energy meter. The Ggamma Meter takes as inputs a set of measurements of frequency (F(t)), radius (r(t)), and gauss clock counts (GCC(t)). The other energy (GgammaBr) assumes the field when the gauss clock starts counting is known. The change in field to time t is given by the measured accumulated gauss clock counts multiplied by the gauss clock calibration (gauss/GCC). In order to deal with experimental data, this calibration factor gets an added ad hoc complication, namely a correction dependent on the rate of change the counting rate. The Ggamma meter takes GCC(t) and together with the past history for this cycle calculates B(t).

  11. Spin-1/2 Optical Lattice Clock

    SciTech Connect (OSTI)

    Lemke, N. D.; Ludlow, A. D.; Barber, Z. W.; Fortier, T. M.; Diddams, S. A.; Jiang, Y.; Jefferts, S. R.; Heavner, T. P.; Parker, T. E.; Oates, C. W.

    2009-08-07

    We experimentally investigate an optical clock based on {sup 171}Yb (I=1/2) atoms confined in an optical lattice. We have evaluated all known frequency shifts to the clock transition, including a density-dependent collision shift, with a fractional uncertainty of 3.4x10{sup -16}, limited principally by uncertainty in the blackbody radiation Stark shift. We measured the absolute clock transition frequency relative to the NIST-F1 Cs fountain clock and find the frequency to be 518 295 836 590 865.2(0.7) Hz.

  12. Global synchronization of parallel processors using clock pulse width modulation

    SciTech Connect (OSTI)

    Chen, Dong; Ellavsky, Matthew R.; Franke, Ross L.; Gara, Alan; Gooding, Thomas M.; Haring, Rudolf A.; Jeanson, Mark J.; Kopcsay, Gerard V.; Liebsch, Thomas A.; Littrell, Daniel; Ohmacht, Martin; Reed, Don D.; Schenck, Brandon E.; Swetz, Richard A.

    2013-04-02

    A circuit generates a global clock signal with a pulse width modification to synchronize processors in a parallel computing system. The circuit may include a hardware module and a clock splitter. The hardware module may generate a clock signal and performs a pulse width modification on the clock signal. The pulse width modification changes a pulse width within a clock period in the clock signal. The clock splitter may distribute the pulse width modified clock signal to a plurality of processors in the parallel computing system.

  13. Novel Phase-Coherent Programmable Clock - Energy Innovation Portal

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

    Return to Search Novel Phase-Coherent Programmable Clock Enabling Higher Precision ... DDS frequency stepping i.e. clock waveforms begin and end at the same phase ...

  14. Magic wavelengths for terahertz clock transitions

    SciTech Connect (OSTI)

    Zhou Xiaoji; Xu Xia; Chen Xuzong; Chen Jingbiao

    2010-01-15

    Magic wavelengths for laser trapping of boson isotopes of alkaline-earth metal atoms Sr, Ca, and Mg are investigated while considering terahertz clock transitions between the {sup 3}P{sub 0}, {sup 3}P{sub 1}, and {sup 3}P{sub 2} metastable triplet states. Our calculation shows that magic wavelengths for laser trapping do exist. This result is important because those metastable states have already been used to make accurate clocks in the terahertz frequency domain. Detailed discussions for magic wavelengths for terahertz clock transitions are given in this article.

  15. Phase measurement system using a dithered clock

    DOE Patents [OSTI]

    Fairley, Christopher R.; Patterson, Steven R.

    1991-01-01

    A phase measurement system which measures the phase shift between two signals by dithering a clock signal and averaging a plurality of measurements of the phase differences between the two signals.

  16. Phase measurement system using a dithered clock

    DOE Patents [OSTI]

    Fairley, C.R.; Patterson, S.R.

    1991-05-28

    A phase measurement system is disclosed which measures the phase shift between two signals by dithering a clock signal and averaging a plurality of measurements of the phase differences between the two signals. 8 figures.

  17. Providing Runtime Clock Synchronization With Minimal Node-to...

    Office of Scientific and Technical Information (OSTI)

    Country of Publication: United States Language: English Subject: 99 GENERAL AND ... service; clock synchronization; MPI; supercomputing; system software; programming tools

  18. The chip-scale atomic clock : prototype evaluation.

    SciTech Connect (OSTI)

    Mescher, Mark; Varghese, Mathew; Lutwak, Robert; Serkland, Darwin Keith; Tepolt, Gary; Geib, Kent Martin; Leblanc, John; Peake, Gregory Merwin; Rashid, Ahmed

    2007-12-01

    The authors have developed a chip-scale atomic clock (CSAC) for applications requiring atomic timing accuracy in portable battery-powered applications. At PTTI/FCS 2005, they reported on the demonstration of a prototype CSAC, with an overall size of 10 cm{sup 3}, power consumption > 150 mW, and short-term stability sy(t) < 1 x 10-9t-1/2. Since that report, they have completed the development of the CSAC, including provision for autonomous lock acquisition and a calibrated output at 10.0 MHz, in addition to modifications to the physics package and system architecture to improve performance and manufacturability.

  19. Extended Salecker-Wigner formula for optimal accuracy in reading a clock via a massive signal particle

    SciTech Connect (OSTI)

    Kudaka, Shoju; Matsumoto, Shuichi

    2007-07-15

    In order to acquire an extended Salecker-Wigner formula from which to derive the optimal accuracy in reading a clock with a massive particle as the signal, von Neumann's classical measurement is employed, by which simultaneously both position and momentum of the signal particle can be measured approximately. By an appropriate selection of wave function for the initial state of the composite system (a clock and a signal particle), the formula is derived accurately. Valid ranges of the running time of a clock with a given optimal accuracy are also given. The extended formula means that contrary to the Salecker-Wigner formula there exists the possibility of a higher accuracy of time measurement, even if the mass of the clock is very small.

  20. Realisation of a compact methane optical clock

    SciTech Connect (OSTI)

    Gubin, M A; Kireev, A N; Konyashchenko, A V; Kryukov, P G; Tausenev, A V; Tyurikov, D A; Shelkovnikov, A S

    2008-07-31

    A compact optical clock based on a double-mode He-Ne/CH{sub 4} optical frequency standard and a femtosecond Er{sup 3+} fibre laser is realised and its stability against a commercial hydrogen frequency standard is measured. (letters)

  1. Entangling the lattice clock: Towards Heisenberg-limited timekeeping

    SciTech Connect (OSTI)

    Weinstein, Jonathan D.; Beloy, Kyle; Derevianko, Andrei

    2010-03-15

    A scheme is presented for entangling the atoms of an optical lattice to reduce the quantum projection noise of a clock measurement. The divalent clock atoms are held in a lattice at a 'magic' wavelength that does not perturb the clock frequency - to maintain clock accuracy - while an open-shell J=1/2 'head' atom is coherently transported between lattice sites via the lattice polarization. This polarization-dependent 'Archimedes' screw' transport at magic wavelength takes advantage of the vanishing vector polarizability of the scalar, J=0, clock states of bosonic isotopes of divalent atoms. The on-site interactions between the clock atoms and the head atom are used to engineer entanglement and for clock readout.

  2. High-Accuracy Optical Clock via Three-Level Coherence in Neutral Bosonic {sup 88}Sr

    SciTech Connect (OSTI)

    Santra, Robin; Arimondo, Ennio; Ido, Tetsuya; Greene, Chris H.; Ye, Jun

    2005-05-06

    An optical atomic clock scheme is proposed that utilizes two lasers to establish coherent coupling between the 5s{sup 2} {sup 1}S{sub 0} ground state of {sup 88}Sr and the first excited state, 5s5p {sup 3}P{sub 0}. The coupling is mediated by the broad 5s5p {sup 1}P{sub 1} state, exploiting the phenomenon of electromagnetically induced transparency. The effective linewidth of the clock transition can be chosen at will by adjusting the laser intensity. By trapping the {sup 88}Sr atoms in an optical lattice, long interaction times with the two lasers are ensured; Doppler and recoil effects are eliminated. Based on a careful analysis of systematic errors, a clock accuracy of better than 2x10{sup -17} is expected.

  3. Micromagic Clock: Microwave Clock Based on Atoms in an Engineered Optical Lattice

    SciTech Connect (OSTI)

    Beloy, K.; Derevianko, A.; Dzuba, V. A.; Flambaum, V. V.

    2009-03-27

    We propose a new class of atomic microwave clocks based on the hyperfine transitions in the ground state of aluminum or gallium atoms trapped in optical lattices. For such elements magic wavelengths exist at which both levels of the hyperfine doublet are shifted at the same rate by the lattice laser field, canceling its effect on the clock transition. A similar mechanism for the magic wavelengths may work in microwave hyperfine transitions in other atoms which have the fine-structure multiplets in the ground state.

  4. System-wide power management control via clock distribution network

    DOE Patents [OSTI]

    Coteus, Paul W.; Gara, Alan; Gooding, Thomas M.; Haring, Rudolf A.; Kopcsay, Gerard V.; Liebsch, Thomas A.; Reed, Don D.

    2015-05-19

    An apparatus, method and computer program product for automatically controlling power dissipation of a parallel computing system that includes a plurality of processors. A computing device issues a command to the parallel computing system. A clock pulse-width modulator encodes the command in a system clock signal to be distributed to the plurality of processors. The plurality of processors in the parallel computing system receive the system clock signal including the encoded command, and adjusts power dissipation according to the encoded command.

  5. Orthogonally referenced integrated ensemble for navigation and timing

    DOE Patents [OSTI]

    Smith, Stephen Fulton; Moore, James Anthony

    2014-04-01

    An orthogonally referenced integrated ensemble for navigation and timing includes a dual-polyhedral oscillator array, including an outer sensing array of oscillators and an inner clock array of oscillators situated inside the outer sensing array. The outer sensing array includes a first pair of sensing oscillators situated along a first axis of the outer sensing array, a second pair of sensing oscillators situated along a second axis of the outer sensing array, and a third pair of sensing oscillators situated along a third axis of the outer sensing array. The inner clock array of oscillators includes a first pair of clock oscillators situated along a first axis of the inner clock array, a second pair of clock oscillators situated along a second axis of the inner clock array, and a third pair of clock oscillators situated along a third axis of the inner clock array.

  6. Orthogonally referenced integrated ensemble for navigation and timing

    DOE Patents [OSTI]

    Smith, Stephen Fulton; Moore, James Anthony

    2013-02-26

    An orthogonally referenced integrated ensemble for navigation and timing includes a dual-polyhedral oscillator array, including an outer sensing array of oscillators and an inner clock array of oscillators situated inside the outer sensing array. The outer sensing array includes a first pair of sensing oscillators situated along a first axis of the outer sensing array, a second pair of sensing oscillators situated along a second axis of the outer sensing array, and a third pair of sensing oscillators situated along a third axis of the outer sensing array. The inner clock array of oscillators includes a first pair of clock oscillators situated along a first axis of the inner clock array, a second pair of clock oscillators situated along a second axis of the inner clock array, and a third pair of clock oscillators situated along a third axis of the inner clock array.

  7. Continuous Nondemolition Measurement of the Cs Clock Transition Pseudospin

    SciTech Connect (OSTI)

    Chaudhury, Souma; Smith, Greg A.; Schulz, Kevin; Jessen, Poul S.

    2006-02-03

    We demonstrate a weak continuous measurement of the pseudospin associated with the clock transition in a sample of Cs atoms. Our scheme uses an optical probe tuned near the D{sub 1} transition to measure the sample birefringence, which depends on the z component of the collective pseudospin. At certain probe frequencies the differential light shift of the clock states vanishes, and the measurement is nonperturbing. In dense samples the measurement can be used to squeeze the collective clock pseudospin and has the potential to improve the performance of atomic clocks and interferometers.

  8. Molecular clocks control mutation rate in human cells

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

    All Issues submit Molecular clocks control mutation rate in human cells Mutational processes may be responsible for a large proportion of human cancer, contribute to human ...

  9. Entanglement of trapped-ion clock states

    SciTech Connect (OSTI)

    Haljan, P. C.; Lee, P. J.; Brickman, K-A.; Acton, M.; Deslauriers, L.; Monroe, C.

    2005-12-15

    A Moelmer-Soerensen entangling gate is realized for pairs of trapped {sup 111}Cd{sup +} ions using magnetic-field insensitive 'clock' states and an implementation offering reduced sensitivity to optical phase drifts. The gate is used to generate the complete set of four entangled states, which are reconstructed and evaluated with quantum-state tomography. An average target-state fidelity of 0.79 is achieved, limited by available laser power and technical noise. The tomographic reconstruction of entangled states demonstrates universal quantum control of two ion qubits, which through multiplexing can provide a route to scalable architectures for trapped-ion quantum computing.

  10. Polarizabilities of the beryllium clock transition

    SciTech Connect (OSTI)

    Mitroy, J.

    2010-11-15

    The polarizabilities of the three lowest states of the beryllium atom are determined from a large basis configuration interaction calculation. The polarizabilities of the 2s{sup 2} {sup 1}S{sup e} ground state (37.73a{sub 0}{sup 3}) and the 2s2p {sup 3}P{sub 0}{sup o} metastable state (39.04a{sub 0}{sup 3}) are found to be very similar in size and magnitude. This leads to an anomalously small blackbody radiation shift at 300 K of -0.018(4) Hz for the 2s{sup 2} {sup 1}S{sup e}-2s2p {sup 3}P{sub 0}{sup o} clock transition. Magic wavelengths for simultaneous trapping of the ground and metastable states are also computed.

  11. Hyperpolarizability Effects in a Sr Optical Lattice Clock

    SciTech Connect (OSTI)

    Brusch, Anders; Le Targat, Rodolphe; Baillard, Xavier; Fouche, Mathilde; Lemonde, Pierre

    2006-03-17

    We report the observation of a higher-order frequency shift due to the trapping field in a {sup 87}Sr optical lattice clock. We show that, at the magic wavelength of the lattice, where the first-order term cancels, the higher-order shift will not constitute a limitation to the fractional accuracy of the clock at a level of 10{sup -18}. This result is achieved by operating the clock at very high trapping intensity up to 400 kW/cm{sup 2} and by a specific study of the effect of the two two-photon transitions near the magic wavelength.

  12. Comparison of various clocks at LANL LAPP facility

    SciTech Connect (OSTI)

    Dighe, Kalpak Arvind

    2010-10-29

    Several 40+ hour data records obtained in Oct 2010 from the Los Alamos Portable Pulser Facility (LAPP) Operational clocks show variations of {approx} 27 nsec. Several 16+ hour data records obtained in Aug 2010 from non-operational clocks like those used operationally from 2005 to the present show variations of {approx} 35 nsec. SLRE variability is xxx +/- yyy sec (std dev). SLRE occasionally show unusual events such as those discussed by Pongratz. We will continue to study and monitor.

  13. Superconducting single flux quantum 20 Gb/s clock recovery circuit

    SciTech Connect (OSTI)

    Kaplunenko, V.; Borzenets, V.; Dubash, N.; Van Duzer, T.

    1997-07-01

    A clock recovery circuit has been successfully tested at frequencies up to 20 GHz. This cell is designed for a rapid-single-flux-quantum (RSFQ) telecommunication data switch. It serves to set the receiver clock in phase with the incoming digital signal. The circuit consists of a dc-to-SFQ converter, ring oscillator [(RO) is a closed-loop RSFQ Josephson transmission line], confluence buffer, and an 8-bit binary counter. The input signal transforms to SFQ pulses, and each pulse resets the phase of the ring oscillator, giving a locking time of 1 bit. Thus, the pull-in (capture) range and hold-in (tracking) range are the same, and strictly depend on the encoding of the input signal. This range is estimated to be about 1 GHz at frequency 20 GHz, if the sequence of consecutive ONEs or ZEROs does not exceed 20 bits. The quality factor Q{sub RO} of ring oscillator is about 2000, which gives a jitter of 50 fs for a 35-junction RO. A sampling technique was used to demonstrate phase recovery (phase locking) with only one incoming pulse per 512 clock periods. {copyright} {ital 1997 American Institute of Physics.}

  14. TURNING BACK THE CLOCK: INFERRING THE HISTORY OF THE EIGHT O'CLOCK ARC

    SciTech Connect (OSTI)

    Finkelstein, Steven L.; Papovich, Casey; Rudnick, Gregory; Egami, Eiichi; Rieke, Marcia J.; Willmer, Christopher N. A.; Le Floc'h, Emeric; Rigby, Jane R.

    2009-07-20

    We present the results from an optical and near-infrared (NIR) spectroscopic study of the ultraviolet-luminous z = 2.73 galaxy, the 8 o'clock arc. Due to gravitational lensing, this galaxy is magnified by a factor of {mu} > 10, allowing in-depth measurements which are usually unfeasible at such redshifts. In the optical spectra, we measured the systemic redshift of the galaxy, z = 2.7322{+-} 0.0012, using stellar photospheric lines. This differs from the redshift of absorption lines in the interstellar medium, z = 2.7302 {+-} 0.0006, implying gas outflows on the order of 160 km s{sup -1}. With H- and K-band NIR spectra, we have measured nebular emission lines of H{alpha}, H{beta}, H{gamma}, [N II], and [O III], which have a redshift z = 2.7333 {+-} 0.0001, consistent with the derived systemic redshift. From the Balmer decrement, we measured the dust extinction in this galaxy to be A{sub 5500} = 1.17 {+-} 36 mag. Correcting the H{alpha} line flux for dust extinction as well as the assumed lensing factor, we measure a star formation rate (SFR) of {approx}270 M{sub sun} yr{sup -1}, which is higher than {approx}85% of star-forming galaxies at z {approx} 2-3. Using combinations of all detected emission lines, we find that the 8 o'clock arc has a gas-phase metallicity of {approx}0.8 Z{sub sun}, showing that enrichment at high redshift is not rare, even in blue, star-forming galaxies. Studying spectra from two of the arc components separately, we find that one component dominates both the dust extinction and SFR, although the metallicities between the two components are similar. We derive the mass via stellar population modeling, and find that the arc has a total stellar mass of {approx}4.2 x 10{sup 11} M{sub sun}, which falls on the mass-metallicity relation at z {approx} 2. Finally, we estimate the total gas mass, and find it to be only {approx}12% of the stellar mass, implying that the 8 o'clock arc is likely nearing the end of a starburst.

  15. Clock-like mutational processes in human somatic cells

    SciTech Connect (OSTI)

    Alexandrov, Ludmil B.; Jones, Philip H.; Wedge, David C.; Sale, Julian E.; Campbell, Peter J.; Nik-Zainal, Serena; Stratton, Michael R.

    2015-11-09

    During the course of a lifetime, somatic cells acquire mutations. Different mutational processes may contribute to the mutations accumulated in a cell, with each imprinting a mutational signature on the cell's genome. Some processes generate mutations throughout life at a constant rate in all individuals, and the number of mutations in a cell attributable to these processes will be proportional to the chronological age of the person. Using mutations from 10,250 cancer genomes across 36 cancer types, we investigated clock-like mutational processes that have been operating in normal human cells. Two mutational signatures show clock-like properties. Both exhibit different mutation rates in different tissues. However, their mutation rates are not correlated, indicating that the underlying processes are subject to different biological influences. For one signature, the rate of cell division may influence its mutation rate. This paper provides the first survey of clock-like mutational processes operating in human somatic cells.

  16. Optical-clock local-oscillator stabilization scheme

    SciTech Connect (OSTI)

    Letchumanan, Valliappan; Gill, Patrick; Sinclair, Alastair G.; Riis, Erling

    2006-04-15

    Stabilization of a laser to an optical-clock transition has been demonstrated using Ramsey's phase-modulation technique. The technique was implemented using a 674 nm laser and a component of the 5 s {sup 2}S{sub 1/2}{yields}4d {sup 2}D{sub 5/2} optical clock transition in a single {sup 88}Sr{sup +} ion. The lock performance observed was consistent with the short-term stability of the local oscillator. Compared with existing frequency-modulation stabilization schemes, this technique offers advantages for use in single-ion optical clocks through its possible increased resolution and the ability to conveniently compensate known systematic shifts.

  17. Tuning the narrow-band beam position monitor sampling clock to remove the aliasing errors in APS storage ring orbit measurements.

    SciTech Connect (OSTI)

    Sun, X.; Singh, O. )

    2007-01-01

    The Advanced Photon Source storage ring employs a real-time orbit correction system to reduce orbit motion up to 50 Hz. This system uses up to 142 narrow-band rf beam position monitors (Nbbpms) in a correction algorithm by sampling at a frequency of 1.53 kHz. Several Nbbpms exhibit aliasing errors in orbit measurements, rendering these Nbbpms unusable in real-time orbit feedback. The aliasing errors are caused by beating effects of the internal sampling clocks with various other processing clocks residing within the BPM electronics. A programmable external clock has been employed to move the aliasing errors out of the active frequency band of the real-time feedback system (RTFB) and rms beam motion calculation. This paper discusses the process of tuning and provides test results.

  18. Atomic clock based on transient coherent population trapping

    SciTech Connect (OSTI)

    Guo Tao; Deng Ke; Chen Xuzong; Wang Zhong

    2009-04-13

    We proposed a scheme to implement coherent population trapping (CPT) atomic clock based on the transient CPT phenomenon. We proved that the transient transmitted laser power in a typical {lambda} system near CPT resonance features as a damping oscillation. Also, the oscillating frequency is exactly equal to the frequency detuning from the atomic hyperfine splitting. Therefore, we can directly measure the frequency detuning and then compensated to the output frequency of microwave oscillator to get the standard frequency. By this method, we can further simplify the structure of CPT atomic clock, and make it easier to be digitized and miniaturized.

  19. p-Wave Cold Collisions in an Optical Lattice Clock

    SciTech Connect (OSTI)

    Lemke, N. D.; Sherman, J. A.; Oates, C. W.; Ludlow, A. D.; Stecher, J. von; Rey, A. M.

    2011-09-02

    We study ultracold collisions in fermionic ytterbium by precisely measuring the energy shifts they impart on the atoms' internal clock states. Exploiting Fermi statistics, we uncover p-wave collisions, in both weakly and strongly interacting regimes. With the higher density afforded by two-dimensional lattice confinement, we demonstrate that strong interactions can lead to a novel suppression of this collision shift. In addition to reducing the systematic errors of lattice clocks, this work has application to quantum information and quantum simulation with alkaline-earth atoms.

  20. Generating clock signals for a cycle accurate, cycle reproducible FPGA based hardware accelerator

    DOE Patents [OSTI]

    Asaad, Sameth W.; Kapur, Mohit

    2016-01-05

    A method, system and computer program product are disclosed for generating clock signals for a cycle accurate FPGA based hardware accelerator used to simulate operations of a device-under-test (DUT). In one embodiment, the DUT includes multiple device clocks generating multiple device clock signals at multiple frequencies and at a defined frequency ratio; and the FPG hardware accelerator includes multiple accelerator clocks generating multiple accelerator clock signals to operate the FPGA hardware accelerator to simulate the operations of the DUT. In one embodiment, operations of the DUT are mapped to the FPGA hardware accelerator, and the accelerator clock signals are generated at multiple frequencies and at the defined frequency ratio of the frequencies of the multiple device clocks, to maintain cycle accuracy between the DUT and the FPGA hardware accelerator. In an embodiment, the FPGA hardware accelerator may be used to control the frequencies of the multiple device clocks.

  1. Circadian Clock genes Per2 and clock regulate steroid production, cell proliferation, and luteinizing hormone receptor transcription in ovarian granulosa cells

    SciTech Connect (OSTI)

    Shimizu, Takashi; Hirai, Yuko; Murayama, Chiaki; Miyamoto, Akio; Miyazaki, Hitoshi; Miyazaki, Koyomi

    2011-08-19

    Highlights: {yields} Treatment with Per2 and Clock siRNAs decreased the number of granulosa cells and LHr expression. {yields}Per2 siRNA treatment did not stimulate the production of estradiol and expression of P450arom. {yields} Clock siRNA treatment inhibited the production of estradiol and expression of P450arom mRNA. {yields}Per2 and Clock siRNA treatment increased and unchanged, respectively, progesterone production in FSH-treated granulosa cells. {yields} The expression of StAR mRNA was increased by Per2 siRNA and unchanged by Clock siRNA. -- Abstract: Circadian Clock genes are associated with the estrous cycle in female animals. Treatment with Per2 and Clock siRNAs decreased the number of granulosa cells and LHr expression in follicle-stimulating hormone FSH-treated granulosa cells. Per2 siRNA treatment did not stimulate the production of estradiol and expression of P450arom, whereas Clock siRNA treatment inhibited the production of estradiol and expression of P450arom mRNA. Per2 and Clock siRNA treatment increased and unchanged, respectively, progesterone production in FSH-treated granulosa cells. Similarly, expression of StAR mRNA was increased by Per2 siRNA and unchanged by Clock siRNA. Our data provide a new insight that Per2 and Clock have different action on ovarian granulosa cell functions.

  2. 2014-08-01 Issuance: Energy Conservation Standard for Refrigerated Bottled or Canned Beverage Vending Machines; Notice of Public Meeting and Availability of the Preliminary Technical Support Document

    Broader source: Energy.gov [DOE]

    This document is a pre-publication Federal Register notice of public meeting and availability of the preliminary technical support document for refrigerated bottled or canned beverage vending machines, as issued by the Deputy Assistant Secretary for Energy Efficiency on August 1, 2014. Though it is not intended or expected, should any discrepancy occur between the document posted here and the document published in the Federal Register, the Federal Register publication controls. This document is being made available through the Internet solely as a means to facilitate the public's access to this document.

  3. Optical Lattice Induced Light Shifts in an Yb Atomic Clock

    SciTech Connect (OSTI)

    Barber, Z. W.; Stalnaker, J. E.; Lemke, N. D.; Poli, N.; Oates, C. W.; Fortier, T. M.; Diddams, S. A.; Hollberg, L.; Hoyt, C. W.; Taichenachev, A. V.; Yudin, V. I.

    2008-03-14

    We present an experimental study of the lattice-induced light shifts on the {sup 1}S{sub 0}{yields}{sup 3}P{sub 0} optical clock transition ({nu}{sub clock}{approx_equal}518 THz) in neutral ytterbium. The 'magic' frequency {nu}{sub magic} for the {sup 174}Yb isotope was determined to be 394 799 475(35) MHz, which leads to a first order light shift uncertainty of 0.38 Hz. We also investigated the hyperpolarizability shifts due to the nearby 6s6p{sup 3}P{sub 0}{yields}6s8p{sup 3}P{sub 0}, 6s8p{sup 3}P{sub 2}, and 6s5f{sup 3}F{sub 2} two-photon resonances at 759.708, 754.23, and 764.95 nm, respectively. By measuring the corresponding clock transition shifts near these two-photon resonances, the hyperpolarizability shift was estimated to be 170(33) mHz for a linear polarized, 50 {mu}K deep, lattice at the magic wavelength. These results indicate that the differential polarizability and hyperpolarizability frequency shift uncertainties in a Yb lattice clock could be held to well below 10{sup -17}.

  4. Mapping the magnetic field vector in a fountain clock

    SciTech Connect (OSTI)

    Gertsvolf, Marina; Marmet, Louis

    2011-12-15

    We show how the mapping of the magnetic field vector components can be achieved in a fountain clock by measuring the Larmor transition frequency in atoms that are used as a spatial probe. We control two vector components of the magnetic field and apply audio frequency magnetic pulses to localize and measure the field vector through Zeeman spectroscopy.

  5. Time

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

    3 4 5 6 7 8 9 10 Time with respect to the BNB Trigger Time [µs] 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Fractional Flash Count per 0.15 µs with respect to Cosmic Background Measured Cosmic Rate (Beam-Off) BNB Trigger Data (Beam-On) [4.51E18 POT]

  6. Time

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

    10 15 20 Time with respect to the NuMI Trigger Time [µs] 0.9 1.0 1.1 1.2 1.3 1.4 1.5 Fractional Flash Count per 0.5 µs with respect to Cosmic Background Measured Cosmic Rate (Beam-Off) NuMI Trigger Data (Beam-On) [4.83E18 POT]

  7. Hyper-Ramsey spectroscopy of optical clock transitions

    SciTech Connect (OSTI)

    Yudin, V. I.; Taichenachev, A. V.; Oates, C. W.; Barber, Z. W.; Lemke, N. D.; Ludlow, A. D.; Sterr, U.; Lisdat, Ch.; Riehle, F.

    2010-07-15

    We present nonstandard optical Ramsey schemes that use pulses individually tailored in duration, phase, and frequency to cancel spurious frequency shifts related to the excitation itself. In particular, the field shifts and their uncertainties can be radically suppressed (by two to four orders of magnitude) in comparison with the usual Ramsey method (using two equal pulses) as well as with single-pulse Rabi spectroscopy. Atom interferometers and optical clocks based on two-photon transitions, heavily forbidden transitions, or magnetically induced spectroscopy could significantly benefit from this method. In the latter case, these frequency shifts can be suppressed considerably below a fractional level of 10{sup -17}. Moreover, our approach opens the door for high-precision optical clocks based on direct frequency comb spectroscopy.

  8. Optical lattice clock with atoms confined in a shallow trap

    SciTech Connect (OSTI)

    Lemonde, Pierre; Wolf, Peter

    2005-09-15

    We study the trap depth requirement for the realization of an optical clock using atoms confined in a lattice. We show that site-to-site tunneling leads to a residual sensitivity to the atom dynamics hence requiring large depths [(50-100)E{sub r} for Sr] to avoid any frequency shift or line broadening of the atomic transition at the 10{sup -17}-10{sup -18} level. Such large depths and the corresponding laser power may, however, lead to difficulties (e.g., higher-order light shifts, two-photon ionization, technical difficulties) and therefore one would like to operate the clock in much shallower traps. To circumvent this problem we propose the use of an accelerated lattice. Acceleration lifts the degeneracy between adjacents potential wells which strongly inhibits tunneling. We show that using the Earth's gravity, much shallower traps (down to 5E{sub r} for Sr) can be used for the same accuracy goal.

  9. Constructive polarization modulation for coherent population trapping clock

    SciTech Connect (OSTI)

    Yun, Peter Danet, Jean-Marie; Holleville, David; Clercq, Emeric de; Guérandel, Stéphane

    2014-12-08

    We propose a constructive polarization modulation scheme for atomic clocks based on coherent population trapping (CPT). In this scheme, the polarization of a bichromatic laser beam is modulated between two opposite circular polarizations to avoid trapping the atomic populations in the extreme Zeeman sublevels. We show that if an appropriate phase modulation between the two optical components of the bichromatic laser is applied synchronously, the two CPT dark states which are produced successively by the alternate polarizations add constructively. Measured CPT resonance contrasts up to 20% in one-pulse CPT and 12% in two-pulse Ramsey-CPT experiments are reported, demonstrating the potential of this scheme for applications to high performance atomic clocks.

  10. A Novel Phase-Coherent Programmable Clock for High-Precision Arbitrary Waveform Generation Applied to Digital Ion Trap Mass Spectrometry

    SciTech Connect (OSTI)

    Koizumi, Hideya; Jatko, William Bruce; Andrews Jr, William H; Whitten, William B; Reilly, Pete

    2010-01-01

    Digital ion trap (DIT) mass spectrometry requires the ability to precisely and accurately produce waveforms. The quality of the mass spectra produced in terms of resolution and mass accuracy depend on the resolution and precision of the applied waveforms. This publication reveals a novel method for the production of arbitrary waveforms in general and then applies the method to the production of DIT waveforms. Arbitrary waveforms can be created by varying the clock frequency input to a programmable read only memory that is then input to a digital-to-analog converter (DAC). The arbitrary waveform is composed of a defined number of points that are triggered to be written after programmed numbers of clock cycles to define the arbitrary waveform. The novelty introduced here is that the direct digital synthesis (DDS) generated clock frequency can be precisely changed as the arbitrary waveform is written because we have developed a method to rapidly switch the DDS frequency exactly at the end of the output clock cycle allowing exact timing of multiple transitions to produce precise and temporally complex waveforms. Changing the frequency only at the end of the output clock cycle is a phase coherent process that permits precise timing between each point in the arbitrary waveform. The waveform generation technique was demonstrated by creating a prototype that was used to operate a digital ion trap mass spectrometer. The jitter in the phase-coherent DDS TTL output that was used as the frequency variable clock was 20 ps. This jitter represents the realizable limit of precision for waveform generation. The rectangular waveforms used to operate the mass spectrometer were created with counters that increased the jitter to 100 ps. The mass resolution achieved was 5000 at m/z = 414. This resolution corresponds to a jitter of 275 ps assuming DC fluctuations and overshoots in the waveform are insignificant. Resolution should improve with increasing mass because the waveforms have

  11. Probing many-body interactions in an optical lattice clock

    SciTech Connect (OSTI)

    Rey, A.M.; Gorshkov, A.V.; Kraus, C.V.; Martin, M.J.; Bishof, M.; Swallows, M.D.; Zhang, X.; Benko, C.; Ye, J.; Lemke, N.D.; Ludlow, A.D.

    2014-01-15

    We present a unifying theoretical framework that describes recently observed many-body effects during the interrogation of an optical lattice clock operated with thousands of fermionic alkaline earth atoms. The framework is based on a many-body master equation that accounts for the interplay between elastic and inelastic p-wave and s-wave interactions, finite temperature effects and excitation inhomogeneity during the quantum dynamics of the interrogated atoms. Solutions of the master equation in different parameter regimes are presented and compared. It is shown that a general solution can be obtained by using the so called Truncated Wigner Approximation which is applied in our case in the context of an open quantum system. We use the developed framework to model the density shift and decay of the fringes observed during Ramsey spectroscopy in the JILA {sup 87}Sr and NIST {sup 171}Yb optical lattice clocks. The developed framework opens a suitable path for dealing with a variety of strongly-correlated and driven open-quantum spin systems. -- Highlights: •Derived a theoretical framework that describes many-body effects in a lattice clock. •Validated the analysis with recent experimental measurements. •Demonstrated the importance of beyond mean field corrections in the dynamics.

  12. Clock-like mutational processes in human somatic cells

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

    Alexandrov, Ludmil B.; Jones, Philip H.; Wedge, David C.; Sale, Julian E.; Campbell, Peter J.; Nik-Zainal, Serena; Stratton, Michael R.

    2015-11-09

    During the course of a lifetime, somatic cells acquire mutations. Different mutational processes may contribute to the mutations accumulated in a cell, with each imprinting a mutational signature on the cell's genome. Some processes generate mutations throughout life at a constant rate in all individuals, and the number of mutations in a cell attributable to these processes will be proportional to the chronological age of the person. Using mutations from 10,250 cancer genomes across 36 cancer types, we investigated clock-like mutational processes that have been operating in normal human cells. Two mutational signatures show clock-like properties. Both exhibit different mutationmore » rates in different tissues. However, their mutation rates are not correlated, indicating that the underlying processes are subject to different biological influences. For one signature, the rate of cell division may influence its mutation rate. This paper provides the first survey of clock-like mutational processes operating in human somatic cells.« less

  13. A low phase noise microwave frequency synthesis for a high-performance cesium vapor cell atomic clock

    SciTech Connect (OSTI)

    François, B.; Boudot, R.; Calosso, C. E.; Danet, J. M.

    2014-09-15

    We report the development, absolute phase noise, and residual phase noise characterization of a 9.192 GHz microwave frequency synthesis chain devoted to be used as a local oscillator in a high-performance cesium vapor cell atomic clock based on coherent population trapping (CPT). It is based on frequency multiplication of an ultra-low phase noise 100 MHz oven-controlled quartz crystal oscillator using a nonlinear transmission line-based chain. Absolute phase noise performances of the 9.192 GHz output signal are measured to be −42, −100, −117 dB rad{sup 2}/Hz and −129 dB rad{sup 2}/Hz at 1 Hz, 100 Hz, 1 kHz, and 10 kHz offset frequencies, respectively. Compared to current results obtained in a state-of-the-art CPT-based frequency standard developed at LNE-SYRTE, this represents an improvement of 8 dB and 10 dB at f = 166 Hz and f = 10 kHz, respectively. With such performances, the expected Dick effect contribution to the atomic clock short term frequency stability is reported at a level of 6.2 × 10{sup −14} at 1 s integration time, that is a factor 3 higher than the atomic clock shot noise limit. Main limitations are pointed out.

  14. Performance of a prototype atomic clock based on lin parallel lin coherent population trapping resonances in Rb atomic vapor

    SciTech Connect (OSTI)

    Mikhailov, Eugeniy E.; Horrom, Travis; Belcher, Nathan; Novikova, Irina

    2010-03-15

    We report on the performance of the first table-top prototype atomic clock based on coherent population trapping (CPT) resonances with parallel linearly polarized optical fields (lin parallel lin configuration). Our apparatus uses a vertical-cavity surface-emitting laser (VCSEL) tuned to the D{sub 1} line of {sup 87}Rb with the current modulation at the {sup 87}Rb hyperfine frequency. We demonstrate cancellation of the first-order light shift by the proper choice of rf modulation power and further improve our prototype clock stability by optimizing the parameters of the microwave lock loop. Operating in these optimal conditions, we measured a short-term fractional frequency stability (Allan deviation) 2x10{sup -11}{tau}{sup -1/2} for observation times 1 s{<=}{tau}{<=}20 s. This value is limited by large VCSEL phase noise and environmental temperature fluctuation. Further improvements in frequency stability should be possible with an apparatus designed as a dedicated lin parallel lin CPT resonance clock with environmental impacts minimized.

  15. Clock synchronization and isotropy of the one-way speed of light

    SciTech Connect (OSTI)

    Will, C.M. )

    1992-01-15

    Experimental tests of the isotropy of the speed of light using one-way propagation are analyzed using a test theory of special relativity. It is shown that, when properly expressed in terms of measurable quantities, the results of such experiments are independent of the method of global synchronization of clocks. Experiments analyzed include a Jet Propulsion Laboratory time-of-flight measurement, a resonant two-photon absorption experiment, the Smithsonian Astrophysical Observatory--NASA 1976 rocket gravitational redshift experiment, and Moessbauer rotor experiments. If the characteristic anisotropy is proportional to {alpha}{ital w}, where {ital w} is the velocity of the Earth relative to the cosmic background radiation, the best bound on {alpha} from these experiments is {vert bar}{alpha}{vert bar}{lt}9{times}10{sup {minus}8}.

  16. Tevatron injection timing

    SciTech Connect (OSTI)

    Saritepe, S.; Annala, G.

    1993-06-01

    Bunched beam transfer from one accelerator to another requires coordination and synchronization of many ramped devices. During collider operation timing issues are more complicated since one has to switch from proton injection devices to antiproton injection devices. Proton and antiproton transfers are clearly distinct sequences since protons and antiprotons circulate in opposite directions in the Main Ring (MR) and in the Tevatron. The time bumps are different, the kicker firing delays are different, the kickers and lambertson magnets are different, etc. Antiprotons are too precious to be used for tuning purposes, therefore protons are transferred from the Tevatron back into the Main Ring, tracing the path of antiprotons backwards. This tuning operation is called ``reverse injection.`` Previously, the reverse injection was handled in one supercycle. One batch of uncoalesced bunches was injected into the Tevatron and ejected after 40 seconds. Then the orbit closure was performed in the MR. In the new scheme the lambertson magnets have to be moved and separator polarities have to be switched, activities that cannot be completed in one supercycle. Therefore, the reverse injection sequence was changed. This involved the redefinition of TVBS clock event $D8 as MRBS $D8 thus making it possible to inject 6 proton batches (or coalesced bunches) and eject them one at a time on command, performing orbit closure each time in the MR. Injection devices are clock event driven. The TCLK is used as the reference clock. Certain TCLK events are triggered by the MR beam synchronized clock (MRBS) events. Some delays are measured in terms of MRBS ticks and MR revolutions. See Appendix A for a brief description of the beam synchronized clocks.

  17. System and method for adaptively deskewing parallel data signals relative to a clock

    DOE Patents [OSTI]

    Jenkins, Philip Nord; Cornett, Frank N.

    2008-10-07

    A system and method of reducing skew between a plurality of signals transmitted with a transmit clock is described. Skew is detected between the received transmit clock and each of received data signals. Delay is added to the clock or to one or more of the plurality of data signals to compensate for the detected skew. The delay added to each of the plurality of delayed signals is updated to adapt to changes in detected skew.

  18. System and method for adaptively deskewing parallel data signals relative to a clock

    DOE Patents [OSTI]

    Jenkins, Philip Nord; Cornett, Frank N.

    2011-10-04

    A system and method of reducing skew between a plurality of signals transmitted with a transmit clock is described. Skew is detected between the received transmit clock and each of received data signals. Delay is added to the clock or to one or more of the plurality of data signals to compensate for the detected skew. The delay added to each of the plurality of delayed signals is updated to adapt to changes in detected skew.

  19. On Loops in Inflation II: IR Effects in Single Clock Inflation...

    Office of Scientific and Technical Information (OSTI)

    Title: On Loops in Inflation II: IR Effects in Single Clock Inflation Authors: Senatore, Leonardo ; Stanford U., ITP KIPAC, Menlo Park ; Zaldarriaga, Matias ; Princeton, Inst. ...

  20. Low-power, miniature {sup 171}Yb ion clock using an ultra-small vacuum package

    SciTech Connect (OSTI)

    Jau, Y.-Y.; Schwindt, P. D. D.; Partner, H.; Prestage, J. D.; Kellogg, J. R.; Yu, N.

    2012-12-17

    We report a demonstration of a very small microwave atomic clock using the 12.6 GHz hyperfine transition of the trapped {sup 171}Yb ions inside a miniature, completely sealed-off 3 cm{sup 3} ion-trap vacuum package. In the ion clock system, all of the components are highly miniaturized with low power consumption except the 369 nm optical pumping laser still under development for miniaturization. The entire clock, including the control electronics, consumes <300 mW. The fractional frequency instability of the miniature Yb{sup +} clock reaches the 10{sup -14} range after a few days of integration.

  1. Comparison of Test Procedures and Energy Efficiency Criteria in Selected International Standards and Labeling Programs for Clothes Washers, Water Dispensers, Vending Machines and CFLs

    SciTech Connect (OSTI)

    Fridley, David; Zheng, Nina; Zhou, Nan

    2010-06-01

    Since the late 1970s, energy labeling programs and mandatory energy performance standards have been used in many different countries to improve the efficiency levels of major residential and commercial equipment. As more countries and regions launch programs covering a greater range of products that are traded worldwide, greater attention has been given to harmonizing the specific efficiency criteria in these programs and the test methods for measurements. For example, an international compact fluorescent light (CFL) harmonization initiative was launched in 2006 to focus on collaboration between Australia, China, Europe and North America. Given the long history of standards and labeling programs, most major energy-consuming residential appliances and commercial equipment are already covered under minimum energy performance standards (MEPS) and/or energy labels. For these products, such as clothes washers and CFLs, harmonization may still be possible when national MEPS or labeling thresholds are revised. Greater opportunity for harmonization exists in newer energy-consuming products that are not commonly regulated but are under consideration for new standards and labeling programs. This may include commercial products such as water dispensers and vending machines, which are only covered by MEPS or energy labels in a few countries or regions. As China continues to expand its appliance standards and labeling programs and revise existing standards and labels, it is important to learn from recent international experiences with efficiency criteria and test procedures for the same products. Specifically, various types of standards and labeling programs already exist in North America, Europe and throughout Asia for products in China's 2010 standards and labeling programs, namely clothes washers, water dispensers, vending machines and CFLs. This report thus examines similarities and critical differences in energy efficiency values, test procedure specifications and other

  2. System and method for time synchronization in a wireless network

    DOE Patents [OSTI]

    Gonia, Patrick S.; Kolavennu, Soumitri N.; Mahasenan, Arun V.; Budampati, Ramakrishna S.

    2010-03-30

    A system includes multiple wireless nodes forming a cluster in a wireless network, where each wireless node is configured to communicate and exchange data wirelessly based on a clock. One of the wireless nodes is configured to operate as a cluster master. Each of the other wireless nodes is configured to (i) receive time synchronization information from a parent node, (ii) adjust its clock based on the received time synchronization information, and (iii) broadcast time synchronization information based on the time synchronization information received by that wireless node. The time synchronization information received by each of the other wireless nodes is based on time synchronization information provided by the cluster master so that the other wireless nodes substantially synchronize their clocks with the clock of the cluster master.

  3. Magnetic blackbody shift of hyperfine transitions for atomic clocks

    SciTech Connect (OSTI)

    Berengut, J. C.; Flambaum, V. V.; King-Lacroix, J.

    2009-12-15

    We derive an expression for the magnetic blackbody shift of hyperfine transitions such as the cesium primary reference transition which defines the second. The shift is found to be a complicated function of temperature, and has a T{sup 2} dependence only in the high-temperature limit. We also calculate the shift of ground-state p{sub 1/2} hyperfine transitions which have been proposed as new atomic clock transitions. In this case interaction with the p{sub 3/2} fine-structure multiplet may be the dominant effect.

  4. Disentangling forms of Lorentz violation with complementary clock comparison experiments

    SciTech Connect (OSTI)

    Altschul, Brett

    2009-03-15

    Atomic clock comparisons provide some of the most precise tests of Lorentz and CPT symmetries in the laboratory. With data from multiple such experiments using different nuclei, it is possible to constrain new regions of the parameter space for Lorentz violation. Relativistic effects in the nuclei allow us to disentangle forms of Lorentz violation which could not be separately measured in purely nonrelativistic experiments. The disentangled bounds in the neutron sectors are at the 10{sup -28} GeV level, far better than could be obtained with any other current technique.

  5. Resolved Atomic Interaction Sidebands in an Optical Clock Transition

    SciTech Connect (OSTI)

    Bishof, M.; Lin, Y.; Swallows, M. D.; Ye, J.; Rey, A. M.; Gorshkov, A. V.

    2011-06-24

    We report the observation of resolved atomic interaction sidebands (ISB) in the {sup 87}Sr optical clock transition when atoms at microkelvin temperatures are confined in a two-dimensional optical lattice. The ISB are a manifestation of the strong interactions that occur between atoms confined in a quasi-one-dimensional geometry and disappear when the confinement is relaxed along one dimension. The emergence of ISB is linked to the recently observed suppression of collisional frequency shifts. At the current temperatures, the ISB can be resolved but are broad. At lower temperatures, ISB are predicted to be substantially narrower and useful spectroscopic tools in strongly interacting alkaline-earth gases.

  6. Beverage Vending Machines

    Broader source: Energy.gov [DOE]

    The Department of Energy (DOE) develops standardized data templates for reporting the results of tests conducted in accordance with current DOE test procedures. Templates may be used by third-party laboratories under contract with DOE that conduct testing in support of ENERGY STAR® verification, DOE rulemakings, and enforcement of the federal energy conservation standards.

  7. On re-setting the fatigue clock on older semisubmersible vessels

    SciTech Connect (OSTI)

    Wade, B.G.

    1994-12-31

    The fatigue strength of a generic submersible, enhanced to a FPF, was determined using 1980 design regulations and compared with 1993 guidelines. The fatigue clock on this older semisubmersible was reset using advances in the fatigue assessment of weld imperfections that were not available at the time this vessel was originally designed. An inspection strategy of critical weld details was established based upon recently available crack growth data and more up-to-date fracture mechanics methods. Examples of this data include crack growth rate and threshold stress intensity factor data. Fracture mechanics analyses were performed that recognized the importance of weld imperfection shape and its evolution throughout life. Recent 3-D finite element analyses of semi-elliptical cracks located at weld toes show that crack shape and proximity of the crack front to the weld toe can significantly affect crack life.

  8. Reliable clock estimation using linear weighted fusion based on pairwise broadcast synchronization

    SciTech Connect (OSTI)

    Shi, Xin Zhao, Xiangmo Hui, Fei Ma, Junyan Yang, Lan

    2014-10-06

    Clock synchronization in wireless sensor networks (WSNs) has been studied extensively in recent years and many protocols are put forward based on the point of statistical signal processing, which is an effective way to optimize accuracy. However, the accuracy derived from the statistical data can be improved mainly by sufficient packets exchange, which will consume the limited power resources greatly. In this paper, a reliable clock estimation using linear weighted fusion based on pairwise broadcast synchronization is proposed to optimize sync accuracy without expending additional sync packets. As a contribution, a linear weighted fusion scheme for multiple clock deviations is constructed with the collaborative sensing of clock timestamp. And the fusion weight is defined by the covariance of sync errors for different clock deviations. Extensive simulation results show that the proposed approach can achieve better performance in terms of sync overhead and sync accuracy.

  9. Clock signal requirement for high-frequency, high dynamic range acquisition systems

    SciTech Connect (OSTI)

    Viscor, Ivo; Halamek, Josef; Villa, Marco

    2005-11-15

    Analog-to-digital converters (ADC's) are increasingly replacing mixers in frequency conversion schemes. To achieve superior performances, in terms of bandwidth and dynamic range, a nearly ideal ADC clock is needed, with a spectral purity higher than the reference signal of the classical mixing scheme. These requirements of spectral purity for the ADC clock are discussed by analyzing in detail the nonuniform sampling process and by characterizing an actual acquisition system. The effect of clock phase imperfections on the output is proportional to the input frequency over sampling frequency ratio. Moreover, at the output we may have a multiple folding of the phase jitter spectrum. These effects are illustrated by three sets of measurements performed using our system: transfer of spurious clock components, aliasing of these components, and transfer of clock phase noise.

  10. Collisional shifts in optical-lattice atom clocks

    SciTech Connect (OSTI)

    Band, Y. B. [Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Atomic Physics Division, A267 Physics, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Ilse Katz Center for Nano-Science, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Vardi, A. [Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)

    2006-09-15

    We theoretically study the effects of elastic collisions on the determination of frequency standards via Ramsey-fringe spectroscopy in optical-lattice atom clocks. Interparticle interactions of bosonic atoms in multiply occupied lattice sites can cause a linear frequency shift, as well as generate asymmetric Ramsey-fringe patterns and reduce fringe visibility due to interparticle entanglement. We propose a method of reducing these collisional effects in an optical lattice by introducing a phase difference of {pi} between the Ramsey driving fields in adjacent sites. This configuration suppresses site-to-site hopping due to interference of two tunneling pathways, without degrading fringe visibility. Consequently, the probability of double occupancy is reduced, leading to cancellation of collisional shifts.

  11. System and method for adaptively deskewing parallel data signals relative to a clock

    DOE Patents [OSTI]

    Jenkins, Philip Nord; Cornett, Frank N.

    2006-04-18

    A system and method of reducing skew between a plurality of signals transmitted with a transmit clock is described. Skew is detected between the received transmit clock and each of received data signals. Delay is added to the clock or to one or more of the plurality of data signals to compensate for the detected skew. Each of the plurality of delayed signals is compared to a reference signal to detect changes in the skew. The delay added to each of the plurality of delayed signals is updated to adapt to changes in the detected skew.

  12. How to make optimal use of maximal multipartite entanglement in clock synchronization

    SciTech Connect (OSTI)

    Ren, Changliang; Hofmann, Holger F.

    2014-12-04

    We introduce a multi-party quantum clock synchronization protocol that makes optimal use of the maximal multipartite entanglement of GHZ-type states. The measurement statistics of the protocol are analyzed and the efficiency is evaluated.

  13. High-stability compact atomic clock based on isotropic laser cooling

    SciTech Connect (OSTI)

    Esnault, Francois-Xavier; Holleville, David; Rossetto, Nicolas; Guerandel, Stephane; Dimarcq, Noel

    2010-09-15

    We present a compact cold-atom clock configuration where isotropic laser cooling, microwave interrogation, and clock signal detection are successively performed inside a spherical microwave cavity. For ground operation, a typical Ramsey fringe width of 20 Hz has been demonstrated, limited by the atom cloud's free fall in the cavity. The isotropic cooling light's disordered properties provide a large and stable number of cold atoms, leading to a high signal-to-noise ratio limited by atomic shot noise. A relative frequency stability of 2.2x10{sup -13{tau}-1/2} has been achieved, averaged down to 4x10{sup -15} after 5x10{sup 3} s of integration. Development of such a high-performance compact clock is of major relevance for on-board applications, such as satellite-positioning systems. As a cesium clock, it opens the door to a new generation of compact primary standards and timekeeping devices.

  14. Theory of an Earth-bound clock comparison experiment as test of the principle of equivalence

    SciTech Connect (OSTI)

    Opat, G.I. Nuclear Physics Laboratory, GL-10, University of Washington, Seattle, Washington ); Unruh, W.G. )

    1991-11-15

    The comparison at sea level of the rates of two atomic clocks of differing geographical latitude is shown to provide a sensitive test of the principle of equivalence. Specifically, clocks of 1/10{sup 15} stability would effectively compare the rate of fall of the excitation energy of an atom with that of sea water to an accuracy of 1/10{sup 14} or better, a comparison which would be extremely difficult by normal techniques.

  15. Paleoclimatology: Second clock supports orbital pacing of the ice ages

    SciTech Connect (OSTI)

    Kerr, R.A.

    1997-05-02

    For a while, it looked as if a water-filled crack in the Nevada desert might doom the accepted explanation of the ice ages. Twenty years ago, the so-called astronomical theory had carried the day. Oceanographers had found evidence implying that the march of ice ages over the last million years was paced by the cyclical stretching and squeezing of Earth`s orbit around the sun, which would have altered the way sunlight fell on the planet`s surface. But in 1988, researchers scuba diving in Nevada`s Devils Hole came up with a climate record--captured in carbonate deposits in the crack-that seemed to contradict this chronology. This article discusses the findings and the puzzles that still remain. The records of sea-level change in Barbados coral appear to be right and the astronomical theory is on solid ground using a new clock based on the radioactive decay of uranium-235 to protactinium-231. However, the Devils Hole record also seems to be correct.

  16. Time measurment system at the SSC

    SciTech Connect (OSTI)

    Arai, Yasuo

    1989-04-01

    A proposal of time measurement system at the SSC experiment is described. An example of a possible scheme for central tracking chambers is shown. Designs of a preamp/shaper/discri chip and a time digitizer chip are described. A method to distribute system clock and power/cooling problems are also discussed.

  17. Observation of the {sup 1}S{sub 0}{yields}{sup 3}P{sub 0} Clock Transition in {sup 27}Al{sup +}

    SciTech Connect (OSTI)

    Rosenband, T.; Schmidt, P. O.; Hume, D. B.; Itano, W. M.; Stalnaker, J. E.; Kim, K.; Diddams, S. A.; Koelemeij, J. C. J.; Bergquist, J. C.; Wineland, D. J.; Fortier, T. M.

    2007-06-01

    We report, for the first time, laser spectroscopy of the {sup 1}S{sub 0}{yields}{sup 3}P{sub 0} clock transition in {sup 27}Al{sup +}. A single aluminum ion and a single beryllium ion are simultaneously confined in a linear Paul trap, coupled by their mutual Coulomb repulsion. This coupling allows the beryllium ion to sympathetically cool the aluminum ion and also enables transfer of the aluminum's electronic state to the beryllium's hyperfine state, which can be measured with high fidelity. These techniques are applied to measure the clock transition frequency {nu}=1 121 015 393 207 851(6) Hz. They are also used to measure the lifetime of the metastable clock state {tau}=20.6{+-}1.4 s, the ground state {sup 1}S{sub 0} g factor g{sub S}=-0.000 792 48(14), and the excited state {sup 3}P{sub 0} g factor g{sub P}=-0.001 976 86(21), in units of the Bohr magneton.

  18. The dark energy cosmic clock: a new way to parametrise the equation of state

    SciTech Connect (OSTI)

    Tarrant, Ewan R.M.; Copeland, Edmund J.; Padilla, Antonio; Skordis, Constantinos E-mail: ed.copeland@nottingham.ac.uk E-mail: skordis@nottingham.ac.uk

    2013-12-01

    We propose a new parametrisation of the dark energy equation of state, which uses the dark energy density, Ω{sub e} as a cosmic clock. We expand the equation of state in a series of orthogonal polynomials, with Ω{sub e} as the expansion parameter and determine the expansion coefficients by fitting to SNIa and H(z) data. Assuming that Ω{sub e} is a monotonic function of time, we show that our parametrisation performs better than the popular Chevallier-Polarski-Linder (CPL) and Gerke and Efstathiou (GE) parametrisations, and we demonstrate that it is robust to the choice of prior. Expanding in orthogonal polynomials allows us to relate models of dark energy directly to our parametrisation, which we illustrate by placing constraints on the expansion coefficients extracted from two popular quintessence models. Finally, we comment on how this parametrisation could be modified to accommodate high redshift data, where any non-monotonicity of Ω{sub e} would need to be accounted for.

  19. A simple analog clock used for reducing pedestal noise

    SciTech Connect (OSTI)

    1996-12-31

    Experimental facilities are inherently noisy places. Try as one might to eliminate it, there always seems to be some residual low frequency electronic hum that works its way into low level analog signals, such as calorimetry into analog-to-digital converters (ADC). At the Fermilab Wide Band Lab, the predominant noise (between experimental hall and counting room, and between electronics racks within experimental hall and within counting room) consists of a combination of 60 Hz plus 180 Hz adding together with equal amplitudes and identical phase. The noise contributions at these low frequencies are easily removed by capacitor-coupling or isolation transformers. This approach works well for most detector systems. However, for the highest rate analog detector systems, e.g. the calorimeters within the beam stops for the electron (RESH-0), positron (POSH-O), and photon (BGM) beams for E-831 lFOCUS, these AC couplers introduce unacceptable signal distortion and rate-dependent analog baseline shifts. The residual 60/180 Hz hum, between these detectors and their ADCS, is typically on the order of 10 revolt peak-to-peak at the Wide Band Laboratory, which drastically smears the pedestal spectra and constitutes the major contribution to the resolution for these detector systems. The author, rather than continue to beat his head against the wall in trying to eliminate all this noise, implemented a simple 60 Hz analog clock ramp which was read into an ADC channel simultaneously as part of the data event record and which indicated the instantaneous phase relative to the 60 Hz AC power at Wide Band Laboratory. The pedestal was then monitored and parameterized as a function of this phase. During analysis, the digitized analog system had its phase-dependent pedestal subtracted, thereby substantially reducing the low-frequency pedestal noise. The 60 Hz analog clock circuit is a simple saw-tooth ramp generator. It is packaged in two NIM modules to provide additional isolation between

  20. Bidirectional CLOCK/BMAL1-dependent circadian gene regulation by retinoic acid in vitro

    SciTech Connect (OSTI)

    Shirai, Hidenori; Oishi, Katsutaka; Ishida, Norio . E-mail: n.ishida@aist.go.jp

    2006-12-15

    A central circadian clock located in the suprachiasmatic nucleus (SCN) of the mammalian hypothalamus entrains peripheral clocks through both neural and humoral factors. Although candidates for entrainment factors have been described, their details remain obscure. Here, we screened ligands for nuclear receptors that affect CLOCK/BMAL1-dependent transactivation of the mouse Period1 (mPer1) gene in NIH3T3 cells. We found that retinoic acids (RAs) significantly up-regulate mPer1 expression in an E-box-dependent manner. We also found that RAs up-regulate the expression of other E-box-dependent circadian genes such as mPer2, arginine vasopressin (mAVP), and peroxisome proliferator-activated receptor {alpha} (mPPAR{alpha}). Surprisingly, the effect of RAs on CLOCK/BMAL1 (E-box)-dependent mRNA expression was bidirectional and depended on the presence of exogenous retinoic acid receptor {alpha} (RAR{alpha}). These results suggest that RAs regulate the CLOCK/BMAL1-dependent transcription of circadian genes in a complex manner.

  1. Digital time delay

    DOE Patents [OSTI]

    Martin, A.D.

    1986-05-09

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay provides a first output signal at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits latch the high resolution data to form a first synchronizing data set. A selected time interval has been preset to internal counters and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses count down the counters to generate an internal pulse delayed by an internal which is functionally related to the preset time interval. A second LCD corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD to generate a second set of synchronizing data which is complementary with the first set of synchronizing data for presentation to logic circuits. The logic circuits further delay the internal output signal with the internal pulses. The final delayed output signal thereafter enables the output pulse generator to produce the desired output pulse at the preset time delay interval following input of the trigger pulse.

  2. Clock-controlled output gene Dbp is a regulator of Arnt/Hif-1β gene expression in pancreatic islet β-cells

    SciTech Connect (OSTI)

    Nakabayashi, Hiroko; Ohta, Yasuharu Yamamoto, Masayoshi; Susuki, Yosuke; Taguchi, Akihiko; Tanabe, Katsuya; Kondo, Manabu; Hatanaka, Masayuki; Nagao, Yuko; Tanizawa, Yukio

    2013-05-03

    Highlights: •Arnt mRNA expressed in a circadian manner in mouse pancreatic islets. •Expressions of Dbp and Arnt damped in the islets of a diabetic model mouse. •DBP and E4BP4 regulate Arnt promoter activity by direct binding. •Arnt may have a role in connecting circadian rhythm and metabolism. -- Abstract: Aryl hydrocarbon receptor nuclear translocator (ARNT)/hypoxia inducible factor-1β (HIF-1β) has emerged as a potential determinant of pancreatic β-cell dysfunction and type 2 diabetes in humans. An 82% reduction in Arnt expression was observed in islets from type 2 diabetic donors as compared to non-diabetic donors. However, few regulators of Arnt expression have been identified. Meanwhile, disruption of the clock components CLOCK and BMAL1 is known to result in hypoinsulinemia and diabetes, but the molecular details remain unclear. In this study, we identified a novel molecular connection between Arnt and two clock-controlled output genes, albumin D-element binding protein (Dbp) and E4 binding protein 4 (E4bp4). By conducting gene expression studies using the islets of Wfs1{sup −/−} A{sup y}/a mice that develop severe diabetes due to β-cell apoptosis, we demonstrated clock-related gene expressions to be altered in the diabetic mice. Dbp mRNA decreased by 50%, E4bp4 mRNA increased by 50%, and Arnt mRNA decreased by 30% at Zeitgever Time (ZT) 12. Mouse pancreatic islets exhibited oscillations of clock gene expressions. E4BP4, a D-box negative regulator, oscillated anti-phase to DBP, a D-box positive regulator. We also found low-amplitude circadian expression of Arnt mRNA, which peaked at ZT4. Over-expression of DBP raised both mRNA and protein levels of ARNT in HEK293 and MIN6 cell lines. Arnt promoter-driven luciferase reporter assay in MIN6 cells revealed that DBP increased Arnt promoter activity by 2.5-fold and that E4BP4 competitively inhibited its activation. In addition, on ChIP assay, DBP and E4BP4 directly bound to D-box elements within the

  3. Nuclear Physics for the Re/Os Clock

    SciTech Connect (OSTI)

    Mosconi, M.; Koehler, Paul Edward; Collaboration, n_TOF

    2008-01-01

    Dating the age of the universe by the {beta}-decay of {sup 187}Re (t{sub 1/2} = 41.2 Gyr) requires the accurate assessment of the s-process reaction flow. The daughter nucleus {sup 187}Os as well as its immediate s-only neighbor {sup 186}Os are shielded from the r-process. Therefore, the radiogenic contribution to {sup 187}Os can be derived via the local approximation of the s-process, which is well justified in this mass region: ({l_angle}{sigma}{r_angle}N{sub s})187 = ({l_angle}{sigma}{r_angle}N{sub s})186. Accordingly, accurate Maxwellian-averaged (n, {gamma}) cross sections have to be known for {sup 186}Os and {sup 187}Os over the full range of s-process temperatures. Because {sup 187}Os has low-lying excited states, which are significantly populated during the s-process, neutron captures on these excited states have to be properly taken into account. The input for the corresponding Hauser-Feshbach calculations can be constrained by deriving the strength functions from a detailed resonance analysis of the measured (n, {gamma}) cross sections as well as by an additional measurement of the inelastic scattering cross section for the first exited level, which dominates the competition between the capture and scattering channels. This contribution reports on measurements of the neutron capture cross sections of {sup 186}Os, {sup 187}Os and {sup 188}Os from the eV region to 1 MeV at the CERN/n{_}TOF facility and of the inelastic scattering cross section of {sup 187}Os around 30 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Based on these results and on a detailed resonance analysis, improved Maxwellian-averaged cross sections were obtained for thermal energies between 5 keV and 100 keV. The implications of these results for the Re/Os clock are discussed.

  4. {sup 87}Sr Lattice Clock with Inaccuracy below 10{sup -15}

    SciTech Connect (OSTI)

    Boyd, Martin M.; Ludlow, Andrew D.; Blatt, Sebastian; Foreman, Seth M.; Ido, Tetsuya; Zelevinsky, Tanya; Ye Jun

    2007-02-23

    Aided by ultrahigh resolution spectroscopy, the overall systematic uncertainty of the {sup 1}S{sub 0}-{sup 3}P{sub 0} clock resonance for lattice-confined {sup 87}Sr has been characterized to 9x10{sup -16}. This uncertainty is at a level similar to the Cs-fountain primary standard, while the potential stability for the lattice clocks exceeds that of Cs. The absolute frequency of the clock transition has been measured to be 429 228 004 229 874.0(1.1) Hz, where the 2.5x10{sup -15} fractional uncertainty represents the most accurate measurement of a neutral-atom-based optical transition frequency to date.

  5. Cold-collision-shift cancellation and inelastic scattering in a Yb optical lattice clock

    SciTech Connect (OSTI)

    Ludlow, A. D.; Lemke, N. D.; Sherman, J. A.; Oates, C. W.; Quemener, G.; Stecher, J. von; Rey, A. M.

    2011-11-15

    Recently, p-wave cold collisions were shown to dominate the density-dependent shift of the clock transition frequency in a {sup 171}Yb optical lattice clock. Here we demonstrate that by operating such a system at the proper excitation fraction, the cold-collision shift is canceled below the 5x10{sup -18} fractional frequency level. We report inelastic two-body loss rates for {sup 3} P{sub 0} -{sup 3} P{sub 0} and {sup 1} S{sub 0} -{sup 3} P{sub 0} scattering. We also measure interaction shifts in an unpolarized atomic sample. Collision measurements for this spin-1/2 {sup 171}Yb system are relevant for high-performance optical clocks as well as strongly interacting systems for quantum information and quantum simulation applications.

  6. Research of 100 MHz ultra-low-jitter clock generating circuit

    SciTech Connect (OSTI)

    Qiu, Duyu; Tan, Feng; Tian, Shulin; Zeng, Hao; Ye, Peng

    2015-04-15

    Jitter which quantifies the quality of a clock is an important specification. It is of great significance for an electronic system. To obtain a good signal-to-noise ratio for sampling systems, there must be clocks with low jitter performances. By using the relationship between jitter and phase noise, the 100 MHz clock generating circuit with ultra-low jitter and phase noise characteristics are studied in this paper. Bipolar junction transistor with low noise figure and low corner frequency should be selected. Inductance and capacitance in the feedback circuit are obviously the main contributions to the jitter. Impacts of the loaded quality factor (Q{sub L}) of the circuit on the jitter are analyzed, and the explicit expression for the jitter based on circuit components is derived as well. The simulation and experiment results are proved to show that the jitter and phase noise characteristics can be improved by increasing Q{sub L} of the circuit.

  7. High resolution time interval meter

    DOE Patents [OSTI]

    Martin, A.D.

    1986-05-09

    Method and apparatus are provided for measuring the time interval between two events to a higher resolution than reliability available from conventional circuits and component. An internal clock pulse is provided at a frequency compatible with conventional component operating frequencies for reliable operation. Lumped constant delay circuits are provided for generating outputs at delay intervals corresponding to the desired high resolution. An initiation START pulse is input to generate first high resolution data. A termination STOP pulse is input to generate second high resolution data. Internal counters count at the low frequency internal clock pulse rate between the START and STOP pulses. The first and second high resolution data are logically combined to directly provide high resolution data to one counter and correct the count in the low resolution counter to obtain a high resolution time interval measurement.

  8. High resolution time interval counter

    DOE Patents [OSTI]

    Condreva, Kenneth J.

    1994-01-01

    A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured.

  9. High resolution time interval counter

    DOE Patents [OSTI]

    Condreva, K.J.

    1994-07-26

    A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured. 3 figs.

  10. Nondestructive Probing of Rabi Oscillations on the Cesium Clock Transition near the Standard Quantum Limit

    SciTech Connect (OSTI)

    Windpassinger, P. J.; Oblak, D.; Petrov, P. G.; Alzar, C. L. Garrido; Appel, J.; Mueller, J. H.; Kjaergaard, N.; Polzik, E. S.; Kubasik, M.; Saffman, M.

    2008-03-14

    We report on the nondestructive observation of Rabi oscillations on the Cs clock transition. The internal atomic state evolution of a dipole-trapped ensemble of cold atoms is inferred from the phase shift of a probe laser beam as measured using a Mach-Zehnder interferometer. We describe a single color as well as a two-color probing scheme. Using the latter, measurements of the collective pseudospin projection of atoms in a superposition of the clock states are performed and the observed spin fluctuations are shown to be close to the standard quantum limit.

  11. Controlling dipole-dipole frequency shifts in a lattice-based optical atomic clock

    SciTech Connect (OSTI)

    Chang, D.E.; Lukin, M.D.; Ye Jun

    2004-02-01

    Motivated by the ideas of using cold alkaline-earth atoms trapped in an optical lattice for realization of optical atomic clocks, we investigate theoretically the perturbative effects of atom-atom interactions on a clock transition frequency. These interactions are mediated by the dipole fields associated with the optically excited atoms. We predict resonancelike features in the frequency shifts when constructive interference among atomic dipoles occur. We theoretically demonstrate that by fine tuning the coherent dipole-dipole couplings in appropriately designed lattice geometries, the undesirable frequency shifts can be greatly suppressed.

  12. Systematic Study of the {sup 87}Sr Clock Transition in an Optical Lattice

    SciTech Connect (OSTI)

    Ludlow, Andrew D.; Boyd, Martin M.; Zelevinsky, Tanya; Foreman, Seth M.; Blatt, Sebastian; Notcutt, Mark; Ido, Tetsuya; Ye Jun

    2006-01-27

    With ultracold {sup 87}Sr confined in a magic wavelength optical lattice, we present the most precise study (2.8 Hz statistical uncertainty) to date of the {sup 1}S{sub 0}-{sup 3}P{sub 0} optical clock transition with a detailed analysis of systematic shifts (19 Hz uncertainty) in the absolute frequency measurement of 429 228 004 229 869 Hz. The high resolution permits an investigation of the optical lattice motional sideband structure. The local oscillator for this optical atomic clock is a stable diode laser with its hertz-level linewidth characterized by an octave-spanning femtosecond frequency comb.

  13. Low-threshold short-cavity diode laser for a miniature atomic clock

    SciTech Connect (OSTI)

    Kargapol'tsev, Sergei V; Velichansky, Vladimir L; Vasil'ev, V V; Kobyakova, M Sh; Morozyuk, A V; Shiryaeva, N V; Konyaev, V P

    2009-06-30

    Short-cavity diode lasers (SCDLs) emitting at the 894-nm D{sub 1} line of caesium are developed. Low threshold currents and power consumption will make it possible to use these lasers in chip-size atomic clocks (CSACs) and magnetometers. The SCDL parameters are comparable with the parameters of surface-emitting lasers. (lasers)

  14. Exploring Ramsey-coherent population trapping atomic clock realized with pulsed microwave modulated laser

    SciTech Connect (OSTI)

    Yang, Jing; Yun, Peter; Tian, Yuan; Tan, Bozhong; Gu, Sihong

    2014-03-07

    A scheme for a Ramsey-coherent population trapping (CPT) atomic clock that eliminates the acousto-optic modulator (AOM) is proposed and experimentally studied. Driven by a periodically microwave modulated current, the vertical-cavity surface-emitting laser emits a continuous beam that switches between monochromatic and multichromatic modes. Ramsey-CPT interference has been studied with this mode-switching beam. In eliminating the AOM, which is used to generate pulsed laser in conventional Ramsey-CPT atomic clock, the physics package of the proposed scheme is virtually the same as that of a conventional compact CPT atomic clock, although the resource budget for the electronics will slightly increase as a microwave switch should be added. By evaluating and comparing experimentally recorded signals from the two Ramsey-CPT schemes, the short-term frequency stability of the proposed scheme was found to be 46% better than the scheme with AOM. The experimental results suggest that the implementation of a compact Ramsey-CPT atomic clock promises better frequency stability.

  15. Synergistic regulation of the mouse orphan nuclear receptor SHP gene promoter by CLOCK-BMAL1 and LRH-1

    SciTech Connect (OSTI)

    Oiwa, Ako; Kakizawa, Tomoko . E-mail: tkaki@hsp.md.shinshu-u.ac.jp; Miyamoto, Takahide; Yamashita, Koh; Jiang, Wei; Takeda, Teiji; Suzuki, Satoru; Hashizume, Kiyoshi

    2007-02-23

    Small heterodimer partner (SHP; NR0B2) is an orphan nuclear receptor and acts as a repressor for wide variety of nuclear hormone receptors. We demonstrated here that mouse SHP mRNA showed a circadian expression pattern in the liver. Transient transfection of the mSHP promoter demonstrated that CLOCK-BMAL1, core circadian clock components, bound to E-box (CACGTG), and stimulated the promoter activity by 4-fold. Liver receptor homologue-1 (LRH-1; NR5A2) stimulated the mSHP promoter, and CLOCK-BMAL1 synergistically enhanced the LRH-1-mediated transactivation. Interestingly, SHP did not affect the CLOCK-BMAL1-mediated promoter activity, but strongly repressed the synergistic activation of CLOCK-BMAL1 and LRH-1. Furthermore, in vitro pull-down assays revealed the existence of direct protein-protein interaction between LRH-1 and CLOCK. In summary, this study shows that CLOCK-BMAL1, LRH-1 and SHP coordinately regulate the mSHP gene to generate the circadian oscillation. The cyclic expression of mSHP may affect daily activity of other nuclear receptors and contribute to circadian liver functions.

  16. Lipoic acid entrains the hepatic circadian clock and lipid metabolic proteins that have been desynchronized with advanced age

    SciTech Connect (OSTI)

    Keith, Dove; Finlay, Liam; Butler, Judy; Gómez, Luis; Smith, Eric; Moreau, Régis; Hagen, Tory

    2014-07-18

    Highlights: • 24 month old rats were supplemented with 0.2% lipoic acid in the diet for 2 weeks. • Lipoic acid shifts phase of core circadian clock proteins. • Lipoic acid corrects age-induced desynchronized lipid metabolism rhythms. - Abstract: It is well established that lipid metabolism is controlled, in part, by circadian clocks. However, circadian clocks lose temporal precision with age and correlates with elevated incidence in dyslipidemia and metabolic syndrome in older adults. Because our lab has shown that lipoic acid (LA) improves lipid homeostasis in aged animals, we hypothesized that LA affects the circadian clock to achieve these results. We fed 24 month old male F344 rats a diet supplemented with 0.2% (w/w) LA for 2 weeks prior to sacrifice and quantified hepatic circadian clock protein levels and clock-controlled lipid metabolic enzymes. LA treatment caused a significant phase-shift in the expression patterns of the circadian clock proteins Period (Per) 2, Brain and Muscle Arnt-Like1 (BMAL1), and Reverse Erythroblastosis virus (Rev-erb) β without altering the amplitude of protein levels during the light phase of the day. LA also significantly altered the oscillatory patterns of clock-controlled proteins associated with lipid metabolism. The level of peroxisome proliferator-activated receptor (PPAR) α was significantly increased and acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) were both significantly reduced, suggesting that the LA-supplemented aged animals are in a catabolic state. We conclude that LA remediates some of the dyslipidemic processes associated with advanced age, and this mechanism may be at least partially through entrainment of circadian clocks.

  17. Quantum methods for clock synchronization: Beating the standard quantum limit without entanglement

    SciTech Connect (OSTI)

    Burgh, Mark de; Bartlett, Stephen D.

    2005-10-15

    We introduce methods for clock synchronization that make use of the adiabatic exchange of nondegenerate two-level quantum systems: ticking qubits. Schemes involving the exchange of N independent qubits with frequency {omega} give a synchronization accuracy that scales as ({omega}{radical}(N)){sup -1}--i.e., as the standard quantum limit. We introduce a protocol that makes use of N{sub c} coherent exchanges of a single qubit at frequency {omega}, leading to an accuracy that scales as ({omega}N{sub c}){sup -1} ln N{sub c}. This protocol beats the standard quantum limit without the use of entanglement, and we argue that this scaling is the fundamental limit for clock synchronization allowed by quantum mechanics. We analyze the performance of these protocols when used with a lossy channel.0.

  18. A compact ultranarrow high-power laser system for experiments with 578 nm ytterbium clock transition

    SciTech Connect (OSTI)

    Cappellini, G.; Lombardi, P.; Mancini, M.; Pagano, G.; Pizzocaro, M.; Fallani, L.; Catani, J.

    2015-07-15

    In this paper, we present the realization of a compact, high-power laser system able to excite the ytterbium clock transition at 578 nm. Starting from an external-cavity laser based on a quantum dot chip at 1156 nm with an intra-cavity electro-optic modulator, we were able to obtain up to 60 mW of visible light at 578 nm via frequency doubling. The laser is locked with a 500 kHz bandwidth to an ultra-low-expansion glass cavity stabilized at its zero coefficient of thermal expansion temperature through an original thermal insulation and correction system. This laser allowed the observation of the clock transition in fermionic {sup 173}Y b with a <50 Hz linewidth over 5 min, limited only by a residual frequency drift of some 0.1 Hz/s.

  19. The consistency condition for the three-point function in dissipative single-clock inflation

    SciTech Connect (OSTI)

    Nacir, Diana López; Porto, Rafael A.; Zaldarriaga, Matias E-mail: rporto@ias.edu

    2012-09-01

    We generalize the consistency condition for the three-point function in single field inflation to the case of dissipative, multi-field, single-clock models. We use the recently introduced extension of the effective field theory of inflation that accounts for dissipative effects, to provide an explicit proof to leading (non-trivial) order in the generalized slow roll parameters and mixing with gravity scales. Our results illustrate the conditions necessary for the validity of the consistency relation in situations with many degrees of freedom relevant during inflation, namely that there is a preferred clock. Departures from this condition in forthcoming experiments would rule out not only single field but also a large class of multi-field models.

  20. Trapping and laser cooling of Ca{sup +} ions toward future optical frequency standards: Observation of clock transitions

    SciTech Connect (OSTI)

    Urabe, S.; Hayasaka, K.; Watanabe, M.

    1994-12-31

    Experimental results of trapping and laser cooling of Ca{sup +} ions for future optical frequency standards are reported. Ca{sup +} ions were trapped and laser-cooled to below 1K. To observe the electric-quadrupole-allowed transitions (clock transitions), the laser diode operated at low temperature was developed. With this laser, the clock transitions were observed using the shelved electron double resonance method.

  1. Engineering Stark Potentials for Precision Measurements: Optical Lattice Clock and Electrodynamic Surface Trap

    SciTech Connect (OSTI)

    Katori, Hidetoshi; Takamoto, Masao; Hachisu, Hidekazu; Fujiki, Jun; Higashi, Ryoichi; Yasuda, Masami; Kishimoto, Tetsuo

    2005-05-05

    Employing the engineered electric fields, we demonstrate novel platforms for precision measurements with neutral atoms. (1) Applying the light shift cancellation technique, atoms trapped in an optical lattice reveal 50-Hz-narrow optical spectrum, yielding nearly an order of magnitude improvement over existing neutral-atom-based clocks. (2) Surface Stark trap has been developed to manipulate scalar atoms that are intrinsically robust to decoherence.

  2. Coherence and Clock Shifts in Ultracold Fermi Gases with Resonant Interactions

    SciTech Connect (OSTI)

    Baym, Gordon; Pethick, C. J.; Yu Zhenhua; Zwierlein, Martin W.

    2007-11-09

    Using arguments based on sum rules, we derive a general result for the average shifts of rf lines in Fermi gases in terms of interatomic interaction strengths and two-particle correlation functions. We show that near an interaction resonance shifts vary inversely with the atomic scattering length, rather than linearly as in dilute gases, thus accounting for the experimental observation that clock shifts remain finite at Feshbach resonances.

  3. A highly miniaturized vacuum package for a trapped ion atomic clock

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

    Schwindt, Peter D. D.; Jau, Yuan-Yu; Partner, Heather; Casias, Adrian; Wagner, Adrian R.; Moorman, Matthew; Manginell, Ronald P.; Kellogg, James R.; Prestage, John D.

    2016-05-12

    We report on the development of a highly miniaturized vacuum package for use in an atomic clock utilizing trapped ytterbium-171 ions. The vacuum package is approximately 1 cm3 in size and contains a linear quadrupole RF Paul ion trap, miniature neutral Yb sources, and a non-evaporable getter pump. We describe the fabrication process for making the Yb sources and assembling the vacuum package. To prepare the vacuum package for ion trapping, it was evacuated, baked at a high temperature, and then back filled with a helium buffer gas. Once appropriate vacuum conditions were achieved in the package, the package wasmore » sealed with a copper pinch-off and was then pumped only by the non-evaporable getter. We demonstrated ion trapping in this vacuum package and the operation of an atomic clock, stabilizing a local oscillator to the 12.6 GHz hyperfine transition of 171Yb+. The fractional frequency stability of the clock was measured to be 2 × 10-11 / τ1/2.« less

  4. Protein-protein interactions in the cyanobacterial KaiABC circadian clock

    SciTech Connect (OSTI)

    Egli, M.; Pattanayek, R.; Pattanayek, S.

    2008-01-10

    The discovery that the central oscillator of the cyanobacterial KaiABC circadian clock can be reconstituted in vitro by the protein components KaiA, KaiB and KaiC renders this biological timer a unique target for biochemical and structural studies. The oscillator can be monitored through changes in the KaiC phosphorylation status that is modulated by KaiA and KaiB. As the 24-h period of the recombinant clock remains unaltered as a result of modest variation of temperature, interactions between the three Kai proteins not only form the basis for rhythmic control of levels of KaiC phosphorylation but also provide temperature compensation. A profound understanding of how this biological timer works requires a dissection of the functions of, and interactions between, the three proteins. Three-dimensional structures of the individual Kai proteins have been determined, and the KaiA-KaiC complex has been studied using hybrid structural methods. This chapter provides an overview of progress in the characterization of the cyanobacterial circadian clock with an emphasis on structural aspects of individual Kai proteins and the binary KaiA-KaiC complex.

  5. Roughness exponent in two-dimensional percolation, Potts model, and clock model

    SciTech Connect (OSTI)

    Redinz, Jose Arnaldo; Martins, Marcelo Lobato

    2001-06-01

    We present a numerical study of the self-affine profiles obtained from configurations of the q-state Potts (with q=2,3, and 7) and p=10 clock models as well as from the occupation states for site percolation on the square lattice. The first and second order static phase transitions of the Potts model are located by a sharp change in the value of the roughness exponent {alpha} characterizing those profiles. The low temperature phase of the Potts model corresponds to flat ({alpha}{approx_equal}1) profiles, whereas its high temperature phase is associated with rough ({alpha}{approx_equal}0.5) ones. For the p=10 clock model, in addition to the flat (ferromagnetic) and rough (paramagnetic) profiles, an intermediate rough (0.5{lt}{alpha}{lt}1) phase{emdash}associated with a soft spin-wave one{emdash}is observed. Our results for the transition temperatures in the Potts and clock models are in agreement with the static values, showing that this approach is able to detect the phase transitions in these models directly from the spin configurations, without any reference to thermodynamical potentials, order parameters, or response functions. Finally, we show that the roughness exponent {alpha} is insensitive to geometric critical phenomena.

  6. Pulse transmission transmitter including a higher order time derivate filter

    DOE Patents [OSTI]

    Dress, Jr., William B.; Smith, Stephen F.

    2003-09-23

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission transmitter includes: a clock; a pseudorandom polynomial generator coupled to the clock, the pseudorandom polynomial generator having a polynomial load input; an exclusive-OR gate coupled to the pseudorandom polynomial generator, the exclusive-OR gate having a serial data input; a programmable delay circuit coupled to both the clock and the exclusive-OR gate; a pulse generator coupled to the programmable delay circuit; and a higher order time derivative filter coupled to the pulse generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  7. Coulomb reacceleration as a clock for nuclear reactions -- II

    SciTech Connect (OSTI)

    Bertulani, C.A.; Bertsch, G.F.

    1994-03-01

    Reacceleration effects in the Coulomb breakup of nuclei are modeled with the two-dimensional time-dependent Schroedinger equation, extending a previous one-dimensional study. The present model better describes the individual contributions of longitudinal and transverse forces to the breakup and reacceleration. Reacceleration effects are found to preserve a strong memory of the pre-breakup phase of the reaction, as was concluded with the one-dimensional model.

  8. Comments on ''The optimization of electronic precision in ultrasonic velocity measurements: A comparison of the time interval averaging and sing around methods'' (J. Acoust. Soc. Am. 73, 1833--1837 (1983))

    SciTech Connect (OSTI)

    Karplus, H.B.

    1984-06-01

    J. D. Aindow and R. C. Chivers (J. Acoust. Soc. Am. 73, 1833 (1983)) compared the precision of the direct ''time-of-flight'' technique with the ''sing-around'' method for sound velocity measurement. Their conclusion is changed by the newer, faster, commercial clocks (2 ns HP5345<0.1 ns HP5370), giving the advantage to the time of flight method. The analysis is herewith augmented by calculating the time jitter in terms of signal to noise ratio, which was correctly shown to be negligible with 100-ns clocks, but becomes increasingly more significant with faster clocks.

  9. Ionization Branching Ratio Control with a Resonance Attosecond Clock

    SciTech Connect (OSTI)

    Argenti, Luca; Lindroth, Eva

    2010-07-30

    We investigate the possibility to monitor the dynamics of autoionizing states in real-time and control the yields of different ionization channels in helium by simulating extreme ultraviolet (XUV) pump IR-probe experiments focused on the N=2 threshold. The XUV pulse creates a coherent superposition of doubly excited states which is found to decay by ejecting electrons in bursts. Prominent interference fringes in the photoelectron angular distribution of the 2s and 2p ionization channels are observed, along with significant out-of-phase quantum beats in the yields of the corresponding parent ions.

  10. Single-Atom Optical Clock with High Accuracy

    SciTech Connect (OSTI)

    Oskay, W. H.; Diddams, S. A.; Donley, E. A.; Fortier, T. M.; Heavner, T. P.; Hollberg, L.; Itano, W. M.; Jefferts, S. R.; Delaney, M. J.; Kim, K.; Levi, F.; Parker, T. E.; Bergquist, J. C.

    2006-07-14

    For the past 50 years, atomic standards based on the frequency of the cesium ground-state hyperfine transition have been the most accurate time pieces in the world. We now report a comparison between the cesium fountain standard NIST-F1, which has been evaluated with an inaccuracy of about 4x10{sup -16}, and an optical frequency standard based on an ultraviolet transition in a single, laser-cooled mercury ion for which the fractional systematic frequency uncertainty was below 7.2x10{sup -17}. The absolute frequency of the transition was measured versus cesium to be 1 064 721 609 899 144.94 (97) Hz, with a statistically limited total fractional uncertainty of 9.1x10{sup -16}, the most accurate absolute measurement of an optical frequency to date.

  11. Artifacts in digital coincidence timing

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

    Moses, W. W.; Peng, Q.

    2014-10-16

    Digital methods are becoming increasingly popular for measuring time differences, and are the de facto standard in PET cameras. These methods usually include a master system clock and a (digital) arrival time estimate for each detector that is obtained by comparing the detector output signal to some reference portion of this clock (such as the rising edge). Time differences between detector signals are then obtained by subtracting the digitized estimates from a detector pair. A number of different methods can be used to generate the digitized arrival time of the detector output, such as sending a discriminator output into amore » time to digital converter (TDC) or digitizing the waveform and applying a more sophisticated algorithm to extract a timing estimator.All measurement methods are subject to error, and one generally wants to minimize these errors and so optimize the timing resolution. A common method for optimizing timing methods is to measure the coincidence timing resolution between two timing signals whose time difference should be constant (such as detecting gammas from positron annihilation) and selecting the method that minimizes the width of the distribution (i.e. the timing resolution). Unfortunately, a common form of error (a nonlinear transfer function) leads to artifacts that artificially narrow this resolution, which can lead to erroneous selection of the 'optimal' method. In conclusion, the purpose of this note is to demonstrate the origin of this artifact and suggest that caution should be used when optimizing time digitization systems solely on timing resolution minimization.« less

  12. Improved spacecraft radio science using an on-board atomic clock: Application to gravitational wave searches

    SciTech Connect (OSTI)

    Tinto, Massimo; Dick, George J.; Prestage, John D.; Armstrong, J. W.

    2009-05-15

    Recent advances in space-qualified atomic clocks (low-mass, low power-consumption, frequency stability comparable to that of ground-based clocks) can enable interplanetary spacecraft radio science experiments at unprecedented Doppler sensitivities. The addition of an on-board digital receiver would allow the up- and down-link Doppler frequencies to be measured separately. Such separate, high-quality measurements allow optimal data combinations that suppress the currently leading noise sources: phase scintillation noise from the Earth's atmosphere and Doppler noise caused by mechanical vibrations of the ground antenna. Here we provide a general expression for the optimal combination of ground and on-board Doppler data and compute the sensitivity such a system would have to low-frequency gravitational waves (GWs). Assuming a plasma scintillation noise calibration comparable to that already demonstrated with the multilink CASSINI radio system, the space-clock/digital-receiver instrumentation enhancements would give GW strain sensitivity of 3.7x10{sup -14} Hz{sup -1/2} for randomly polarized, monochromatic GW signals isotropically distributed over the celestial sphere, over a two-decade ({approx}0.0001-0.01 Hz) region of the low-frequency band. This is about an order of magnitude better than currently achieved with traditional two-way coherent Doppler experiments. The utility of optimally combining simultaneous up- and down-link observations is not limited to GW searches. The Doppler tracking technique discussed here could be performed at minimal incremental cost to improve also other radio science experiments (i.e., tests of relativistic gravity, planetary and satellite gravity field measurements, atmospheric and ring occultations) on future interplanetary missions.

  13. Pulse transmission receiver with higher-order time derivative pulse correlator

    DOE Patents [OSTI]

    Dress, Jr., William B.; Smith, Stephen F.

    2003-09-16

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a higher-order time derivative pulse correlator; a demodulation decoder coupled to the higher-order time derivative pulse correlator; a clock coupled to the demodulation decoder; and a pseudorandom polynomial generator coupled to both the higher-order time derivative pulse correlator and the clock. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  14. Optical lattice polarization effects on magnetically induced optical atomic clock transitions

    SciTech Connect (OSTI)

    Taichenachev, A. V.; Yudin, V. I.; Oates, C. W.

    2007-08-15

    We derive the frequency shift for a forbidden optical transition J=0{yields}J{sup '}=0 caused by the simultaneous actions of an elliptically polarized lattice field and a static magnetic field. We find that a simple configuration of lattice and magnetic fields leads to a cancellation of this shift to first order in lattice intensity and magnetic field. In this geometry, the second-order lattice intensity shift can be minimized as well by use of optimal lattice polarization. Suppression of these shifts could considerably enhance the performance of the next generation of atomic clocks.

  15. Theory of magic optical traps for Zeeman-insensitive clock transitions in alkali-metal atoms

    SciTech Connect (OSTI)

    Derevianko, Andrei

    2010-05-15

    Precision measurements and quantum-information processing with cold atoms may benefit from trapping atoms with specially engineered, 'magic' optical fields. At the magic trapping conditions, the relevant atomic properties remain immune to strong perturbations by the trapping fields. Here we develop a theoretical analysis of magic trapping for especially valuable Zeeman-insensitive clock transitions in alkali-metal atoms. The involved mechanism relies on applying a magic bias B field along a circularly polarized trapping laser field. We map out these B fields as a function of trapping laser wavelength for all commonly used alkalis. We also highlight a common error in evaluating Stark shifts of hyperfine manifolds.

  16. Frequency Shift of the Cesium Clock Transition due to Blackbody Radiation

    SciTech Connect (OSTI)

    Angstmann, E. J.; Dzuba, V. A.; Flambaum, V. V.

    2006-07-28

    We perform ab initio calculations of the frequency shift induced by a static electric field on the cesium clock hyperfine transition. The calculations are used to find the frequency shifts due to blackbody radiation. Our result [{delta}{nu}/E{sup 2}=-2.26(2)x10{sup -10} Hz/(V/m){sup 2}] is in good agreement with early measurements and ab initio calculations performed in other groups. We present arguments against recent claims that the actual value of the effect might be smaller. The difference ({approx}10%) between ab initio and semiempirical calculations is due to the contribution of the continuum spectrum in the sum over intermediate states.

  17. Gyromagnetic factors and atomic clock constraints on the variation of fundamental constants

    SciTech Connect (OSTI)

    Luo Feng; Olive, Keith A.; Uzan, Jean-Philippe

    2011-11-01

    We consider the effect of the coupled variations of fundamental constants on the nucleon magnetic moment. The nucleon g-factor enters into the interpretation of the measurements of variations in the fine-structure constant, {alpha}, in both the laboratory (through atomic clock measurements) and in astrophysical systems (e.g. through measurements of the 21 cm transitions). A null result can be translated into a limit on the variation of a set of fundamental constants, that is usually reduced to {alpha}. However, in specific models, particularly unification models, changes in {alpha} are always accompanied by corresponding changes in other fundamental quantities such as the QCD scale, {Lambda}{sub QCD}. This work tracks the changes in the nucleon g-factors induced from changes in {Lambda}{sub QCD} and the light quark masses. In principle, these coupled variations can improve the bounds on the variation of {alpha} by an order of magnitude from existing atomic clock and astrophysical measurements. Unfortunately, the calculation of the dependence of g-factors on fundamental parameters is notoriously model-dependent.

  18. A high-overtone bulk acoustic wave resonator-oscillator-based 4.596 GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

    SciTech Connect (OSTI)

    Daugey, Thomas; Friedt, Jean-Michel; Martin, Gilles; Boudot, Rodolphe

    2015-11-15

    This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596 GHz frequency source. A 2.298 GHz signal, generated by an oscillator constructed around a thermally controlled two-port aluminum nitride-sapphire HBAR resonator with a Q-factor of 24 000 at 68 °C, is frequency multiplied by 2–4.596 GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency of the HBAR is measured to be −23 ppm/ °C at 2.298 GHz. The measured phase noise of the 4.596 GHz source is −105 dB rad{sup 2}/Hz at 1 kHz offset and −150 dB rad{sup 2}/Hz at 100 kHz offset. The 4.596 GHz output signal is used as a local oscillator in a laboratory-prototype Cs microcell-based coherent population trapping atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter implemented in the 2.298 GHz HBAR-oscillator loop, preventing the need for a high-power-consuming direct digital synthesis. The short-term fractional frequency stability of the free-running oscillator is 1.8 × 10{sup −9} at one second integration time. In locked regime, the latter is improved in a preliminary proof-of-concept experiment at the level of 6.6 × 10{sup −11} τ{sup −1/2} up to a few seconds and found to be limited by the signal-to-noise ratio of the detected CPT resonance.

  19. Direct Excitation of the Forbidden Clock Transition in Neutral {sup 174}Yb Atoms Confined to an Optical Lattice

    SciTech Connect (OSTI)

    Barber, Z.W.; Hoyt, C.W.; Oates, C.W.; Hollberg, L.; Taichenachev, A.V.; Yudin, V.I.

    2006-03-03

    We report direct single-laser excitation of the strictly forbidden (6s{sup 2}){sup 1}S{sub 0}{r_reversible}(6s6p){sup 3}P{sub 0} clock transition in {sup 174}Yb atoms confined to a 1D optical lattice. A small ({approx}1.2 mT) static magnetic field was used to induce a nonzero electric dipole transition probability between the clock states at 578.42 nm. Narrow resonance linewidths of 20 Hz (FWHM) with high contrast were observed, demonstrating a resonance quality factor of 2.6x10{sup 13}. The previously unknown ac Stark shift-canceling (magic) wavelength was determined to be 759.35{+-}0.02 nm. This method for using the metrologically superior even isotope can be easily implemented in current Yb and Sr lattice clocks and can create new clock possibilities in other alkaline-earth-like atoms such as Mg and Ca.

  20. Cold Atom Clock Test of Lorentz Invariance in the Matter Sector

    SciTech Connect (OSTI)

    Wolf, Peter; Chapelet, Frederic; Bize, Sebastien; Clairon, Andre

    2006-02-17

    We report on a new experiment that tests for a violation of Lorentz invariance (LI), by searching for a dependence of atomic transition frequencies on the orientation of the spin of the involved states (Hughes-Drever type experiment). The atomic frequencies are measured using a laser cooled {sup 133}Cs atomic fountain clock, operating on a particular combination of Zeeman substates. We analyze the results within the framework of the Lorentz violating standard model extension (SME), where our experiment is sensitive to a largely unexplored region of the SME parameter space, corresponding to first measurements of four proton parameters and improvements by 11 and 13 orders of magnitude on the determination of four others. In spite of the attained uncertainties, and of having extended the search into a new region of the SME, we still find no indication of LI violation.

  1. period-1 encodes an ATP-dependent RNA helicase that influences nutritional compensation of the Neurospora circadian clock

    SciTech Connect (OSTI)

    Emerson, Jillian M.; Bartholomai, Bradley M.; Ringelberg, Carol; Baker, Scott E.; Loros, Jennifer J.; Dunlap, Jay C.

    2015-12-22

    Mutants in the period-1 (prd-1) gene, characterized by a recessive allele, display a reduced growth rate and period lengthening of the developmental cycle controlled by the circadian clock. We refined the genetic location of prd-1 and used whole genome sequencing to find the mutation defining it, confirming the identity of prd-1 by rescuing the mutant circadian phenotype via transformation. PRD-1 is an RNA helicase whose orthologs, DDX5 and DDX17 in humans and Dbp2p in yeast, are implicated in various processes including transcriptional regulation, elongation, and termination, 23 ribosome biogenesis, and RNA decay. Although prdi-1smutantssiois an ATP-dependent RNA helicase, member of a sub-family display a long period (~25 hrs) circadian developmental cycle, they interestingly display a wild type period when the core circadian oscillator is tracked using a frq-luciferase transcriptional fusion under conditions of limiting nutritional carbon; the core oscillator runs with a long period under glucose-sufficient conditions. Thus PRD-1 clearly impacts the circadian oscillator and is not only part of a metabolic oscillator ancillary to the core clock. PRD-1 is an essential protein and its expression is neither light-regulated nor clock-regulated. However, it is transiently induced by glucose; in the presence of sufficient glucose PRD-1 is in the nucleus until glucose runs out which elicits its disappearance from the nucleus. Because circadian period length is carbon concentration-dependent, prd­-1 may be formally viewed as clock mutant with defective nutritional compensation of circadian period length.

  2. Single-mode vertical-cavity surface emitting lasers for {sup 87}Rb-based chip-scale atomic clock

    SciTech Connect (OSTI)

    Derebezov, I. A. Haisler, V. A.; Bakarov, A. K.; Kalagin, A. K.; Toropov, A. I.; Kachanova, M. M.; Gavrilova, T. A.; Semenova, O. I.; Tretyakov, D. B.; Beterov, I. I.; Entin, V. M.; Ryabtsev, I. I.

    2010-11-15

    The results of numerical simulation and study of lasing characteristics of semiconductor verticalcavity surface-emitting lasers based on Al{sub x}Ga{sub 1-x}As alloys are presented. Lasers exhibit stable single-mode lasing at a wavelength of 795 nm at low operating currents {approx}1.5 mA and an output power of 350 {mu}W, which offers prospects of their applications in next-generation chip-scale atomic clocks

  3. Dependence of nuclear magnetic moments on quark masses and limits on temporal variation of fundamental constants from atomic clock experiments

    SciTech Connect (OSTI)

    Flambaum, V.V.; Tedesco, A.F.

    2006-05-15

    We calculate the dependence of the nuclear magnetic moments on the quark masses, including the spin-spin interaction effects, and obtain limits on the variation of the fine structure constant {alpha} and (m{sub q}/{lambda}{sub QCD}) using recent atomic clock experiments examining hyperfine transitions in H, Rb, Cs, Yb{sup +}, and Hg{sup +} and the optical transition in H, Hg{sup +}, and Yb{sup +}.

  4. Characterization and calibration of a viscoelastic simplified potential energy clock model for inorganic glasses

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

    Chambers, Robert S.; Tandon, Rajan; Stavig, Mark E.

    2015-07-07

    In this study, to analyze the stresses and strains generated during the solidification of glass-forming materials, stress and volume relaxation must be predicted accurately. Although the modeling attributes required to depict physical aging in organic glassy thermosets strongly resemble the structural relaxation in inorganic glasses, the historical modeling approaches have been distinctly different. To determine whether a common constitutive framework can be applied to both classes of materials, the nonlinear viscoelastic simplified potential energy clock (SPEC) model, developed originally for glassy thermosets, was calibrated for the Schott 8061 inorganic glass and used to analyze a number of tests. A practicalmore » methodology for material characterization and model calibration is discussed, and the structural relaxation mechanism is interpreted in the context of SPEC model constitutive equations. SPEC predictions compared to inorganic glass data collected from thermal strain measurements and creep tests demonstrate the ability to achieve engineering accuracy and make the SPEC model feasible for engineering applications involving a much broader class of glassy materials.« less

  5. Characterization and calibration of a viscoelastic simplified potential energy clock model for inorganic glasses

    SciTech Connect (OSTI)

    Chambers, Robert S.; Tandon, Rajan; Stavig, Mark E.

    2015-07-07

    In this study, to analyze the stresses and strains generated during the solidification of glass-forming materials, stress and volume relaxation must be predicted accurately. Although the modeling attributes required to depict physical aging in organic glassy thermosets strongly resemble the structural relaxation in inorganic glasses, the historical modeling approaches have been distinctly different. To determine whether a common constitutive framework can be applied to both classes of materials, the nonlinear viscoelastic simplified potential energy clock (SPEC) model, developed originally for glassy thermosets, was calibrated for the Schott 8061 inorganic glass and used to analyze a number of tests. A practical methodology for material characterization and model calibration is discussed, and the structural relaxation mechanism is interpreted in the context of SPEC model constitutive equations. SPEC predictions compared to inorganic glass data collected from thermal strain measurements and creep tests demonstrate the ability to achieve engineering accuracy and make the SPEC model feasible for engineering applications involving a much broader class of glassy materials.

  6. Public health assessment for public health implications of radiation contamination at former clock factories located in Bristo (Hartford County), New Haven, (New Haven County), Thomaston (Litchfield County), and Waterbury (New Haven County), Connecticut, Region 1. Final report

    SciTech Connect (OSTI)

    1999-01-29

    This public health assessment was developed (1) to evaluate the radiation data collected by the Connecticut Department of Environmental Protection (CT DEP) at structures that once housed clock factories in four Connecticut municipalities, and (2) to determine whether a public health hazard exists at any of these sites from the contamination. Contamination was detected at levels that may pose a health risk to current occupants at the former Waterbury Clock Factory, the former Lux Clock Factory, and the former Benrus Clock Company buildings in Waterbury; the former Sessions Clock Company in Bristol; and the former Seth Thomas Clock Company in Thomaston. However, none of the radiation levels detected pose an immediate health problem. The Connecticut Department of Public Health recommends that individuals be disassociated from areas with radiation at levels exceeding 15 mRem/year.

  7. Provably secure time distribution for the electric grid

    SciTech Connect (OSTI)

    Smith IV, Amos M; Evans, Philip G; Williams, Brian P; Grice, Warren P

    2015-01-01

    We demonstrate a quantum time distribution (QTD) method that combines the precision of optical timing techniques with the integrity of quantum key distribution (QKD). Critical infrastructure is dependent on microprocessor- and programmable logic-based monitoring and control systems. The distribution of timing information across the electric grid is accomplished by GPS signals which are known to be vulnerable to spoofing. We demonstrate a method for synchronizing remote clocks based on the arrival time of photons in a modifed QKD system. This has the advantage that the signal can be veried by examining the quantum states of the photons similar to QKD.

  8. Identification of a Glycogen Synthase Kinase-3[beta] Inhibitor that Attenuates Hyperactivity in CLOCK Mutant Mice

    SciTech Connect (OSTI)

    Kozikowski, Alan P.; Gunosewoyo, Hendra; Guo, Songpo; Gaisina, Irina N.; Walter, Richard L.; Ketcherside, Ariel; McClung, Colleen A.; Mesecar, Andrew D.; Caldarone, Barbara

    2012-05-02

    Bipolar disorder is characterized by a cycle of mania and depression, which affects approximately 5 million people in the United States. Current treatment regimes include the so-called 'mood-stabilizing drugs', such as lithium and valproate that are relatively dated drugs with various known side effects. Glycogen synthase kinase-3{beta} (GSK-3{beta}) plays a central role in regulating circadian rhythms, and lithium is known to be a direct inhibitor of GSK-3{beta}. We designed a series of second generation benzofuran-3-yl-(indol-3-yl)maleimides containing a piperidine ring that possess IC{sub 50} values in the range of 4 to 680 nM against human GSK-3{beta}. One of these compounds exhibits reasonable kinase selectivity and promising preliminary absorption, distribution, metabolism, and excretion (ADME) data. The administration of this compound at doses of 10 to 25 mg kg{sup -1} resulted in the attenuation of hyperactivity in amphetamine/chlordiazepoxide-induced manic-like mice together with enhancement of prepulse inhibition, similar to the effects found for valproate (400 mg kg{sup -1}) and the antipsychotic haloperidol (1 mg kg{sup -1}). We also tested this compound in mice carrying a mutation in the central transcriptional activator of molecular rhythms, the CLOCK gene, and found that the same compound attenuates locomotor hyperactivity in response to novelty. This study further demonstrates the use of inhibitors of GSK-3{beta} in the treatment of manic episodes of bipolar/mood disorders, thus further validating GSK-3{beta} as a relevant therapeutic target in the identification of new therapies for bipolar patients.

  9. Arrest of propagating brittle cracks in low toughness pipe with clock spring reinforcements. Topical report, December 1992-November 1995

    SciTech Connect (OSTI)

    Block, N.; Kishel, J.; Stephens, D.R.

    1995-12-01

    Results obtained in this project generally correlated with work earlier by NCF Industries in 1990, although a greater number of brittle cracks were generated in most of the tests in this project. They verified that design of an external arrest section is much more stringent for termination of multiple brittle cracks at temperatures providing lower shelf toughness of the pipe steel. Arrest of brittle cracks appears feasible with tightly applied external fiberglass wraps of proper design. According, additional work to define design needed for reproducible arrests of multiple brittle cracks by Clock Spring is warranted.

  10. Vending Machine Controls | Open Energy Information

    Open Energy Info (EERE)

    Contact needs updating Image needs updating Reference needed Missing content Broken link Other Additional Comments Cancel Submit Category: Articles with outstanding TODO tasks...

  11. Nanosecond-level time synchronization of autonomous radio detector stations for extensive air showers

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

    Aab, Alexander

    2016-01-29

    To exploit the full potential of radio measurements of cosmic-ray air showers at MHz frequencies, a detector timing synchronization within 1 ns is needed. Large distributed radio detector arrays such as the Auger Engineering Radio Array (AERA) rely on timing via the Global Positioning System (GPS) for the synchronization of individual detector station clocks. Unfortunately, GPS timing is expected to have an accuracy no better than about 5 ns. In practice, in particular in AERA, the GPS clocks exhibit drifts on the order of tens of ns. We developed a technique to correct for the GPS drifts, and an independentmore » method used for cross-checks that indeed we reach nanosecond-scale timing accuracy by this correction. First, we operate a “beacon transmitter” which emits defined sine waves detected by AERA antennas recorded within the physics data. The relative phasing of these sine waves can be used to correct for GPS clock drifts. In addition to this, we observe radio pulses emitted by commercial airplanes, the position of which we determine in real time from Automatic Dependent Surveillance Broadcasts intercepted with a software-defined radio. From the known source location and the measured arrival times of the pulses we determine relative timing offsets between radio detector stations. We demonstrate with a combined analysis that the two methods give a consistent timing calibration with an accuracy of 2 ns or better. Consequently, the beacon method alone can be used in the future to continuously determine and correct for GPS clock drifts in each individual event measured by AERA.« less

  12. Microstructure for ferroelastic transitions from strain pseudo-spin clock models in two and three dimensions: a mean field analysis

    SciTech Connect (OSTI)

    Lookman, Turab; Vasseur, Romain

    2009-01-01

    We obtain the microstructure of ferroelastic transitions in two and three dimensions from the solution of their corresponding discrete pseudo-spin models. In two dimensions we consider two transitions each from the high symmetry square and triangle symmetries: square-to-rectangle (SR), square-to-oblique (SO), triangle-to-centered rectangle (TR) and triangle-to-oblique (TO). In three dimensions we study the corresponding spin model for the cubic to tetragonal transition. The Landau free energies for these transitions result in N+ I states clock models (Z{sub N}) with long range interactions and we derive mean-field self-consistency equations for the clock model Hamiltonians. The microstructures from the mean-field solutions of the models are very similar to those obtained from the original continuum models or Monte Carlo simulations on the spin models (in the SR case), illustrating that these discrete models capture the salient physics. The models, in the presence of disorder, provide the basis for the study of the strain glass phase observed in martensitic alloys.

  13. Quantum-noise-limited interferometric measurement of atomic noise: Towards spin squeezing on the Cs clock transition

    SciTech Connect (OSTI)

    Oblak, Daniel; Tittel, Wolfgang; Vershovski, Anton K.; Mikkelsen, Jens K.; Soerensen, Jens L.; Petrov, Plamen G.; Garrido Alzar, Carlos L.; Polzik, Eugene S.

    2005-04-01

    We investigate theoretically and experimentally a nondestructive interferometric measurement of the state population of an ensemble of laser-cooled and trapped atoms. This study is a step toward generation of (pseudo)spin squeezing of cold atoms targeted at the improvement of the cesium clock performance beyond the limit set by the quantum projection noise of atoms. We calculate the phase shift and the quantum noise of a near-resonant optical probe pulse propagating through a cloud of cold {sup 133}Cs atoms. We analyze the figure of merit for a quantum nondemolition (QND) measurement of the collective pseudospin and show that it can be expressed simply as a product of the ensemble optical density and the pulse-integrated rate of the spontaneous emission caused by the off-resonant probe light. Based on this, we propose a protocol for the sequence of operations required to generate and utilize spin squeezing for the improved atomic clock performance via a QND measurement on the probe light. In the experimental part we demonstrate that the interferometric measurement of the atomic population can reach a sensitivity of the order of {radical}(N{sub at}) in a cloud of N{sub at} cold atoms, which is an important benchmark toward the experimental realization of the theoretically analyzed protocol.

  14. Design and testing of a radiation tolerant Clock, Control and Monitor (CCM) module for the CMS HCAL electronics

    SciTech Connect (OSTI)

    Scott Holm et al.

    2002-11-20

    A Clock, Control and Monitoring (CCM) Module is being designed for the Hadron Calorimeter subsystem of the CMS Detector. The CMS detector has been designed to detect cleanly the diverse signatures of new physics at the Large Hadron Collider. This CCM module will be responsible for low skew clock and beam crossing marker distribution, monitoring of voltages and temperatures and as the interface between the main control system and the Front End Modules. The CCM module will reside in the HCAL Readout Box that will be mounted on the HCAL detector. Due to this physical location the CCM module will need to work within a radiation environment with minimal access over a ten-year period. The electronics are expected to see a total neutron fluence of 1.3 x 10{sup 11} n/cm{sup 2} and a total ionizing dose of 330 rads over the 10 year running period. This paper will detail the design of the CCM Module including the selecting and testing of devices that will operate within the radiation field.

  15. Temperature and pressure shift of the Cs clock transition in the presence of buffer gases: Ne, N{sub 2}, Ar

    SciTech Connect (OSTI)

    Kozlova, Olga; Guerandel, Stephane; Clercq, Emeric de

    2011-06-15

    The ground-state hyperfine resonance line of alkali-metal atoms is frequency shifted in the presence of noble or molecular gases. The buffer gases used in vapor-cell atomic clocks thus induce a temperature-dependent shift of the clock transition frequency. We report on measurements of the pressure and temperature dependence of the Cs clock transition frequency in the presence of Ne, Ar, and N{sub 2} buffer gases. The pressure in the sealed glass vapor cells is measured by means of the shift of the Cs D{sub 1} line. We have also investigated the temperature dependence of the optical shift. From these measurements, we infer the pressure and temperature coefficients of the hyperfine frequency shift. It is then possible to predetermine gas mixture ratios that cancel the temperature sensitivity at a given temperature. This prediction is confirmed experimentally for Ar-N{sub 2} mixtures. These results can be useful for improving the long-term frequency stability of Cs vapor-cell clocks.

  16. Ab initio calculations of external-field shifts of the 661-nm quadrupolar clock transition in neutral Ag atoms

    SciTech Connect (OSTI)

    Topcu, Suat; Nasser, Jamil; Daku, Latevi Max Lawson; Fritzsche, Stephan

    2006-04-15

    Frequency shifts of the Ag I 4d{sup 10}5s {sup 2}S{sub 1/2}(F=0,M{sub F}=0) to 4d{sup 9}5s{sup 2} {sup 2}D{sub 5/2}(F{sup '}=2,M{sub F{sup '}}=0) electric-quadrupole transition at 330.6 nm due to external fields are calculated using multiconfigurational self-consistent field methods. As this forbidden transition is free from first order Doppler and Zeeman effects, it is under investigation for the realization of an atomic optical clock. The calculated perturbations are the light shift, the blackbody frequency shift, and the quadratic Zeeman shift. Results show that a total uncertainty of 10{sup -18} could be reach without confining the atoms in a Lamb-Dicke regime in an optical lattice.

  17. Pulse transmission receiver with higher-order time derivative pulse generator

    DOE Patents [OSTI]

    Dress, Jr., William B.; Smith, Stephen F.

    2003-08-12

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a front-end amplification/processing circuit; a synchronization circuit coupled to the front-end amplification/processing circuit; a clock coupled to the synchronization circuit; a trigger signal generator coupled to the clock; and at least one higher-order time derivative pulse generator coupled to the trigger signal generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  18. Relativistic general-order coupled-cluster method for high-precision calculations: Application to the Al{sup +} atomic clock

    SciTech Connect (OSTI)

    Kallay, Mihaly; Nataraj, H. S.; Sahoo, B. K.; Das, B. P.; Visscher, Lucas

    2011-03-15

    We report the implementation of a general-order relativistic coupled-cluster method for performing high-precision calculations of atomic and molecular properties. As a first application, the black-body radiation shift of the Al{sup +} clock has been estimated precisely. The computed shift relative to the frequency of the 3s{sup 2} {sup 1}S{sub 0}{sup e}{yields}3s3p {sup 3}P{sub 0}{sup o} clock transition given by (-3.66{+-}0.60)x10{sup -18} calls for an improvement over the recent measurement with a reported result of (-9{+-}3)x10{sup -18}[Phys. Rev. Lett. 104, 070802 (2010)].

  19. Measurement of the second-order Zeeman effect on the sodium clock transition in the weak-magnetic-field region using the scalar Aharonov-Bohm phase

    SciTech Connect (OSTI)

    Numazaki, Kazuya; Imai, Hiromitsu; Morinaga, Atsuo

    2010-03-15

    The second-order Zeeman effect of the sodium clock transition in a weak magnetic field of less than 50 {mu}T was measured as the scalar Aharonov-Bohm phase by two-photon stimulated Raman atom interferometry. The ac Stark effect of the Raman pulse was canceled out by adopting an appropriate intensity ratio of two photons in the Raman pulse. The Ramsey fringes for the pulse separation of 7 ms were obtained with a phase uncertainty of {pi}/200 rad. The nondispersive feature of the scalar Aharonov-Bohm phase was clearly demonstrated through 18 fringes with constant amplitude. The Breit-Rabi formula of the sodium clock transition was verified to be {Delta}{nu}=(0.222{+-}0.003)x10{sup 12}xB{sup 1.998{+-}0.004} in a magnetic field of less than 50 {mu}T.

  20. The hard X-ray shortages prompted by the clock bursts in GS 1826-238

    SciTech Connect (OSTI)

    Ji, Long; Zhang, Shu; Chen, YuPeng; Zhang, Shuang-Nan; Li, Jian; Torres, Diego F.; Kretschmar, Peter

    2014-02-10

    We report on a study of GS 1826-238 using all available Rossi X-Ray Timing Explorer observations, concentrating on the behavior of the hard X-rays during type-I bursts. We find a hard X-ray shortage at 30-50 keV prompted by the shower of soft X-rays coming from type-I bursts. This shortage happens with a time delay after the peak of the soft flux of 3.6 ± 1.2 s. The behavior of hard X-rays during bursts indicates cooling and reheating of the corona, during which a large amount of energy is required. We speculate that this energy originates from the feedback of the type-I bursts to the accretion process, resulting in a rapid temporary increase of the accretion rate.

  1. Coulomb reacceleration as a clock for nuclear reactions: A two-dimensional model

    SciTech Connect (OSTI)

    Bertulani, C.A. ); Bertsch, G.F. )

    1994-05-01

    Reacceleration effects in the Coulomb breakup of nuclei are modeled with the two-dimensional time-dependent Schroedinger equation, extending a previous one-dimensional study. The present model better describes the individual contributions of longitudinal and transverse forces to the breakup and reacceleration. Reacceleration effects are found to preserve a strong memory of the pre-breakup phase of the reaction, as was concluded with the one-dimensional model.

  2. Double core hole production in N{sub 2} : beating the auger clock.

    SciTech Connect (OSTI)

    Fang, L.; Hoener, M.; Gessner, O.; Tarantelli, F.; Pratt, S. T.; Kornilov, O.; Buth, C.; Guhr, M.; Kanter, E. P.; Bostedt, C.; Bozek, J. D.; Bucksbaum, P. H.; Chen, M.; Coffee, R.; Cryan, J.; Glownia, J. M.; Kukk, E.; Leone, S. R.; Berrah, N.

    2010-01-01

    We investigate the creation of double K-shell holes in N{sub 2} molecules via sequential absorption of two photons on a time scale shorter than the core-hole lifetime by using intense x-ray pulses from the Linac Coherent Light Source free electron laser. The production and decay of these states is characterized by photoelectron spectroscopy and Auger electron spectroscopy. In molecules, two types of double core holes are expected, the first with two core holes on the same N atom, and the second with one core hole on each N atom. We report the first direct observations of the former type of core hole in a molecule, in good agreement with theory, and provide an experimental upper bound for the relative contribution of the latter type.

  3. Double Core-Hole Production in N{sub 2}: Beating the Auger Clock

    SciTech Connect (OSTI)

    Fang, L.; Berrah, N.; Hoener, M.; Gessner, O.; Kornilov, O.; Tarantelli, F.; Pratt, S. T.; Kanter, E. P.; Buth, C.; Guehr, M.; Bucksbaum, P. H.; Cryan, J.; Glownia, M.; Bostedt, C.; Bozek, J. D.; Coffee, R.; Chen, M.; Kukk, E.; Leone, S. R.

    2010-08-20

    We investigate the creation of double K-shell holes in N{sub 2} molecules via sequential absorption of two photons on a time scale shorter than the core-hole lifetime by using intense x-ray pulses from the Linac Coherent Light Source free electron laser. The production and decay of these states is characterized by photoelectron spectroscopy and Auger electron spectroscopy. In molecules, two types of double core holes are expected, the first with two core holes on the same N atom, and the second with one core hole on each N atom. We report the first direct observations of the former type of core hole in a molecule, in good agreement with theory, and provide an experimental upper bound for the relative contribution of the latter type.

  4. The magnetospheric clock of Saturn—A self-organized plasma dynamo

    SciTech Connect (OSTI)

    Olson, J.; Brenning, N.

    2013-08-15

    The plasma in the inner magnetosphere of Saturn is characterized by large-amplitude azimuthal density variations in the equatorial plane, with approximately a sinusoidal dependence on the azimuthal angle [D. A. Gurnett et al., Science 316, 442 (2007)]. This structure rotates with close to the period of the planet itself and has been proposed to steer other nonaxisymmetric phenomena, e.g., the Saturn kilometric radiation SKR [W. S. Kurth et al., Geophys. Res. Lett. 34, L02201 (2007)], and inner-magnetosphere magnetic field perturbations [D. J. Southwood and M. G. Kivelson, J. Geophys. Res. 112(A12), A12222 (2007)]. There is today no consensus regarding the basic driving mechanism. We here propose it to be a plasma dynamo, located in the neutral gas torus of Enceladus but coupled both inwards, through electric currents along the magnetic field lines down to the planet, and outwards through the plasma flow pattern there. Such a dynamo mechanism is shown to self-regulate towards a state that, with realistic parameters, can reproduce the observed configuration of the magnetosphere. This state is characterized by three quantities: the Pedersen conductivity in the polar cap, the ionization time constant in the neutral gas torus, and a parameter characterizing the plasma flow pattern. A particularly interesting property of the dynamo is that regular (i.e., constant-amplitude, sinusoidal) variations in the last parameter can lead to complicated, non-periodic, oscillations around the steady-state configuration.

  5. TIMING APPARATUS

    DOE Patents [OSTI]

    Bennett, A.E.; Geisow, J.C.H.

    1956-04-17

    The timing device comprises an escapement wheel and pallet, a spring drive to rotate the escapement wheel to a zero position, means to wind the pretensioned spring proportional to the desired signal time, and a cam mechanism to control an electrical signal switch by energizing the switch when the spring has been wound to the desired position, and deenergizing it when it reaches the zero position. This device produces an accurately timed signal variably witain the control of the operator.

  6. Time Off

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

    Time Off Time Off A comprehensive benefits package with plan options for health care and retirement to take care of our employees today and tomorrow. Contact Benefits Office (505) 667-1806 Email Time Off Work schedules A variety of work schedules are available that allow flexibility for workers and Laboratory programs. The most popular work schedule is the 9/80-employees work 80 hours over a 9 workday (two week) period, with a Friday off every other week. Holidays The Lab recognizes these 12

  7. Observation and Absolute Frequency Measurements of the {sup 1}S{sub 0}-{sup 3}P{sub 0} Optical Clock Transition in Neutral Ytterbium

    SciTech Connect (OSTI)

    Hoyt, C.W.; Barber, Z.W.; Oates, C.W.; Fortier, T.M.; Diddams, S.A.; Hollberg, L.

    2005-08-19

    We report the direct excitation of the highly forbidden (6s{sup 2}){sup 1}S{sub 0}{r_reversible}(6s6p){sup 3}P{sub 0} optical transition in two odd isotopes of neutral ytterbium. As the excitation laser frequency is scanned, absorption is detected by monitoring the depletion from an atomic cloud at {approx}70 {mu}K in a magneto-optical trap. The measured frequency in {sup 171}Yb (F=1/2) is 518 295 836 591.6{+-}4.4 kHz. The measured frequency in {sup 173}Yb (F=5/2) is 518 294 576 847.6{+-}4.4 kHz. Measurements are made with a femtosecond-laser frequency comb calibrated by the National Institute of Standards and Technology cesium fountain clock and represent nearly a 10{sup 6}-fold reduction in uncertainty. The natural linewidth of these J=0 to J=0 transitions is calculated to be {approx}10 mHz, making them well suited to support a new generation of optical atomic clocks based on confinement in an optical lattice.

  8. Structural model of the circadian clock KaiB-KaiC complex and mechanism for modulation of KaiC phosphorylation

    SciTech Connect (OSTI)

    Pattanayek, Rekha; Williams, Dewight R; Pattanayek, Sabuj; Mori, Tetsuya; Johnson, Carl H; Stewart, Phoebe L; Egli, Martin

    2010-03-08

    The circadian clock of the cyanobacterium Synechococcus elongatus can be reconstituted in vitro by the KaiA, KaiB and KaiC proteins in the presence of ATP. The principal clock component, KaiC, undergoes regular cycles between hyper- and hypo-phosphorylated states with a period of ca. 24 h that is temperature compensated. KaiA enhances KaiC phosphorylation and this enhancement is antagonized by KaiB. Throughout the cycle Kai proteins interact in a dynamic manner to form complexes of different composition. We present a three-dimensional model of the S. elongatus KaiB-KaiC complex based on X-ray crystallography, negative-stain and cryo-electron microscopy, native gel electrophoresis and modelling techniques. We provide experimental evidence that KaiB dimers interact with KaiC from the same side as KaiA and for a conformational rearrangement of the C-terminal regions of KaiC subunits. The enlarged central channel and thus KaiC subunit separation in the C-terminal ring of the hexamer is consistent with KaiC subunit exchange during the dephosphorylation phase. The proposed binding mode of KaiB explains the observation of simultaneous binding of KaiA and KaiB to KaiC, and provides insight into the mechanism of KaiB's antagonism of KaiA.

  9. The Time Domain Crossbar (TDX): A high speed, high density, FPGA design

    SciTech Connect (OSTI)

    Schreiber, A.L.

    1993-12-31

    As system clock rates of electronic designs steadily increase, the need for high bandwidth communication between designs in the system becomes critical. The Time Domain Crossbar (TDX) provides programmable, high-speed communications bandwidth across the user I/O pins of a VME backplane. The TDX timemultiplexes 20MHz byte-wide data onto 80MHz byte-wide data for transmission between boards. A programmable register set allows the user to open and close virtual communicaton channels by configuring independent data paths between sets of boards. Because each additional TDX board provides another crossbar, the overall system bandwidth increases with the number of TDX boards.

  10. Real-time Optical Network for Accelerator Control

    SciTech Connect (OSTI)

    Lee, Keun

    2012-06-27

    The timing requirements of a modern accelerator complex call for several features. The first is a system for high precision relative timing among accelerator components. Stabilized fiber links have already been demonstrated to achieve sub-10 femtoseconds relative timing precision. The second is a system for timing distribution of absolute time with sufficient precision to identify a specific RF bucket. The White Rabbit technology is a promising candidate to deliver the absolute time that is linked to the GPS clock. In this study we demonstrated that these two technologies can be combined in a way that the absolute time information can be delivered to the stabilized fiber link system. This was accomplished by researching the design of the stabilized fiber and White Rabbit systems and devising adaptation modules that facilitate co-existence of both systems in the same FPGA environment. We built a prototype system using off-the-shelf products and implemented a proof-of-concept version of the FPGA firmware. The test verified that the White Rabbit features operate correctly under the stabilized fiber system environment. This work demonstrates that turn-key femtosecond timing systems with absolute time information can be built cost effectively and deployed in various accelerator environments. This will lead to many new applications in chemistry, biology and surface dynamics, to name a few.

  11. Selection and amplification of a single optical frequency comb mode for laser cooling of the strontium atoms in an optical clock

    SciTech Connect (OSTI)

    Liu, Hui; Yin, Mojuan; Kong, Dehuan; Xu, Qinfang; Zhang, Shougang; Chang, Hong

    2015-10-12

    In this paper, we report on the active filtering and amplification of a single mode from an optical femtosecond laser comb with mode spacing of 250 MHz by optical injection of two external-cavity diode lasers operating in cascade to build a narrow linewidth laser for laser cooling of the strontium atoms in an optical lattice clock. Despite the low injection of individual comb mode of approximately 50 nW, a single comb line at 689 nm could be filtered and amplified to reach as high as 10 mW with 37 dB side mode suppression and a linewidth of 240 Hz. This method could be applied over a broad spectral band to build narrow linewidth lasers for various applications.

  12. Final Report [Regulated mRNA Decay in Arabidopsis: A global analysis of differential control by hormones and the circadian clock

    SciTech Connect (OSTI)

    Green, Pamela J.

    2010-03-18

    The long-term goal of this research was to better understand the influence of mRNA stability on gene regulation, particularly in response to hormones and the circadian clock. The primary aim of this project was to examine this using DNA microarrays, small RNA analysis and other approaches. We accomplished these objectives, although we were only able to detect small changes in mRNA stability in response to these stimuli. However, the work also contributed to a major breakthrough allowing the identification of small RNAs on a genomic scale in eukaryotes. Moreover, the project prompted us to develop a new way to analyze mRNA decay genome wide. Thus, the research was hugely successful beyond our objectives.

  13. ATLAS: A Small, Light Weight, Time-Synchronized Wind-Turbine Data Acquistion System

    SciTech Connect (OSTI)

    Berg, D.E.; Robertson, P.; Zayas, J.

    1998-11-09

    Wind energy researchers at Sandia National Laboratories have developed a small, lightweight, time- synchronized, robust data acquisition system to acquire long-term time-series data on a wind turbine rotor. A commercial data acquisition module is utilized to acquire data simultaneously from multip!e strain-gauge, analog, and digital channels. Acquisition of rotor data at precisely the same times as acquisition of ground data is ensured by slaving the acquisition clocks on the rotor- based data unit and ground-based units to the Global Positioning Satellite (GPS) system with commercial GPS receiver units and custom-built and programmed programmable logic devices. The acquisition clocks will remain synchronized within two microseconds indefinitely. Field tests have confirmed that synchronization can be maintained at rotation rates in excess of 350 rpm, Commercial spread-spectrum radio modems are used to transfer the rotor data to a ground- based computer concurrently with data acquisition, permitting continuous acquisition of data over a period of several hours, days or even weeks.

  14. Purchasing Energy-Efficient Refrigerated Beverage Vending Machines...

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

    ... Future electricity price trends and a 3% discount rate are from Energy Price Indices and Discount Factors for Life-Cycle Cost Analysis - 2015: Annual Supplement to NIST Handbook ...

  15. List of Vending Machine Controls Incentives | Open Energy Information

    Open Energy Info (EERE)

    Eligible Technologies Active APS - Energy Efficiency Solutions for Business (Arizona) Utility Rebate Program Arizona Commercial Industrial Institutional Local Government Retail...

  16. Dephosphorylation of the Core Clock Protein KaiC in the Cyanobacterial KaiABC Circadian Oscillator Proceeds via an ATP Synthase Mechanism

    SciTech Connect (OSTI)

    Egli, Martin; Mori, Tetsuya; Pattanayek, Rekha; Xu, Yao; Qin, Ximing; Johnson, Carl H.

    2014-10-02

    The circadian clock of the cyanobacterium Synechococcus elongatus can be reconstituted in vitro from three proteins, KaiA, KaiB, and KaiC in the presence of ATP, to tick in a temperature-compensated manner. KaiC, the central cog of this oscillator, forms a homohexamer with 12 ATP molecules bound between its N- and C-terminal domains and exhibits unusual properties. Both the N-terminal (CI) and C-terminal (CII) domains harbor ATPase activity, and the subunit interfaces between CII domains are the sites of autokinase and autophosphatase activities. Hydrolysis of ATP correlates with phosphorylation at threonine and serine sites across subunits in an orchestrated manner, such that first T432 and then S431 are phosphorylated, followed by dephosphorylation of these residues in the same order. Although structural work has provided insight into the mechanisms of ATPase and kinase, the location and mechanism of the phosphatase have remained enigmatic. From the available experimental data based on a range of approaches, including KaiC crystal structures and small-angle X-ray scattering models, metal ion dependence, site-directed mutagenesis (i.e., E318, the general base), and measurements of the associated clock periods, phosphorylation patterns, and dephosphorylation courses as well as a lack of sequence motifs in KaiC that are typically associated with known phosphatases, we hypothesized that KaiCII makes use of the same active site for phosphorylation and dephosphorlyation. We observed that wild-type KaiC (wt-KaiC) exhibits an ATP synthase activity that is significantly reduced in the T432A/S431A mutant. We interpret the first observation as evidence that KaiCII is a phosphotransferase instead of a phosphatase and the second that the enzyme is capable of generating ATP, both from ADP and P{sub i} (in a reversal of the ATPase reaction) and from ADP and P-T432/P-S431 (dephosphorylation). This new concept regarding the mechanism of dephosphorylation is also supported by the

  17. Crystal Structure of the Redox-Active Cofactor Dibromothymoquinone Bound to Circadian Clock Protein KaiA and Structural Basis for Dibromothymoquinone's Ability to Prevent Stimulation of KaiC Phosphorylation by KaiA

    SciTech Connect (OSTI)

    Pattanayek, Rekha; Sidiqi, Said K.; Egli, Martin

    2013-09-19

    KaiA protein that stimulates KaiC phosphorylation in the cyanobacterial circadian clock was recently shown to be destabilized by dibromothymoquinone (DBMIB), thus revealing KaiA as a sensor of the plastoquinone (PQ) redox state and suggesting an indirect control of the clock by light through PQ redox changes. Here we show using X-ray crystallography that several DBMIBs are bound to KaiA dimer. Some binding modes are consistent with oligomerization of N-terminal KaiA pseudoreceiver domains and/or reduced interdomain flexibility. DBMIB bound to the C-terminal KaiA (C-KaiA) domain and limited stimulation of KaiC kinase activity by C-KaiA in the presence of DBMIB demonstrate that the cofactor may weakly inhibit KaiA-KaiC binding.

  18. UGE Scheduler Cycle Time

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

    UGE Scheduler Cycle Time UGE Scheduler Cycle Time Genepool Cycle Time Genepool Daily Genepool Weekly Phoebe Cycle Time Phoebe Daily Phoebe Weekly What is the Scheduler Cycle? The...

  19. A High Resolution, Multi-stop, Time-to-Digital Converter for Nuclear Time-of-Flight Measurements

    SciTech Connect (OSTI)

    D. F. Spencer; J. Cole; M. Drigert; R. Aryaeinejad

    2006-01-01

    A high-resolution, multi-stop, time-to-digital converter (TDC) was designed and developed to precisely measure the times-of-flight (TOF) of incident neutrons responsible for induced fission and capture reactions on actinide targets. The minimum time resolution is 1 ns. The TDC design was implemented into a single, dual-wide CAMAC module. The CAMAC bus is used for command and control as well as an alternative data output. A high-speed ECL interface, compatible with LeCroy FERA modules, was also provided for the principle data output path. An Actel high-speed field programmable gate array (FPGA) chip was incorporated with an external oscillator and an internal multiple clock phasing system. This device implemented the majority of the high-speed register functions, the state machine for the FERA interface, and the high-speed counting circuit used for the TDC conversion. An external microcontroller was used to monitor and control system-level changes. In this work we discuss the performance of this TDC module as well as its application.

  20. DARPA looks beyond GPS for positioning, navigating, and timing

    SciTech Connect (OSTI)

    Kramer, David

    2014-10-01

    Cold-atom interferometry, microelectromechanical systems, signals of opportunity, and atomic clocks are some of the technologies the defense agency is pursuing to provide precise navigation when GPS is unavailable.

  1. Modeling highway travel time distribution with conditional probability models

    SciTech Connect (OSTI)

    Oliveira Neto, Francisco Moraes; Chin, Shih-Miao; Hwang, Ho-Ling; Han, Lee

    2014-01-01

    ABSTRACT Under the sponsorship of the Federal Highway Administration's Office of Freight Management and Operations, the American Transportation Research Institute (ATRI) has developed performance measures through the Freight Performance Measures (FPM) initiative. Under this program, travel speed information is derived from data collected using wireless based global positioning systems. These telemetric data systems are subscribed and used by trucking industry as an operations management tool. More than one telemetric operator submits their data dumps to ATRI on a regular basis. Each data transmission contains truck location, its travel time, and a clock time/date stamp. Data from the FPM program provides a unique opportunity for studying the upstream-downstream speed distributions at different locations, as well as different time of the day and day of the week. This research is focused on the stochastic nature of successive link travel speed data on the continental United States Interstates network. Specifically, a method to estimate route probability distributions of travel time is proposed. This method uses the concepts of convolution of probability distributions and bivariate, link-to-link, conditional probability to estimate the expected distributions for the route travel time. Major contribution of this study is the consideration of speed correlation between upstream and downstream contiguous Interstate segments through conditional probability. The established conditional probability distributions, between successive segments, can be used to provide travel time reliability measures. This study also suggests an adaptive method for calculating and updating route travel time distribution as new data or information is added. This methodology can be useful to estimate performance measures as required by the recent Moving Ahead for Progress in the 21st Century Act (MAP 21).

  2. Structures of KaiC Circadian Clock Mutant Proteins: A New Phosphorylation Site at T426 and Mechanisms of Kinase, ATPase and Phosphatase

    SciTech Connect (OSTI)

    Pattanayek, Rekha; Mori, Tetsuya; Xu, Yao; Pattanayek, Sabuj; Johnson, Carl H.; Egli, Martin

    2010-09-02

    The circadian clock of the cyanobacterium Synechococcus elongatus can be reconstituted in vitro by three proteins, KaiA, KaiB and KaiC. Homo-hexameric KaiC displays kinase, phosphatase and ATPase activities; KaiA enhances KaiC phosphorylation and KaiB antagonizes KaiA. Phosphorylation and dephosphorylation of the two known sites in the C-terminal half of KaiC subunits, T432 and S431, follow a strict order (TS {yields} pTS {yields} pTpS {yields} TpS {yields} TS) over the daily cycle, the origin of which is not understood. To address this void and to analyze the roles of KaiC active site residues, in particular T426, we determined structures of single and double P-site mutants of S. elongatus KaiC. The conformations of the loop region harboring P-site residues T432 and S431 in the crystal structures of six KaiC mutant proteins exhibit subtle differences that result in various distances between Thr (or Ala/Asn/Glu) and Ser (or Ala/Asp) residues and the ATP {gamma}-phosphate. T432 is phosphorylated first because it lies consistently closer to P{gamma}. The structures of the S431A and T432E/S431A mutants reveal phosphorylation at T426. The environments of the latter residue in the structures and functional data for T426 mutants in vitro and in vivo imply a role in dephosphorylation. We provide evidence for a third phosphorylation site in KaiC at T426. T426 and S431 are closely spaced and a KaiC subunit cannot carry phosphates at both sites simultaneously. Fewer subunits are phosphorylated at T426 in the two KaiC mutants compared to phosphorylated T432 and/or S431 residues in the structures of wt and other mutant KaiCs, suggesting that T426 phosphorylation may be labile. The structures combined with functional data for a host of KaiC mutant proteins help rationalize why S431 trails T432 in the loss of its phosphate and shed light on the mechanisms of the KaiC kinase, ATPase and phosphatase activities.

  3. Absolute Frequency Measurement of the {sup 40}Ca{sup +} 4s {sup 2}S{sub 1/2}-3d {sup 2}D{sub 5/2} Clock Transition

    SciTech Connect (OSTI)

    Chwalla, M.; Kim, K.; Monz, T.; Riebe, M.; Schindler, P.; Villar, A. S.; Haensel, W.; Benhelm, J.; Kirchmair, G.; Roos, C. F.; Blatt, R.; Abgrall, M.; Santarelli, G.; Rovera, G. D.; Laurent, Ph.

    2009-01-16

    We report on the first absolute transition frequency measurement at the 10{sup -15} level with a single, laser-cooled {sup 40}Ca{sup +} ion in a linear Paul trap. For this measurement, a frequency comb is referenced to the transportable Cs atomic fountain clock of LNE-SYRTE and is used to measure the {sup 40}Ca{sup +} 4s {sup 2}S{sub 1/2}-3d {sup 2}D{sub 5/2} electric-quadrupole transition frequency. After the correction of systematic shifts, the clock transition frequency {nu}{sub Ca{sup +}}=411 042 129 776 393.2(1.0) Hz is obtained, which corresponds to a fractional uncertainty within a factor of 3 of the Cs standard. In addition, we determine the Landeg factor of the 3d{sup 2}D{sub 5/2} level to be g{sub 5/2}=1.200 334 0(3)

  4. Daylight Savings Time Starts

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

    Daylight Savings Time Starts Daylight Savings Time Starts WHEN: Mar 08, 2015 3:00 AM - 11:59 PM WHERE: World Time Zones CATEGORY: Holiday INTERNAL: Calendar Login Daylight Savings...

  5. UGE Scheduler Cycle Time

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

    UGE Scheduler Cycle Time UGE Scheduler Cycle Time Genepool Cycle Time Genepool Scheduler Cycle Time Genepool Jobs Dispatched / Hour What is the Scheduler Cycle? The Univa Grid Engine Scheduler cycle performs a number of important tasks, including: Prioritizing Jobs Reserving Resources for jobs requesting more resources (slots / memory) Dispatching jobs or tasks to the compute nodes Evaluating job dependencies The "cycle time" is the length of time it takes the scheduler to complete all

  6. ARM - Datastreams - mfraaf

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

    sentences that must be received before clock adjustment. unitless gpsready ( time ) ...rationfactorfilter6 Number of times the clock has been changed since the program started ...

  7. ARM - Datastreams - saszefilterbands

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

    degC chillertemperature ( time ) Spectrometer internal clock ticks for InGaAs NIR spectrometer s clockticksnir ( time ) Spectrometer internal clock ticks for Si VIS ...

  8. Doppler-Free Spectroscopy of the {sup 1}S{sub 0}-{sup 3}P{sub 0} Optical Clock Transition in Laser-Cooled Fermionic Isotopes of Neutral Mercury

    SciTech Connect (OSTI)

    Petersen, M.; Chicireanu, R.; Dawkins, S. T.; Magalhaes, D. V.; Mandache, C.; Le Coq, Y.; Clairon, A.; Bize, S.

    2008-10-31

    We report direct laser spectroscopy of the {sup 1}S{sub 0}-{sup 3}P{sub 0} transition at 265.6 nm in fermionic isotopes of neutral mercury in a magneto-optical trap. Measurements of the frequency against the LNE-SYRTE primary reference using an optical frequency comb yield 1 128 575 290 808.4{+-}5.6 kHz in {sup 199}Hg and 1 128 569 561 139.6{+-}5.3 kHz in {sup 201}Hg. The uncertainty, allowed by the observation of the Doppler-free recoil doublet, is 4 orders of magnitude lower than previous indirect determinations. Mercury is a promising candidate for future optical lattice clocks due to its low sensitivity to blackbody radiation.

  9. Possibility of an optical clock using the 6 {sup 1}S{sub 0}{yields}6 {sup 3}P{sub 0}{sup o} transition in {sup 171,173}Yb atoms held in an optical lattice

    SciTech Connect (OSTI)

    Porsev, Sergey G.; Derevianko, Andrei; Fortson, E.N.

    2004-02-01

    We report calculations assessing the ultimate precision of an atomic clock based on the 578 nm 6 {sup 1}S{sub 0}{yields}6 {sup 3}P{sub 0} transition in Yb atoms confined in an optical lattice trap. We find that this transition has a natural linewidth less than 10 mHz in the odd Yb isotopes, caused by hyperfine coupling. The shift in this transition due to the trapping light acting through the lowest order ac polarizability is found to become zero at the magic trap wavelength of about 752 nm. The effects of Rayleigh scattering, multipole polarizabilities, vector polarizability, and hyperfine induced electronic magnetic moments can all be held below 1 mHz (about one part in 10{sup 18}). In the case of the hyperpolarizability, however, larger shifts due to nearly resonant terms cannot be ruled out without an accurate measurement of the magic wavelength.

  10. The Y-12 Times

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

    Gail Powell Elaine Ruth Ray Smith Donna Watson Lisa Xiques times times the B&W Technical Services Y-12, LLC, a partnership between Babcock & Wilcox Technical Services Group Inc. ...

  11. Time-Resolved

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

    and time) three correspond to the three broad categories of synchrotron experimental measurement techniques: spectroscopy (energy), scattering (momentum), and imaging...

  12. The tunneling solutions of the time-dependent Schroedinger equation for a square-potential barrier

    SciTech Connect (OSTI)

    Elci, A.; Hjalmarson, H. P.

    2009-10-15

    The exact tunneling solutions of the time-dependent Schroedinger equation with a square-potential barrier are derived using the continuous symmetry group G{sub S} for the partial differential equation. The infinitesimal generators and the elements for G{sub S} are represented and derived in the jet space. There exist six classes of wave functions. The representative (canonical) wave functions for the classes are labeled by the eigenvalue sets, whose elements arise partially from the reducibility of a Lie subgroup G{sub LS} of G{sub S} and partially from the separation of variables. Each eigenvalue set provides two or more time scales for the wave function. The ratio of two time scales can act as the duration of an intrinsic clock for the particle motion. The exact solutions of the time-dependent Schroedinger equation presented here can produce tunneling currents that are orders of magnitude larger than those produced by the energy eigenfunctions. The exact solutions show that tunneling current can be quantized under appropriate boundary conditions and tunneling probability can be affected by a transverse acceleration.

  13. A 24 hr global campaign to assess precision timing of the millisecond pulsar J1713+0747

    SciTech Connect (OSTI)

    Dolch, T.; Lam, M. T.; Cordes, J.; Chatterjee, S.; Bassa, C.; Hessels, J. W. T.; Janssen, G.; Kondratiev, V.; Bhattacharyya, B.; Jordan, C.; Keith, M.; Champion, D. J.; Karuppusamy, R.; Kramer, M.; Lazarus, P.; Cognard, I.; Demorest, P. B.; Jenet, F. A.; Jones, G.; and others

    2014-10-10

    The radio millisecond pulsar J1713+0747 is regarded as one of the highest-precision clocks in the sky and is regularly timed for the purpose of detecting gravitational waves. The International Pulsar Timing Array Collaboration undertook a 24 hr global observation of PSR J1713+0747 in an effort to better quantify sources of timing noise in this pulsar, particularly on intermediate (1-24 hr) timescales. We observed the pulsar continuously over 24 hr with the Arecibo, Effelsberg, GMRT, Green Bank, LOFAR, Lovell, Nançay, Parkes, and WSRT radio telescopes. The combined pulse times-of-arrival presented here provide an estimate of what sources of timing noise, excluding DM variations, would be present as compared to an idealized √N improvement in timing precision, where N is the number of pulses analyzed. In the case of this particular pulsar, we find that intrinsic pulse phase jitter dominates arrival time precision when the signal-to-noise ratio of single pulses exceeds unity, as measured using the eight telescopes that observed at L band/1.4 GHz. We present first results of specific phenomena probed on the unusually long timescale (for a single continuous observing session) of tens of hours, in particular interstellar scintillation, and discuss the degree to which scintillation and profile evolution affect precision timing. This paper presents the data set as a basis for future, deeper studies.

  14. Facilities Study For enXco Development Corp.

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

    ... The disturbance equipment shall also be equipped with a GPS time synch clock. This ... SPS Amarillo Operations Center THE SOUTHWEST POWER POOL WAN GPS Clock The Interconnection ...

  15. ZERO-TIME INDICATOR

    DOE Patents [OSTI]

    Sander, H.H.

    1960-08-30

    The travel time of a nuclear shock wave from its point of origin to a location can be determined accurately by an apparatus for noting and comparably recording both zerotime, as indicated by the electromagnetic transient associated with the nuclear detonation, and shock wave arrival time.

  16. Task Time Tracker

    Energy Science and Technology Software Center (OSTI)

    2013-07-24

    This client-side web app tracks the amount of time spent on arbitrary tasks. It allosw the creation of an unlimited number of arbitrarily named tasks ans via simple interactions, tracks the amount of time spent working on the drfined tasks.

  17. TIME CALIBRATED OSCILLOSCOPE SWEEP

    DOE Patents [OSTI]

    Owren, H.M.; Johnson, B.M.; Smith, V.L.

    1958-04-22

    The time calibrator of an electric signal displayed on an oscilloscope is described. In contrast to the conventional technique of using time-calibrated divisions on the face of the oscilloscope, this invention provides means for directly superimposing equal time spaced markers upon a signal displayed upon an oscilloscope. More explicitly, the present invention includes generally a generator for developing a linear saw-tooth voltage and a circuit for combining a high-frequency sinusoidal voltage of a suitable amplitude and frequency with the saw-tooth voltage to produce a resultant sweep deflection voltage having a wave shape which is substantially linear with respect to time between equal time spaced incremental plateau regions occurring once each cycle of the sinusoidal voltage. The foregoing sweep voltage when applied to the horizontal deflection plates in combination with a signal to be observed applied to the vertical deflection plates of a cathode ray oscilloscope produces an image on the viewing screen which is essentially a display of the signal to be observed with respect to time. Intensified spots, or certain other conspicuous indications corresponding to the equal time spaced plateau regions of said sweep voltage, appear superimposed upon said displayed signal, which indications are therefore suitable for direct time calibration purposes.

  18. TIMING OF SHOCK WAVES

    DOE Patents [OSTI]

    Tuck, J.L.

    1955-03-01

    This patent relates to means for ascertaining the instant of arrival of a shock wave in an exploslve charge and apparatus utilizing this means to coordinate the timing of two operations involving a short lnterval of time. A pair of spaced electrodes are inserted along the line of an explosive train with a voltage applied there-across which is insufficient to cause discharge. When it is desired to initiate operation of a device at the time the explosive shock wave reaches a particular point on the explosive line, the device having an inherent time delay, the electrodes are located ahead of the point such that the ionization of the area between the electrodes caused by the traveling explosive shock wave sends a signal to initiate operation of the device to cause it to operate at the proper time. The operated device may be photographic equipment consisting of an x-ray illuminating tube.

  19. Parallel time integration software

    Energy Science and Technology Software Center (OSTI)

    2014-07-01

    This package implements an optimal-scaling multigrid solver for the (non) linear systems that arise from the discretization of problems with evolutionary behavior. Typically, solution algorithms for evolution equations are based on a time-marching approach, solving sequentially for one time step after the other. Parallelism in these traditional time-integrarion techniques is limited to spatial parallelism. However, current trends in computer architectures are leading twards system with more, but not faster. processors. Therefore, faster compute speeds mustmore » come from greater parallelism. One approach to achieve parallelism in time is with multigrid, but extending classical multigrid methods for elliptic poerators to this setting is a significant achievement. In this software, we implement a non-intrusive, optimal-scaling time-parallel method based on multigrid reduction techniques. The examples in the package demonstrate optimality of our multigrid-reduction-in-time algorithm (MGRIT) for solving a variety of parabolic equations in two and three sparial dimensions. These examples can also be used to show that MGRIT can achieve significant speedup in comparison to sequential time marching on modern architectures.« less

  20. Time of Flight

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

    of Flight Techniques Since the LANSCE proton beam is pulsed, the energy of the neutrons that are produced can be determined by Time-of-Flight (TOF) techniques. Neutron Time-of-Flight Since the LANSCE proton beam is pulsed, the energy of the neutrons that are produced can be determined by Time-of-Flight (TOF) techniques. The proton beam pulse strikes the tungsten neutron production target and neutrons, gamma rays and charged particles are produced. The charged particles are removed from the beam

  1. VARIABLE TIME DELAY MEANS

    DOE Patents [OSTI]

    Clemensen, R.E.

    1959-11-01

    An electrically variable time delay line is described which may be readily controlled simuitaneously with variable impedance matching means coupied thereto such that reflections are prevented. Broadly, the delay line includes a signal winding about a magnetic core whose permeability is electrically variable. Inasmuch as the inductance of the line varies directly with the permeability, the time delay and characteristic impedance of the line both vary as the square root of the permeability. Consequently, impedance matching means may be varied similariy and simultaneously w:th the electrically variable permeability to match the line impedance over the entire range of time delay whereby reflections are prevented.

  2. Drug Retention Times

    SciTech Connect (OSTI)

    Center for Human Reliability Studies

    2007-05-01

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user.

  3. Time-Resolved

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

    Ultrafast Spectroscopy of Warm Dense Matter Real-Time Chemical Imaging of Bacterial Biofilm Development Using Light to Control How X Rays Interact with Matter X-Ray Imaging of...

  4. Method and system for selecting data sampling phase for self timed interface logic

    DOE Patents [OSTI]

    Hoke, Joseph Michael; Ferraiolo, Frank D.; Lo, Tin-Chee; Yarolin, John Michael

    2005-01-04

    An exemplary embodiment of the present invention is a method for transmitting data among processors over a plurality of parallel data lines and a clock signal line. A receiver processor receives both data and a clock signal from a sender processor. At the receiver processor a bit of the data is phased aligned with the transmitted clock signal. The phase aligning includes selecting a data phase from a plurality of data phases in a delay chain and then adjusting the selected data phase to compensate for a round-off error. Additional embodiments include a system and storage medium for transmitting data among processors over a plurality of parallel data lines and a clock signal line.

  5. Time Card Entry System

    SciTech Connect (OSTI)

    Montierth, B. S.

    1996-05-07

    The Time Card Entry System was developed for the Department of Enegy, Idaho Operations Office (DOE-ID) to interface with the DOE headquarters (DOE-HQ) Electronic Time and Attendance (ETA) system for payroll. It features pop-up window pick lists for Work Breakdown Structure numbers and Hour Codes and has extensive processing that ensures that time and attendance reported by the employee fulfills U.S. Government/OMB requirements before Timekeepers process the data at the end of the two week payroll cycle using ETA. A tour of duty profile (e.g., ten hour day, four day week with Sunday, friday and Saturday off), previously established in the ETA system, is imported into the Time Card Entry System by the timekeepers. An individual''s profile establishes the basis for validation of time of day and number of hours worked per day. At the end of the two cycle, data is exported by the timekeepers from the Time Card Entry System into ETA files.

  6. Time Card Entry System

    Energy Science and Technology Software Center (OSTI)

    1996-05-07

    The Time Card Entry System was developed for the Department of Enegy, Idaho Operations Office (DOE-ID) to interface with the DOE headquarters (DOE-HQ) Electronic Time and Attendance (ETA) system for payroll. It features pop-up window pick lists for Work Breakdown Structure numbers and Hour Codes and has extensive processing that ensures that time and attendance reported by the employee fulfills U.S. Government/OMB requirements before Timekeepers process the data at the end of the two weekmore » payroll cycle using ETA. A tour of duty profile (e.g., ten hour day, four day week with Sunday, friday and Saturday off), previously established in the ETA system, is imported into the Time Card Entry System by the timekeepers. An individual''s profile establishes the basis for validation of time of day and number of hours worked per day. At the end of the two cycle, data is exported by the timekeepers from the Time Card Entry System into ETA files.« less

  7. Climate Time-Machine

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

    Climate Time-Machine Climate Time-Machine 20th Century Reanalysis Project Explores Earth's Past and Future Climate January 25, 2011 Berkeley Lab Contact: Jon Bashor, jbashor@lbl.gov, +1 510 486 5849 Wiley-Blackwell Contact: Ben Norman, lifesciencenews@wiley.com,+44(0)1243 770 375 Science Contact: Jeffrey Whitaker, Jeffrey.S.Whitaker@noaa.gov, +1 303 497 6313 2011-01-25-20C-Climate.jpg A dust storm approaching Stratford, TX on April 18, 1935. The 20th Century Reanalysis Project will provide

  8. Genepool Time Heatmaps

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

    Genepool Time Heatmaps Heatmap of Time and Slots Requested vs Time Waited (in hours) | Queue: All | Last 7 Days Time Requested Slots <1h 1-2h 2-6h 6-12h 12-24h 24-36h 36-48h 48h-1wk >1wk Job Count Longest Wait 1 23.0 (233) 0.37 (1819) 27.54 (49888) 5.85 (124593) 1.23 (39835) 0.34 (732) 0 0.4 (224) 0.02 (1) 217325 538.96 2 0 0.01 (19) 2.54 (78) 0.2 (140) 0.99 (2683) 0 0 0 0 2920 9.1 4 0.08 (1) 0 2.82 (141) 0.36 (143) 1.07 (12) 0.06 (5) 0.01 (5) 0.06 (1) 1.3 (5) 313 20.48 6 0.01 (2) 0 0.09

  9. Time and Attendance Reporting

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2004-10-22

    DOE O 535.1 establishes the Department's requirements and responsibilities governing time and attendance reporting. The purpose of this revision is to reflect the transition of payroll processing from the Capital Accounting Center to the Defense Finance and Accounting System. Cancels DOE O 3600.1B. Canceled by DOE O 322.1C.

  10. Time Series Database

    Energy Science and Technology Software Center (OSTI)

    2007-11-02

    TSDB is a Python module for storing large volumes of time series data. TSDB stores data in binary files indexed by a timestamp. Aggregation functions (such as rate, sum, avg, etc.) can be performed on the data, but data is never discarded. TSDB is presently best suited for SNMP data but new data types are easily added.