| Key Planning Factors for Recovery from a Radiological Terrorism Incident |
01 Sep 2012 |
34 pages |
| Authors:
Brooke R Buddemeier; Annmarie R Wood-Zika; Robert P Fischer; Joshua E Valentine; LAWRENCE LIVERMORE NATIONAL LAB CA
|
 | This technical report is scientifically based technical guidance to provide FEMA with a summary of key response planning factors to consider when responding to a radiological incident caused by a radiological dispersal device (RDD). Guided by the National Disaster Recovery Framework and the National Preparedness Goals, this document identifies key technical planning areas that may be used to inform subsequent FEMA response and recovery guidance documents. The document employs a ... |
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| Collisional Dynamics, Lasing and Stimulated Raman Scattering in Optically Pumped Cesium and Potassium Vapors |
22 Mar 2012 |
119 pages |
| Authors:
Kirk C Brown; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| This dissertation explores collisional dynamics, lasing and stimulated Raman scattering in cesium and potassium vapors. The spin orbit mixing and quenching cross sections of several buffer gas species are measured. The ne-structure mixing cross sections for He, CH4 and C2H6 are 14 + or - 3, 35 + or - 6 and 73 + of - 10 A sq, respectively. The 2P3/2 state is quenched more rapidly than the 2P1/2 ... |
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| Cesium Absorption Spectrum Perturbed by Argon: Observation of Non-Lorentzian Wing Properties |
Mar 2012 |
88 pages |
| Authors:
Gordon E Lott; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| The purpose of this research was to observe the core and far wing absorption spectra of the D1 and D2 lines of cesium (Cs) perturbed by argon (Ar). A 1.33 m scanning monochromator with a PMT detector was used to measure the spectra from 8300 Ang. to 9100 Ang. A heat pipe was used to control the Cs concentration and Ar pressure allowing for a broad range of spectra to ... |
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| Merging Maser and Cesium Clocks in Timescales |
Oct 2011 |
3 pages |
| Authors:
Demetrios Matsakis; Gianna Panfilo; NAVAL OBSERVATORY WASHINGTON DC
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| A variety of ways exist to combine clocks with different characteristics in a timescale. At the US Naval Observatory, for example, a process called dynamic weighting is used, which generates a timescale from a frequency scale that weighs recent maser data relatively higher than older maser data. A Kalman Filter could assign different phase, frequency, and frequency drift process noises to the different clock types. In this paper we use ... |
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| Precision Control of Ultracold Molecules in Optical Lattices |
20 Jul 2011 |
8 pages |
| Authors:
Svetlana Kotochigova; TEMPLE UNIV PHILADELPHIA PA DEPT OF PHYSICS
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| During the reported period robust and sensitive techniques to produce and control ultracold polar KRb and RbCs as well as homonuclear Cs2 and Sr2 molecules have been developed. Factors that affect precision measurements and many-body quantum-collective experiments with these molecules have been analyzed. As part of these efforts the coherent transfer between weakly-bound Feshbach molecules and ro-vibrational ground state have been studied. In particular, high-precision calculations of the electronic potentials ... |
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| Measurements with Multiple Operational Fountain Clocks |
May 2011 |
4 pages |
| Authors:
Steven Peil; Scott Crane; James Hanssen; Thomas B Swanson; Christopher R Ekstrom; NAVAL OBSERVATORY WASHINGTON DC
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| The U.S. Naval Observatory (USNO) maintains an ensemble of atomic clocks for the generation of a Master Clock, the physical realization of UTC(USNO). As many as 20 hydrogen masers and 70 commercial cesium clocks can contribute to the ensemble. The timescale used to generate UTC(USNO) relies on the short-term frequency stability of the masers and the long-term stability of the cesium clocks. To advance timekeeping activities, 7 rubidium fountain clocks ... |
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| Development of a Micro-Fabricated Total-Field Magnetometer |
MAR 2011 |
176 pages |
| Authors:
Mark Prouty; GEOMETRICS INC SAN JOSE CA
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| Magnetometers are one of the basic instruments used for the detection and discrimination of unexploded ordnance (UXO). Cesium vapor atomic magnetometers are commonly used since their readings are independent of the orientation of the sensor, which eliminates the noise problems due to rotation or even vibration of other types of sensors. In order to better discriminate UXO from clutter or scrap, a high spatial density of readings is desirable. In ... |
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| Three Body Recombination and Photoassociative Ultracold Collisions Studied Using Translational Energy |
27-Feb-2009 |
10 pages |
| Authors:
James P Shaffer; OKLAHOMA UNIV NORMAN
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| In this work, a Rydberg atom imaging spectrometer to study individual collision events in an ultracold gas was developed. The apparatus achieved velocity resolution of 2.5 cm/s. This resolution allows all known ultracold collision processes to be resolved. The spectrometer was tested on low energy Rydberg atom collisions occurring in an ultracold gas of Cs atoms. To analyze this data, a procedure for calculating the interactions between high lying Rydberg ... |
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| Steering a Time Scale |
01-Dec-2008 |
15 pages |
| Authors:
Judah Levine; NATIONAL INST OF STANDARDS AND TECHNOLOGY BOULDER CO TIME AND FREQUENCY DIV
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| A time scale is a procedure for combining the data from an ensemble of clocks or frequency standards. The input data to the ensemble algorithm are generally the time (or frequency) differences between each of the members and the reference device for the system. Therefore, the overall time and frequency of the ensemble are free parameters and must be continuously adjusted using external data and a steering algorithm. In addition, ... |
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| Multi-Sensor Systems Development for UXO Detection and Discrimination: Man-Portable Dual Magnetic/Electromagnetic Induction Sensor |
FEB 2008 |
41 pages |
| Authors:
David Wright; Jr. Bennett Hollis H.; Linda P. Dove; John H. Ballard; Morris P. Fields; Tere A. DeMoss; Dwain K. Butler; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
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| An unexploded ordnance (UXO) survey instrument that simultaneously collects total field magnetic data and frequency domain electromagnetic (FDEM) data was developed and tested for the detection and characterization of buried UXO objects. The system comprised an FDEM sensor operating at a single frequency of 9.8 kHz and a cesium vapor magnetometer. The system was tested in dynamic survey (detection) and cued analysis (characterization) modes at the Naval Research Laboratory Blossom ... |
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| Physics of Spin-Polarized Media |
21 NOV 2007 |
10 pages |
| Authors:
William Happer; Yuan-Yu Jau; PRINCETON UNIV NJ
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| The work supported by this AFOSR grant focused on fundamental physics and the applications of spin-polarized species. Some of the most notable accomplishments were as follows: (1) using optically pumped alkali-metal vapor to polarize the nuclei of solid materials; (2) making much simpler atomic clocks with the physics of push-pull optical pumping, an efficient new pumping method that the authors discovered during the course of the grant; (3) nonlinear "pressure ... |
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| Long-Term Clock Behavior of GPS IIR Satellites |
01-Nov-2007 |
21 pages |
| Authors:
Marvin Epstein; Todd Dass; John Rajan; Paul Gilmour; ITT CORP CLIFTON NJ SPACE SYSTEMS DIV
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| The ITT-developed GPS IIR satellite payloads have been on orbit since 1997, and have proven to be the best family of clocks in the GPS constellation. At this time, there is a substantial recorded history of clock behavior, including over 60 clock years of space operation. The age of the oldest clock is over 9 years. A review of the record shows a number of significant characteristics that were not ... |
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| Composite Clocks With 3-State Models |
01-Nov-2007 |
21 pages |
| Authors:
James R Wright; ANALYTICAL GRAPHICS INC EXTON PA
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| Previous analyses of composite clocks have been presented with 2-state clock models for random clock phase and frequency deviations. But Kalman filter estimate errors due to 3-state clock frequency-drift deviations have not been previously presented. I have employed the 3-state Zucca-Tavella clock model to simulate an ensemble of four 3-state clocks. I have found a dominant common component for 3-state clock Kalman filter phase errors with the curvature of a ... |
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| Frequency Domain Electromagnetic Sensor Array Development |
17-Sep-2007 |
24 pages |
| Authors:
David J Wright; SCIENCE APPLICATIONS INTERNATIONAL CORP (SAIC) CARY NC ADVANCED SENSORS AND ANALYSIS DIVISION
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| A laboratory prototype frequency domain electromagnetic induction sensor array suitable for simultaneous operation with an array of cesium vapor total field magnetometers has been designed and fabricated and has undergone limited bench testing. The design is based on the GEM-3 active primary field cancellation technology, which creates a "magnetic cavity" for each receive coil in the array. The array's magnetometers would be mounted inside the receive coils, within the magnetic ... |
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| Collision Broadening Using Alkali-Filled, Hollow Core Fibers |
SEP 2007 |
77 pages |
| Authors:
Luke P. Rodgers; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT/DEPT OF ENGINEERING PHYSICS
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| The goal of this research was to demonstrate the possibility of collision broadening in a cesium-filled, hollow-core fiber as an alternative to the proven technique of pressure broadening. Theoretically, the absorption spectrum should collisionally broaden due to the presence of fiber walls. An absorption dip located at 852.34nm was recorded in a pressure broadened comparison leg. This data was used as a baseline during analysis of the fiber leg's data. ... |
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| The "Worried Well" Response to CBRN Events: Analysis and Solutions |
JUN 2007 |
64 pages |
| Authors:
Fred P. Stone; AIR UNIV MAXWELL AFB AL COUNTER PROLIFERATION CENTER
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| Chemical, biological, radiological, or nuclear (CBRN) weapons in the hands of a terrorist or a rogue state is one of the greatest threats to the security of the United States. These weapons of mass destruction (WMD) can cause catastrophic loss of life and innumerable injuries and can challenge the U.S. health care system beyond its capacity to provide treatment. Most hospitals do not have the beds, equipment, staff, or facilities ... |
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| Time and Frequency Activities at the U.S. Naval Observatory |
01 JAN 2007 |
15 pages |
| Authors:
Demetrios Matsakis; NAVAL OBSERVATORY WASHINGTON DC TIME SERVICE DIV
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| The U.S. Naval Observatory (USNO) has provided timing for the Navy and the Department of Defense since 1830 and, in cooperation with other institutions, has also provided timing for the United States and the international community. Its Master Clock (MC) is the source of UTC (USNO), the USNO's realization of Coordinated Universal Time (UTC), which has stayed within 5 ns RMS of UTC since 1999. The data used to generate ... |
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| USNO Master Clock Design Enhancements |
JAN 2007 |
9 pages |
| Authors:
P. Koppang; J. Skinner; D. Johns; NAVAL OBSERVATORY WASHINGTON DC
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| The authors have implemented several enhancements to the U.S. Naval Observatory (USNO) Master Clock system. Design changes to the system include the use of a Kalman filter for phase and frequency estimates, decreasing the time interval between steers, and the redesign of control parameters. The present control system utilizes "real-time" data estimates of the differences between the Master Clock and a time scale that combines hydrogen masers and commercial cesium ... |
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| New Experimental Approaches and Theoretical Modeling Methods for Laser Cooling Atoms and Molecules |
27 JUL 2006 |
13 pages |
| Authors:
T. H. Bergeman; H. J. Metcalf; STATE UNIV OF NEW YORK AT STONY BROOK RESEARCH FOUNDATION
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| The first part of this project involved continued development of theoretical models of diatomic molecular electronic level structure for application to the production of ultracold diatomic molecules via photoassociation. Recently, there has been considerable interest in producing molecules at the temperatures achieved for laser-cooled atoms, for applications to "coherent chemistry," studies of molecule-atom and molecule-molecule interactions. Bose condensates of molecules and for quantum computing. It is advantageous to produce cold ... |
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| Characterization of Boron Atom Aggregation |
26 JUN 2005 |
38 pages |
| Authors:
John P. Maier; BASEL UNIV (SWITZERLAND)
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| The broad objectives of this IRI project which ran during three years June 2002- May 2005 were the investigations of the spectroscopic properties of boron species their aggregation and reactions in matrices ranging from neon to those doped with hydrogen. The studies of the aggregation properties were hampered by the lack of spectroscopic knowledge on the electronic transitions of the polyatomic boron molecules and their ions. Thus it was clear ... |
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| Radiochemical and Chemical Constituents in Water from Selected Wells and Springs from the Southern Boundary of the Idaho National Laboratory to the Hagerman Area, Idaho, 2003 |
2005 |
33 pages |
| Authors:
Gordon W. Rattray; Amy J. Wehnke; L. F. Hall; Linford J. Campbell; GEOLOGICAL SURVEY RESTON VA
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| The U.S. Geological Survey and the Idaho Department of Water Resources, in cooperation with the U.S. Department of Energy, sampled water from 14 sites as part of an ongoing study to monitor the water quality of the eastern Snake River Plain aquifer between the southern boundary of the Idaho National Laboratory (INL) and the Burley-Twin Falls-Hagerman area. The State of Idaho, Department of Environmental Quality, Division of INL Oversight and ... |
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| Application of Control Theory in the Formation of a Timescale |
SEP 2004 |
9 pages |
| Authors:
P. Koppang; D. Johns; J. Skinner; NAVAL OBSERVATORY WASHINGTON DC
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| We have created a timescale that joins the short-term stability of several hydrogen masers with the long-term capabilities of an ensemble of cesium frequency standards. Control theory is utilized in a system design that combines frequency standards with varied properties. The system steers a maser ensemble with respect to a cesium ensemble while minimally perturbing the maser short- term performance. Results are given from both simulated and measured data. Systems ... |
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| The Chip-Scale Atomic Clock - Recent Development Progress |
SEP 2004 |
13 pages |
| Authors:
R. Lutwak; D. Emmons; T. English; W. Riley; SYMMETRICOM-TECHNOLOGY REALIZATION CENTER BEVERLY MA
|
| We have undertaken the development of a chip-scale atomic clock (CSAC) whose design goals include short-term stability, sigma(sub y)(tau=1 hour) , of 1x10(exp 11) with a total power consumption of 30 mW and an overall device volume of 1 cu cm. The stringent power requirement dominates the physics package architecture, dictating a small (<5 mm(exp 3) gaseous atomic ensemble interrogated by a low-power semiconductor laser. At PTTI 2002, we reported ... |
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| The APL Time And Frequency Lab |
SEP 2004 |
7 pages |
| Authors:
R. A. Dragonette; M. Miranian; M. J. Reinhart; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
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| The APL Time and Frequency Laboratory supports a wide variety of current and upcoming NASA missions that span the solar system from the study of the Sun's coronal mass ejections to the examination of the planet Pluto and the Kuiper Belt objects. This support can be in the form of providing precise time and frequency to the integration and testing of new hardware or the time- stamping of ground-receipt telemetry ... |
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| End Resonances for Atomic Clocks |
SEP 2004 |
13 pages |
| Authors:
A. B. Post; Y. Y. Jau; N. N. Kuzma; A. M. Braun; S. Lipp; SARNOFF CORP PRINCETON NJ
|
| we discuss advantages of the "end" resonances for miniaturized, chip- scale atomic clocks based on alkali-vapor cells filled with high-pressure buffer gases. Compared to the commonly used 0-0 resonance clock design, these advantages include a high signal-to-noise ratio, a narrower linewidth at high vapor densities, and a significantly reduced sensitivity to the frequency stability of the pump laser at high buffer-gas pressure. We report our measurements of the (133) Cs ... |
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| Cooling and Trapping of Atoms and Particles |
AUG 2004 |
11 pages |
| Authors:
Steven Chu; STANFORD UNIV CA BOARD OF TRUSTEES
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| In this work, we report a summary of the more than 60 magnetic field- induced Feshbach resonances in ultracold collisions of ground-state cesium atoms. The detection is based on elastic, inelastic and radiative collision processes. The observations have allowed us to improve upon the interaction potentials between cesium atoms, which, in turn, allowed us to predict the possible magnetic field regions where the Bose condensation of cesium atoms would be ... |
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| Molecular and Isotopic Records of Combustion Inputs to the Environment Over the Last 250 Years |
JUN 2004 |
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| Authors:
Ana L. DeLima; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
 | The most ubiquitous source of polycyclic aromatic hydrocarbons (PARs) to the environment is incomplete combustion. This study generated a high- resolution historical record of pyrogenic PAR emissions since pre-industrial times from anoxic aquatic sediments, allowing for detailed comparison with energy consumption data. We show that an increase in PAR concentrations over the last decade may be due to a rise in emissions from diesel-powered vehicles. Compound-specific radiocarbon measurements demonstrated unequivocally ... |
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| Proceedings of the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (35th) (CD-ROM) |
2004 |
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| Authors:
NAVAL OBSERVATORY WASHINGTON DC
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| ELECTRONIC FILE CHARACTERISTICS: 98 files; Adobe Acrobat (.PDF). PHYSICAL DESCRIPTION: 1 computer laser optical disc (CD-ROM); 4 3/4 in.; 41.5 MB. SYSTEMS DETAIL NOTE: ABSTRACT: This document is a compilation of technical papers presented at the 35th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting held 2-4 December 2003 at the Hilton Resort on Mission Bay at San Diego, Calif. Paper categories: - Recent developments in rubidium, ... |
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| Velocity-Tunable Magneto-Optical -Trap-Based Cold Cs Atomic Beam |
30 DEC 2003 |
12 pages |
| Authors:
H. Wang; W. F. Buell; AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
|
| In this paper, the authors report on their observation and investigation of a MOT-based, low-velocity Cs atomic beam for atomic clock applications. A continuous Cs atomic beam is generated from a vapor-cell magneto-optical trap (MOT) of Cs atoms by forming a leak tunnel along one of the trapping laser beams. The mean velocity of the cold Cs beam is measured by the time of flight (TOF) technique to be 7.3 ... |
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| Proceedings of the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (34th) Held in the Hyatt Regency Hotel, Reston, Virginia on 3-5 December 2002 (CD-ROM) |
2003 |
|
| Authors:
Dave Gillard; Donald H. Mitchell; Lisa Nelson; Steven Hutsell; Edoardo Detoma; NAVAL OBSERVATORY WASHINGTON DC
|
| ELECTRONIC FILE CHARACTERISTICS: 26 files; Adobe Acrobat (.PDF). PHYSICAL DESCRIPTION: 1 computer laser optical disc (CD-ROM); 4 3/4 in.; 36.5 MB. SYSTEMS DETAIL NOTE: IBM-clone PC-compatible. ABSTRACT: This document is a compilation of technical papers presented at the 34th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting held 3-5 December 2002 at the Hyatt Regency Hotel at Reston, Virginia. Papers are in the following categories: - Recent ... |
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| Kalman Filter Characterization of Cesium Clocks and Hydrogen Masers |
01-Dec-2002 |
17 pages |
| Authors:
Lee A Breakiron; NAVAL OBSERVATORY WASHINGTON DC
|
| Our previous PTTI paper demonstrated that a two-state Kalman filter involving the parameters frequency and frequency drift, when properly implemented, produces frequencies for hydrogen masers that generate a stable mean timescale, at least for cases involving simulated and low-noise real data. The current paper extends the investigation to the noisier data actually employed in the USNO operational timescale. Results for about 500 days of postprocessed data for 12 masers and ... |
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| DRDC Ottawa Participation in the SILENE Accident Dosimetry Intercomparison Exercise. June 10-21, 2002 |
NOV 2002 |
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| Authors:
L. Prud'homme-Lalonde; T. Cousins; D. Wilkinson; B. Ford; T. Jones; DEFENCE RESEARCH AND DEVELOPMENT CANADAOTTAWA (ONTARIO)
|
| DRDC Ottawa (and formerly as DREO) has participated in two NATO- sponsored and one TTCP-sponsored dosimetry intercomparisons. The SILENE international Accident Dosimetry Intercomparison Exercise at Valduc, France in June 2002 coincided with DRDC Ottawa work designed to refine its proposed criticality dosimetry system (consisting of Rh foils for neutron dosimetry and the combination of CaF2:Mn and Al2O3 TLDs for gamma-ray dosimetry). In addition, DRDC Ottawa has recently substantially expanded its ... |
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| Optimization of Technique Factors for full-Field Digital Mammography and Comparison of Optimized Techniques to Screen-Film Mammography |
SEP 2002 |
13 pages |
| Authors:
Eric A. Berns; R. E. Hendrick; NORTHWESTERN UNIV EVANSTON IL
|
| The technical objectives of this study are to determine optimum techniques for a flat-panel Cesium- iodide silicon-diode full-field digital mammography system and to compare those optimized techniques to screen-film mammography at equal breast doses This project continued in the second year with work focused on analyzing the data and writing a manuscript for publication Statistical analysis was performed using the SAS software package comparing contrast-detail scores and looking for trends ... |
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| Characterization of Boron Atom Aggregation |
02 APR 2002 |
6 pages |
| Authors:
John P. Maler; BASEL UNIV (SWITZERLAND)
|
| This report results from a contract tasking University of Basel as follows: The contractor will investigate and understand the electronic spectra of matrix isolated B, B2, B3 and higher clusters and to apply these understandings in quantitative analysis of B atom reactions in rare gas cryogenic solids. A number of experiments were undertaken and theoretical calculations in order to understand the details of the complex vibronic structure in the electronic ... |
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| SYNTHETIC APERTURE RADAR SIGNATURES OF MOVING TARGEETS, |
FEB 2002 |
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| Authors:
Victor C. Chen; Ronald Lipps; MAITLAND BOTTOMS; NAVAL RESEARCH LAB WASHINGTON DC
|
| (U) THIS PAPER DISCUSSES SYNTHETIV APERTURE RADAR SIGNATURES OF MOVING TARGETS. THE PAPER DISCUSSES THE SIGNATURES OF STATIONARY AND MOVING TARGETS IN THE TIME DOMAIN, THE DOPPLER FREQUENCY DOMAIN, AND THE JOINT TIME-FREQUENCY DOMAIN. SIMULATED AND MEASURED RADAR DATA ARE USED TO DEMONSTRATE THAT THE TIME-FREQUENCY SIGNATURE CAN HELP DISTINGUISH MOVING TARGETS FROM STATIONARY TARGETS. |
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| The Distribution and History of Nuclear Weapons Related Contamination in Sediments from the Ob River, Siberia as Determined by Isotopic Ratios of Plutonium Neptunium, and Cesium |
FEB 2002 |
|
| Authors:
Timothy C. Kenna; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| This thesis addresses the sources and transport of nuclear weapons related contamination in the Ob River region. The atom ratios 240Pu/239Pu, 237Np/239Pu, and 137Cs/240Pu, contained in sediments from the region and measured by magnetic-sector ICP-MS, are used to distinguish between global fallout and contamination derived from local sources. Data presented in this study demonstrate that non-fallout contamination has been transported the full length of the tributaries draining the nuclear facilities, ... |
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| Proceedings of the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (33rd) Held in Long Beach, California on 27-29 November 2001 (CD-ROM) |
2002 |
|
| Authors:
Kenneth J. Johnston; Joseph D. White; Pete Lopez; NAVAL OBSERVATORY WASHINGTON DC
|
| ELECTRONIC FILE CHARACTERISTICS: 82 files; Adobe Acrobat (.PDF). PHYSICAL DESCRIPTION: 1 computer laser optical disc (CD-ROM); 4 3/4 in.; 319 MB. SYSTEMS DETAIL NOTE: IBM-clone PC-compatible; Adobe Acrobat Reader 5.0.5 is included on disc. ABSTRACT: This document is a compilation of technical papers presented at the 33rd Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting held 27-29 November 2001 held at the Hyatt Regency Hotel at Long ... |
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| Primary Frequency Standards at NIST |
01-Nov-2001 |
13 pages |
| Authors:
Robert Drullinger; NATIONAL INST OF STANDARDS AND TECHNOLOGY BOULDER CO TIME AND FREQUENCY DIV
|
| NIST has a more than 50-year history of developing ever more accurate atomic frequency standards. For most of that time, the technology was based on thermal atomic beams of cesium atoms, and the accuracy improvement was approximately a factor of 10 every 7 years. To put this into some kind of perspective, both the period of this history and the rate of improvement are almost identical to the development of ... |
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| Optically Pumped Cesium-Beam Frequency Standard for GPS-III |
01-Nov-2001 |
15 pages |
| Authors:
R Lutwak; P Vlitas; D Emmons; R M Garvey; DATUM-TIMING TEST AND MEASUREMENT BEVERLY MA
|
| We describe an optically pumped cesium-beam frequency standard under development for deployment on the GPS-III satellite constellation. The objective of the project is to demonstrate the feasibility of a space qualified optically pumped cesium-beam frequency standard exhibiting a short-term stability of sigma y (Tau) <6 x 10(exp-12) tau (exp -1/2) with lifetime and reliability comparable to that of the current GPS-IIF cesium standards. In this paper, we report on the ... |
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| Update on Time and Frequency Activities at PTB |
01-Nov-2001 |
9 pages |
| Authors:
Peter Hetzel; Andreas Bauch; PHYSIKALISCH-TECHNISCHE BUNDESANSTALT BRAUNSCHWEIG (GERMANY)
|
| The activities in the field of time and frequency metrology pursued at PTB are reviewed. Among the recent milestones have been the development and quasi-continuous operation of a cesium fountain frequency standard, the realization of a free atomic time scale TAF (PTB) based on the fountain results, and the cooperation in international time comparison projects using GPS carrier-phase receivers and TWSTFT in Ku-band and X-band. |
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| Characterization of Boron Atom Aggregation |
30 MAY 2001 |
5 pages |
| Authors:
John P. Maier; BASEL UNIV (SWITZERLAND)
|
| This report results from a contract tasking Institut fur Physikalische Chemie as follows: The contractor will investigate growth formation of boron clusters using mass selected beams produced from a cesium sputter source. These experimental results will be compared with theoretical analysis conducted by the Propulsion Directorate at Edwards AFB, CA. A technical report discussing the results obtained and analysis to the theoretical studies will be delivered at the completion of ... |
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| Remote-Sensing Cultural Resources Survey of the Houma Navigation Canal, Dredge Island Creation Project, Terrebonne Parish, Louisiana |
MAR 2001 |
72 pages |
| Authors:
Charles E. Pearson; COASTAL ENVIRONMENTS INC BATON ROUGE LA
|
| In June 2000, a cultural resources, remote-sensing survey was conducted of an approximately 450-acre area located adjacent to the Houma Navigation Canal in Terrebonne Bay in Terrebonne Parish, Louisiana. This area has been selected for the construction of an artificial island habitat using shoal material removed from the adjacent Houma navigation Canal. The survey was conducted to locate and assess significant historic shipwrecks or other underwater cultural resources that may ... |
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| Detection of the Gravitational Redshift of the Cesium Frequency Standard at CRL |
01-Nov-2000 |
9 pages |
| Authors:
Mizuhiko Hosokawa; Noboru Kotake ;Kuniyasu Imamura; Noriyuki Kurihara; COMMUNICATIONS RESEARCH LAB TOKYO (JAPAN)
|
| We have detected the gravitational redshift of a Cs frequency standard that has been transported from CRL Tokyo headquarters, at an altitude of 80 m, to Mt. Ohtakadoya LF standard frequency station, located at an altitude of 794 m, about 250 km far from the CRL Tokyo headquarters. In the Mt. Ohtakadoya LF station, three Cs clocks are equipped to be the references of standard frequency radio signal emission, and ... |
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| Compact CW Cold Beam Cesium Atomic Clock |
15 JUL 2000 |
12 pages |
| Authors:
W. F. Buell; B. Jaduszliwer; AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
|
| We present a novel cesium beam physics package, which uses optical techniques to combine the high signal-to-noise ratios achievable by optical pumping and beam brightening with the narrow linewidth allowed by a slow atomic beam. Our design can be realized in a compact, robust package suitable for space applications. Our approach differs from other laser-cooled clocks in that we use a cold-atom source that provides a continuous ... |
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| Time and Standards - An Overview |
MAR 2000 |
9 pages |
| Authors:
Bernard Guinot; OBSERVATOIRE DE PARIS (FRANCE)
|
| Have the frequency stability and accuracy reached a level of quality that exceeds needs in astrometry? This paper attempts to answer this question. After recalling current performances of time and frequency standards and their use in establishing time scales, the author considers their limitations in astronomical observations and studies. For expressing the value of almost all quantities, the accuracy of the frequency standards is sufficient. However, an improved stability could ... |
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| Proceedings of the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (31st) Held in Dana Point, California on 7-9 December 1999 (CD-ROM) |
2000 |
|
| Authors:
Thomas E. Parker; O. J. Oaks; Donald H. Mitchell; Patrick C. Fenton; Paul A. Koppang; NAVAL OBSERVATORY WASHINGTON DC
|
| ELECTRONIC FILE CHARACTERISTICS: 112 files; Adobe Acrobat (.PDF). PHYSICAL DESCRIPTION: 1 computer laser optical disc (CD-ROM); 4 3/4 in.; 58.4 MB. SYSTEMS DETAIL NOTE: IBM-clone PC-compatible. ABSTRACT: This document is a compilation of technical papers presented at the 31st Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting held 7-9 December 1999 at Marriott's Laguna Cliffs Resort at Dana Point, California. Papers are in the following categories: Recent ... |
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| Development of a Multiple Time Source Comparison System for Disseminative Services in Taiwan |
Dec-1999 |
6 pages |
| Authors:
S Y Lin; C S Liao; C C Lin; NATIONAL STANDARD TIME AND FREQUENCY LAB TAOYUAN (TAIWAN)
|
| A multiple time source comparison system (MTCS) has been implemented that is enhancing the reliability of the time source of our time disseminative service, including the Network Time Protocol (NTP) server, Taiwan's Computer Time Service (TCTS), and the Speaking Clocks Service. The time sources of MTCS are two HP407ZA cesium-beam clocks with a micro-phase-stepper and an IRIG-B time-code generator in two shielded rooms; the other source is GPS. We designed ... |
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| The Pervasive Societal Impact of Time and Frequency |
Dec-1999 |
10 pages |
| Authors:
Helmut Hellwig; DEPUTY ASSISTANT SECRETARY (AIR FORCE) (SCIENCE TECHNOLOGY AND ENGINEERING) WASHINGTON DC
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| This talk will paint a picture of these changes that were enabled by time and frequency technology, and provide examples ranging from clocks in the home, to hiking/driving in uncharted areas, to the reduction of the threat of weapons of mass destruction. |
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| Time and Frequency Activities at the National Physical Laboratory |
Dec-1999 |
10 pages |
| Authors:
John A Davis; NATIONAL PHYSICAL LAB TEDDINGTON (UNITED KINGDOM)
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| The Time and Frequency Section of the National Physical Laboratory (NPL) has an active program of work in time and frequency metrology. This paper provides an overview of this section's principal activities. These include: maintenance and development of the national time scale UTC (NPL), development of a new cesium fountain clock, time-transfer activities, development of clock algorithms, technology-transfer activities, and time and frequency dissemination in the UK. |
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| Comparison of Common-View and One-Way GPS Time Transfer Over a 4000-KM East-West Baseline |
Dec-1999 |
13 pages |
| Authors:
Robin Giffard; Bob Pitcock; AGILENT LABORATORIES PALO ALTO CA
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| We have recently established a stable time scale in the Standards Laboratory at the Santa Clara site of Agilent Technologies to provide a reference for developing and testing GPS time-transfer products. The time scale consists of a high performance cesium frequency standard that is steered to follow UTC(USNO, MC) using the output of a commercial GPS-disciplined oscillator. The disciplined oscillator technique is subject to various errors, such as antenna position, ... |
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Reports by Keyword(s)
CESIUM
