81 Matching Results

Search Results

Advanced search parameters have been applied.

Final Report, Next-Generation Mega-Voltage Cargo-Imaging System for Cargo Conainer Inspection, March 2007

Description: The UNLV Research Foundation, as the primary award recipient, teamed with Varian Medical Systems-Security & Inspection Products and the University of Nevada Las Vegas (UNLV) for the purpose of conducting research and engineering related to a "next-generation" mega-voltage imaging (MVCI) system for inspection of cargo in large containers. The procurement and build-out of hardware for the MVCI project has been completed. The K-9 linear accelerator and an optimized X-ray detection system capable of efficiently detecting X-rays emitted from the accelerator after they have passed through the device is under test. The Office of Science financial assistance award has made possible the development of a system utilizing a technology which will have a profound positive impact on the security of U.S. seaports. The proposed project will ultimately result in critical research and development advances for the "next-generation" Linatron X-ray accelerator technology, thereby providing a safe, reliable and efficient fixed and mobile cargo inspection system, which will very significantly increase the fraction of cargo containers undergoing reliable inspection as the enter U.S. ports. Both NNSA/NA-22 and the Department of Homeland Security's Domestic Nuclear Detection Office are collaborating with UNLV and its team to make this technology available as soon as possible.
Date: March 27, 2007
Creator: Dr. James Clayton, Ph.D., Varian Medical Systems-Security & Inspection Products; Dr. Emma Regentova, Ph.D, University of Nevada Las Vegas & Dr. Evangelos Yfantis, Ph.D., University of Nevada, Las Vegas
Partner: UNT Libraries Government Documents Department

The Gated X-ray Detector for the National Ignition Facility

Description: Two new gated x-ray imaging cameras have recently been designed, constructed and delivered to the National Ignition Facility in Livermore, CA. These Gated X-ray Detectors are each designed to fit within an aluminum airbox with a large capacity cooling plane and are fitted with an array of environmental housekeeping sensors. These instruments are significant different from earlier generations of gated x-ray images due in parts to an innovative impendence matching scheme, advanced phosphor screens, pulsed phosphor circuits, precision assembly fixturing, unique system monitoring and complete remote computer control. Preliminary characterization has shown repeatable uniformity between imaging strips, improved spatial resolution and no detectable impendence reflections.
Date: May 18, 2006
Creator: Oertel, J A; Barnes, C; Archuleta, T; Casper, L; Fatherley, V; Heinrichs, T et al.
Partner: UNT Libraries Government Documents Department

Digital Radiography and Computed Tomography Project -- Fully Integrated Linear Detector ArrayStatus Report

Description: The field-portable Digital Radiography and Computed Tomography (DRCT) x-ray inspection systems developed for the Project Manager for NonStockpile Chemical Materiel (PMNSCM) over the past 13 years have used linear diode detector arrays from two manufacturers; Thomson and Thales. These two manufacturers no longer produce this type of detector. In the interest of insuring the long term viability of the portable DRCT single munitions inspection systems and to improve the imaging capabilities, this project has been investigating improved, commercially available detectors. During FY-10, detectors were evaluated and one in particular, manufactured by Detection Technologies (DT), Inc, was acquired for possible integration into the DRCT systems. The remainder of this report describes the work performed in FY-11 to complete evaluations and fully integrate the detector onto a representative DRCT platform.
Date: September 1, 2011
Creator: Roney, Tim; Seifert, Robert; Pink, Bob & Smith, Mike
Partner: UNT Libraries Government Documents Department

Single scintillation crystal versus Phoswich detectors for in vivo low- energy photon detection

Description: The development of in vivo body-count measurement systems for the detection of low-energy photons from americium and plutonium has stressed the importance of low background counting rates for better sensitivity. The measurement systems are develeped for use in the body-counting facility, which has been in operation at the Rocky Flats Plant, to detect exposures in humans from radioactive materials. The facility is in a separate building and houses the body courter which consists of thick steel walls. The detectors within the body counter section are arranged over a table or couch and can be positioned over various parts of the body of an individual being checked for the presence of radioactive materials. The systems in current use provide an improvement in background counting rates for sodium-iodide thallium detectors with the two- crystal sandwich or Phoswich scintillator. The two types of electronic configurations used with the Phoswich detectors demonstrate improvements in background counting rates over results from a single crystal detector. Tabulated data comparing the operating parameters of a single crystal and a dual-crystal configuration are included. (auth)
Date: January 1, 1974
Creator: Tyree, W. H.
Partner: UNT Libraries Government Documents Department

Instrumentation for environmental monitoring. Volume 3. Radiation

Description: A comprehensive survey of instrunnentation for environmental monitoring is being carried out by the Lawrence Berkeley Laboratory under a grant from the Natioral Science Foundation. Instruments being investigated are those useful for measurements of Air Quality, Water Quality, Radiation, and Biomedical Parameters related to environmental research and monitoring. Consideration is given to instruments and techniques presently in use and to those developed for other purposes but having possible applications to this work. The results of the survey are given as (a) descriptions of the physical and operating characteristics of available instruments, (b) critical comparisons among instrumentation methods, and (c) recommendations of promising methodology and development of new instrumentation. The survey material is compiled in 5 loose- leaf volumes which can be periodically updated. An update for volume 3 on radiation instrumentation is presented. New pages are included for insertion in the introductory material and also under the headings nuclear reactors, combination instruments, alpha particle instrumentation, beta particle instrumentation, x and gamma radiation monitoring instrumentation, gamma spectrometry, neutron monitoring instrumentation, personnel dosimetry, radionuclides (strontium -89 and -90, iodine -129 and -131, radium, uranium, plutonium, and instrument notes), and infrared. (WHK)
Date: October 1, 1973
Partner: UNT Libraries Government Documents Department

Spectroscopic diagnostics of high temperature plasmas

Description: A three-year research program for the development of novel XUV spectroscopic diagnostics for magnetically confined fusion plasmas is proposed. The new diagnostic system will use layered synthetic microstructures (LSM) coated, flat and curved surfaces as dispersive elements in spectrometers and narrow band XUV filter arrays. In the framework of the proposed program we will develop impurity monitors for poloidal and toroidal resolved measurements on PBX-M and Alcator C-Mod, imaging XUV spectrometers for electron density and temperature fluctuation measurements in the hot plasma core in TEXT or other similar tokamaks and plasma imaging devices in soft x-ray light for impurity behavior studies during RF heating on Phaedrus T and carbon pellet ablation in Alcator C-Mod. Recent results related to use of multilayer in XUV plasma spectroscopy are presented. We also discuss the latest results reviewed to q{sub o} and local poloidal field measurements using Zeeman polarimetry.
Date: January 1, 1990
Creator: Moos, W.
Partner: UNT Libraries Government Documents Department

Development and application of photosensitive device systems to studies of biological and organic materials

Description: This report describes progress as of the third year of a 3-year DoE grant for 1/1/92 to 12/31/92. Because this is the last year of a 3- year grant cycle, this report will summarize progress over the entire 3-year period. The overall goals of the grant are to develop novel instrumentation and techniques for the performance of biological and materials research, and especially for the development of x-ray detectors suitable for use at storage ring sources. Research progress has been excellent and the overall goals, as well as most of the specific goals have been successfully met.
Date: May 15, 1992
Creator: Gruner, S.M. & Reynolds, G.T.
Partner: UNT Libraries Government Documents Department

Soft x-ray measurement of internal tearing mode structure in a reversed-field pinch

Description: The structure of internally resonant tearing modes has been studied in the Madison Symmetric Torus reversed-field pinch with a soft x-ray detector system consisting of an imaging array at one toroidal location and several detectors at different toroidal locations. The toroidal mode numbers of m = 1 structures are in the range n = {minus}5, {minus}6, {minus}7. The modes propagate with phase velocity v = 1--6 {times} 10{sup 6} cm/s, larger than the diamagnetic drift velocity v{sub d} {approximately} 5 {times} 10{sup 5} cm/s. Phase locking between modes with different n in manifested as a beating of soft x-ray signals which is found to be strongest near the resonant surfaces of the modes (r/a = 0.1 -- 0.5). 15 refs., 5 figs.
Date: September 16, 1991
Creator: Chartas, G. & Hokin, S.
Partner: UNT Libraries Government Documents Department

X-ray microscope assemblies. Final report and metrology report

Description: This is the Final Report and Metrology Report prepared under Lawrence Livermore Laboratory Subcontract 9936205, X-ray Microscope Assemblies. The purpose of this program was to design, fabricate, and perform detailed metrology on an axisymmetric grazing-incidence x-ray microscope (XRMS) to be used as a diagnostic instrument in the Lawrence Livermore Laser Fusion Program. The optical configuration chosen for this device consists of two internally polished surfaces of revolution: an hyperboloid facing the object; and a confocal, co-axial elliposid facing the image. This arrangement is known as the Wolter Type-I configuration. The grazing angle of reflection for both surfaces is approximately 1/sup 0/. The general optical performance goals under this program were to achieve a spatial resolution in the object plane in the soft x-ray region of approximately 1 micron, and to achieve an effective solid collecting angle which is an appreciable fraction of the geometric solid collecting angle.
Date: April 13, 1981
Creator: Zehnpfennig, T.F.
Partner: UNT Libraries Government Documents Department

Nuclear effects group program for Fiscal Year 1963

Description: This report provides a summary of the Nuclear Effects Group Program for fiscal year 1963. Efforts in space physics and instrumentation are detailed for the space exploration effort. Pinex type experiments are proposed, as are Phonex, Nuclear Emulsion Research and Low Energy X-Rays Measurements projects.
Date: March 1, 1962
Creator: Gilbert, F. C.
Partner: UNT Libraries Government Documents Department

Continuous Holdup Measurements with Silicon P-I-N Photodiodes

Description: We report on the behavior of silicon P-I-N photodiodes used to perform holdup measurements on plumbing. These detectors differ from traditional scintillation detectors in that no high-voltage is required, no scintillator is used (gamma and X rays are converted directly by the diode), and they are considerably more compact. Although the small size of the diodes means they are not nearly as efficient as scintillation detectors, the diodes' size does mean that a detector module, including one or more diodes, pulse shaping electronics, analog-to-digital converter, embedded microprocessor, and digital interface can be realized in a package (excluding shielding) the size of a pocket calculator. This small size, coupled with only low-voltage power requirement, completely solid-state realization, and internal control functions allows these detectors to be strategically deployed on a permanent basis, thereby reducing or eliminating the need for manual holdup measurements. In this paper, we report on the measurement of gamma and X rays from {sup 235}U and {sup 238}U contained in steel pipe. We describe the features of the spectra, the electronics of the device and show how a network of them may be used to improve estimates of inventory in holdup.
Date: May 1, 2002
Creator: Bell, Z.W.; Oberer, R.B.; Williams, J.A.; Smith, D.E. & Paulus, M.J.
Partner: UNT Libraries Government Documents Department

Technical Report on DOE project: X-ray physics of materials (proposal No.Z817)

Description: The SRI-CAT was able to order the construction of the First Optics Enclosure, the second enclosure housing the monochromator and the first user station, and various motors, controllers, and electronics for the control of the hard x-ray beamline components.
Date: January 1, 2001
Creator: Colella, Roberto & Durbin, Stephen
Partner: UNT Libraries Government Documents Department

The utility of diamond sensors for space flight

Description: Los Alamos National Laboratory has developed diamond sensors with interdigitated electrodes that operate in a photoconducting mode. The specific application for this work was for the Department of Energy`s instruments flown on the Global Positioning System satellites. Sensors have been fabricated and tested for their response to low-energy x-rays. These sensors can be operated to extremely high volumetric radiation doses. We find that the sensors are extremely useful for situations where the surface radiation dose is not excessive, but that this limit is exceeded for the GPS orbit. It is possible that further studies and special detector arrangements or auxiliary heating of the sensor may push this limit to higher values.
Date: March 1996
Creator: Higbie, P. R.; Han, S. S. & Wagner, R. S.
Partner: UNT Libraries Government Documents Department

A general technique for characterizing x-ray position sensitive arrays

Description: We present a general statistical technique for characterizing x-ray sensitive linear diode arrays and CCD arrays. We apply this technique to characterize the response of a linear diode array, Princeton Instrument model X-PDA, and a virtual phase CCD array, TI 4849, to direct illumination by x-rays. We find that the response of the linear array is linearly proportional to the incident intensity and uniform over its length to within 2 %. Its quantum efficiency is 38 % for Cu K{sub {alpha}} x-rays. The resolution function is evaluated from the spatial autocorrelation function and falls to 10 % of its peak value after one pixel. On the other hand, the response of the CCD detecting system to direct x-ray exposure is non-linear. To properly quantify the scattered x-rays, one must correct for the non- linearity. The resolution is two pixels along the serial transfer direction. We characterize the noise of the CCD and propose a model that takes into account the non-linearity and the resolution function to estimate the quantum efficiency of the detector. The quantum efficiency is 20 %.
Date: March 1, 1994
Creator: Dufresne, E.; Bruning, R.; Sutton, M.; Rodricks, B. & Stephenson, G.B.
Partner: UNT Libraries Government Documents Department

A new MBE CdTe photoconductor array detector for X-ray applications

Description: A CdTe photoconductor array x-ray detector was grown using Molecular Beam Epitaxially (MBE) on a Si (100) substrate. The temporal response of the photoconductor arrays is as fast as 21 psec risetime and 38 psec Full Width Half Maximum (FWHM). Spatial and energy responses were obtained using x-rays from a rotating anode and synchrotron radiation source. The spatial resolution of the photoconductor was good enough to provide 75 {micro}m FWHM using a 50 {micro}m synchrotron x-ray beam. A substantial number of x-ray photons are absorbed effectively within the MBE CdTe layer as observed from the linear response up to 15 keV. These results demonstrate that MBE grown CdTe is a suitable choice of the detector materials to meet the requirements for x-ray detectors in particular for the new high brightness synchrotron sources.
Date: October 1, 1994
Creator: Yoo, S.S.; Sivananthan, S.; Faurie, J.P.; Rodricks, B.; Bai, J. & Montano, P.A.
Partner: UNT Libraries Government Documents Department

Study of electron-capture delayed fission in Am-232

Description: An automated x-ray-fission coincidence system was designed and constructed by LLNL and Lawrence Berkeley National Laboratory (LBNL) for use inside the Gammasphere high efficiency gamma-ray detector array at LBNL. The x-ray-fission coincidence apparatus detection station consists of two surface barrier detectors (for detection of fission fragments) and two high-purity Ge (HPGe) planar x-ray detectors (for measurement of x-rays and low-energy gamma rays). The detection station is placed inside Gammasphere at the 88-Inch Cyclotron at LBNL and used in conjunction with Gammasphere to measure the x-rays, low-energy gamma-rays and fission fragments resulting from the ECDF process. A series of collaborative experiment between LLNL, LBNL, and LANL utilizing various components of the x-ray-fission coincidence apparatus to measure x-rays and gamma-rays in the decay of a stationary {sup 252}Cf source were performed to test the various components of the x-ray-fission coincidence apparatus. The test experiments have been completed and the data is currently being analyzed by LBNL. Preliminary test results indicate that the system performed better than expected (e.g., the x-ray detectors performed better than expected with no evidence of microphonic noise that would reduce the photon energy resolution).
Date: March 18, 1996
Creator: Kreek, S.A.; Hall, H.L.; Hoffman, D.C.; Strellis, D. & Gregorich, K.E.
Partner: UNT Libraries Government Documents Department

New mechanism for lightning initiation

Description: This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). To distinguish radio-frequency (rf) signals generated by lightning from the electromagnetic pulse produced by a nuclear explosion, it is necessary to understand the fundamental nature of thunderstorm discharges. The recent debate surrounding the origin of transionospheric pulse pairs (TIPPs) detected by the BLACKBEARD experiment aboard the ALEXIS satellite illustrates this point. We have argued that TIPP events could originate from the upward propagating discharges recently identified by optical images taken from the ground, from airplanes, and from the space shuttle. In addition, the Gamma Ray Observatory (GRO) measurements of x-ray bursts originating from thunderstorms are almost certainly associated with these upward propagating discharges. When taken together, these three measurements point directly to the runaway electron mechanism as the source of the upward discharges. The primary goal of this research effort was to identify the specific role played by the runaway-air-breakdown mechanism in the general area of thunderstorm electricity and in so doing develop lightning models that predict the optical, rf, and x-ray emissions that are observable from space.
Date: October 1, 1996
Creator: Roussel-Dupre, R.; Buchwald, M. & Gurevich, A.
Partner: UNT Libraries Government Documents Department

Wire number doubling in plasma-shell regime increases z-accelerator x-ray power

Description: Doubling the number of tungsten wires from 120 to 240, keeping the mass fixed, increased the radiated x-ray power relative to the electrical power at the insulator stack of the z accelerator by (40{+-}20)% for 8.75- and 20-mm-radii z-pinch wire arrays. Radiation-magneto-hydrodynamic calculations suggest that the arrays were operating in the {open_quotes}plasma shell{close_quotes} regime, where the plasmas generated by the individual wires merge prior to the inward implosion of the entire array.
Date: November 1, 1997
Creator: Sanford, T.W.L.; Spielman, R.B. & Chandler, G.A.
Partner: UNT Libraries Government Documents Department

Hot-Electron Tunneling sensors for high-resolution x-ray and gamma-ray spectroscopy

Description: Over the past 2 years, we have been studying the use of Hot Electron Tunneling sensors for use in high-energy-resolution x-ray and gamma-ray spectrometers. These sensors promise several advantages over existing cryogenic sensors, including simultaneous high count rate and high resolution capability, and relative ease of use. Using simple shadow mask lithography, we verified the basic principles of operation of these devices and discovered new physics in their thermal behavior as a function applied voltage bias. We also began to develop ways to use this new sensor in practical x-ray and gamma-ray detectors based on superconducting absorbers. This requires the use of quasiparticle trapping to concentrate the signal in the sensing elements.
Date: February 7, 1997
Creator: Mears, C.A.; Labov, S.E.; Frank, M. & Netel, H.
Partner: UNT Libraries Government Documents Department

Development of laser-plasma diagnostics using ultrafast atomic-scale dynamics. 96-ERD-046 final report

Description: Ultrashort laser pulse systems allow examination of intense, ultrafast laser-plasma interactions. More specifically, intense laser irradiation can induce short xuv/x-ray bursts from the surface of condensed phase targets. Ultrafast xuv/x-ray detection is needed to understand laser-plasma interactions in this dynamic regime. Support of the Stockpile Stewardship and Management Program requires this critical understanding. Our effort here has been to extend understanding of atomic-scale dynamics in such environments with the goal of developing next generation ultrafast xuv/x-ray diagnostics where the sensors will be the atoms and ions themselves and the time resolution will approach that of the induced atomic transitions ({approx} a few femtoseconds). Pivotal contributions to the rapidly developing field of highly nonperturbative interactions of ultrashort pulse lasers with atoms/ions have been made at this laboratory. In the visible/infrared wavelength regions the temporal and spectral content of ultrashort laser pulses are now reliably monitored within a single pulse using frequency resolved optical gating (FROG) which is based on rapid nonlinear optical processes such as the Kerr effect. New applications of this basic concept are still being developed. Corresponding detection for the xuv/x-ray wavelengths does not exist and is urgently needed in many laboratory programs. The FROG technique cannot be applied in the xuv/x-ray region. Current x-ray streak camera technology is limited to {approx}0.5 picosecond resolution.
Date: March 1, 1997
Creator: Bolton, P.R.; Kulander, K.C. & Boreham, B.W.
Partner: UNT Libraries Government Documents Department