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in subjects: "X-Ray Detection"

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Spectral distribution of the two-photon decay of He-like krypton

We report Progress on a measurement of the spectral distribution of photons from the two-photon decay of the 2{sup 1}S{sub 0} level in heliumlike krypton. A measurement of the exact shape of the continuum singles spectrum of the two-photon decay in heliumlike ions provides a sensitive probe of the calculation of the transition probability. In our experiment a beam of Kr{sup 34+} ions is excited using a thin carbon foil and the subsequent decays are observed in an array of four x-ray detectors.

Date: October 1, 1994

Creator: Ali, R.; Ahmad, I. & Berry, H. G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

X-Ray Emission From National Ignition Facility Indirect Drive Targets

We have performed a series of 1-D numerical simulations of the x-ray emission from National Ignition Facility (NIF) targets. Results are presented in terms of total x-ray energy, pulse length, and spectrum. Scaling of x-ray emissions is presented for variations in both target yield and hohlraum thickness. Experiments conducted on the Nova facility provide some validation of the computational tools and methods.

Date: June 4, 1996

Creator: Anderson, A. T.; Managan, R. A.; Tobin, M. T. & Peterson, P. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High-efficiency photoionization detector

A high efficiency photoionization detector using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36 +- 0.02 eV, and a vapor pr… more

Date: May 12, 1981

Creator: Anderson, D.F.

Item Type: Patent

Partner: UNT Libraries Government Documents Department

open access

Status of the WAND (Waste Assay for Nonradioactive Disposal) project as of July 1997

The WAND (Waste Assay for Nonradioactive Disposal) system can scan thought-to-be-clean, low-density waste (mostly paper and plastics) to determine whether the levels of any contaminant radioactivity are low enough to justify their disposal in normal public landfills or similar facilities. Such a screening would allow probably at least half of the large volume of low-density waste now buried at high cost in LANL`s Rad Waste Landfill (Area G at Technical Area 54) to be disposed of elsewhere at a … more

Date: March 1998

Creator: Arnone, G. J.; Foster, L. A.; Foxx, C. L.; Hagan, R. C.; Martin, E. R.; Myers, S. C. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Use of Synchrotron Radiation for Electron Identification at High Luminosity

Synchrotron radiation has been used successfully to identify electrons of 10 to 30 GeV traversing a field length of 30 kG-m. Since comparable field lengths are a feature of many proposed collider detectors, and since this is an electron energy range of interest at ..sqrt..s approx. = 1 TeV, we consider whether such a device could be useful in the L = 10/sup 33/ environment.

Date: 1983

Creator: Aronson, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Development of a fast pixel array detector for use in microsecond time-resolved x-ray diffraction

A large-area pixel x-ray detector is being developed to collect eight successive frames of wide dynamic range two-dimensional images at 200kHz rates. Such a detector, in conjunction with a synchrotron radiation x-ray source, will enable time-resolved x-ray studies of proteins and other materials on time scales which have previously been inaccessible. The detector will consist of an array of fully-depleted 150 micron square diodes connected to a CMOS integrated electronics layer with solder bump… more

Date: August 1, 1995

Creator: Barna, S.L.; Gruner, S.M. & Shepherd, J.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Experimental configuration of direct drive cylindrical implosions on the Omega Laser

Details about the cylindrical implosions using direct-drive irradiation on the OMEGA Laser facility are provided. The experimental configuration, including orientation, construction, and mounting of the targets is described. An attempt to characterize the modulation transfer function of the primary x-ray framing camera diagnostic results in insufficient exposure contrast but relative agreement with other determinations. The x-ray intensity of the titanium backlighter driven by the 2.5-nsec line… more

Date: December 31, 1998

Creator: Barnes, C.W.; Tubbs, D.L. & Beck, J.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Resonant nuclear scattering of synchrotron radiation: Detector development and specular scattering from a thin layer of {sup 57}Fe

This thesis explores resonant nudear scattering of synchrotron radiation. An introductory chapter describes some useful concepts, such as speedup and coherent enhancement, in the context of some basic physical principles. Methods of producing highly monochromatic synchrotron beams usmg either electronic or nuclear scattering are also discussed. The body of the thesis concentrates on detector development and specular scattering from iynthetic layered materials. A detector employing n-dcrochannel… more

Date: April 1, 1995

Creator: Baron, A.Q.R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Measurements with a 35 psec gate time microchannel plate camera

Measurements of the x-ray gate time of 0.2 mm thick microchannel plates with an L/D aspect ratio of 20 as opposed to the more usual L/D=40, demonstrate that gate times of 35 ps can be achieved. Good agreement with time dependent modelling is demonstrated. 7 refs., 4 figs., 2 tabs.

Date: July 1, 1990

Creator: Bell, P.E.; Kilkenny, J.D.; Hanks, R. & Landen, O.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Neutron Detection with a Cryogenic Spectrometer

Cryogenic calorimeters are used for x-ray detection because of their exquisite energy resolution and have found application in x-ray astronomy, and the search for dark matter. These devices operate by detecting the heat pulse produced by ionization in an absorber cooled to temperatures below 1 K. Such temperatures are needed to lower the absorber's heat capacity to the point that the deposition of even a few eV results in a measurable temperature excursion. Typical absorbers for dark matte… more

Date: June 23, 2003

Creator: Bell, Z. W.; Lamberti, V. E.; Carpenter, D. A. & Cristy, S. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Continuous Holdup Measurements with Silicon P-I-N Photodiodes

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… more

Date: May 1, 2002

Creator: Bell, Z. W.; Oberer, R. B.; Williams, J. A.; Smith, D. E. & Paulus, M. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Determining How Magnetic Helicity Injection Really Works

OAK-B135 The goal of the Caltech program is to determine how helicity injection works by investigating the actual dynamics and topological evolution associated with magnetic relaxation. A new coaxial helicity injection source has been constructed and brought into operation. The key feature of this source is that it has maximum geometric simplicity. Besides being important for fusion research, this work also has astrophysical implications. Photos obtained using high-speed cameras show a clear se… more

Date: October 9, 2001

Creator: Bellan, Paul M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A 2D smart pixel detector for time-resolved protein crystallography

A smart pixel detector is being developed for Time Resolved Crystallography for biological and material science applications. Using the Pixel detector presented here, the Laue method will enable the study of the evolution of structural changes that occur within the protein as a function of time. The x-ray pixellated detector is assembled to the integrated circuit through a bump bonding process. Within a pixel size of 150 x 150 {mu}m{sup 2}, a low noise preamplifier-shaper, a discriminator, a 3 … more

Date: October 1, 1995

Creator: Beuville, E.; Cork, C. & Earnest, T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The ALEXIS data processing package: An update

The ALEXIS experiment (Array of Low Energy X-ray Imaging Sensors), is a mini-satellite containing six wide angle EUV/ultrasoft x-ray telescopes. Its purpose is to map out the sky in three narrow (5%) bandpasses around 66, 71, and 93 eV. The 66 and 71 eV bandpasses are centered on intense Fe emission lines which are characteristic of million-degree plasmas such as the one thought to produce the soft x-ray background. The 93 eV bandpass is not near any strong emission lines and is more sensitive … more

Date: February 1, 1993

Creator: Bloch, J. J.; Smith, B. W. & Edwards, B. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

On orbit performance of the ALEXIS EUV telescopes

The Array of Low Energy X-ray Imaging Sensors (ALEXIS) satellite is Los Alamos` first attempt at building and flying a low cost, rapid development, technology demonstration and scientific space mission. The ALEXIS satellite contains the two experiments: the ALEXIS telescope array, (which consists of six EUV/ultrasoft x-ray telescopes utilizing multilayer mirrors, each with a 33 degree field-of-view), and a VHF ionospheric experiment called Blackbeard. A ground station located at Los Alamos excl… more

Date: August 1, 1994

Creator: Bloch, J.; Edwards, B. & Priedhorsky, W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design, performance, and calibration of the ALEXIS ultrasoft x-ray telescopes

The Array of Low Energy X-ray Imaging Sensors (ALEXIS) experiment consists of six wide angle EUV/ultrasoft x-ray telescopes utilizing normal incidence multilayer mirrors, flown a miniature satellite to map out the sky in three narrow bandpasses around 66, 71, and 95 eV. The 66 and 71 eV bandpasses are centered on intense Fe emission lines which are characteristic of million degree plasmas such as the one thought to produce the soft x-ray background. The 95 eV bandpass has a higher throughput an… more

Date: January 1, 1990

Creator: Bloch, J.J.; Ameduri, F.; Priedhorsky, W.C.; Roussel-Dupre, D.; Smith, B.W. (Los Alamos National Lab., NM (USA)); Siegmund, O.H.W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The ALEXIS data processing package: An update

Date: January 1, 1993

Creator: Bloch, J.J.; Smith, B.W. & Edwards, B.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

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

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 i… more

Date: March 1, 1997

Creator: Bolton, P.R.; Kulander, K.C. & Boreham, B.W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Linear, position-sensitive x-ray detector used for real-time calculations of small-angle scattering parameters with submillisecond resolution

The advent of high-intensity X-ray synchrotron sources has made possible the measurement of fluctuations in small-angle scattering parameters from typical specimens on a submillisecond time scale in real-time. The fundamental design of any fast detector system optimized for such measurements will incorporate some type of solid state detector array capable of rapid encoding algorithms. A prototype with a self-scanning photodiode array has been designed and tested at beamline 1 to 4 at the Stanfo… more

Date: January 1, 1984

Creator: Borso, C.S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A GaAs Detector for Dark Matter and Solar Neutrino Research

The ability to produce large GaAs crystals with the requisite electronic properties to be fabricated into charged particle and photon detectors would provide a detector medium that would find numerous applications in both applied and fundamental research. Various applications would likely include x-ray detectors on satellites, environmental monitoring, medical imaging, bore hole mining spectroscopy, searches for dark matter, and solar neutrino research. We have carried out the development of Ga… more

Date: August 2000

Creator: Bowles, T. J.; Hime, A.; Gavrin, V.; Kozlova, Y.; Veretenkin, E.; Markov, A. V. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Analysis of radiation-induced microchemical evolution in 300 series stainless steel

The irradiation of 300 series stainless steel by fast neutrons leads to an evolution of alloy microstructures that involves not only the formation of voids and dislocations, but also an extensive repartitioning of elements between various phases. This latter evolution has been shown to be the primary determinant of the alloy behavior in response to the large number of variables which influence void swelling and irradiation creep. The combined use of scanning transmission electron microscopy and… more

Date: March 1, 1980

Creator: Brager, H. R. & Garner, F. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Filtered fluorescer x-ray detector

Recently, an instrument capable of measuring x-rays between 8 and 90 keV was conceived to help understand conditions pertaining to pulsed power research. This resulted in the development of a versatile device that would incrementally detect x-rays emitted at predetermined energy bands over this range. To accomplish this, an array of well characterized filter-fluorescer combinations were produced which would allow fluoresced x-rays to be observed by time resolved electro-optical devices. As many… more

Date: April 1, 1995

Creator: Bruns, H. C.; Emig, J. A.; Thoe, R. S.; Springer, P. T. & Hernandez, J. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Intelligent self-configuring client-server analysis software for high-resolution X and gamma-ray spectrometry

The Safeguards Technology Program at the Lawrence Livermore National Laboratory is developing isotopic analysis software that is constructed to be adaptable to a wide variety of applications and requirements. The MGA++ project will develop an analysis capability based on an architecture consisting of a set of tools that can be configured by an executive to perform a specific task. The software will check the results or progress of an analysis and change assumptions and methodology as required t… more

Date: July 1, 1995

Creator: Buckley, W.M. & Carlson, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Improved 50 ps response x-ray detector with optical applications

We have improved the impulse response characteristics of the LLNL 50 ps detector significantly. The detector has also been improved mechanically to permit much greater ease of assembly and repair. We are investigating modified versions of this design for optical applications. The detector was developed to complement the recording capability of our Thomson-CSF 4 GHz oscilloscopes in laser driven ICF fusion experiments research.

Date: September 30, 1981

Creator: Campbell, D.; Tirsell, G. & Laird, W.

Item Type: Article

Partner: UNT Libraries Government Documents Department