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Avalanche transistor pulser for fast-gated operation of micro-channel plate image-intensifiers

Description: Transistors operated in the avalanche mode are employed to generate a 1000 volt 10 to 30 nsec wide pulse with less than 4 nsec rise and fall times. This pulse is resistively attenuated to approximately equal to 270 volts and drives the image intensifier tube which is a load of approximately equal to 200 pf. To reduce stray inductance and capacitance, transistor chips were assembled on a thick-film hybrid substrate. Circuit parameters, operating conditions, and coupling to the microchannel plate… more
Date: January 1, 1977
Creator: Lundy, A.; Parker, J. R.; Lunsford, J. S. & Martin, A. D.
Partner: UNT Libraries Government Documents Department
open access

Radiation protection: an analysis of thyroid blocking. [Effectiveness of KI in reducing radioactive uptake following potential reactor accident]

Description: An analysis was performed to provide guidance to policymakers concerning the effectiveness of potassium iodide (KI) as a thyroid blocking agent in potential reactor accident situations, the distance to which (or area within which) it should be distributed, and its relative effectiveness compared to other available protective measures. The analysis was performed using the Reactor Safety Study (WASH-1400) consequence model. Four categories of accidents were addressed: gap activity release acciden… more
Date: January 1, 1980
Creator: Aldrich, D.C. & Blond, R.M.
Partner: UNT Libraries Government Documents Department
open access

Time-Resolved Doubly Bent Crystal X-Ray Spectrometer

Description: X-ray spectroscopy is an essential tool in high temperature plasma research. We describe a time-resolved x-ray spectrometer suitable for measuring spectra in harsh environments common to many very high energy density laboratory plasma sources. The spectrometer consisted of a doubly curved Si(111) crystal diffraction element, a WL-1201 (ZnO:Ga) phosphor, a coherent fiber optic array, and two visible streak cameras. The spectrometer design described here has a minimum time resolution of 1.3 ns wi… more
Date: January 1, 1988
Creator: Hockaday, M. P.; Wilke, M. D.; Blake, R. L.; Vaninetti, J.; Gray, N. T. & Nedrow, P. T.
Partner: UNT Libraries Government Documents Department
open access

Development and testing of a Monte Carlo code system for analysis of ionization chamber responses

Description: To predict the perturbation of interactions between radiation and material by the presence of a detector, a differential Monte Carlo computer code system entitled MICAP was developed and tested. This code system determines the neutron, photon, and total response of an ionization chamber to mixed field radiation environments. To demonstrate the ability of MICAP in calculating an ionization chamber response function, a comparison was made to 05S, an established Monte Carlo code extensively used t… more
Date: January 1, 1986
Creator: Johnson, J.O. & Gabriel, T.A.
Partner: UNT Libraries Government Documents Department
open access

New liquid scintillators for fiber-optic applications

Description: New long-wavelength-emitting, high-speed, liquid scintillators have been developed and tailored specifically for plasma diagnostic experiments employing fiber optics. These scintillators offer significant advantages over commercially available plastic scintillators in terms of sensitivity and bandwidth. FWHM response times as fast as 350 ps have been measured. Emission spectra, time response data, and relative sensitivity information are presented.
Date: January 1, 1981
Creator: Lutz, S. S.; Franks, L. A.; Flournoy, J. M. & Lyons, P. B.
Partner: UNT Libraries Government Documents Department
open access

Comparison of cesium iodide and gold photocathodes for x-ray streak cameras

Description: X-ray streak cameras at Lawrence Livermore Laboratory use gold transmission photocathodes for x-ray detection. Other photocathode materials which might provide improved sensitivity without loss of temporal resolution are of interest. Of particular interest are dielectrics such as cesium iodide. Simultaneous measurements of the sensitivity to 500 eV x-rays of both gold and cesium iodide photocathodes in the LLL Soft X-ray Streak Camera were made. Enhanced sensitivity with the Csl photocathodes i… more
Date: January 1, 1979
Creator: Stradling, G.L.; Medecki, H.; Attwood, D.T.; Kauffman, R.L. & Henke, B.L.
Partner: UNT Libraries Government Documents Department
open access

Shuttering Efficiencies of Nanosecond-Gated Photoemissive Shutter Tubes

Description: Recent studies show that effective shuttering of photoemissive tubes, such as Silicon-Intensified-Target Vidicons (SITVs) and Microchannel-plate Image Intensifier Tubes (MCPTs), can vary widely depending upon the extent of their opacity to an input flux of photons. Optical feedthrough signals from photon transmission through the photocathode to the target or phosphor ranging from 10/sup -4/ to 10/sup -9/ (when compared with gated signals) were measured for a large sampling of commercially avail… more
Date: January 1, 1985
Creator: Yates, George J.; Jaramillo, Steven A.; Pagano, Thomas S. & Black, J.Paul
Partner: UNT Libraries Government Documents Department
open access

Readout techniques and radiation damage of undoped cesium iodide

Description: Several readout techniques for undoped CsI have been studied which utilize the fast scintillation component for speed, and the high photon yield for good energy resolution. Quantum yields have been measured for samples up to 30 cm in length using photomultiplier tubes, wavelength shifters, and silicon photodiodes. A study has also been made of the scintillation properties of undoped CsI. It is found that the light output and decay time of the 310 nm fast component increases and the emission spe… more
Date: January 1, 1989
Creator: Woody, C.L.; Levy, P.W.; Kierstead, J.A.; Skwarnicki, T.; Sobolewski, Z.; Goldberg, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Dynamic positron emission tomography in man using small bismuth germanate crystals

Description: Primary considerations for the design of positron emission tomographs for medical studies in humans are the need for high imaging sensitivity, whole organ coverage, good spatial resolution, high maximum data rates, adequate spatial sampling with minimum mechanical motion, shielding against out of plane activity, pulse height discrimination against scattered photons, and timing discrimination against accidental coincidences. We discuss the choice of detectors, sampling motion, shielding, and ele… more
Date: April 1, 1982
Creator: Derenzo, S.E.; Budinger, T.F.; Huesman, R.H. & Cahoon, J.L.
Partner: UNT Libraries Government Documents Department
open access

Overview of thick-film technology as applied to solar cells

Description: Thick-film technology was developed by the electronics industry as a means of fabricating components and miniature circuitry. Today, the solar cell industry is looking at screen printing as an alternate to more expensive, high-vacuum techniques in several of the production steps during the manufacture of silicon solar cells. Screen printing is already fairly well established as a means of providing electrical contact to a cell and for the formation of a back surface field. Now under investigati… more
Date: January 1, 1980
Creator: Firor, K. & Hogan, S.
Partner: UNT Libraries Government Documents Department
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Quantitative Comparison of Different Microchannel Plate Image Intensifier Tubes as Nanosecond Light Shutters in Coupled Video Systems

Description: A comparison of different manufacturers' microchannel plate image intensifier tubes (MCPTs) in coupled bideo systems is presented. Comparative performances in the areas of optical gating speed, resolution, gain, and phosphor efficiency are discussed. Relative sensitivities for various combinations of coupled MCPT/TV imager systems including P-20 and P-20R phosphors cascaded to FPS (focus projection and scan) electrostatic vidicons with silicon or Sb/sub 2/S/sub 3/ targets and CID (charge inject… more
Date: January 1, 1986
Creator: Jaramillo, Steven A. & Yates, George J.
Partner: UNT Libraries Government Documents Department
open access

Diagnostic phosphors for photon beams at the ALS and APS

Description: Some tests have been made of phosphors for photon beam diagnosis. Plasma sprayed coatings were checked for damage and decay during a period of several ampere-hours of irradiation from the NSLS Xray ring. Surface temperatures were measured and extrapolated to give an indication of the temperatures expected in more powerful photon beams. Based on our findings we have chosen plasma-sprayed coatings of Europium-doped Yttrium Oxide as the best candidate for use on masks and flags in white'' photon b… more
Date: January 1, 1991
Creator: Shu, Deming (Argonne National Lab., IL (United States)); Warwick, T. (Lawrence Berkeley Lab., CA (United States)) & Johnson, E.D. (Brookhaven National Lab., Upton, NY (United States))
Partner: UNT Libraries Government Documents Department
open access

High-resolution CT system for elemental mapping

Description: The performance of a low-temperature CCD camera for application in computed tomography (CT) was tested on beamline II-3 at the Stanford Synchrotron Radiation Laboratory (SSRL). In the present system, transmitted x-rays are converted to visible light on a phosphor-coated optical face plate. This light illuminates a thermoelectrically cooled CCD, which is operated as a charge counting device. By modulating the energy of the x-ray beam, we can obtain elemental and chemical-state information about … more
Date: August 1, 1986
Creator: Kinney, J.H.; Johnson, Q.C.; Brase, J.M.; Nichols, M.C.; Nusshardt, R. & Bonse, U.
Partner: UNT Libraries Government Documents Department
open access

Study of rare muon decay modes with the crystal box

Description: We report on a search for the lepton family-number-nonconserving decays ..mu../sup +/..-->..e/sup +/e/sup -/e/sup +/, ..mu../sup +/..-->..e/sup +/..gamma.., and ..mu../sup +/..-->..e/sup +/..gamma gamma.., using the Crystal Box detector at LAMPF. The experiment was run in the stopped muon channel at LAMPF during the winter and summer of 1984. Muons were stopped in the middle of a detector system consisting of a cylindrical drift chamber, a plastic scintillator hodoscope, and a segmented array o… more
Date: January 1, 1985
Creator: Sandberg, V.; Bolton, R. D.; Bowman, J. D.; Carlini, R. D.; Copper, M. D.; Doung-Van, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Position-sensitive detection of slow neutrons: Survey of fundamental principles

Description: This paper sets forth the fundamental principles governing the development of position-sensitive detection systems for slow neutrons. Since neutrons are only weakly interacting with most materials, it is not generally practical to detect slow neutrons directly. Therefore all practical slow neutron detection mechanisms depend on the use of nuclear reactions to convert'' the neutron to one or more charged particles, followed by the subsequent detection of the charged particles. The different conv… more
Date: January 1, 1992
Creator: Crawford, R.K.
Partner: UNT Libraries Government Documents Department
open access

Comparison of detector materials for time-of-flight positron tomography

Description: Knowledge of detection efficiency and timing resolution is essential when comparing detector materials for time-of-flight positron tomography. We present results of Monte Carlo calculations of the detection efficiency of plastic, lead loaded plastic, NaI(T1), liquid xenon, bismuth germanate (BGO), CsF, BaF/sub 2/, Ge, and HgI/sub 2/ for 511 keV photons. We also use recently published values of timing resolution for these detector materials to tabulate the quantity (efficiency)/sup 2//(time reso… more
Date: June 1, 1982
Creator: Derenzo, S.E.
Partner: UNT Libraries Government Documents Department
open access

Remote temperature-measurement instrumentation for a heated rotating turbine disk

Description: Thermographic-phosphor (TP) remote temperature sensors were installed on a turbine disk and subjected to thermal and centrifugal stresses in a spin-pit test. The sensors were placed at three different radii on the disk, which was run at 6600, 9330, 11400, and 13200 rpm at nominal temperatures of ambient, 300) degree)F, 600)degree)F, 900)degree)F, and 1250)degree)F (149)degree)C, 316)degree)C, 482)degree)C, and 677)degree)C, respectively). The paper gives details of the TP temperature-measuremen… more
Date: January 1, 1988
Creator: Lutz, S. S.; Turley, W. D.; Borella, H. M.; Noel, B. W.; Cates, M. R. & Probert, M. R.
Partner: UNT Libraries Government Documents Department
open access

Adsorption of energy in photocatalytic reactors

Description: The dissociation of water to hydrogen and oxygen requires energy ..delta..G/sub 298/ = 228 kJ/mole. By irradiating a semiconductor with light of energy greater than this amount, one may produce electrons in the excited state and electron vacancies at the surface that can perform the photochemical reduction (2H/sup +/ + 2e/sup -/ ..-->.. 2H ..-->.. H/sub 2/) and oxidation (20H/sup -/ + 2/sup +/ ..-->.. H/sub 2/O/sub 2/ ..-->.. H/sub 2/O + (1/2)O/sub 2/). There are several semiconductors, SrTiO/s… more
Date: July 1, 1985
Creator: Somorjai, G.A.
Partner: UNT Libraries Government Documents Department
open access

Iodine chemical forms in LWR severe accidents

Description: Calculated data from seven severe accident sequences in light water reactor plants were used to assess the chemical forms of iodine in containment. In most of the calculations for the seven sequences, iodine entering containment from the reactor coolant system was almost entirely in the form of CsI with very small contributions of I or HI. The largest fraction of iodine in forms other than CsI was a total of 3.2% as I plus HI. Within the containment, the CsI will deposit onto walls and other su… more
Date: January 1, 1991
Creator: Weber, C.F.; Beahm, E.C. & Kress, T.S.
Partner: UNT Libraries Government Documents Department
open access

Status of the Los Alamos Anger camera

Description: Results of preliminary tests of the neutron Anger camera being developed at Los Alamos are presented. This detector uses a unique encoding scheme involving parellel processing of multiple receptive fields. Design goals have not yet been met, but the results are very encouraging and improvements in the test procedures are expected to show that the detector will be ready for use on a small-angle scattering instrument next year. 3 refs., 4 figs.
Date: January 1, 1985
Creator: Seeger, P.A. & Nutter, M.J.
Partner: UNT Libraries Government Documents Department
open access

Proposed method for remote thermometry in turbine engines. [Eu-doped yttrium oxide]

Description: The method uses laser-induced fluorescence from a pulsed uv laser to excite a rare-earth-oxide phosphor bonded in a thin layer to the surface to be measured. The luminescent decay times of certain lines are temperature-dependent. Initial results indicate that at least one phosphor, europium-doped yttrium oxide, is usable to 950/sup 0/C. (DLC)
Date: January 1, 1985
Creator: Noel, B. W.; Cates, M. R.; Allison, S. W.; Borella, H. M.; Franks, L. A. & Marshall, B. R.
Partner: UNT Libraries Government Documents Department
open access

Luminescence from metals and insulators

Description: The term luminescence is normally applied to light emission that is not explainable by the mechanisms discussed by the other speakers in this meeting. Specifically, it is not transition radiation, surface plasmon radiation, or bremsstrahlung. One normally thinks of luminescence as arising from one-electron transitions within a medium. This talk consists of an overview of luminescence from condensed matter under irradiation by either energetic particles or photons. The author begins with organic… more
Date: January 1, 1985
Creator: Crawford, O.H.
Partner: UNT Libraries Government Documents Department
open access

Energy levels and lifetimes of 2P/sup 5/3S3D quartets in Na I

Description: The 2p/sup 5/3s3d/sup 4/L levels in NAI can decay in three ways: El transitions to 2p/sup 5/3s3p levels (/sup 4/L allowed), El transitions to 2p/sup 6/Nl/sup 2/L (spin forbidden), and autoionization to 2p/sup 6/Kl/sup 2/L (spin-forbidden). Multi-configuration Hartree-Fock calculations with Breit-Pauli corrections were preformed for each mode of decay with special emphasis given to the 2p/sup 5/3s3p/sup 4/L - 2p/sup 5/3s3d/sup 4/L transitions. 3 refs., 4 tabs.
Date: January 1, 1986
Creator: Fischer, C. F.
Partner: UNT Libraries Government Documents Department
open access

Neutron measurements in the FRX-C/LSM magnetic compression experiment

Description: Neutron measurements are being pursued as an ion temperature diagnostic in the FRX-C/LSM Magnetic Compression Experiment. One can easily see that the d-d neutron emission is a sensitive measure of ion heating during adiabatic magnetic compression of FRCs. The reaction rate may be written as R = (1/2) n N {l angle}{sigma}v{r angle}, where n and N are the deuterium density and inventory. The fusion reactivity varies as {l angle}{sigma}v{r angle} {proportional to} T{sup 5.6} for T {approx equal} 1… more
Date: January 1, 1989
Creator: Chrien, R. E. & Baron, M. H.
Partner: UNT Libraries Government Documents Department
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