3,113 Matching Results

Search Results

Advanced search parameters have been applied.

in subjects: "Sensitivity"

open access

Validation and sensitivity of a simulated photograph technique for visibility modeling

The Los Alamos Scientific Laboratory (LASL) visibility model is capable of producing simulated before and after pictures that illustrate visual effects of smoke plumes. Although the model has been under development for a few years, until recently there had been very little testing of the model against field experience or testing of sensitivity of the model results to numerical approximations used in the model. Further validation and sensitivity testing of the LASL model began in late 1979. The … more

Date: January 1, 1980

Creator: Williams, M.; Chan, L.Y. & Lewis, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Development of a low intensity current monitor system

This report documents the development of a current transformer system used to measure pulsed ion beam currents with a wide dynamic intensity range (nA to mA, and factor of 10{sup 6}). Peak beam currents at the LAMPF accelerator typically range from 100 to nA to 40 mA with pulse widths varying from 30 to 1000 {mu}s. Signal conditioning of the peak current output provides an average current readout with a range of 1 nA to 2 mA, noise of approximately {plus minus}0.5 nA, and accuracy of {plus minu… more

Date: January 1, 1991

Creator: Gallegos, F.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Energy dependence of metallic-encapsulated thermoluminescent dosimeters. Annual report

The gamma-ray energy responses of encapsulated /sup 7/LiF and CaF/sub 2/:Mn thermoluminescent dosimeters were measured and compred to calculated values. This study was performed in order to improve the accuracy of gamma-ray heating measurements made in polyenergetic gamma-ray fields such as Argonne National Laboratory's Zero Power Reactors. Equations used in the development of the TERC/III computer code and code input parameters are specified. A section on TLD precision is also included. Compar… more

Date: June 1980

Creator: Simons, G. G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

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

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Ultraviolet imaging of hydrogen flames

We have assembled an ultraviolet-sensitive intensified camera for observing hydrogen combustion by imaging the OH, A/sup 2/..sigma.. - X/sup 2//Pi/ bandhead emissions near 309 nm. The camera consists of a quartz and CaF achromat lense-coupled to an ultraviolet image intensifier which is in turn fiber-coupled to a focus projection scan (FPS) vidicon. The emission band is selected with interference filters which serve to discriminate against background. The camera provides optical gain of 100 to … more

Date: January 1, 1988

Creator: Yates, G. J.; Wilke, M. & King, N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fractional charge search

A device to search for fractional charge in matter is described. The sample is coupled to a low-noise amplifier by a periodically varying capacitor and the resulting signal is synchronously detected. The varying capacitor is constructed as a rapidly spinning wheel. Samples of any material in volumes of up to 0.05 ml may be searched in less than an hour.

Date: June 1, 1982

Creator: Innes, W.; Klein, S.; Perl, M. & Price, J.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Proposal to assemble a high resolution-electron sensitive-energy flow calorimeter in the NEULAND spectrometer

A ..gamma.. catcher and a liquid scintillation calorimeter module in a simple configuration that is well suited to the investigation of several different neutrino induced processes are described. The variety of neutrino beams now available at Fermilab and synchrotron intensity and energy together with the high resolution calorimeter allow a multiplicity of experiments to be carried out with a single detector configuration.

Date: January 1, 1977

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Diagnosing vegetation injury caused by air pollution

The structure and function of plants in relation to air pollution injury is discussed. The sources, atmospheric chemistry, monitoring data, symptomatology, factors affecting plant response, injury threshold doses, air quality standards, relative sensitivity of plants, and leaf tissue analysis are discussed for major air pollutants. Among the pollutants discussed are: the photochemical oxidants (ozone, PAN, nitrogen oxides, sulfur dioxide, and fluorides). Minor pollutants discussed in the same f… more

Date: February 1, 1978

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Introduction to albedo neutron dosimeters

The design, operation, calibration, and performance of albedo neutron dosimeters are discussed. An albedo neutron dosimeter is designed to measure the flux of thermal neutrons which leave the body when a person is exposed to fast energy neutrons. The fast neutrons are scattered and moderated in the body, and many have lost most of their initial energy and emerge as thermal neutrons. The albedo neutron dosimeter is designed to detect this flux of thermal neutrons by using a thermal neutron detec… more

Date: January 16, 1978

Creator: Hankins, D.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Spatial adaptation on video display terminals

Spatial adaptation, in the form of a frequency-specific reduction in contrast sensitivity, can occur when the visual system is exposed to certain stimuli. We employed vertical sinusoidal test gratings to investigate adaptation to the horizontal structure of text presented on a standard video display terminal. The parameters of the contrast sensitivity test were selected on the basis of waveform analysis of spatial luminance scans of the text stimulus. We found that subjects exhibited a small, b… more

Date: January 1, 1989

Creator: Greenhouse, D.S.; Bailey, I.L.; Howarth, P.A. & Berman, S.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Calculation of Savannah River K Reactor Mark-22 assembly LOCA/ECS power limits

This paper summarizes the results of TRAC-PF1/MOD3 calculations of Mark-22 fuel assembly of loss-of-coolant accident/emergency cooling system (LOCA/ECS) power limits for the Savannah River Site (SRS) K Reactor. This effort was part of a larger effort undertaken by the Los Alamos National Laboratory for the US Department of Energy to perform confirmatory power limits calculations for the SRS K Reactor. A method using a detailed three-dimensional (3D) TRAC model of the Mark-22 fuel assembly was d… more

Date: January 1, 1992

Creator: Fischer, S. R.; Farman, R. F. & Birdsell, S. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sensitivity and uncertainty analysis for functionals of the time-dependent nuclide density field. [ORIGEN-A]

An approach to extend the present ORNL sensitivity program to include functionals of the time-dependent nuclide density field is developed. An adjoint equation for the nuclide field was derived previously by using generalized perturbation theory; the present derivation makes use of a variational principle and results in the same equation. The physical significance of this equation is discussed and compared to that of the time-dependent neutron adjoint equation. Computational requirements for de… more

Date: April 1, 1978

Creator: Williams, M.L. & Weisbin, C.R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A toxicological study of gadolinium nitrate

The sensitization study in the guinea pig did not show gadolinium nitrate to have potential sensitizing properties. Skin application studies in the rabbit demonstrated that it was cutaneously a severe irritant. This material was considered an irritant in the rabbit eye application studies. 3 refs., 1 tab.

Date: May 1, 1988

Creator: London, J.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Response of LOFT SPNDs to reactor coolant density variations during a LOCA simulation

Analysis of self-powered neutron detector (SPND) data taken during loss-of-coolant experiment (LOCE) L2-3 conducted in the Loss-of-Fluid Test (LOFT) facility has shown that the detectors are sensitive, in a qualitative sense, to coolant density variations in the reactor core. These results provide a strong impetus for determining the applicability of self-powered nuclear flux detectors for liquid level measurement in the reactor vessel of a pressurized water reactor (PWR) during transient condi… more

Date: January 1, 1980

Creator: Adams, J.P. & Berta, V.T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Neutron response of a new albedo-neutron dosimeter

The Los Alamos Scientific Laboratory is converting from a film badge to a badge containing thermoluminescent dosimeters (TLD's). The new dosimeter consists of a plastic badge holding an aluminum card which contains three TLD-700 and one TLD-600 Harshaw LiF chips. In the albedo-neutron portion of the badge, based on Hankins' design, the TLD-600 and one TLD-700 chips are shielded from thermal neutrons by 0.026-inch-thick cadmium. From the difference in readings of these two TLD's, the neutron dos… more

Date: January 1, 1978

Creator: Blackstock, A. W.; Cortez, J. R.; Littlejohn, G. J. & Storm, E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Review of information processing in medical imaging. Proceedings of fifth international conference, Nashville, Tennessee, June 27--July 1, 1977

Forty-three papers discuss methods for improvement of the images from radionuclide scans and radiographs for diagnostic purposes. Abstracts of three papers have appeared previously in ERA.

Date: January 1, 1978

Creator: Brill, A. B.; Price, R. R.; McClain, W. J. & Landay, M. W. (comps.)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High-sensitivity transuranic waste assay by simultaneous proton and thermal-neutron interrogation using an electron linear accelerator

Simultaneous photon and neutron interrogation from electron linear accelerator pulses is used as the basis for a unique assay technique for transuranics. Both prompt and delayed neutrons from the induced fissions are counted on a single detection system, and the contributions from each interrogating flux are resolved. Detection limits (3 sigma) for /sup 239/Pu were estimated to be 3 mg for prompt fission neutrons and 6 mg for delayed neutrons. The technique also provides a clear distinction bet… more

Date: January 1, 1982

Creator: Franks, L. A.; Pigg, J. L.; Caldwell, J. T.; Cates, M. R.; Kunz, W. E. & Noel, B. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Minimum detectable activities of contamination control survey equipment

The Instrumentation External Dosimetry (I ED) Section of the Health Physics Department at the Pacific Northwest Laboratory (PNL) has performed a series of tests to determine the ability of portable survey instruments used at Hanford to detect radioactive contamination at levels required by DOE 5480.11. This semi-empirical study combines instrumental, statistical, and human factors as necessary to derive operational detection limits. These threshold detection values have been compared to existin… more

Date: August 1, 1991

Creator: Goles, R. W.; Baumann, B. L. & Johnson, M. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

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

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.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

MC3644 detonator development status report for the period ending October 30, 1981

The MC3644 detonator is being developed as a replacement for the MC3132 flying plate detonator in the parachute deployment system of the B83 weapon. The MC3644 is a CP, deflagration-to-detonation transition device. Two models are being developed: an interim design using the MC3423 ignitor and a new production version with a one-piece ignitor/header assembly. Features of both designs are described. Results of development tests involving the interim design are presented. No-fire sensitivity test … more

Date: January 1, 1982

Creator: Jacobson, A. K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Experimental evaluation of the differential die-away pulsed-neutron technique for the fissile assay of hot irradiated fuel waste

Hot irradiated fuel waste packages containing self neutron sources up to 10/sup 7/ n/s may be assayed successfully with a 25-mg /sup 239/Pu detection sensitivity using a differential die-away fissile assay system based on a Sandia-designed 14-MeV neutron generator. With a minor design change, our system can accommodate contact gamma dose rates up to 10/sup 4/ R/h with no loss of fissile assay sensitivity.

Date: January 1, 1982

Creator: Caldwell, J.T. & Kunz, W.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sensitivity of the eastern United States to acid precipitation impacts on surface waters

Efforts to identify areas of the United States where soils and freshwaters might be sensitive to acidification have proceeded from analyses of large scale geologic maps. These are useful in a general way but a finer scale analysis has been needed. We have carried out such an analysis for the eastern United States based primarily on geologic maps of scales 1:250,000 to 1:500,000. This report is a synopsis of and excerpted from that effort. Other workers have prepared maps on a similar scale of t… more

Date: March 1, 1980

Creator: Hendrey, G. R.; Galloway, J. N.; Norton, S. A. & Schofield, C. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Proton microprobe analysis of zinc in skeletal tissues. [Proton induced x-ray emission analysis]

A proton microprobe with windowless exit port was used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton microprobe is uniquely suited to this work since it combines high sensitivity for zinc determinations in thick samples with good spatial resolution. Measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations a… more

Date: June 1, 1980

Creator: Doty, S. B.; Jones, K. W.; Kraner, H. W.; Shroy, R. E. & Hanson, A. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

LOFT differential pressure uncertainty analysis

A performance analysis of the LOFT differential pressure (..delta..P) measurement is presented. Along with completed descriptions of test programs and theoretical studies that have been conducted on the ..delta..P, specific sources of measurement uncertainty are identified, quantified, and combined to provide an assessment of the ability of this measurement to satisfy the SDD 1.4.1C (June 1975) requirement of measurement of differential pressure.

Date: March 1, 1977

Creator: Evans, R.P.; Biladeau, G.L. & Quinn, P.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department