J.B. McCaslin

Lawrence Berkeley National Laboratory

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R. H. Thomas

University of California System

Lloyd D. Stephens

Ames Research Center

W.P. Swanson

Indiana University Bloomington

A. R. Smith

University of California, Berkeley

AР

Alan Р. Smith

Liverpool School of Tropical Medicine

L.B. Hughes

Ames Research Center

Jennifer Hewitt

University of Central Florida

A. J. Elwyn

Fermi National Accelerator Laboratory

J.W. Baum

Brookhaven National Laboratory

T.M. Jenkins

Stanford Synchrotron Radiation Lightsource

Cooperative Institutions

Lawrence Berkeley National Laboratory

University of California, Berkeley

Fermi National Accelerator Laboratory

European Organization for Nuclear Research

Stanford University

University of California, Los Angeles

Brookhaven National Laboratory

SLAC National Accelerator Laboratory

University of Chicago

Carleton University

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VERSATILE FAST NEUTRON DETECTOR

J.B. McCaslin

Neutron Detection

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Measurements ofdpbackward elastic scattering at 3.43, 4.50, 5.75, and 6.60GeVcincident deuteron momentum

Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields (1974)

L. Dubal C. K. Hargrove E. P. Hincks R. J. McKee H. Mes

Differential cross sections for $\mathrm{dp}$ elastic scattering from 60\ifmmode^\circ\else\textdegree\fi{} to 175\ifmmode^\circ\else\textdegree\fi{} center of momentum (c.m.) were measured at 3.43, 4.50, 5.75, and 6.60 $\frac{\mathrm{GeV}}{c}$ incident deuteron momentum. The measurements were made with a two-arm magnetic spectrometer, making use of multiwire proportional chamber detectors. The deuterons were accelerated at the Bevatron of the Lawrence Berkeley Laboratory. Data are compared with predictions of the baryon-pickup model and the one-pion-exchange model. The backward dip at 180\ifmmode^\circ\else\textdegree\fi{} c.m. for 4.5 $\frac{\mathrm{GeV}}{c}$, predicted by Craigie and Wilkin using the one-pion-exchange model, is not observed, but reasonable fits to the momentum variation and angular distributions are found. When the data are plotted against the variable $\ensuremath{\Delta}$ of the baryon-pickup model, the $s$ dependence is greatly reduced.

Momentum (technical analysis)

10.1103/physrevd.9.597

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Citations (21)

Relative attenuation characteristics of some shielding materials for PuB neutrons. [2. 2 MeV]

P.S. Bringham J.B. McCaslin

Relative attenuation measurements of 2.2 MeV neutrons in up to 12 inches of shield are reported for the following shielding materials: polyethylene, water, spodumene-gypsum, Gypsum (wet and dry), and concrete. (SDF)

10.2172/7323280

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Ames Collaborative Study of Cosmic Ray Neutrons

Health Physics (1978)

Jennifer Hewitt L.B. Hughes J.W. Baum A. V. Kuehner J.B. McCaslin

Cosmic ray neutron flux densities, neutron dose equivalent rates, and exposure rates for ionizing radiation were measured in a series of flights at 12.5 km (41,000 ft) in an Ames Research Center high-altitude aircraft. Instrumentation and analysis techniques were used which had been developed to measure accelerator-produced radiation. Neutron instrumentation consisted of Bonner spheres, threshold detectors, a moderated BF, counter, and a liquid scintillation spectrometer. A dose-equivalent meter from Brookhaven National Laboratory and an argon-filled ionization chamber were also flown. On three flights at average geomagnetic latitudes of 45, 38, and 48°N the neutron dose equivalent rates were 0.20, 0.14, and 0.22 mrem/hr. The corresponding exposure rates from the ionizing component were 0.37, 0.31, and 0.41 mR/hr. As measured by the liquid scintillation counter, the dose equivalent from 3- to 13-MeV neutrons is 30% of the total for all neutrons. The flux measured in this energy range agrees with the calculated values of Armstrong (Ar73). At a geomagnetic latitude of 43°N, a plot of the exposure rate against the pressure altitude yielded a relaxation length of 140 g/cm2. Simultaneous measurements of the neutron and ionizing components verified that the former is more sensitive to changes in geomagnetic latitude. A neutron spectrum derived from Bonner sphere measurements indicates that the flux densities in the Hess spectrum may be two or three times too high and that the evaporation bump at 1 MeV may not exist.

Equivalent dose

Geomagnetic latitude

Neutron monitor

Proportional counter

10.1097/00004032-197804000-00008

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Neutron shielding for PEP

J.B. McCaslin R. H. Thomas

To facilitate preliminary siting considerations for PEP, estimates of the earth overburden needed for radiation shielding are required. This note reports shielding estimates based upon considerations of hadron (neutron) production alone. Muon shielding estimates will be given a later note. Calculations are reported for a simplified model in which the proton storage ring is located at constant depth below a horizontal plane. General formulae are first developed and then applied to a specific design on the SLAC site. 5 refs., 4 figs., 1 tab.

Overburden

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A METAL-OXIDE-SEMICONDUCTOR ELECTROMETER IONIZATION CHAMBER

J.B. McCaslin

Electrometer

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An Evaluation of NTA Film in an Accelerator Environment and Comparisons with CR-39

Radiation Protection Dosimetry (1987)

N.A. Greenhouse T.M. de Castro J.B. McCaslin A.R. Smith Ruopeng Sun

The Lawrence Berkeley Laboratory (LBL) has enjoyed decades of successful experience with NTA film because of the relatively energetic neutron spectra in the workplace and a cool, low humidity environment. The recognised existence of softer neutron spectra at some locations at LBL, and the availability of CR-39 as a possible alternative dosemeter prompted this study to determine neutron dosemeter adequacy in these areas. CR-39 offers several advantages over NTA film, including lack of latent track fading, the potential for automated readout, and improved response to lower energy neutrons. The CR-39 detection threshold of 0.1 MeV or less made it a particularly attractive possible alternative for neutron dosimetry at LBL's lower energy accelerators. A dosimetry study was conducted at one location at the SuperHILAC where the average neutron energy was about 0.5 MeV and the maximum was about 20 MeV. Neutron fluence, energy spectrum and dose equivalent measurements were made with a variety of active instruments at this accelerator during exposure of a rotating phantom, upon which NTA film and CR-39 dosemeters were attached. The results indicated that with standard calibration techniques both dosemeter types responded adequately to at least half of the total measured dose equivalent.

Equivalent dose

CR-39

Bonner sphere

10.1093/oxfordjournals.rpd.a080022

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SOME USES AND CHARACTERISTICS OP MOS TRANSISTORS FOR HEALTH PHYSICS APPLICATIONS

J.B. McCaslin

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Practical neutron dosimetry at high energies

J.B. McCaslin R. H. Thomas

m ws«* UNIVERSITY OF CALIFORNIA LBL-11652 Lawrence Berkeley Laboratory Engineering & Technical Services Division Presented a the European Seminar on Radiation Protection Quantities for External Exposure, Physikalisch-Technische Bundesanstalt, Braunschweig Federal Republic of Germany, October 13-15, 1980 PRACTICAL NEUTRON DOSIMETRY AT HIGH ENERGIES J.B. McCaslin and R.H. Thomas October 1980 Prepared for the U.S. Department of Energy under Contract W-7405-ENG-48 DISTRIBUTION OF THIS DOCUMEHI IS UNLIMITED

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Citations (7)

Ground scattering contribution in neutron calibrations.

PubMed (1983)

J.B. McCaslin Lloyd D. Stephens R. H. Thomas

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Citations (1)