The efficient design of access penetrations at high-energy proton accelerators is desirable for both economic and personnel protection reasons. This paper reports on a series of measurements made in a personnel access labyrinth which viewed an A1 target bombarded by 400-GeV protons from the Fermilab Tevatron. Measurements of absorbed dose in the labyrinth using tissue-equivalent ion chambers were consistent with theoretical predictions of both the relative attenuation through the penetration and the absolute magnitude near the target. The multisphere technique was used to determine the neutron energy spectrum in one section of the labyrinth. A recombination chamber was used to measure the quality factor of the radiation field in two sections of the labyrinth. Good agreement with the quality factor deduced from the multisphere result was obtained at the same measurement location.
Angular-distribution and total-cross-section measurements have been made for the 14 N( 14 N, 13 N) 15 N reaction over a range of energies. For center-of-mass energies below about 6.5 MeV, the tunneling theory of neutron transfer is shown to give a good account of the data. At higher energies, nuclear absorption occurs for the close collisions and spoils the tunneling description. These results show why earlier descriptions of this reaction by the tunneling theory were unsuccessful. -T~-, . -T . | E(e.-..) = 0.«M«V J H \ T yAa/ACl J if{*-•))*-\ \y fA-
An experiment is described for measuring the momentum and energy of relativistic electrons from a radioactive beta source. Electrons are momentum-selected in a simple beta-ray spectrometer and then measured for energy with a surface barrier detector. The results illustrate to students a clear confirmation of the relativistic energy–momentum relationship, and provide an accurate measure of the rest mass of electrons and the speed of light. The apparatus we describe also can be used in experiments for measuring beta spectra.
Abtruct-The Princeton Plasma Physics Laboratory (PPPL) began fusion experiments in 1951.In the early years, the major health physics concerns were associated with x radiation produced by energetic electrons in the plasma. Within the past year, neutron and 3H production from 2H-2H (represented hereafter as D-D) reactions has increased significantly on the larger fusion devices. Tritium retention noted in graphite tiles underscores the significance of material selection in present and future 3H-fueled fusion devices. This paper reports on operational health physics radiation measurements made on various PPPL machines over the past 10 y.
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