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Title: FISSION SPECTRUM

Abstract

Measurements of the spectrum of the fission neutrons of 25 are described, in which the energy of the neutrons is determined from the ionization produced by individual hydrogen recoils. The slow neutrons producing fission are obtained by slowing down the fast neutrons from the Be-D reaction of the Stanford cyclotron. In order to distinguish between fission neutrons and the remaining fast cyclotron neutrons both the cyclotron current and the pusle amplifier are modulated. A hollow neutron container, in which slow neutrons have a lifetime of about 2 milliseconds, avoids the use of large distances. This method results in much higher intensities than the usual modulation arrangement. The results show a continuous distribution of neutrons with a rather wide maximum at about 0.8 MV falling off to half of its maximum value at 2.0 MV. The total number of netrons is determined by comparison with the number of fission fragments. The result seems to indicate that only about 30% of the neutrons have energies below .8 MV. Various tests are described which were performed in order to rule out modification of the spectrum by inelastic scattering.

Authors:
;
Publication Date:
Research Org.:
Los Alamos National Laboratory (LANL), Los Alamos, NM
Sponsoring Org.:
US Atomic Energy Commission
OSTI Identifier:
4408656
Report Number(s):
AECD-3158; LADC-934
NSA Number:
NSA-05-004245
Resource Type:
Technical Report
Resource Relation:
Other Information: Decl. May 4, 1951
Country of Publication:
United States
Language:
English
Subject:
PHYSICS; BERYLLIUM; CYCLOTRONS; DEUTERON BEAMS; EFFICIENCY; ENERGY; FAST NEUTRONS; FISSION; FISSION PRODUCTS; INSTRUMENTS; IONIZATION; IRRADIATION; MEASURED VALUES; NEUTRONS; NUCLEAR REACTIONS; PROTONS; RECOILS; SCATTERING; SLOWDOWN; SPECTRA; TESTING; THERMAL NEUTRONS; URANIUM 235; VARIATIONS

Citation Formats

Bloch, F., and Staub, H.. FISSION SPECTRUM. United States: N. p., 1943. Web. doi:10.2172/4408656.
Bloch, F., & Staub, H.. FISSION SPECTRUM. United States. doi:10.2172/4408656.
Bloch, F., and Staub, H.. Wed . "FISSION SPECTRUM". United States. doi:10.2172/4408656. https://www.osti.gov/servlets/purl/4408656.
@article{osti_4408656,
title = {FISSION SPECTRUM},
author = {Bloch, F. and Staub, H.},
abstractNote = {Measurements of the spectrum of the fission neutrons of 25 are described, in which the energy of the neutrons is determined from the ionization produced by individual hydrogen recoils. The slow neutrons producing fission are obtained by slowing down the fast neutrons from the Be-D reaction of the Stanford cyclotron. In order to distinguish between fission neutrons and the remaining fast cyclotron neutrons both the cyclotron current and the pusle amplifier are modulated. A hollow neutron container, in which slow neutrons have a lifetime of about 2 milliseconds, avoids the use of large distances. This method results in much higher intensities than the usual modulation arrangement. The results show a continuous distribution of neutrons with a rather wide maximum at about 0.8 MV falling off to half of its maximum value at 2.0 MV. The total number of netrons is determined by comparison with the number of fission fragments. The result seems to indicate that only about 30% of the neutrons have energies below .8 MV. Various tests are described which were performed in order to rule out modification of the spectrum by inelastic scattering.},
doi = {10.2172/4408656},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Aug 18 00:00:00 EDT 1943},
month = {Wed Aug 18 00:00:00 EDT 1943}
}

Technical Report:

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