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Title: EMISSION OF PROMPT GAMMA RAYS IN THERMAL NEUTRON FISSION OF U-235

Abstract

The angular distrubutions of prompt fission gamma rays with respect to the direction of selected fission fragments in the thermal neutron fission of U/ sup 235/, were studied for two different gamma energy groups using a gridded ionization chamber-scintillation detector assembly. The ionization chamber measured the fragment kinetic energies and the angles of their tracks with respect to the flight direction of the gamma rays detected by a plastic scintillator placed along the electric field direction of the chamber. A timeof- flight method was used to eliminate fission neutron background. From the measured angular distributions with respect to the direction of the selected light fragments, the laboratory anisotropies {N(0 deg ) -- N(90 deg )}/N(0 deg ) for gamma energies >180 and 510 kev were found to be 14.9% and 12.2%, respectively. For the ratio of the intensities of the gamma rays of energies?180 kev along the direction of the selected light and heavy fragments, a value of (0.985 plus or minus 0.024) was obtained, showing that the laboratory anisotropies with respect to the light and heavy fragments are nearly the same. These measurements definitely show the existence of a significant anisotropy of gamma emission in the emitting fragment systemmore » after making allowance for the motion of the fragments. The emission anisotropy is explained as arising due to the polarized angular momenta of the fission fragments, which also enhances the gamma ray emission. The gamma emission from the rotating fragments is discussed with respect to the observed number and the spectrum of the gamma rays. (auth)« less

Authors:
;
Publication Date:
Research Org.:
India. Atomic Energy Establishment, Trombay
OSTI Identifier:
4162325
Report Number(s):
AEET/NP/7
NSA Number:
NSA-18-001000
Resource Type:
Technical Report
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-64
Country of Publication:
Country unknown/Code not available
Language:
English
Subject:
PHYSICS; ANGULAR DISTRIBUTION; ANGULAR MOMENTUM; ANISOTROPY; BACKGROUND; ELECTRIC FIELDS; EMISSION; ENERGY RANGE; FISSION; FISSION PRODUCTS; GAMMA RADIATION; IONIZATION CHAMBERS; KEV RANGE; MEASURED VALUES; MOMENTUM; MOTION; PARTICLE TRACKS; POLARIZATION; ROTATION; SCINTILLATION COUNTERS; SPECTRA; THERMAL NEUTRONS; URANIUM 235; VELOCITY

Citation Formats

Kapoor, S S, and Ramanna, R. EMISSION OF PROMPT GAMMA RAYS IN THERMAL NEUTRON FISSION OF U-235. Country unknown/Code not available: N. p., 1963. Web.
Kapoor, S S, & Ramanna, R. EMISSION OF PROMPT GAMMA RAYS IN THERMAL NEUTRON FISSION OF U-235. Country unknown/Code not available.
Kapoor, S S, and Ramanna, R. 1963. "EMISSION OF PROMPT GAMMA RAYS IN THERMAL NEUTRON FISSION OF U-235". Country unknown/Code not available.
@article{osti_4162325,
title = {EMISSION OF PROMPT GAMMA RAYS IN THERMAL NEUTRON FISSION OF U-235},
author = {Kapoor, S S and Ramanna, R},
abstractNote = {The angular distrubutions of prompt fission gamma rays with respect to the direction of selected fission fragments in the thermal neutron fission of U/ sup 235/, were studied for two different gamma energy groups using a gridded ionization chamber-scintillation detector assembly. The ionization chamber measured the fragment kinetic energies and the angles of their tracks with respect to the flight direction of the gamma rays detected by a plastic scintillator placed along the electric field direction of the chamber. A timeof- flight method was used to eliminate fission neutron background. From the measured angular distributions with respect to the direction of the selected light fragments, the laboratory anisotropies {N(0 deg ) -- N(90 deg )}/N(0 deg ) for gamma energies >180 and 510 kev were found to be 14.9% and 12.2%, respectively. For the ratio of the intensities of the gamma rays of energies?180 kev along the direction of the selected light and heavy fragments, a value of (0.985 plus or minus 0.024) was obtained, showing that the laboratory anisotropies with respect to the light and heavy fragments are nearly the same. These measurements definitely show the existence of a significant anisotropy of gamma emission in the emitting fragment system after making allowance for the motion of the fragments. The emission anisotropy is explained as arising due to the polarized angular momenta of the fission fragments, which also enhances the gamma ray emission. The gamma emission from the rotating fragments is discussed with respect to the observed number and the spectrum of the gamma rays. (auth)},
doi = {},
url = {https://www.osti.gov/biblio/4162325}, journal = {},
number = ,
volume = ,
place = {Country unknown/Code not available},
year = {Tue Jan 01 00:00:00 EST 1963},
month = {Tue Jan 01 00:00:00 EST 1963}
}

Technical Report:
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