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A Study of the Energy Dependence of the Th 232 Capture Cross Section in the Energy Region 0.1 to 3.4 eV

Abstract

Using the fast chopper at the Stockholm reactor R1 a comparison between the (n, {gamma}) cross sections for thorium and copper has been made in the energy interval 0.1 to 3.4 eV. The (n, {gamma}) cross section for copper follows the 1/v law sufficiently well in this energy interval to be used as a 1/v standard. The deviation at 3.4 eV does not exceed 5 %. The capture cross section, {sigma}, for thorium decreases more rapidly than 1/v and the deviation is found to be close to 60 % at 3.4 eV. If one assumes that the deviation is caused essentially by a single negative resonance this should be located at 5.1 {+-} 0.5 eV. Furthermore, if a value of 24 meV for {gamma}{sub {gamma}}, the radiation width for the negative resonance, is used one finds that {gamma}{sub n}{sup 0}, the reduced neutron width for the same resonance, amounts to 1.82 {+-} 0.25 meV. Using these parameters together with the resonance parameters for the positive resonances a value of the total microscopic scattering cross section at 0.025 eV has been calculated as 12.2 {+-} 0.4 b. A value of the contributions above 0.5 eV to the resonance integral from the  More>>
Authors:
Publication Date:
Nov 15, 1967
Product Type:
Technical Report
Report Number:
AE-304
Resource Relation:
Other Information: 9 refs., 6 figs., 1 tab.
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; THORIUM 232; CAPTURE; NEUTRON REACTIONS; EV RANGE 01-10; ENERGY DEPENDENCE; RESONANCE ABSORPTION; CROSS SECTIONS
OSTI ID:
20956292
Research Organizations:
AB Atomenergi, Nykoeping (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
TRN: SE0708726
Availability:
Commercial reproduction prohibited; OSTI as DE20956292
Submitting Site:
SWDN
Size:
30 pages
Announcement Date:
Dec 31, 2007

Citation Formats

Lundgren, G. A Study of the Energy Dependence of the Th 232 Capture Cross Section in the Energy Region 0.1 to 3.4 eV. Sweden: N. p., 1967. Web.
Lundgren, G. A Study of the Energy Dependence of the Th 232 Capture Cross Section in the Energy Region 0.1 to 3.4 eV. Sweden.
Lundgren, G. 1967. "A Study of the Energy Dependence of the Th 232 Capture Cross Section in the Energy Region 0.1 to 3.4 eV." Sweden.
@misc{etde_20956292,
title = {A Study of the Energy Dependence of the Th 232 Capture Cross Section in the Energy Region 0.1 to 3.4 eV}
author = {Lundgren, G}
abstractNote = {Using the fast chopper at the Stockholm reactor R1 a comparison between the (n, {gamma}) cross sections for thorium and copper has been made in the energy interval 0.1 to 3.4 eV. The (n, {gamma}) cross section for copper follows the 1/v law sufficiently well in this energy interval to be used as a 1/v standard. The deviation at 3.4 eV does not exceed 5 %. The capture cross section, {sigma}, for thorium decreases more rapidly than 1/v and the deviation is found to be close to 60 % at 3.4 eV. If one assumes that the deviation is caused essentially by a single negative resonance this should be located at 5.1 {+-} 0.5 eV. Furthermore, if a value of 24 meV for {gamma}{sub {gamma}}, the radiation width for the negative resonance, is used one finds that {gamma}{sub n}{sup 0}, the reduced neutron width for the same resonance, amounts to 1.82 {+-} 0.25 meV. Using these parameters together with the resonance parameters for the positive resonances a value of the total microscopic scattering cross section at 0.025 eV has been calculated as 12.2 {+-} 0.4 b. A value of the contributions above 0.5 eV to the resonance integral from the 'tail' of the negative resonance and the 1/v - parts of the positive resonances has also been calculated giving the result 1.6 b. Finally, the g-factor (Westcott's nomenclature) for a Maxwellian spectrum at 20 deg C becomes 0.994.}
place = {Sweden}
year = {1967}
month = {Nov}
}