THE THERMAL NEUTRON CAPTURE CROSS SECTION AND THE RESONANCE ABSORPTION INTEGRAL OF Th230 (IONIUM)

1958 ◽  
Vol 36 (8) ◽  
pp. 989-996 ◽  
Author(s):  
M. J. Cabell
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Neutron Capture ◽  
Half Life ◽  
Capture Cross Section ◽  
Resonance Absorption ◽  
Thermal Neutron Capture ◽  
Resonance Capture ◽  
Capture Cross ◽  
Neutron Capture Cross Section

The thermal neutron capture cross section and the resonance capture integral of Th230 have been determined by an activation method. Assumptions are made that the thermal capture cross section and the resonance capture integral of Co59 are 36.5 barns and 48.6 barns respectively, that the half-life of Th230 is 8.00 × 104 years, and that Th230 behaves as a 1/v absorber in the subcadmium region. Based on these assumptions values of σ2200 = 21.4 ± 0.3 barns and of 937 ± 32 barns for the resonance absorption integral (from 0.5 ev to ∞) have been obtained for Th230.The half-life of Th231 has been determined as 25.52 ± 0.01 hours.

THERMAL NEUTRON CAPTURE CROSS-SECTION OF Na23 AND Mn55

1953 ◽  
Vol 31 (3) ◽  
pp. 204-206 ◽  
Author(s):  
Rosalie M. Bartholomew ◽  
R. C. Hawkings ◽  
W. F. Merritt ◽  
L. Yaffe
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Cross Sections ◽  
Neutron Capture ◽  
Half Life ◽  
Capture Cross Section ◽  
Thermal Neutron Capture ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Capture Cross Sections

The thermal neutron capture cross sections of Na23 and Mn55 have been determined using the activation method. The values are 0.53 ± 0.03 and 12.7 ± 0.3 barns respectively with respect to σAul97 = 93 barns. These agree well with recent pile oscillator results. The half-life for Mn56 is found to be 2.576 ± 0.002 hr.

THE THERMAL NEUTRON CAPTURE CROSS SECTION OF AU198 AND THE HALF-LIFE OF AU199

1955 ◽  
Vol 33 (8) ◽  
pp. 457-465 ◽  
Author(s):  
R. E. Bell ◽  
R. L. Graham ◽  
L. Yaffe
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Neutron Capture ◽  
Half Life ◽  
Capture Cross Section ◽  
Neutron Cross Section ◽  
Thermal Neutron Capture ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Thermal Neutron Cross Section

The thermal neutron capture cross section of radioactive Au198 has been measured by the activation method as 26,000 ± 1200 barns, assuming 99 barns for the thermal neutron cross section of Au197. Metallic Au197 was bombarded in fluxes up to 9 × 1013 thermal neutrons cm.−2 sec.−1 to produce a mixture of Au198 and Au199 by the successive neutron capture reactions Au197(n, γ)Au198(n, γ)Au199. The ratio of the Au199 activity to Au198 activity so produced yields σc(Au197). In a preliminary experiment, the half-life of Au199 was measured as 3.148 ± 0.010 days.

THE PURIFICATION, DETERMINATION, AND NEUTRON CAPTURE CROSS SECTION OF ACTINIUM-227

1959 ◽  
Vol 37 (6) ◽  
pp. 1094-1103 ◽  
Author(s):  
M. J. Cabell
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
Exchange Chromatography ◽  
Thermal Neutron Capture ◽  
Resonance Capture ◽  
Capture Cross ◽  
Neutron Capture Cross Section

Procedures are described for (a) the separation by ion exchange chromatography of submicrogram quantities of Ac227 from its daughters and (b) the absolute determination of Ac227 by measurement of the rate of growth of α-particle emission from an initially pure source. These procedures are utilized in the determination of the reactor and thermal neutron capture cross sections and the resonance capture integral of Ac227 by an activation method.Assuming 36.5 barns for the thermal neutron capture cross section of Co59, a value of σ2200 = 814 ± 13 barns has been obtained for Ac227. The resonance capture integral (from 0.5 ev to ∞) was found to be 1177 ± 19 barns relative to 48.6 barns for the resonance capture integral of Co59.

EFFECTIVE AND THERMAL NEUTRON CAPTURE CROSS SECTION AND RESONANCE CAPTURE INTEGRAL OF Pr-143

1959 ◽  
Vol 37 (8) ◽  
pp. 907-915 ◽  
Author(s):  
J. C. Roy ◽  
L. P. Roy
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
Thermal Neutron Capture ◽  
Resonance Capture ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
Cross Section Formula ◽  
Effective Neutron

The effective neutron capture cross section,[Formula: see text]; the 2200 meters/sec neutron capture cross section, σ0, and the resonance capture integral, RI, of Pr-143 have been measured by an activation method. The values are: [Formula: see text], σ0 = 89 ± 10, and RI = 190 ± 25 barns respectively. The neutron fluxes have been measured with cobalt monitors. All these values have been calculated according to the Westcott convention, which has been outlined insofar as it can be applied to activation work.

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