Anomalous 96Zr resonance integral to thermal activation cross-section ratio and the neutron activation resonance integral of 94Zr and 96Zr

1970 ◽  
Vol 48 (20) ◽  
pp. 2362-2370 ◽  
Author(s):  
M. D. Ricabarra ◽  
R. Turjanski ◽  
G. H. Ricabarra
Keyword(s):  
Cross Section ◽  
Mass Region ◽  
Resonance Integral ◽  
Activation Cross Section ◽  
Energy Agency ◽  
Order Of Magnitude ◽  
Gamma Sources ◽  
Strength Functions ◽  
Thermal Cross Section ◽  
Reduced Activity

Values of the reduced activity resonance integral relative to the thermal cross section, I′/σ0, of 96Zr and 94Zr were determined relative to gold by measuring cadmium ratios in a reactor spectrum.Due to the anomalous characteristics of 96Zr a measurement of I′/σ0 for 96Zr was undertaken in a "quasi" thermal spectrum.96Zr and 94Zr activation resonance integrals were also determined by measuring the ratio of effective activation cross section of zirconium to 55Mn. International Atomic Energy Agency (IAEA) calibrated gamma sources were used to determine the samples' absolute activities. A lithium-drifted germanium γ-ray spectrometer was used in all cases to resolve the activities of the irradiated samples.The results for 96Zr are I′/σ0 = 879 ± 96, I′ = 4.97 ± 0.50 b, and σ0 = 5.7 ± 10 mb; for 94Zr I′/σ0 = 5.87 ± 0.05, I′ = 0.369 ± 0.037 b, and derived σ0 = 63 ± 8 mb.I′/σ0 for 96Zr is an order of magnitude or more greater than that found for stable isotopes. This suggests that almost 100% of the activation resonance integral of 96Zr consists of p-neutron captures. This fact is not consistent with the present knowledge of p-strength functions in the 90 < A < 130 mass region.

THE RATIO OF THE RESONANCE INTEGRAL TO THE THERMAL NEUTRON CROSS SECTION FOR Sm152

1961 ◽  
Vol 39 (8) ◽  
pp. 1184-1192 ◽  
Author(s):  
W. H. Walker ◽  
R. E. Green
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Neutron Cross Section ◽  
Resonance Integral ◽  
Half Maximum ◽  
Thin Foils ◽  
Flight Measurement ◽  
Thermal Neutron Cross Section ◽  
Thermal Cross Section ◽  
Made In

Cadmium ratio measurements have been made in similar lattice positions in ZEEP with thin foils of Sm152 and gold. From a comparison of these cadmium ratios we find[Formula: see text]If gσ0 is assumed to be 212 ± 12 barns, then I′ = 3100 ± 200 barns. On the assumption that only one resonance in Sm152, at 8 ev, contributes appreciably to both the resonance integral and the thermal cross section, it follows that g = 1 and that Γ, the width at half-maximum of the total cross section resonance, is 193 ± 5 milli-ev. Because of the appreciable disagreement between this value and one reported earlier, a new time-of-flight measurement of the resonance parameters has been made, and it is reported in the next paper (Chrien 1961).

Neutron activation resonance integrals of 74Se, 78Se, 80Se, 81Br, 127I, 130Te, 138Ba, 140Ce, and 142Ce

1968 ◽  
Vol 46 (22) ◽  
pp. 2473-2483 ◽  
Author(s):  
M. D. Ricabarra ◽  
R. Turjanski ◽  
G. H. Ricabarra ◽  
C. B. Bigham
Keyword(s):  
Neutron Activation ◽  
Cross Section ◽  
Thermal Activation ◽  
Resonance Integral ◽  
Secondary Standard ◽  
Activation Cross Section ◽  
Neutron Spectra ◽  
Relative Activation ◽  
Γ Ray ◽  
Activation Rates

A lithium-drift germanium γ-ray spectrometer has been used to make accurate intercomparisons of the ratio of resonance-integral to thermal-activation cross section by measuring cadmium ratios or relative activation rates in two different neutron spectra. The standard, gold, or secondary standard, indium, was mixed uniformly in the samples and the activities resolved with the spectrometer. Expressed as Westcott s0 values, the results relative to s0 = 17.7 for gold were as follows: 74Se = 10.3 ± 0.1, 78Se = 12.3 ± 0.3, 80Se = 2.65 ± 0.02, 81Br = 24.3 ± 0.5, 127I = 27.8 ± 0.5, 130Te = 2.10 ± 0.07, 138Ba = 0.649 ± 0.004, 140Ce = 0.476 ± 0.003, 142Ce = 0.865 ± 0.005.

Measurement and Evaluation of the Activation Resonance Integral of 146Nd, 148Nd, and 150Nd

1973 ◽  
Vol 51 (13) ◽  
pp. 1454-1462 ◽  
Author(s):  
M. D. Ricabarra ◽  
R. Turjanski ◽  
G. H. Ricabarra
Keyword(s):  
Cross Section ◽  
Gamma Ray ◽  
Resonance Integral ◽  
Correction Factors ◽  
Gamma Ray Spectrometer ◽  
Spectral Correction ◽  
Reactor Spectrum ◽  
Measurement And Evaluation ◽  
Thermal Cross Section ◽  
Integral Data

Values of the ratio of the reduced activition resonance integral to the thermal cross section, I′/σ0, of 146Nd, 148Nd, and 150Nd were determined relative to gold by measuring cadmium ratios. A lithium-drifted germanium gamma-ray spectrometer was used to resolve the activities of the irradiated samples. The results are: for 146Nd I′/σ0 = 1.42 ± 0.10 and with an assumed σ0 = 1.4 b, I′ = 1.99 ± 0.20 b; for 148Nd I′/σ0 = 4.22 ± 0.14 and with an assumed σ0 = 2.5 b, I′ = 10.5 ± 0.9 b; and for 150Nd I′/σ0 = 13.7 ± 0.8 and with an assumed σ0 = 1.2 b, I′ = 16.4 ± 2.8 b.The resolved and unresolved epithermal integrals of 146Nd, 148Nd, and 150Nd were calculated. Values of the spectral correction factor were also calculated, so the resonance integral could be obtained from the epithermal integral data measured in our reactor spectrum in this experiment. Epithermal integral and spectral correction factors are listed in the text.The most important result of this investigation is that the 148Nd activation reduced resonance integral is about half of the previously recommended value and consequently the radiative width for 148Nd is also about half of the previously accepted value.

scholarly journals Cross-section measurements of the 94Mo(γ,n) and 90Zr(γ,n) reactions using real photons at the HIγS facility

2018 ◽  
Vol 178 ◽  
pp. 03007
Author(s):  
Adriana Banu ◽  
Jack Silano ◽  
Hugon Karwowski ◽  
Evan Meekins ◽  
Megha Bhike ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
National Laboratory ◽  
Mass Region ◽  
Reaction Cross ◽  
Photon Beams ◽  
Los Alamos National Laboratory ◽  
Section Measurement ◽  
Strength Functions ◽  
Reaction Cross Sections

The photodisintegration reaction cross-sections for 94Mo(γ,n) and 90Zr(γ,n) have been experimentally investigated with quasi-monochromatic photon beams at the High Intensity γ-Ray Source (HIγS) facility, Triangle University Nuclear Laboratory (TUNL). The measurements were focused primarily on studying the energy dependence of the photoneutron cross sections, which is the most direct way of testing statistical models, and were performed close to the respective neutron thresholds and above up to ~ 20 MeV. Neutrons from the (γ,n) reactions were detected using a 4π assembly of 3He proportional counters developed at Los Alamos National Laboratory and presently available at TUNL. While the 94Mo(γ,n) cross section measurement aims to contribute to a broader investigation for understanding the γ-process (the mechanism responsible for the nucleosynthesis of the so-called p-nuclei), the information from the 90Zr(γ,n) data is relevant to constrain QRPA calculations of γ-ray strength functions in this mass region. In this contribution, we will present our preliminary results of the total (γ,n) excitation functions for the two photoneutron reactions on 94Mo and 90Zr.

MEASUREMENT OF RADIATIVE CAPTURE RESONANCE INTEGRALS IN A THERMAL REACTOR SPECTRUM, AND THE THERMAL CROSS SECTION OF Pu-240

1960 ◽  
Vol 38 (1) ◽  
pp. 57-77 ◽  
Author(s):  
W. H. Walker ◽  
C. H. Westcott ◽  
T. K. Alexander
Keyword(s):  
Cross Section ◽  
Neutron Beam ◽  
Cross Sections ◽  
Radiative Capture ◽  
Effective Cross Section ◽  
Mean Value ◽  
Resonance Integral ◽  
Thermal Reactor ◽  
Thermal Cross Section ◽  
Radiative Neutron Capture

An apparatus is described which detects γ-rays emitted by a thin target placed in a well-denned neutron beam. It has been used to determine the Cd ratios of Au and Pu-240, from which the ratio of the resonance integral to the 2200 m/s cross section for radiative neutron capture in Pu-240 has been deduced, using Au as a reference standard. Using this ratio and previously measured values of the resonance integral of Pu-240 and its effective cross section in two positions in the NRX reactor, three separate estimates of the 2200 m/s cross section of Pu-240 have been made. The mean value is 270 ± 17 barns.In an auxiliary experiment to indicate the shape of the epithermal spectrum of the neutron beam, the activation Cd ratios of Mn and In were compared with that of Au. These results, combined with the known 2200 m/s capture cross sections of these nuclides, yield new values of the radiative capture resonance integrals for both Mn and In.

scholarly journals Thermal Cross Section And Resonance Integral Measurements Of57Co(n,γ)58Co Reaction

2002 ◽  
Vol 39 (sup2) ◽  
pp. 441-443 ◽  
Author(s):  
Nora Lía Maidana ◽  
Vito Roberto Vanin ◽  
Paulo Regmaldo Pascholati ◽  
Mauro da Silva Dias ◽  
Marina Fallone Koskinas
Keyword(s):  
Cross Section ◽  
Resonance Integral ◽  
Thermal Cross Section
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