Measurement of keV-Neutron Capture Cross Sections and Capture Gamma-Ray Spectra of 140Ce and 141Pr.

The neutron capture cross section of praseodymium ( 141 Pr) has been measured relative to the 10 B(n, αγ ) standard cross section in the energy region from 0.003 eV to 140 keV by the neutron time-of-flight (TOF) method with a 46-MeV electron linear accelerator (linac) of the Research Reactor Institute, Kyoto University (KURRI). An assembly of Bi 4 Ge 3 O 12 (BGO) scintillators was used for the capture cross section measurement. In addition, the thermal neutron cross section (2,200 m/s value) of the 141 Pr(n, γ ) 142 Pr reaction has been also measured by an activation method at the heavy water thermal neutron facility of the Kyoto University Reactor (KUR). The thermal neutron flux was monitored with the 197 Au(n, γ ) 198 Au standard cross section. The above TOF measurement has been normalized to the current activation data (11.6±1.3 b) at 0.0253 eV.The evaluated data in JENDL-3.3, ENDF/B-VI, and JEF-2.2 have been in general agreement with the current result, except that the JENDL-3.3 and the JEF-2.2 values are clearly lower than the measurement in the cross section minimum region from about 10 to 500 eV.

Section: Resultssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Neutron Capture Cross Section Measurement of Praseodymium in the Energy Region from 0.003 eV to 140 keV

Yoon

Lee

Yamamoto

et al. 2003

“…The multiplicities of 209 Bi are much smaller than those of lanthanoids. [18][19][20][21] Moreover, the reduced multiplicities are not constant, i.e. depending on the incident neutron energies, in contrast to those of lanthanoids.…”

Section: Resultsmentioning

confidence: 99%

Measurement of keV-Neutron Capture Cross Sections and Capture Gamma-Ray Spectra of²⁰⁹Bi

Saito

Igashira

Kawakami

et al. 2004

Self Cite

The capture cross sections and capture -ray spectra of 209 Bi were measured in a neutron energy region from 5 to 80 keV and at 520 keV, using pulsed keV neutrons from the 7 Li(p; n) 7 Be reaction and a time-of-flight method. The capture rays from a bismuth or standard gold sample were detected with a large anti-Compton NaI(Tl) spectrometer. The capture yield of the bismuth or gold sample was obtained by applying a pulse-height weighting technique to the corresponding capture -ray pulse-height spectrum. The derived capture cross sections from 5 to 80 keV were in good agreement with recent measurements, but that at 520 keV was about half of previous measurements. This large discrepancy at 520 keV was ascribed to the incorrect background-subtraction in the previous measurements from a comparison between the present and previous capture -ray spectra. Strong transitions from the capture states to low lying states of 210 Bi were observed in the present -ray spectra. The multiplicities of observed rays were obtained from the -ray spectra.

“…The representative example is the anomalous bump shown in the experiments of the capture gamma-ray spectra. [7][8][9][10][11][12][13] According to a theoretical analysis and experiments, the bump could be considered to have the electric or magnetic properties of decaying gamma similar to the giant electric or magnetic resonances. So far, the bump has not been regarded as an essential nuclear property because it does not…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Neutron Capture Gamma-ray Spectra for⁸⁹Y,⁹³Nb,¹²⁷I,¹³³Cs,¹⁴¹Pr,¹⁹⁷Au,^natTl, and²⁰⁹Bi

Kim

Lee

2007

The neutron capture gamma-ray spectra for 8 nuclides, 89 Y, 93 Nb, 127 I, 133 Cs, 141 Pr, 197 Au, nat Tl, and 209 Bi, were calculated by using the Hauser-Feshbach statistical model, and their results were compared with the available experimental data. Two dominant ingredients to perform the statistical calculation were the level densities described by the Gilbert-Cameron approach with an improved systematics, and the gamma-ray transmission coefficients described by gamma-ray strength functions. Although various gamma-ray strength functions with a Lorentzian formula have been developed by using the photonuclear data or a microscopic analysis, they have failed to reproduce the occasional anomalous bumps observed near or below a neutron binding. In this work, we could reproduce the bumps well by adding a Lorentzian with an energy-temperature dependent width into a giant electric dipole resonance with an enhanced generalized Lorentzian. In addition, we introduced a correction function so as to compensate for the shortcomings due to missing levels or level-cuts.