Techniques have been developed in the frame of the CONRAD Nuclear data analysis code in order to take into account the multiple scattering correction for capture yields. The resonance shape analysis of these capture data have to account for these corrections during the fitting procedure. Analytical formulae and Monte Carlo simulations can be performed through Multiple-Scattering-Correction module in the CONRAD code in order to estimate the differential and total capture yields. Monte Carlo method accounts for usual biasing techniques (implicite capture and Russian roulette). This experimental correction procedure is checked against other codes like REFIT and SAMMY which are extensively used for cylindrical sample analysis. In this work, xenon spherical samples have been studied. Capture and transmission measurements of gaseous samples have been performed at the GELINA facility of the Institute for Reference Materials and Measurements (IRMM) by P. Mutti, F. Corvi and A. Brusegan. For the capture measurements, spherical samples with diameter of 8cm were used. Due to the spherical shape of the sample, equivalent cylinder (h ≈ 5.33cm) was taken into account in SAMMY or REFIT analysis (spherical model is not implemented in these codes). These results are compared with analysis involving multiple scattering correction for spherical targets available in CONRAD.

A series of neutron-capture cross-section measurements on various krypton isotopes has been performed at the Geel Electron Linear Accelerator (GELINA). The total cross section of Kr-84 and the capture cross section of Kr-86 and Kr-82 have been measured in the energy range from 0 up to 400 keV. Moreover, capture cross-section data for Kr-80 and Kr-83 have been obtained for a limited energy range, namely from 0 up to 5 keV, from a natural krypton sample. The main goal of the measurement campaign was to provide reliable nuclear data for s-process nucleosynthesis calculation. We performed a series of calculations for stars with mass from M = 1.5M(circle dot) to M = 3M(circle dot) and metallicity from solar down to 1/6 of solar with the aim to reproduce the krypton isotopic ratios found in silicon-carbide grains.

High-resolution neutron capture cross-section measurements on Ni-60 have been performed at the Geel Linear Accelerator in the energy range from 1 to 450 keV. An experimentally determined weighting function, obtained by a total energy detection set-up, has been applied to the measured capture spectra. The parameters of 275 resonances have been determined in a recent reanalysis using the FANAC R-matrix shape fitting code. Accurate values of the maxwellian-averaged capture cross section for stellar temperatures ranging from kT = 5 to 100 keV, corresponding to different scenarios of s-process stellar nucleosynthesis, have been calculated. The distributions of partial radiative widths for s- and p-wave resonances have been derived. A correlation of 0.64 between capture and reduced neutron widths is compatible with the presence of nonstatistical effects in the capture of 60Ni. (C) 2002 Elsevier Science B.V. All rights reserved.

In this paper neutron resonance capture analysis (NRCA) is explored as a new method to analyse the elemental composition of materials and objects using a pulsed beam of epithermal neutrons and a time-of-flight system to recognize resonances of isotopes in the energy range from about 1 to 10 keV. Some test experiments have been carried out with bronze artefacts. Advantages, as compared to instrumental neutron activation analysis (INAA), are the low activation of the objects and the direct availability of results after the measurement.

The Science and Culture Series — Advanced Scientific CultureHadrons, Nuclei and Applications, pp. 372-375 (2001) No AccessTHE STELLAR NEUTRON CAPTURE RATE OF 208PBH. BEER, W. ROCHOW, P. MUTTI, F. CORVI, K.-L. KRATZ, and B. PFEIFFERH. BEERForschungszentrum Karlsruhe, Institut für Kernphysik, P. O. Box 3640, D–76021 Karlsruhe, Germany, W. ROCHOWPhysikalisches Institut, Universität Tübingen, Auf der Morgenstelle 14, D–72076 Tübingen, Germany, P. MUTTICEC, JRC, Institute for Reference Materials and Measurements, Retieseweg, B–2440 Geel, Belgium, F. CORVICEC, JRC, Institute for Reference Materials and Measurements, Retieseweg, B–2440 Geel, Belgium, K.-L. KRATZInstitut für Kernchemie, Universität Mainz, Fritz-Strassmann- Weg 2, D-55099 Mainz, Germany, and B. PFEIFFERInstitut für Kernchemie, Universität Mainz, Fritz-Strassmann- Weg 2, D-55099 Mainz, Germanyhttps://doi.org/10.1142/9789812810922_0070Cited by:1 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: The Maxwellian average neutron capture (MAC) cross section of 208Pb has been reinvestigated. With the activation technique the MAC cross section was measured at a thermonuclear energy of kT=52 keV. The termination of the s–process has been analyzed. Independent calculations of s– and r–process yield a consistent decomposition for the the Pb and Bi isotopic s– and r–contributions. FiguresReferencesRelatedDetailsCited By 1Cited by lists all citing articles based on Crossref citation.THE END OF NUCLEOSYNTHESIS: PRODUCTION OF LEAD AND THORIUM IN THE EARLY GALAXYIan U. Roederer, Karl-Ludwig Kratz, Anna Frebel, Norbert Christlieb and Bernd Pfeiffer et al.5 June 2009 | The Astrophysical Journal, Vol. 698, No. 2 Recommended Hadrons, Nuclei and ApplicationsMetrics History PDF download

The neutron capture cross section of Tc-99 has been measured from 3 eV to 90 keV at the pulsed white neutron source GELINA at Geel using the time-of-flight method. The Tc-99(n,gamma) reaction was detected at a flight path of 28.32 m with two C6D6 total energy gamma-ray detectors using a pulse height weighting method. From these data the Maxwellian-averaged neutron capture cross section has been calculated at several temperatures between 5 and 100 keV.

This paper gives a brief overview of Parity violation effects at neutron p-wave resonances observed by the TRIPLE collaboration at Los Alamos together with some information about neutron resonance capture gamma spectroscopy experiments carried out by the Geel collaboration in relation to these parity violation experiments.

Recent results from measurements performed at the GELINA and Rez reactor facilities in the neutron resonance and thermal energy regions with targets of Ag-107,Ag-109 and In-115 are presented. These measurements are of interest for parity violation and photon strength function studies.

Parity nonconservation (PNC) was studied in p-wave resonances in indium by measuring the helicity dependence of the neutron total cross section in the neutron energy range 6.0-316 eV with the time-of-flight method at LANSCE. A total of 36 p-wave neutron resonances were studied in {sup 115}In, and statistically significant asymmetries were observed for nine cases. An analysis treating the PNC matrix elements as random variables yields a weak matrix element of M=(0.67{sub -0.12}{sup +0.16}) meV and a weak spreading width of {gamma}{sub w}=(1.30{sub -0.43}{sup +0.76})x10{sup -7} eV. (c) 2000 The American Physical Society.

Measurements of prompt gamma rays, following neutron capture in Ag-107 and Ag-109 have been performed at the GELINA facility in the resonance energy region up to about 1 keV. From the intensities of low- and high energy gamma rays the spins of 53 Ag-107 and 78 Ag-109 s- and p-wave resonances have been assigned. These spectroscopic quantities are important for the interpretation of data from parity violation experiments performed by the TRIPLE Collaboration. The intensities of low-energy transitions showed a dependence not only on the spin of the resonance but also on its parity. This effect allows the assignment of the parity of the resonances and may open new perspectives in the study of the gamma decay of the compound nucleus.

The Krypton isotopes lie in one of the most sensitive, complicated and, therefore, interesting region of the s-process nucleosynthesis. This mass region, in fact, receives substantial contribution from both the weak and the main component of the s-process. In addition to that, the branching in the s-process path at 85Kr can deliver important information on the neutron flux. The total cross section of 84Kr and the capture cross section of 86Kr have been measured and the MAC cross sections calculated with the aim to reduce the uncertainties in the s-process models due to nuclear parameters.

Parity nonconservation (PNC) was studied in {ital p}-wave resonances in Ag by measuring the helicity dependence of the neutron total cross section. Transmission measurements on natural Ag were performed in the energy range 32 to 422 eV with the time-of-flight method at the Manuel Lujan Neutron Scattering Center at Los Alamos National Laboratory. A total of 15 {ital p}-wave neutron resonances were studied in {sup 107}Ag and nine {ital p}-wave resonances in {sup 109}Ag. Statistically significant asymmetries were observed for eight resonances in {sup 107}Ag and for four resonances in {sup 109}Ag. An analysis treating the PNC matrix elements as random variables yields a weak spreading width of {Gamma}{sub w}=(2.67{sub {minus}1.21}{sup +2.65}){times}10{sup {minus}7} eV for {sup 107}Ag and {Gamma}{sub w}=(1.30{sub {minus}0.74}{sup +2.49}){times}10{sup {minus}7} eV for {sup 109}Ag. thinsp {copyright} {ital 1999} {ital The American Physical Society}

Parity nonconservation (PNC) was studied in p-wave resonances in Ag by measuring the helicity dependence of the neutron total cross section. Transmission measurements on natural Ag were performed in the energy range 32 to 422 eV with the time-of-flight method at the Manuel Lujan Neutron Scattering Center at Los Alamos National Laboratory. A total of 15 p-wave neutron resonances were studied in Ag-107 and nine p-wave resonances in Ag-109. Statistically significant asymmetries were observed for eight resonances in Ag-107 and for four resonances in Ag-109. An analysis treating the PNC matrix elements as random variables yields a weak spreading width of Gamma(w) =(2.67(-1.21)(+2.65))X10(-7) eV for Ag-107 and Gamma(w)=(1.30(-0.74)(+2.49))X10(-7)eV for Ag-109. [S0556-2813(99)03102-7].