skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Measurements of neutron capture cross-sections at n{sub T}OF

Abstract

Capture cross-sections on isotopes relevant to accelerator driven systems for energy production and nuclear waste transmutation, and to stellar nucleosynthesis have been studied at the innovative neutron time of flight facility n{sub T}OF at CERN. The extremely high instantaneous neutron flux and the low background conditions in the experimental area make this facility unique for accurate measurements on low-mass or radioactive samples. The n{sub T}OF facility is described, together with the features of the experimental apparata used. First results of the experimental campaign 2002-2004 are presented.

Authors:
; ; ; ;  [1]; ; ;  [2]; ; ; ; ; ; ;  [3]; ; ; ; ;  [4]
  1. INFN, Bari (Italy)
  2. INFN, Trieste (Italy)
  3. CEA/Saclay - DSM (France)
  4. CIEMAT (Spain) (and others)
Publication Date:
OSTI Identifier:
21054827
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 884; Journal Issue: 1; Conference: 6. Latin American symposium on nuclear physics and applications, Iguazu (Argentina), 3-7 Oct 2005; Other Information: DOI: 10.1063/1.2710591; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ACCELERATOR DRIVEN TRANSMUTATION; CAPTURE; CERN; CROSS SECTIONS; NEUTRON FLUX; NEUTRON REACTIONS; NEUTRONS; NUCLEOSYNTHESIS; RADIOACTIVE WASTE DISPOSAL; RADIOACTIVE WASTE PROCESSING; RADIOACTIVE WASTES; TIME-OF-FLIGHT METHOD

Citation Formats

Tagliente, G., Colonna, N., Lorusso, G., Marrone, S., Terlizzi, R., Abbondanno, U., Milazzo, P. M., Moreau, C., Aerts, G., Andriamonje, S., Berthoumieux, E., Gunsing, F., Pancin, J., Perrot, L., Plukis, A., Alvarez-Velarde, F., Cano-Ott, D., Embid-Segura, M., Gonzalez-Romero, E., and Villamarin, D. Measurements of neutron capture cross-sections at n{sub T}OF. United States: N. p., 2007. Web. doi:10.1063/1.2710591.
Tagliente, G., Colonna, N., Lorusso, G., Marrone, S., Terlizzi, R., Abbondanno, U., Milazzo, P. M., Moreau, C., Aerts, G., Andriamonje, S., Berthoumieux, E., Gunsing, F., Pancin, J., Perrot, L., Plukis, A., Alvarez-Velarde, F., Cano-Ott, D., Embid-Segura, M., Gonzalez-Romero, E., & Villamarin, D. Measurements of neutron capture cross-sections at n{sub T}OF. United States. doi:10.1063/1.2710591.
Tagliente, G., Colonna, N., Lorusso, G., Marrone, S., Terlizzi, R., Abbondanno, U., Milazzo, P. M., Moreau, C., Aerts, G., Andriamonje, S., Berthoumieux, E., Gunsing, F., Pancin, J., Perrot, L., Plukis, A., Alvarez-Velarde, F., Cano-Ott, D., Embid-Segura, M., Gonzalez-Romero, E., and Villamarin, D. Mon . "Measurements of neutron capture cross-sections at n{sub T}OF". United States. doi:10.1063/1.2710591.
@article{osti_21054827,
title = {Measurements of neutron capture cross-sections at n{sub T}OF},
author = {Tagliente, G. and Colonna, N. and Lorusso, G. and Marrone, S. and Terlizzi, R. and Abbondanno, U. and Milazzo, P. M. and Moreau, C. and Aerts, G. and Andriamonje, S. and Berthoumieux, E. and Gunsing, F. and Pancin, J. and Perrot, L. and Plukis, A. and Alvarez-Velarde, F. and Cano-Ott, D. and Embid-Segura, M. and Gonzalez-Romero, E. and Villamarin, D.},
abstractNote = {Capture cross-sections on isotopes relevant to accelerator driven systems for energy production and nuclear waste transmutation, and to stellar nucleosynthesis have been studied at the innovative neutron time of flight facility n{sub T}OF at CERN. The extremely high instantaneous neutron flux and the low background conditions in the experimental area make this facility unique for accurate measurements on low-mass or radioactive samples. The n{sub T}OF facility is described, together with the features of the experimental apparata used. First results of the experimental campaign 2002-2004 are presented.},
doi = {10.1063/1.2710591},
journal = {AIP Conference Proceedings},
number = 1,
volume = 884,
place = {United States},
year = {Mon Feb 12 00:00:00 EST 2007},
month = {Mon Feb 12 00:00:00 EST 2007}
}
  • Accurate and reliable neutron-capture cross-section data for actinides are necessary for the proper design, safety regulation, and precise performance assessment of transmutation devices such as Fast Critical Reactors or Accelerator Driven Systems. In particular, the neutron-capture cross sections of 237Np, 240Pu, and 243Am play a key role in the design and optimization of a strategy for the Nuclear Waste Transmutation. The listed cross sections have been measured in 2004 at n{sub T}OF with a high accuracy due to a combination of features unique in the world: high instantaneous neutron fluence and excellent energy resolution of the n{sub T}OF facility, innovativemore » Data Acquisition System based on flash ADCs, and the use of a high-performance BaF2 Total Absorption Calorimeter as a detection device.« less
  • Accurate and reliable neutron capture cross section data for actinides are necessary for the proper design, safety regulation and precise performance assessment of transmutation devices such as Fast Critical Reactors or Accelerator Driven Systems. In particular, the neutron capture cross sections of 237Np, 240Pu and 243Am play a key role in the design and optimization of strategies for the Transmutation of Nuclear Waste. The listed cross sections have been measured in 2004 at n{sub T}OF with a high accuracy due to a combination of features unique in the world: high instantaneous neutron fluence and excellent energy resolution of the n{submore » T}OF facility, innovative Data Acquisition System based on flash ADCs and the use of a high performance BaF2 Total Absorption Calorimeter as a detection device.« less
  • The neutron capture cross sections for Zr isotopes have important implications in nuclear technologies as well in the field of nuclear astrophysics. The innovative features of the n{sub T}OF CERN facility allowed for an accurate determination of the capture cross sections for these isotopes. The preliminary results of the measurements show capture-resonance strengths systematically smaller than in previously available data.
  • Neutron total and capture cross sections of /sup 32/S have been measured up to 1100 keV neutron energy (E/sub exc/(/sup 33/S) =9700 keV). Spin and parity assignments have been made for 28 of the 64 resonances found in this region. Values of total radiation widths, reduced neutron widths, level spacings, and neutron strength functions have been evaluated for s/sub 1/2/, p/sub 1/2/, p/sub 3/2/, and d/sub 5/2/ levels. Single particle contributions using the valency model account for a significant portion of the total radiation width only for the p/sub 1/2/-wave resonances. A significant number of resonances can be identified withmore » reported levels excited in /sup 32/S(d,p) and /sup 29/Si(..cap alpha..,n) reactions. A calculation of the Maxwellian average cross section appropriate to stellar interiors indicates an average capture cross section at 30 keV, sigma-bar approx. = 4.2(2) mb, a result that is relatively insensitive to the assumed stellar temperature. Direct (potential) capture and the s-wave resonance capture contributions to the thermal capture cross section do not fully account for the reported thermal cross section (530 +- 40 mb) and a bound state is invoked to account for the discrepancy.« less
  • The precise determination of the neutron capture cross sections of {sup 186}Os and {sup 187}Os is important to define the s-process abundance of {sup 187}Os at the formation of the solar system. This quantity can be used to evaluate the radiogenic component of the abundance of {sup 187}Os due to the decay of the unstable {sup 187}Re (t{sub 1/2}=41.2 Gyr) and from this to infer the time duration of the nucleosynthesis in our galaxy (Re/Os cosmochronometer). The neutron capture cross sections of {sup 186}Os, {sup 187}Os, and {sup 188}Os have been measured at the CERN n{sub T}OF facility from 1more » eV to 1 MeV, covering the entire energy range of astrophysical interest. The measurement has been performed by time-of-flight technique using isotopically enriched samples and two C{sub 6}D{sub 6} scintillation detectors for recording the prompt gamma rays emitted in the capture events. Maxwellian averaged capture cross sections have been determined for thermal energies between kT=5 and 100 keV corresponding to all possible s-process scenarios. The estimated uncertainties for the values at 30 keV are 4.1, 3.3, and 4.7% for {sup 186}Os, {sup 187}Os, and {sup 188}Os, respectively.« less