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Title: Total absorption γ -ray spectroscopy of the β -delayed neutron emitters Br 87 , Br 88 , and Rb 94

Abstract

We investigate the decay of Br-87,Br-88 and Rb-94 using total absorption gamma-ray spectroscopy. These important fission products are beta-delayed neutron emitters. Our data show considerable beta gamma intensity, so far unobserved in high-resolution gamma-ray spectroscopy, from states at high excitation energy. We also find significant differences with the beta intensity that can be deduced from existing measurements of the beta spectrum. We evaluate the impact of the present data on reactor decay heat using summation calculations. Although the effect is relatively small it helps to reduce the discrepancy between calculations and integral measurements of the photon component for U-235 fission at cooling times in the range 1-100 s. We also use summation calculations to evaluate the impact of present data on reactor antineutrino spectra. We find a significant effect at antineutrino energies in the range of 5 to 9 MeV. In addition, we observe an unexpected strong probability for. emission from neutron unbound states populated in the daughter nucleus. The. branching is compared to Hauser-Feshbach calculations, which allow one to explain the large value for bromine isotopes as due to nuclear structure. However the branching for Rb-94, although much smaller, hints of the need to increase the radiative width gammamore » by one order of magnitude. This increase in gamma would lead to a similar increase in the calculated (n, gamma) cross section for this very neutron-rich nucleus with a potential impact on r process abundance calculations.« less

Authors:
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Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Nuclear Physics; Spanish Ministerio de Economia y Competitividad (MINECO); University of Valencia; Academy of Finland - Centre of Excellence
OSTI Identifier:
1376891
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review C; Journal Volume: 95; Journal Issue: 2
Country of Publication:
United States
Language:
English

Citation Formats

Valencia, E., Tain, J. L., Algora, A., Agramunt, J., Estevez, E., Jordan, M. D., Rubio, B., Rice, S., Regan, P., Gelletly, W., Podolyák, Z., Bowry, M., Mason, P., Farrelly, G. F., Zakari-Issoufou, A., Fallot, M., Porta, A., Bui, V. M., Rissanen, J., Eronen, T., Moore, I., Penttilä, H., Äystö, J., Elomaa, V. -V., Hakala, J., Jokinen, A., Kolhinen, V. S., Reponen, M., Sonnenschein, V., Cano-Ott, D., Garcia, A. R., Martínez, T., Mendoza, E., Caballero-Folch, R., Gomez-Hornillos, B., Gorlichev, V., Kondev, F. G., Sonzogni, A. A., and Batist, L. Total absorption γ -ray spectroscopy of the β -delayed neutron emitters Br87 , Br88 , and Rb94. United States: N. p., 2017. Web. doi:10.1103/PhysRevC.95.024320.
Valencia, E., Tain, J. L., Algora, A., Agramunt, J., Estevez, E., Jordan, M. D., Rubio, B., Rice, S., Regan, P., Gelletly, W., Podolyák, Z., Bowry, M., Mason, P., Farrelly, G. F., Zakari-Issoufou, A., Fallot, M., Porta, A., Bui, V. M., Rissanen, J., Eronen, T., Moore, I., Penttilä, H., Äystö, J., Elomaa, V. -V., Hakala, J., Jokinen, A., Kolhinen, V. S., Reponen, M., Sonnenschein, V., Cano-Ott, D., Garcia, A. R., Martínez, T., Mendoza, E., Caballero-Folch, R., Gomez-Hornillos, B., Gorlichev, V., Kondev, F. G., Sonzogni, A. A., & Batist, L. Total absorption γ -ray spectroscopy of the β -delayed neutron emitters Br87 , Br88 , and Rb94. United States. doi:10.1103/PhysRevC.95.024320.
Valencia, E., Tain, J. L., Algora, A., Agramunt, J., Estevez, E., Jordan, M. D., Rubio, B., Rice, S., Regan, P., Gelletly, W., Podolyák, Z., Bowry, M., Mason, P., Farrelly, G. F., Zakari-Issoufou, A., Fallot, M., Porta, A., Bui, V. M., Rissanen, J., Eronen, T., Moore, I., Penttilä, H., Äystö, J., Elomaa, V. -V., Hakala, J., Jokinen, A., Kolhinen, V. S., Reponen, M., Sonnenschein, V., Cano-Ott, D., Garcia, A. R., Martínez, T., Mendoza, E., Caballero-Folch, R., Gomez-Hornillos, B., Gorlichev, V., Kondev, F. G., Sonzogni, A. A., and Batist, L. Wed . "Total absorption γ -ray spectroscopy of the β -delayed neutron emitters Br87 , Br88 , and Rb94". United States. doi:10.1103/PhysRevC.95.024320.
@article{osti_1376891,
title = {Total absorption γ -ray spectroscopy of the β -delayed neutron emitters Br87 , Br88 , and Rb94},
author = {Valencia, E. and Tain, J. L. and Algora, A. and Agramunt, J. and Estevez, E. and Jordan, M. D. and Rubio, B. and Rice, S. and Regan, P. and Gelletly, W. and Podolyák, Z. and Bowry, M. and Mason, P. and Farrelly, G. F. and Zakari-Issoufou, A. and Fallot, M. and Porta, A. and Bui, V. M. and Rissanen, J. and Eronen, T. and Moore, I. and Penttilä, H. and Äystö, J. and Elomaa, V. -V. and Hakala, J. and Jokinen, A. and Kolhinen, V. S. and Reponen, M. and Sonnenschein, V. and Cano-Ott, D. and Garcia, A. R. and Martínez, T. and Mendoza, E. and Caballero-Folch, R. and Gomez-Hornillos, B. and Gorlichev, V. and Kondev, F. G. and Sonzogni, A. A. and Batist, L.},
abstractNote = {We investigate the decay of Br-87,Br-88 and Rb-94 using total absorption gamma-ray spectroscopy. These important fission products are beta-delayed neutron emitters. Our data show considerable beta gamma intensity, so far unobserved in high-resolution gamma-ray spectroscopy, from states at high excitation energy. We also find significant differences with the beta intensity that can be deduced from existing measurements of the beta spectrum. We evaluate the impact of the present data on reactor decay heat using summation calculations. Although the effect is relatively small it helps to reduce the discrepancy between calculations and integral measurements of the photon component for U-235 fission at cooling times in the range 1-100 s. We also use summation calculations to evaluate the impact of present data on reactor antineutrino spectra. We find a significant effect at antineutrino energies in the range of 5 to 9 MeV. In addition, we observe an unexpected strong probability for. emission from neutron unbound states populated in the daughter nucleus. The. branching is compared to Hauser-Feshbach calculations, which allow one to explain the large value for bromine isotopes as due to nuclear structure. However the branching for Rb-94, although much smaller, hints of the need to increase the radiative width gamma by one order of magnitude. This increase in gamma would lead to a similar increase in the calculated (n, gamma) cross section for this very neutron-rich nucleus with a potential impact on r process abundance calculations.},
doi = {10.1103/PhysRevC.95.024320},
journal = {Physical Review C},
number = 2,
volume = 95,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2017},
month = {Wed Feb 01 00:00:00 EST 2017}
}