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Author  |
Valencia, E. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Estevez, E.; Jordan, M.D.; Rubio, B. |
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Title |
Total absorption gamma-ray spectroscopy of the beta-delayed neutron emitters Br-87, Br-88, and Rb-94 |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
95 |
Issue |
2 |
Pages |
024320 - 18pp |
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Keywords |
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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 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. |
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Address |
[Valencia, E.; Tain, J. L.; Algora, A.; Agramunt, J.; Estevez, E.; Jordan, M. D.; Rubio, B.] Univ Valencia, CSIC, Inst Fis Corpuscular, Apartado Correos 22085, E-46071 Valencia, Spain, Email: tain@ific.uv.es |
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Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Conference |
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Notes |
WOS:000394662200002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3015 |
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Author |
Tain, J.L.; Algora, A.; Agramunt, J.; Guadilla, V.; Jordan, M.D.; Montaner-Piza, A.; Rubio, B.; Valencia, E.; Cano-Ott, D.; Gelletly, W.; Martinez, T.; Mendoza, E.; Podolyak, Z.; Regan, P.; Simpson, J.; Smith, A.J.; Strachan, J. |
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Title |
A decay total absorption spectrometer for DESPEC at FAIR |
Type |
Journal Article |
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Year |
2015 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
803 |
Issue |
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Pages |
36-46 |
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Keywords |
Total absorption gamma-ray spectrometer; Scintillation detectors; Beta decay; High-energy beam fragmentation facilities |
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Abstract |
This paper presents the design of a total absorption gamma-ray spectrometer for the determination of beta-decay intensity distributions of exotic nuclear species at the focal plane of the FAIR-NUSTAR Super Fragment Separator. The spectrometer is a key instrument in the DESPEC experiment and the proposed implementation follows extensive design studies and prototype tests. Two options were contemplated, based on Nal(TI) and LaBr3:Ce inorganic scintillation crystals respectively. Monte Carlo simulations and technical considerations determined the optimal configurations consisting of sixteen 15 x 15 x 25 cm(3) crystals for the Nal(Tl) option and one hundred and twenty-eight 5.5 x 5.5 x 11 cm(3) crystals for the LaBr3:Ce option. Minimization of dead material was crucial for maximizing the spectrometer full-energy peak efficiency. Module prototypes were build to verify constructional details and characterize their performance. The measured energy and timing resolution was found to agree rather well with estimates based on simulations of scintillation light transport and collection. The neutron sensitivity of the spectrometer, important when measuring beta-delayed neutron emitters, was investigated by means of Monte Carlo simulations. |
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Address |
[Tain, J. L.; Algora, A.; Agramunt, J.; Guadilla, V.; Jordan, M. D.; Montaner-Piza, A.; Rubio, B.; Valencia, E.] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, Spain, Email: tain@ific.uv.es |
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Publisher |
Elsevier Science Bv |
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English |
Summary Language |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000363464600007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2431 |
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Author |
Tain, J.L. et al; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M.D. |
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Title |
Enhanced gamma-Ray Emission from Neutron Unbound States Populated in beta Decay |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
115 |
Issue |
6 |
Pages |
062502 - 5pp |
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Keywords |
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Abstract |
Total absorption spectroscopy is used to investigate the beta-decay intensity to states above the neutron separation energy followed by gamma-ray emission in Br-87,Br-88 and Rb-94. Accurate results are obtained thanks to a careful control of systematic errors. An unexpectedly large. intensity is observed in all three cases extending well beyond the excitation energy region where neutron penetration is hindered by low neutron energy. The gamma branching as a function of excitation energy is compared to Hauser-Feshbach model calculations. For Br-87 and Br-88 the gamma branching reaches 57% and 20%, respectively, and could be explained as a nuclear structure effect. Some of the states populated in the daughter can only decay through the emission of a large orbital angular momentum neutron with a strongly reduced barrier penetrability. In the case of neutron-rich Rb-94 the observed 4.5% branching is much larger than the calculations performed with standard nuclear statistical model parameters, even after proper correction for fluctuation effects on individual transition widths. The difference can be reconciled by introducing an enhancement of 1 order of magnitude in the photon strength to neutron strength ratio. An increase in the photon strength function of such magnitude for very neutron-rich nuclei, if it proves to be correct, leads to a similar increase in the (n, gamma) cross section that would have an impact on r process abundance calculations. |
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Address |
[Tain, J. L.; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M. D.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: tain@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000359059100002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2319 |
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Author |
Tain, J.L. et al; Algora, A.; Estevez, E.; Rubio, B.; Valencia, E.; Jordan, D. |
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Title |
Beta Decay Studies of Neutron Rich Nuclei Using Total Absorption Gamma-ray Spectroscopy and Delayed Neutron Measurements |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of the Korean Physical Society |
Abbreviated Journal |
J. Korean Phys. Soc. |
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Volume |
59 |
Issue |
2 |
Pages |
1499-1502 |
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Keywords |
Beta decay; Delayed neutron emission; Total absorption gamma-ray spectroscopy; Neutron detectors; Nuclear technology; Nuclear astrophysics |
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Abstract |
A complete characterisation of the beta-decay of neutron-rich nuclei can be obtained from the measurement of beta-delayed gamma rays and, whenever the process is energetically possible, beta-delayed neutrons. The accurate determination of the beta-intensity distribution and the beta-delayed neutron emission probability is of great relevance in the fields of reactor technology and nuclear astrophysics. A programme for combined measurements using the total absorption gamma-ray spectroscopy technique and both neutron counters and neutron time-of-flight spectrometers is presented. |
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Address |
[Tain, JL; Algora, A; Estevez, E; Rubio, B; Valencia, E; Jordan, D] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia 46071, Spain, Email: tain@ific.uv.es |
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Publisher |
Korean Physical Soc |
Place of Publication |
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English |
Summary Language |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0374-4884 |
ISBN |
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Area |
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Conference |
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Notes |
WOS:000294080700010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
730 |
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Author |
Rice, S. et al; Algora, A.; Tain, J.L.; Valencia, E.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M.D. |
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Title |
Total absorption spectroscopy study of the beta decay of Br-86 and Rb-91 |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
96 |
Issue |
1 |
Pages |
014320 - 10pp |
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Keywords |
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Abstract |
The beta decays of Br-86 and Rb-91 have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the Ion Guide Isotope Separator On-Line facility in Jyvaskyla and further purified using the JYFLTRAP. Br-86 and Rb-91 are considered to be major contributors to the decay heat in reactors. In addition, Rb-91 was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decaywas well known from high-resolution measurements. Our results show that both decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should be renormalized. The relative impact of the studied decays in the prediction of the decay heat and antineutrino spectrum from reactors has been evaluated. |
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Address |
[Rice, S.; Gelletly, W.; Regan, P. H.; Bowry, M.; Farrelly, G. F.; Mason, P.; Podolyak, Zs.] Univ Surrey, Dept Phys, Guildford GU2 7XH, Surrey, England, Email: algora@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000406526600003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3226 |
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