Total Absorption Spectroscopy Study of Rb-92 Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape

The antineutrino spectra measured in recent experiments at reactors are inconsistent with calculations based on the conversion of integral beta spectra recorded at the ILL reactor. Rb-92 makes the dominant contribution to the reactor antineutrino spectrum in the 5-8 MeV range but its decay properties are in question. We have studied Rb-92 decay with total absorption spectroscopy. Previously unobserved beta feeding was seen in the 4.5-5.5 region and the GS to GS feeding was found to be 87.5(25)%. The impact on the reactor antineutrino spectra calculated with the summation method is shown and discussed

Observation of low- and high-energy gamow-teller phonon excitations in nuclei

Y. Fujita et al. ; 5 pags. ; 3 figs. PACS numbers: 24.30.Cz, 25.55.Kr, 27.40.+zGamow-Teller (GT) transitions in atomic nuclei are sensitive to both nuclear shell structure and effective residual interactions. The nuclear GT excitations were studied for the mass number A=42, 46, 50, and 54 >f-shell> nuclei in (He3, t) charge-exchange reactions. In the Ca42→Sc42 reaction, most of the GT strength is concentrated in the lowest excited state at 0.6 MeV, suggesting the existence of a low-energy GT phonon excitation. As A increases, a high-energy GT phonon excitation develops in the 6-11 MeV region. In the Fe54→Co54 reaction, the high-energy GT phonon excitation mainly carries the GT strength. The existence of these two GT phonon excitations are attributed to the 2 fermionic degrees of freedom in nuclei. © 2014 American Physical Society.This work was in part supported by MEXT, Japan (Grants No. 13002001, No. 15540274, and No. 18540270); MICINN, Spain (Grant No. FPA200806419-C02-01). Y. F. and B. R. acknowledge the support of the Japan-Spain collaboration program by JSPS and CSIC.Peer Reviewe

High-resolution study of Gamow-Teller excitations in the Ca42(He3,t)Sc42 reaction and the observation of a “low-energy super-Gamow-Teller state”

Y. Fujita et al.; 15 pags.; 6 figs.; 7 tabs.; PACS number(s): 21.10.Hw, 25.55.Kr, 27.40.+z, 25.40.Ep© 2015 American Physical Society. To study the Gamow-Teller (GT) transitions from the Tz=+1 nucleus Ca42 to the Tz=0 nucleus Sc42, where Tz is the z component of isospin T, we performed a (p,n)-type (He3,t) charge-exchange reaction at 140 MeV/nucleon and scattering angles around 0. With an energy resolution of 29 keV, states excited by GT transitions (GT states) could be studied accurately. The reduced GT transition strengths B(GT) were derived up to the excitation energy of 13 MeV, assuming the proportionality between the cross sections at 0 and B(GT) values. The main part of the observed GT transition strength is concentrated in the lowest 0.611-MeV, Jπ=1+ GT state. All the other states at higher energies are weakly excited. Shell-model calculations could reproduce the gross feature of the experimental B(GT) distribution, and random-phase-approximation calculations including an attractive isoscalar interaction showed that the 0.611-MeV state has a collective nature. It was found that this state has all of the properties of a >low-energy super-Gamow-Teller state.> It is expected that low-lying Jπ=1+ GT states have T=0 in the Tz=0 nucleus Sc42. However, T=1 states are situated in a higher energy region. Assuming an isospin-analogous structure in A=42 isobars, analogous T=1, 1+ states are also expected in Ca42. Comparing the Ca42(He3,t)Sc42 and Ca42(p,p′) spectra measured at 0, candidates for T=1 GT states could be found in the 10-12-MeV region of Sc42. They were all weakly excited. The mass dependence of the GT strength distributions in Sc isotopes is also discussed.Y.F. also acknowledges the support of MEXT, Japan under Grants No. 18540270, No. 22540310, and No. 15K05104. Y.F. and B.R. are grateful for the support of the Japan-Spain collaboration program by JSPS and CSIC; A.A., E.E.A., and B.R. are thankful for the support of Spanish Ministry under Grants No. FPA2005-03993, No. FPA2008-06419-C02-01, and No. FPA2011-24553. G.S. acknowledges the support of TUBITAK, Turkey under Research Scholarship No. BIDEB 2214. J.M.D., C.J.G., R.M., G.P., and R.G.T.Z. are grateful for the support of the US NSF under Grants No. PHY-0606007 and No. PHY-0822648 (JINA). M.C., J.G., and A.K. acknowledge the support of the OTKA Foundation, Hungary, under Grant No. K106035. This work was in part supported by the RIKENCNS joint research project on large-scale nuclear-structure calculations.Peer Reviewe

βDelayed γRay spectroscopy of heavy neutron rich nuclei “south” of lead

Relativistic projectile fragmentation of a 208Pb primary beam has been used to produce neutron-rich nuclei with proton-holes relative to the Z = 82 shell closure, i.e., “south” of Pb. βDelayed γRay spectroscopy allows to investigate the structural properties of such nuclei with A ~ 195 → 205. The current work presents transitions de-exciting excited states in 204Au, which are the first spectroscopic information on this N = 125 isotone.Agramunt Ros, Jorge, [email protected] ; Algora, Alejandro, [email protected] ; Molina Palacios, Francisco Manuel, [email protected] ; Rubio Barroso, Berta, [email protected]

β-Delayed and isomer spectroscopy of neutron-rich Ta and W isotopes

Decays of neutron-rich A ~ 190 nuclei have been studied following projectile fragmentation of a 208Pb beam on a 9Be target at the GSI Fragment Separator. Gamma-ray decays from previously reported isomeric states in 188Ta, 190W and 192, 193Re were used as internal calibrations for the particle identification analysis, together with the identification of previously unreported isomeric decays in 189Ta and 191W. The current work also identifies β-delayed γ rays following the decay of 188Ta to 188W for the first time.Algora, Alejandro, [email protected] ; Molina Palacios, Francisco Manuel, [email protected]; Rubio Barroso, Berta, [email protected]

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

TAS measurements for neutrino physics and nuclear structure: study of the beta decays of 150Er, 152,156Yb and 188,190,192Pb

211 páginas. Tesis Doctoral del Departamento de Física Atómica, Molecular y Nuclear, de la Universidad de Valencia, y del Instituto de Física Corpuscular (IFIC). Fecha de lectura: 4 junio 2012.En este trabajo se presentaron medidas realizadas con la técnica de espectroscopía de absorción total o TAS (Total Absorption Spectroscopy), y se discutó el análisis de la desintegración beta de seis núcleos diferentes, relevante para dos aplicaciones. El objetivo de este trabajo era obtener la intensidad beta a los niveles de interés poblados en la desintegración. En la aplicación a la física de neutrinos, se presentaron las medidas de los núcleos 152Y b, 150Er y 156Y b realizadas con la técnica TAS, ya que estos núcleos podrían ser utilizados en la producción de haces de neutrinos en instalaciones de haces beta y/o instalaciones de haces de captura electrónica (Parte II). La determinación precisa de las intensidades beta tiene aquí un interés práctico, ya que está relacionada con la distribución de energía de los neutrinos producidos. Esta aplicación también es importante para la estructura nuclear, ya que confirma la probabilidad beta a estados en núcleos en los cuales se espera que la fuerza de Gamow-Teller (GT) se encuentre dentro de la ventana de energía disponible Q. En la segunda aplicación, se presentaron las medidas realizadas con la técnica TAS de los núcleos 192Pb, 190Pb y 188Pb (Parte III). En este caso, la forma del núcleo padre se dedujo a partir del perfil de la fuerza beta experimental en el núcleo hijo comparándola con el resultado de cálculos teóricos.Este proyecto ha recibido apoyo de: MEC FPA 2002-04181-004-03, FPA 2005-03993, FPA 2008-02878, FPA2008-06419-C02-01 y PROMETEO 2008/004. Apoyo parcial: Ramón y Cajal y contrato Marie Curie RTN-MRTNCT-2006-035505.Peer reviewe

Isomeric states observed in heavy neutron-rich nuclei populated in the fragmentation of a (208)Pb beam

Heavy neutron-rich nuclei were populated via the fragmentation of a E/A = 1 GeV (208)(82)Pb beam. Secondary fragments were separated and identified and subsequently implanted in a passive stopper. By the detection of delayed gamma rays, isomeric decays associated with these nuclei have been identified. A total of 49 isomers were detected, with the majority of them observed for the first time. The newly discovered isomers are in (204,205)(80)Hg, (201,202,204,205)(79)Au, (197,203,204)(78)Pt, (195,199-203)(77)Ir, (193,197-199)(76)Os, (196)(75)Re, (190,191)(74)W, and (189)(73)Ta. Possible level schemes are constructed and the structure of the nuclei discussed. To aid the interpretation, shell-model as well as BCS calculations were performed. ©2011 American Physical SocietyThis work is supported by the EPSRC (UK) and AWE plc. (UK), the EU Access to Large Scale Facilities Programme (EURONS, EU Contract No. 506065), The Swedish Research Council, The Polish Ministry of Science and Higher Education, The Bulgarian Science Fund, The US Department of Energy (Grant No. DE-FG02-91ER-40609), The Spanish Ministerio de Ciencia e Innovacion under Contract No. FPA2009- 13377-C02-02, The German BMBF, The Hungarian Science Foundation, and the Italian INFN.Peer Reviewe

Decay of the N=126, 213Fr nucleus

Pragati et al. ; 8 págs.; 9 figs.; 2 tabs. ; Open Access funded by Creative Commons Atribution Licence 3.0γ rays following the EC/β+ and α decay of the N = 126, Fr213 nucleus have been observed at the CERN isotope separator on-line (ISOLDE) facility with the help of γ-ray and conversion-electron spectroscopy. These γ rays establish several hitherto unknown excited states in Rn213. Also, five new α-decay branches from the Fr213 ground state have been discovered. Shell model calculations have been performed to understand the newly observed states in Rn213. Published by the American Physical SocietyFinancial support from the European Union Sixth Framework through RII3-EURONS Contract No. 506065, the UK STFC, the Spanish MINECO through Grants No. FPA2005-03993, No. FPA2013-41267-P, No. FPA2014-52823-C2-1-P, and No. FPA2015-65035-P, and the Centro de Excelencia Severo Ochoa del IFIC SEV-2014-0398 Projects is gratefully acknowledged. Pragati acknowledges financial support from the Ministry of Human Resource Development, Government of India.Peer Reviewe

Total Absortion Spectroscopy of Fission Fragments Relevant for Reactor Antineutrino Spectra Determination

8 pags., 3 figs., 1 tab. ; Presented at the XXXIV Mazurian Lakes Conference on Physics, Piaski, Poland, September 6–13, 2015.The contribution of each fission fragment to the reactor antineutrino spectra was determined using the summation method based on the existing information on fission yields and decay data contained in nuclear databases and the reactor evolution code MURE. The beta decay of some of the main contributors has been studied using the Total Absorption Spectroscopy (TAS) technique during two experimental campaigns at the IGISOL facility, in Jyväskylä (Finland). Results on the decay of 92Rb, the most important contributor in the 4–8 MeV energy region are reported. The status of the analysis of the second experiment is presented as well.Peer Reviewe