4 research outputs found
Total Absorption Spectroscopy Study of Rb 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 makes the dominant contribution to the
reactor spectrum in the 5-8 MeV range but its decay properties are in question.
We have studied Rb 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.Comment: 6 pages, 3 figure
Total Absorption Spectroscopy of Fission Fragments Relevant for Reactor Antineutrino Spectra and Decay Heat Calculations
Volume: 111 Host publication title: WONDER-2015 Host publication sub-title: 4TH INTERNATIONAL WORKSHOP ON NUCLEAR DATA EVALUATION FOR REACTOR APPLICATIONS Isbn(print): 978-2-7598-1970-6Beta decay of fission products is at the origin of decay heat and antineutrino emission in nuclear reactors. Decay heat represents about 7% of the reactor power during operation and strongly impacts reactor safety. Reactor antineutrino detection is used in several fundamental neutrino physics experiments and it can also be used for reactor monitoring and non-proliferation purposes. Rb-92,Rb-93 are two fission products of importance in reactor antineutrino spectra and decay heat, but their beta-decay properties are not well known. New measurements of Rb-92,Rb-93 beta-decay properties have been performed at the IGISOL facility (Jyvaskyla, Finland) using Total Absorption Spectroscopy (TAS). TAS is complementary to techniques based on Germanium detectors. It implies the use of a calorimeter to measure the total gamma intensity de-exciting each level in the daughter nucleus providing a direct measurement of the beta feeding. In these proceedings we present preliminary results for Rb-93, our measured beta feedings for Rb-92 and we show the impact of these results on reactor antineutrino spectra and decay heat calculations.Peer reviewe
Level structure of 221Ac and 217Fr from decay spectroscopy, and reflection asymmetry in 221Ac
225Pa and 221Ac were produced at the IGISOL facility through proton-induced fusion-evaporation reactions and have been studied using α-particle spectroscopy, as well as αâÎł and α-electron coincidence spectroscopy. The level scheme of 221Ac, daughter of 225Pa, and of 217Fr, daughter of 221Ac were reconstructed. An interpretation of 221Ac levels as K=5/2± and K=3/2± parity-doublet bands is proposed. Such bands appear in reflection-asymmetric models and would be an indication of a static reflection asymmetric shape for 221Ac.peerReviewe
Total Absorption Spectroscopy of Fission Fragments Relevant for Reactor Antineutrino Spectra and Decay Heat Calculations
Beta decay of fission products is at the origin of decay heat and antineutrino
emission in nuclear reactors. Decay heat represents about 7% of the reactor power during
operation and strongly impacts reactor safety. Reactor antineutrino detection is used
in several fundamental neutrino physics experiments and it can also be used for reactor
monitoring and non-proliferation purposes. 92,93Rb are two fission products of importance
in reactor antineutrino spectra and decay heat, but their ÎČ-decay properties are not well
known. New measurements of 92,93Rb ÎČ-decay properties have been performed at the
IGISOL facility (JyvÀskylÀ, Finland) using Total Absorption Spectroscopy (TAS). TAS
is complementary to techniques based on Germanium detectors. It implies the use of a
calorimeter to measure the total gamma intensity de-exciting each level in the daughter
nucleus providing a direct measurement of the beta feeding. In these proceedings we
present preliminary results for 93Rb, our measured beta feedings for 92Rb and we show
the impact of these results on reactor antineutrino spectra and decay heat calculations.peerReviewe