Beta-strength and anti-neutrino spectra from total absorption spectroscopy of a decay chain 142Cs→142Ba→142La

M Wolińska-Cichocka ,E A Mccutchan ,Aleksandra Fijał Kowska ,K C Goetz ,C D Nesaraja ,N T Brewer ,B C Rasco ,A A Sonzogni ,S Go ,D W Stracener ,M Karny ,C J Gross ,J A Winger ,T T King ,R Grzywacz ,Y Xiao ,C J Zachary ,K P Rykaczewski ,Enhong Wang ,E F Zganjar

doi:10.1051/epjconf/201714610005

Abstract

Beta decays of mass A = 142 isobaric chain starting from 142 Cs have been investigated by means of Modular Total Absorption Spectrometer (MTAS) and on-line mass separation at Oak Ridge National Laboratory. The beta strength distribution derived for 142 Cs decay from MTAS spectra is showing significant differences in β-feeding pattern when compared to the values listed at nuclear databases. MTAS results are shifting the associated anti-neutrino energy spectrum towards lower energies. A decay pattern deduced for 142 Ba is similar to earlier reported results.

Highlights

The Modular Total Absorption Spectrometer (MTAS) array has been designed, constructed, characterized and applied to the decay studies of 238 U fission products at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory [1,2,3]
The significant differences between β-feeding values derived from MTAS measurement and Evaluated Nuclear Structure Data Files (ENSDF) database are substantially impacting the reference reactor antineutrino flux and its spectral properties, see, e.g., [8]
In this paper we present MTAS results on measured 142Cs and 142Ba activities compared to GEANT4 simulations using currently available ENSDF entries [12]

Summary

Introduction

The Modular Total Absorption Spectrometer (MTAS) array has been designed, constructed, characterized and applied to the decay studies of 238 U fission products at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory [1,2,3]. Over seventy decay products of 238 U fission products measured at ORNL include 22 decays of high priority for decay heat analysis [4]. These measurements include the 142Cs activity assessed recently as the third most important contributor to the high energy vspectra in nuclear reactors [5,6,7]. The significant differences between β-feeding values derived from MTAS measurement and Evaluated Nuclear Structure Data Files (ENSDF) database are substantially impacting the reference reactor antineutrino flux and its spectral properties, see, e.g., [8]

The modular total absorption spectrometer

MTAS measurement and ENSDF database comparison

Decay of 142 Ba

High energy part of reactor anti-neutrino spectrum for 142Cs

Findings

Summary