The β-decay of ⁷¹Kr: Precise measurement of the half-life

¹ Instituto de Fisica Corpuscular, CSIC-Universitat de Valéncia, E-46071 Valéncia, Spain
² Institute for Nuclear Research (Atomki), H-4026 Debrecen, Hungary
³ University of Debrecen, Doctoral School of Physics, H-4032 Debrecen, Egyetem tér 1, Hungary
⁴ RIKEN – Nishina Center, Wako, Saitama 351-0198, Japan
⁵ Instituto de Estructura de la Materia, IEM-CSIC, E-28006 Madrid, Spain
⁶ Grand Accélérateur National d Ions Lourds, B.P. 55027, F-14076 Caen Cedex 05, France
⁷ Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Legnaro I-35020, Italy
⁸ Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova I-35131, Italy
⁹ Dipartimento di Fisica dell Universitá degli Studi di Padova, Padova I-35131, Italy
¹⁰ Eötvös Loránd University, Institute of Physics, H-1053 Budapest, Hungary
¹¹ Faculty of Physics, VNU Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam
¹² Centre d Etudes Nucléaires de Bordeaux-Gradignan, UMR 5797 Université de Bordeaux CNRS/IN2P3, Gradignan Cedex, France
¹³ Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
¹⁴ Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047, Japan
¹⁵ Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan
¹⁶ CEFNEN, Comisión Chilena de Energía Nuclear, Nueva Bilbao, 12501, Las Condes, Santiago, Chile
¹⁷ Institute of Nuclear Physics, University of Cologne, D-50937 Cologne, Germany
¹⁸ Physik Department E12, Technische Universität München, D-85748 Garching, Germany
¹⁹ National Institute for Physics and Nuclear Engineering IFIN-HH, P.O. Box MG-6, Bucharest-Magurele, Romania
²⁰ Department of Physics, Istanbul University, Istanbul 34134, Turkey
²¹ Department of Natural Sciences, Tokyo City University, Setagaya-ku, Tokyo 158-8557, Japan
²² Department of Physics, Tokyo University of Science, Noda, Chiba 278-8510, Japan
²³ IRFU/DPhN, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
²⁴ >Department of Physics, University of York, Heslington, York YO 10 5DD, United Kingdom
²⁵ Department of Physics, University of Hong Kong, Pokfulam, Hong Kong
²⁶ GSI, Planckstrasse 1, D-64291 Darmstadt, Germany
²⁷ Millennium Institute for Subatomic Physics at High Energy Frontier - SAPHIR

^* e-mail: algora@ific.uv.es
^** e-mail: ggkiss@atomki.hu

Published online: 8 December 2023

Abstract

The very proton-rich ⁷¹Kr isotope was produced through the in-flight fragmentation of ⁷⁸Kr on a beryllium target at RIKEN – Nishina Center in order to study its β-decay properties. A stack of double-sided silicon strip detectors, called WAS3ABi, was used as the decay station, where the detection of ion implants, β-decays and β-delayed protons took place. Beta-delayed γ-rays were measured using a system of 84 HPGe detectors, called EURICA, surrounding the decay station. The main goal of the present study was the precise measurement of the half-life of ⁷¹Kr, as in the literature there is an almost 10 σ difference between the most precise independent results. Implant–β time correlations, implant–proton time correlations and implant–β–γ time correlations were all used to derive the half-life value, followed by a thorough investigation of systematic uncertainties for each method. As these values were found to be consistent, the weighted average t_1/2 = 94.40⁺¹⁹ms is reported as a new half-life value in this work. Furthermore a total of 26 previously unreported γ following the β-decay of ⁷¹Kr were also identified in the analysis.