First high-statistics and high-resolution recoil-ion data from the WITCH retardation spectrometer

P. Finlay; M. Breitenfeldt; T. Porobić; E. Wursten; G. Ban; M. Beck; C. Couratin; X. Fabian; X. Fléchard; P. Friedag; F. Glück; A. Herlert; A. Knecht; V. Y. Kozlov; E. Liénard; G. Soti; M. Tandecki; E. Traykov; S. Van Gorp; Ch. Weinheimer; D. Zákoucký; N. Severijns

doi:10.1140/epja/i2016-16206-y

2022 Impact factor 2.7

Hadrons and Nuclei

Open Access

Eur. Phys. J. A (2016) 52: 206
https://doi.org/10.1140/epja/i2016-16206-y

Regular Article - Experimental Physics

First high-statistics and high-resolution recoil-ion data from the WITCH retardation spectrometer

P. Finlay¹^*, M. Breitenfeldt¹, T. Porobić¹, E. Wursten¹, G. Ban², M. Beck³, C. Couratin¹, X. Fabian², X. Fléchard², P. Friedag³, F. Glück⁴, A. Herlert⁵, A. Knecht¹^,6, V. Y. Kozlov⁴, E. Liénard², G. Soti¹, M. Tandecki⁷, E. Traykov⁸, S. Van Gorp⁹, Ch. Weinheimer³, D. Zákoucký¹⁰ and N. Severijns¹

¹ Instituut voor Kern-en Stralingsfysica, KU Leuven University, Celestijnenlaan 200D, 3001, Leuven, Belgium
² LPC Caen, Normandie Univ., ENSICAEN, UNICAEN, CNRS/IN2P3, 14000, Caen, France
³ Institut für Kernphysik, Universität Münster, Wilhelm-Klemm-Strasse 9, D-48149, Münster, Germany
⁴ Institut für Kernphysik, Karlsruhe Institute of Technology, Postfach 3640, 76021, Karlsruhe, Germany
⁵ FAIR, Planckstr. 1, 64291, Darmstadt, Germany
⁶ PH Department, CERN, CH-1211, Geneva 23, Switzerland
⁷ TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver BC, Canada
⁸ GANIL, CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076, Caen, France
⁹ Atomic Physics Laboratory, RIKEN, 351-0198, Saitama, Japan
¹⁰ Nuclear Physics Institute, ASCR, 250 68, Rez, Czech Republic

^* e-mail: paul.finlay@kuleuven.be

Received: 3 June 2016
Accepted: 23 June 2016
Published online: 27 July 2016

Abstract

The first high-statistics and high-resolution data set for the integrated recoil-ion energy spectrum following the decay of ³⁵Ar has been collected with the WITCH retardation spectrometer located at CERN-ISOLDE. Over 25 million recoil-ion events were recorded on a large-area multichannel plate (MCP) detector with a time-stamp precision of 2ns and position resolution of 0.1mm due to the newly upgraded data acquisition based on the LPC Caen FASTER protocol. The number of recoil ions was measured for more than 15 different settings of the retardation potential, complemented by dedicated background and half-life measurements. Previously unidentified systematic effects, including an energy-dependent efficiency of the main MCP and a radiation-induced time-dependent background, have been identified and incorporated into the analysis. However, further understanding and treatment of the radiation-induced background requires additional dedicated measurements and remains the current limiting factor in extracting a beta-neutrino angular correlation coefficient for ³⁵Ar decay using the WITCH spectrometer.