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

Finlay, Paul; Breitenfeldt, Martin; Porobic, Tomica; Wursten, Elise; Ban, G; Beck, M; Couratin, C; Fabian, X; Flechard, X; Friedag, P; Gluck, F; Herlert, A; Knecht, A; Kozlov, VY; Lienard, E; Soti, Gergely; Tandecki, M; Traykov, E; Van Gorp, S; Weinheimer, C; Zakoucky, D; Severijns, Nathal

doi:10.1140/epja/i2016-16206-y

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

Author:

Finlay, Paul

Breitenfeldt, Martin ; Porobic, Tomica ; Wursten, Elise ; Ban, G ; Beck, M ; Couratin, C ; Fabian, X ; Flechard, X ; Friedag, P ; Gluck, F ; Herlert, A ; Knecht, A ; Kozlov, VY ; Lienard, E ; Soti, Gergely ; Tandecki, M ; Traykov, E ; Van Gorp, S ; Weinheimer, C ; Zakoucky, D ; Severijns, Nathal

Keywords:

beta decay, weak interaction, retardation spectrometer, Penning trap, WITCH, beta-neutrino correlation, Science & Technology, Physical Sciences, Physics, Nuclear, Physics, Particles & Fields, Physics, ELECTRON, NUCLEAR, PHYSICS, TESTS, MASS, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, 5106 Nuclear and plasma physics, 5107 Particle and high energy physics, 5110 Synchrotrons and accelerators

Abstract:

The first high-statistics and high-resolution data set for the integrated recoil-ion energy spectrum following the β+ 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 micro-channel plate (MCP) detector with a time-stamp precision of 2 ns 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.