Eur. Phys. J. D (2012) 66: 118
https://doi.org/10.1140/epjd/e2012-20674-7

Regular Article

Time of Flight system to investigate positronium cooling

¹ Dipartimento di Fisica, Università di Trento and INFN, Gruppo collegato di Trento, Via Sommarive 14, 38050 Povo, Trento, Italy
² INFN Padova, Via Marzolo 8, 35131 Padova, Italy

^a e-mail: di.noto@science.unitn.it

Received: 23 November 2011
Received in final form: 8 February 2012
Published online: 17 May 2012

Abstract

A positronium Time of Flight (TOF) apparatus, conceived to work with continuous positron beams of intensity up to ~10⁶ positrons/s, was developed. The geometry of the TOF chamber and the acquisition chain are described in detail. The performances of the set up were preliminary tested with a laboratory positron beam of ~5 × 10³ positrons/s by measuring the Time of Flight of Ps emitted from oxidized nanochannels produced in a Si single crystal. A TOF spectrum of ~10⁴ events was collected in 9 days with a time resolution of 8 ns. The analysis of the TOF spectrum is discussed. This apparatus is going to be assembled at the intense positron source NEPOMUC at FRM-II reactor, where the measurement time of each spectrum will be reduced to less than 2 h, making this TOF system appropriate to investigate positronium emission after cooling in porous materials held at cryogenic temperature.