The FAMU experiment at RIKEN-RAL to study the muon transfer rate from hydrogen to other gases

Abstract

A: The aim of the FAMU (Fisica degli Atomi Muonici) experiment is to realize the first measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen ∆E h f s 1S , by using the RIKEN-RAL intense pulsed muon beam and a high-energy mid-infrared tunable laser. This requires a detailed study of the muon transfer mechanism at different temperatures and hence at different epithermal states of the muonic system. The experimental setup involves a cryogenic pressurized gas target and a detection system based on silicon photomultipliers-fiber beam hodoscopes and high purity Germanium detectors and Cerium doped Lanthanium Bromide crystals, for X-rays detection at energies around 100 keV.Simulation, construction and detector performances of the FAMU apparatus at RAL are reported in this paper.

FAMU: latest results in the measurement of the transfer rate from $mu$p to oxygen

“…The optimal beam momentum for the experiment was chosen to be 57 MeV/c. A more detailed description of the setup is given in reference [12].…”

Large area LaBr3:Ce crystals read by SiPM arrays with improved timing and temperature gain drift control

“…Different schemes may be used for powering the cells of a SiPM array, from parallel ganging, to series ganging or to hybrid ganging, as shown in reference [11]. The standard parallel ganging of SiPMs inside an array provides a good FWHM energy resolution: up to ∼ 3%, comparable to what obtained with a conventional PMT readout [12], but with poor timing properties for larger SiPM arrays (e.g. 1 inch array).…”

Ce:LaBr$_3$ crystals with SiPM array readout and temperature control for the FAMU experiment at RAL

“…Therefore the main X-rays detector system for the experiment was based on 1" circular Ce:LaBr 3 crystals, 1" long, read by UBA Hamamatsu R11265U-200 PMTs with active divider (up to eight arranged in two detachable half crowns). In addition, an R & D was pursued to complement these detectors with crystals equipped with SiPM readout to instrument regions of more difficult access, see reference [7] for further details.…”