Construction of the experimental set-up for ultra slow muon generation by thermal Mu ionization method at RIKEN-RAL

At KEK-MSL we have been pursuing the Ultra Slow Muon Project, in which ther mal muonium atoms (designated as Mu; consisting of a mu(+) and an e(-)) are generated from the surface of a hot tungsten foil, placed at the primary 5 00 MeV proton beam line and ionized by intense lasers synchronized with the emission of Mn. However, because of the high radiation in the primary prot on beam line where the present set-up is installed, a slow muon generation started not from a primary proton beam but with much higher intense surface muons is seriously required, in order to understand slow muon generation m ore deeply and to obtain more intense slow muons. Therefore, we are plannin g to perform a slow muon generation using intense surface muons, taking the advantage of the intensity of the proton beam at ISIS of 200 mu A being ab out 40 times as large as that of KEK-MSL. In this report, we are presenting a new set-up, a slow beam optics and a laser system operated at 25 Hz prep ared for the generation of ultra slow muons at the RIKEN-RAL muon facility. (C) 2000 Elsevier Science B.V. All rights reserved.