Speaker
Jaakko Henrik Koivuniemi
(Ruhr-Universitaet Bochum (DE))
Description
In the COMPASS Drell-Yan programme a negative hadron beam (97% π − , 2.5% K −
and 0.5% p) with momentum 190 GeV/c is used. The beam intensity reaches up
to 10$^8$ particles/s. The polarizable solid state NH3 target is placed
inside the mixing chamber of a large horizontal helium-3/4 dilution cryostat.
A large acceptance superconducting solenoid magnet with nominal field of 2.5 T
is used to polarize the protons by microwave pumping around electron spin
frequency. Due to the space needed by the hadron absorber the target platform
had to be moved 2.3 m upstream from SIDIS position of run 2011. The upgrade
of the target system and the initial commissioning are discussed.
Primary author
Jaakko Henrik Koivuniemi
(Ruhr-Universitaet Bochum (DE))
