Speaker
Description
The Compressed Baryonic Matter (CBM) experiment at the future FAIR complex will investigate the phase diagram of strongly interacting matter at high baryon density and moderate temperatures in A+A collisions from 2-11 AGeV at the SIS 100 accelerator setup.
One of the key detector components foreseen to cope with the CBM physics program is the RICH detector, providing efficient and clean electron identification and pion suppression (up to 8 GeV/c momentum). It will be made of a CO2 gaseous radiator, Multi-Anode Photo-Multipliers for photon detection and about 80 trapezoidal glass mirror tiles, equally distributed in two half-spheres and used as focusing elements with spectral reflectivity down to the UV range. In CBM the RICH detector and a muon detector system (MuCh) will be exchanged on a (bi-)yearly basis. This requires to carefully design a stable mirror system which also allows (bi-)yearly crane operations.
To guarantee a rigid and stable mirror system of the RICH detector even if being craned in and out of the measuring position, a mirror supporting frame reinforced with channel bars and mounting scheme were designed. To reduce the material budget, a lightweight version of the mirror supporting frame was designed in aluminium. A full scale prototype was produced and its key components were tested. Tests on latest mirror supporting frames and pillars will be shown.
For careful monitoring of the mirror positions, an alignment control system is being developed which goes together with software routines for misalignment corrections. To that extent, a developed correction cycle employs two complementary methods, the CLAM method developed by the COMPASS experiment and a technique inspired from the HERA-B experiment. The correction cycle aims at the automatic detection of misalignments and includes them to correct collected data. Results from an automated correction routine and the correction impacts on the matching efficiency of the RICH detector will be presented.
