Speaker
Description
The detector architecture consists in a hybrid MPGD combination:
two layers of Thick-GEMs (THGEM), the first of which also acts
as a reflective photocathode thanks to a CsI film is deposited
on its top face, are coupled to a bulk MICROMEGAS with pad
segmented anode kept at positive high voltage (HV), while the
micromesh is grounded; the signals are read-out via capacitive
coupling from a second set of pads parallel to the anode ones.
The THGEMs are segmented in order to reduce the energy released
in case of occasional discharges. The power supply system is based
on commercial components by CAEN. Two original elements are
present in the architecture of the HV power supply system:
(i) The distribution to the THGEM segments and to the MICROMEGAS
anode pads has been optimized in order to minimize the propagation
of occasional discharges to other detector sectors.
(ii) The detector gain is kept stable in spite of the variation of the
environmental parameters, namely pressure P and temperature T,
compensating the HV according to the P and T evolution.
The HV system and its performance are described in detail.
Poster presented on behalf of the Trieste COMPASS group
