Berlin 2005 – wissenschaftliches Programm

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T: Teilchenphysik

T 408: Spurkammern III

T 408.6: Vortrag

Montag, 7. März 2005, 17:45–18:00, TU H3025

Test measurements for the Silicon system of the HERMES Recoil Detector — •Svyatoslav Balashov — Zeuthen, Hankelweg 13

The HERMES detector at the HERA accelerator is going to be equipped with a Recoil Detector (RD). The RD will surround the interaction point of HERMES. One of its experimental goals is to detect slow protons that miss the standard HERMES acceptance. The Silicon system of the RD consists of 2 layers of silicon sensors 300um thick, surrounding the interaction point in a diamond shape. The readout part of the Silicon system is based on the HELIX chip that has programmable parameters which control many features of chip operation, in particular the shape of the input signal. For the readout of the Silicon system the method of charge division is used to enlarge the dynamic range, necessary to detect simultaneously minimum ionizing pions (MIPs) and highly ionizing slow protons. This is accomplished by splitting the signal for a high-gain and a low-gain readout chip. The Silicon system of the RD consists of 8 separate modules. Before installation of the detector every Silicon module is to be checked and calibrated in terms of functionality (production test), gain, input signal’s shape and sampling time for high-gain and low-gain chips, and crosstalk between neighbouring channels. The Silicon system of the RD will be tested in a Tandem accelerator (slow protons, no MIP signals), at the DESY Testbeam (3 GeV electrons, i.e. MIPs), with a Laser (red light providing large signals at large rates), and with cosmics (commissioning readout software, alignment).