CdTe photoconductors for LHC luminosity monitoring

Detectors made from CdTe photoconductors are being used with great success in LEP to monitor the vertical beam emittance. They can withstand tremendous irradiation of up to 1013 Gy from hard X-rays. For the LHC it is proposed to measure the relative luminosity with monitors located inside absorbers 142 m downstream of the interaction points. The detectors will receive an integrated dose of about 108 Gy per year there, where the high neutron flux is of particular concern. polycrystalline-CdTe detectors were recently tested for speed, sensitivity before and after receiving up to 1015 neutrons/cm2. The test results are presented here, along with a comparison of the calculated charge deposition in silicon, diamond and GaAs detectors.