[en] 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. Thick 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