High-rate timing resistive plate chambers with ceramic electrodes

摘要

We describe recent advances in developing radiation-hard ceramic resistive plate chambers (CRPCs) with Si_3N_4/SiC composites. Bulk resistivity measurements for this material for different manufacturing processes are reported. The results show that the bulk resistivity ρ can vary between 10~7 and 10~(13) Ω cm. The varistor type behaviour of the material is analysed. A comparison with other materials used in timing RPCs is given. We describe the assembly and tests of CRPC prototypes in electron and proton beams. For a prototype with ρ ～ 5 × 10~9 Ω cm, the efficiency of the detectors is 95% at a flux of 2 × 10~5 cm~(-2) s~(-1). The time resolution at the same flux is about 120 ps. A prototype with ρ ～ 2 × 10~(10) Ω cm shows an efficiency of about 85% up to fluxes of 5 × 10~4 cm~(-2) s~(-1) with a time resolution better than 80 ps. The results are compared with RPC models.