The development and evaluation of solid-state detector arrays for high energy x-ray imaging

Several detector modules which consist of linear CdWO₄ crystal arrays optically coupled to photodiode arrays were developed for a high energy X-ray NDT system. An electron linear accelerator (LINAC) which produces pulsive X rays with maximum energy of 9 MeV is used for X ray source. 16 channels were assembled in each module, with crystal size of 0.8 mm × 5 mm × 30 mm and pitch size of 1.3 mm. Lead spacers were placed between crystals to reduce the cross-talk. Based on M-C simulation, the detection efficiency of the detector can reach 70%, energy deposit rate 30%, while crosstalk can be reduced to 5%. After fabrication, we tested their performances under the radiation sources of ⁶⁰Co, 6 MeV LINAC and 9 MeV LINAC. The results show that the arrays satisfy the meet of the NDT system.