Mid Sweden University

Silicon Charge Coupled Devices (CCD)covered with a scintillating film are now available on the market for use in digital medical imaging. However, these devices could still be improved in terms of sensitivity and especially spatial resolution by coating the CCD with an array of scintillating waveguides. In this work, we fabricated such waveguides by first etching pores in silicon, then performing metallization or oxidation of the pore walls and finally filling the pores with CsI(Tl). The resulting structures were observed using SEM and tested under X-ray exposure. The detector performances were also compared with simulations, indicating that the optimal pore depth for metallized macropore arrays is about 80 um while it is around 350 um for oxidized ones. This result, together with the roughness of the metal coating, explains why lower performances were measured experimentally with the metallized macropores. Indeed, our macropore arrays had depths in the range of 210-390 um, which is favorable to oxidized structures.