Simulations of Si(Li) x-ray detector response

Si(Li) lineshapes are generated using a model that incorporates Monte Carlo simulation of the interactions of the incident photon, a very simple appro ach to energy deposition by the primary (Auger and photo-) electrons, and a n analytical approximation for diffusion of thermalized. secondary electron s. The aim of the work is illustrative rather than quantitative. Interactio ns in the metal contact produce various spectrum artefacts, and interaction s in the silicon produce a low-energy shelf structure with well-defined ste ps that have recently been observed experimentally but that are not mention ed in previous Monte Carlo simulation work, although they are to be expecte d on the basis of electron transport. Details of this structure are strongl y influenced by pulse processing time in the electronic system. Artefacts a rising from a silicon dead layer can enhance the escape peak intensity, and can assist in estimating this layer's thickness. Inclusion in the simulati on of Goto's model for secondary electron diffusion, incorporating reflecti on at the metal-Si interface, results in a truncated low-energy shelf, whos e threshold energy is determined by the reflection coefficient; its intensi ty can also be predicted from an earlier, simple, analytical model that com bines finite, primary, electron range effects with carrier losses in a regi on of incomplete charge collection whose thickness is well defined. Copyrig ht (C) 2001 John Wiley & Sons, Ltd.