Digital Electronics for Silicon Drift Detectors

Silicon drift detectors (SDDs), a new class of energy dispersive detector that operates at near-room temperature, have just started to become commercially available. SDDs achieve energy resolutions comparable to the best Si(Li) detectors but at much shorter peaking times. The use of these detectors has resulted in photon throughput rates exceeding 1 MHz, exceeding the capabilities of existing pulse processor electronics to produce a clean spectrum. We have existing technology that can handle the raw count rates, but not with the desired spectral quality. We propose to develop the processing algorithms necessary to produce a clean spectrum under extremely high count rate conditions. In addition, since one of the main target applications for this technology is high speed x-ray full spectrum mapping, we will develop algorithms to properly handle the assignment of x-rays to pixels as well as to apply individual deadtime corrections to each pixel. Finally, we propose to develop the high speed communications interface necessary to transfer the large volume of mapping data to the host computer for display and storage on disk.