MythenII: A 128 channel single photon counting readout chip

Abstract

The MythenII readout chip has specifically been developed as the front end chip for a silicon strip detector for powder diffraction at the SLS. It works in single photon counting mode and each channel consists of a charge sensitive preamp followed by two gain stages, a comparator with a 6arctime of bit trim DAC and a 24 bit gateable counter. The noise of 195 electrons ENC allows to detect photons with energies as low as 5 keV. The maximum photon count rate is up to about 3 MHz per channel and the minimum readout time is shorter than 100 μ s . Besides powder diffraction, the chip can be beneficially used for many different X-ray applications (e.g. small angle scattering and scanning imaging [D. Dreossi, et al., Nucl. Instr. and Meth. A 570 (2007) 160]).