Development of a silicon micro-strip detector with single photon sensitivity for fast dynamic diffraction experiments at a synchrotron radiation beam.
Time resolved experiments on the diffraction of synchrotron radiation (SR) from crystalline materials give information on the evolution of a material structure after a heat, electron beam or plasma interaction with the material. Changes in the material structure happen within a microsecond scale and a detector with corresponding parameters is needed. SR channel 8 of the VEPP-4M storage ring provides radiation from the 7-pole wiggler that allows to get up to several tens photons within 1 $mu$s from a W crystal for the most intensive diffraction peak. In order to perform experiments that allow to measure the evolution of W crystalline structure under the impact of powerful laser beam, a new detector is developed, that can provide information about the distribution of scattered SR flux in space and its evolution in time at a microsecond scale. The detector based on the silicon p-on-n micro-strip sensor with DC metal strips. The sensor contains 1024 30 mm long strips with 50 micron pitch. 64 strips are bonded to the front-end electronics based on APC128 ASICs. The APC128 ASIC contains 128 channels that consist of low noise integrator with 32 analogue memory cells. The integrator equivalent noise charge is about 2000 electrons and thus the signal from individual photons with energy above 40 keV can be observed. The analogue memory can be readout with 10 MHz rate. The first measurements with the beam scattered from W crystal with energy near 60 keV demonstrated the capability of this prototype to observe spatial distribution of the photon flux with the intensity from below one photon per channel up to ~100 photons per channel with frame rate from 1 MHz up to 10 kHz. The future development of full-size detector will be discussed in the presentation.