First results from the tests of a new full-size prototype of a silicon microstrip detector with integrating readout for studies of material deformations under pulsed heat load are presented. The prototype includes the silicon microstrip sensor with 1024 30 mm long strips with 50 um pitch, half of which are connected to the inputs of analogue pipeline ASICs APC128. The readout electronics can integrate charge released in the sensor under synchrotron radiation within exposure time from 100 ns to tens microseconds. Spatial resolution measured at an energy of X-rays about 70 keV is close to 100 um (FWHM). Next steps of this development including the change of sensor material to GaAs and usage of the new ASIC DMXG64B for the readout electronics are discussed.