Single shot grating interferometry demonstrated using direct conversion detection
Researchers at the Paul Scherrer Institute's Swiss Light Source in Villigen, Switzerland, have developed an X-ray grating interferometry setup which does not require an analyzer grating, by directly detecting the fringes generated by the phase grating with a high resolution detector. The 25um pitch GOTTHARD microstrip detector utilizes a direct conversion sensor in which the charge generated from a single absorbed photon is collected by more than one channel. Therefore it is possible to interpolate to achieve a position resolution finer than the strip pitch. The micron-level resolution delivered by the detector together with the appropriate algorithm to analyze the recorded fringe allows the differential phase signal to be retrieved. The interferometer's flux efficiency is increased by a factor of 2 compared to a standard Talbot-Lau interferometer by avoiding the use of the analyzer grating, which will lead to faster acquisition times and a potential dose reduction.