High frame rate X-ray imaging with a 256×256 pixel single photon counting Medipix2 detector

We report on high frame rate X-ray imaging tests with the Medipix2 single photon counting detector (256 × 256 pixel, 55 μm pitch, 13 bit counter) bump-bonded to a 300-μm or 700-μm thick silicon pixel detector. Image data are readout serially at a maximum frequency of 86 MHz, and each image frame corresponds to roughly 1 Mbit. After implementing a new version of the dedicated Medisoft 4.1 software for the operation of the Medipix2 imaging system, the maximum possible frame rate increased from a few frames per second (fps) up to 51 fps (10% duty cycle). At 30 fps, the duty cycle is 47%. Dynamic imaging tests have been made by irradiating with an X-ray tube (25 kVp, 1 mA) an absorbing edge being translated at a constant speed. A flood field irradiation test (35 kVp, 1 mA, 36 fps, 10 ms acquisition time per frame) easily detected a 0.15-s glitch in the X-ray tube output during the beam turn-on transient. Applications of this new option for the Medipix2 imaging system are in the field of cineradiography, dynamic X-ray imaging and synchrotron radiation imaging, albeit where the limited area (14 mm × 14 mm) is not an issue.