OPTIMAL SIGNAL-TO-NOISE RATIO

Fig. 1: Absence of readout noise and dark current in PILATUS hybrid pixel detectors.
Images of a single PILATUS module without exposure to an X-ray source with 100 ms (a) or 1 hour (b) of acquisition time. a)  After a short acquisition time, all pixels have zero counts, since no noise is added onto the readout of the image. b) After a long acquisition time, most pixels still have zero counts, since no dark current accumulates during long exposure and no noise is added during readout. In addition to the absence of dark current, the low average count rate of 0.2 cts/h/pixel provides a further advantage over integrating detectors, i.e., that high energy cosmic radiation only contributes one single count per detected event.

Fig. 1: Absence of readout noise and dark current in PILATUS hybrid pixel detectors.
Images of a single PILATUS module without exposure to an X-ray source with 100 ms (a) or 1 hour (b) of acquisition time. a)  After a short acquisition time, all pixels have zero counts, since no noise is added onto the readout of the image. b) After a long acquisition time, most pixels still have zero counts, since no dark current accumulates during long exposure and no noise is added during readout. In addition to the absence of dark current, the low average count rate of 0.2 cts/h/pixel provides a further advantage over integrating detectors, i.e., that high energy cosmic radiation only contributes one single count per detected event.