Experience with the CSPAD during dedicated detector runs at LCLS

In-house developed cameras and other commercial detectors are typically tested with x-ray tubes and at synchrotron beamlines before being deployed and used for science experiments. In a prototyping phase, this is needed to understand and characterize the behavior of the detector. In a more advanced development phase, measurements with x-rays are required to characterize and calibrate the camera. Tests at synchrotron beamlines in actual experimental conditions are indeed a valuable source for detector developers. However, when all photons arrive at once, as for FELs, the response of the detector can be very different from that obtained with a synchrotron beam which behaves more like a CW (continuous) source. This behavior was already observed during users runs at LCLS and recently investigated during dedicated detector beamtime. The linearity of the response of the Cornell-SLAC Pixel Array Detector (CSPAD) was investigated. Results are presented and discussed.