CMOS Imaging Detectors as X-ray Detectors for Synchrotron Radiation Experiments

CMOS imagers are matrix‐addressed photodiode arrays, which have been utilized in devices such as commercially available digital cameras. The pixel size of CMOS imagers is usually larger than that of CCD and smaller than that of TFT, giving them a unique position. Although CMOS x‐ray imaging devices have already become commercially available, they have not been used as an x‐ray area detector in synchrotron radiation experiments. We tested performance of a CMOS detector from Rad‐icon (Shad‐o‐Box1024) in medical imaging, small‐angle scattering, and protein crystallography experiments. It has pixels of 0.048 mm square, read‐out time of 0.45 sec, 12‐bit ADC, and requires a frame grabber for image acquisition. The detection area is 5‐cm square. It uses a Kodak Min‐R scintillator screen as a phosphor. The sensitivity to x‐rays with an energy less than 15 keV was low because of the thick window materials. Since the readout noise is high, the dynamic range is limited to 2000. The biggest advantages of this detector are cost‐effectiveness (about 10,000 US dollars) and compactness (thickness < 3 cm, weight < 2 kg).