Hybrid Pixel Array Detectors (HPAD) were developed at the beginning of this millennium[1] and have since replaced imaging plates and charge-coupled device (CCD) detectors at synchrotrons. These HPAD detectors offer a number of advantages such as fast data read-out and low visible noise but are not without their limitations. One of the most prominent is that HPAD detectors suffer from charge sharing noise. This occurs when a X-ray photon gets absorbed within more than one pixel of an HPAD detector. In many of today’s detectors 20% of the pixel area are affected by this charge sharing noise. In addition, HPAD detectors suffer from other shortcomings, such as count rate limitation and parallax effects for high energy radiation (e.g. Mo-Kα and Ag-Kα radiation).
These shortcomings in combination with the availability of X-ray free-electron lasers (XFEL) have triggered the search for more promising technology and led to the development of next generation detectors such as the Jungfrau[2], the Adaptive Gain Integrating Pixel Detector and the Cornell-SLAC Pixel Array Detector. All these detectors are Charge-integrating Pixel Array Detectors (CPAD), eliminating the disadvantages of a HPAD detector, like count rate capability, pixel size or the low energy limit[3].
The recent introduction of the PHOTON II CPAD brings the technology developed for XFEL sources into the home lab. The PHOTON II features the largest monolithic active area of 10 × 14 cm2, the highest detective quantum efficiency and the highest frame rate of any home laboratory detector. By design, the PHOTON II also completely eliminates the charge sharing noise and parallax issues.
This new CPAD technology takes Pixel Array Detectors to the next level and it is anticipated that we will see a subsequent change of detector technology in the near future not only at the synchrotron beamlines but also within the home lab.