Lappeenranta University of Technology (LUT), Finland, publishes PhD Thesis "Novel Solutions for Improving Solid-State Photon Detector Performance and Manufacturing" by Vladislav Marochkin. The thesis discusses Pixpolar MIG pixel, silicon drift detectors, and 3D radiation detectors. The doctoral dissertation defense is scheduled for December 15, 2016. A discussion of operational principles of the photon detectors starts with an interesting quote on page 17:
"When a photon interacts with silicon it creates electron-hole pairs, the amount of which is dependent on photon energy. “The energy required to create an electron-hole pair in silicon is 3.6 eV. The band gap of silicon is 1.12 eV at room temperature and the average energy needed to create a single pair, called the radiation ionization energy, is empirically found to be about three times the band gap energy of the semiconductor. This is due to the phonon excitation, which is required for momentum conservation” (Luukka, 2006)."