The SISWICH, a detector telescope with intrinsic calibration

To overcome the difficulty of calibration for PHOSWICH counters, a silicon-scintillator sandwich (SISWICH) has been built. This detector consists of a silicon PIN photodiode glued to the front of a CsI(Tl) scintillator crystal. The signal coming from the PIN diode contains the energy loss of the particle in the silicon, which is fast (nuclear counter effect), and the light output of the scintillator, which is slow. The component coming from the nuclear counter effect can be calibrated with a pulsar. Therefore, since the energy loss of a particle with known Z has been measured, its energy is known, and this can be used to calibrate the signal from the scintillator.