Polarization dependence of trap detectors

The sensitivity of a series of silicon trap detectors has been measured as a function of beam polarization. Measurements and numerical simulation show that very small departures from the ideal orientation of the photodiodes mounted in the trap induces a significant sensitivity to the state of polarization of the beam. Consequences of this polarization dependence for the use of trap detectors as transfer detectors in high-accuracy applications, particularly in cryogenic radiometry, are discussed.