Silicon drift detector
Silicon drift detectors (SDDs) are X-ray radiation detectors used in x-ray spectrometry (EDS) and electron microscopy. Their chief characteristics compared with other X-ray detectors are:
high count rates
comparatively high energy resolution (e.g. 125 eV for Mn Kα wavelength)
Peltier cooling
Working principle
Like other solid state X-ray detectors, silicon drift detectors measure the energy of an incoming photon by the amount of ionization it produces in the detector material. In the SDD, this material is high purity silicon with a very low leakage current. The high purity allows for the use of Peltier cooling instead of the traditional liquid nitrogen. The major distinguishing feature of a SDD is the transversal field generated by a series of ring electrodes that causes charge carriers to 'drift' to a small collection electrode. The 'drift' concept of the SDD (which was imported from particle physics) allows significantly higher count rates coupled with a very low capacitance of the detector.
