Large area, low capacitance Si(Li) detectors for low noise, high rate X-ray applications

Summary form only. Large-area, single-element Si(Li) detectors have been fabricated using a novel geometry which yields detectors with reduced capacitance and hence reduced noise at short amplifier shaping times. A typical 6-mm-thick device with an active area of 175 mm² has a capacitance of 0.5 pF for a conventional planar device with equivalent thickness and area. These low-capacitance detectors, in conjunction with low-capacitance FETs, will result in spectrometers capable of running at very high count rates while still maintaining excellent energy resolution. The spectral response of the low capacitance detectors to a wide range of X-ray energies at 77 K is comparable to that of typical state-of-the-art conventional Si(Li) devices. The spectral response to 2-60 keV X-rays was investigated