Electron Radiation Damage Effects in Silicon Surface-Barrier Detectors

Abstract

Silicon surface-barrier detectors have been irradiated at room temperature with monoenergetic electrons in the energy range of 200 keV to 1 MeV. The changes of detector reverse leakage current, noise, capacitance and alpha-particle counting response were determined. In general, detector current and noise increased with electron fluence and energy for electron energies of 400 keV and above. Detector capacitances tended to decrease slightly for electron fluences up to 1013 cm 2 and increase at higher fluences. No significant degradation of detector performance was observed as a result of irradiation with 200-keV electrons for fluences up to 1016 cm2. The effects of damage on detector performance were reduced when the rear, aluminum contact was irradiated rather than the front, gold contact.

Serious Degradation Characters of CdTe Nuclear Detector by Electron or Gamma Irradiations

“…Above the gamma fluence of 107R, the main a-peak doubles to ci1 and a2. The double peaking effect [13] has been already found in a Si surfacebarrier detector irradiated with electrons when the electron irradiation was performed at the Au electrode. The lower energy peak c2 may be caused by slow rising pulses.…”

“…The lower energy peak c2 may be caused by slow rising pulses. It has been reported [13] that an appearance of double spectral peaks becomes prominent by increasing the electron fluence and then a1 (5.47 MeV) peak completely disappears at the higher electron fluence above 1015 e/cmZ at room temperature. In Si surfacebarrier detectors, it has been suggested that the loss of charge collection rate and the multiple peaking effects observed after electron irradiation is due to the trapping of charge carriers on irradiated-induced lattice defects.…”

“…The gamma-ray detector was set in a vaccum cr-ostat with temperature ranging from 77 to 323 K. The 2Am 13 Ba, 5 Co and 137Cs (10 vCi or 1 mCi) are used as an uncollimated gamma-ray source for a gamma-ray spectroscopy. The distance between the gamma source and the detector was approximately 10 mm.…”

Energy dispersive x-ray spectrometry

“…The deadlayer is the major factor in the drop of efficiency in the region below 5 keV, other than the beryllium window. The energy region of 3-4 keV, which usually is calibrated with Np M x-rays from 24 1 Am decay [15], has a high continuum coming from the strong 59.6 keV y-ray in the decay of 241 Am, but fluorescent excitation with SsFe leaves a clean background all the way down to noise level (<185 eV). Targets of elemental Mg, A1, Si, S, and compounds CaF 2 and KC1 have been used for this region [59,60].…”

“…An 241 Am source (100 mCi) is used to excite K x-rays from 6.40 to 48.8 keV in targets ranging from iron to erbium [61]. Since the NaI(TI) detector does not resolve the Ka and K0 peaks, a correction must be applied for known KP/Ka ratios to obtain the net Ka x-ray intensity for a comparison with that from the semiconductor detector.…”