Dead time corrections for X-ray intensity measurements with a Si(Li) detector

Dead time corrections in X-ray peak intensity measurements carried out with a Si(Li) detector are large. The use of the 'live time' method of timing takes account of most of the loss of counts resulting simply from the length of the pulses, but for peak measurements a further correction is required to allow for pulse pile up in the main amplifier. Dead time effects were investigated by recording the Al K peak at various count rates, using a pure Al sample with accurately measured incident electron current. A simple correction formula was found to be adequate for correcting peak intensities in spectra recorded at up to 10000 counts/s. It was found that the use of pile up rejection did not significantly complicate the dead time correction. Measurements on FeK alpha X-rays confirmed that the correction is insensitive to X-ray energy, provided the live time system is used.