Detection of true Gaussian shaped pulses at high count rates

Abstract

A new true Gaussian digital shaper of detector pulses is tested and compared to the standard trapezoidal shaper in terms of output count rate, amplitude resolution and biasing the output shaped pulses. The true Gaussian shaper allows for shaping detector pulses into a symmetrical form which width can be considerably less than their rise time. Standard trapezoidal shapers cannot provide such short pulses. Therefore, the dead time of the true Gaussian shaper can be considerably reduced in regards to that of trapezoidal shaper. The output count rate of the true Gaussian and trapezoidal pulses are compared in a wide range of input count rates. The maximal output count rate of the true Gaussian shaper has been found to exceed in several times the rate of the trapezoidal shapers. The true Gaussian shapers provide better resolution and biasing-free measurements of pulse amplitudes at high count rates. The tests have been performed by modeling output signals of silicon drift detector (SDD) VITUS H7 equipped with AXAS-D pre-amplifier developed by KETEK GmbH for measurements of soft X-ray spectra at high count rates.