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Abstract

One of the most recent developments in equipment for high and/or varying count rates, as encountered in the gamma-ray spectrometry needed for INAA via short-lived radionuclides, is the advent of EG&G Ortecs DSPEC plus . This all-in-one apparatus provides digital signal processing and zero-dead-time counting. One such DSPEC unit was tested at IRI with respect to performance as a function of count rate. Optimum parameter settings for different applications were established. It is concluded that this spectrometer allows for measurements with count rates up to at least 10 5 cps with an accuracy of a few percent (depending on the calibration approach), a peak position stability of 5 . 10 3 %. and a peak width stability of 5%. It is also concluded that the normal spectrum provides a good estimate for the uncertainties in the zero-dead-time spectrum acquired with this spectrometer.

Neutron activation analysis and X-ray Rayleigh and Raman scattering of hair and nail clippings as noninvasive bioindicators for Cu liver status in Labrador Retrievers

“…Details of the irradiation facility, gamma-ray spectrometer, and associated quality assurance have been published elsewhere [ 11 ]. The spectrometer is equipped with ORTEC DSPEC-PLUS electronics, which allows for adequate dead-time correction [ 12 ]. It is obvious that, particularly in the nail and hair samples, several other elements such as Ca, Mg, and S were also quantified on the basis of their short halflife radionuclides, measured simultaneously with 66 Cu.…”

Dead Time in the Gamma‐Ray Spectrometry

“…Counts to memory ¼ input pulses to amplifier T Live T Real (17) Where T live is the live time and T real is the real time of the counting system.…”

“…The dead-time correction under such conditions may be true if changing the dead time dominantly affected measured radioisotopes [17,18]. Zero dead-time losses correction is almost the same as the loss-free counting.…”

“…In this case, dead-time corrections can only be accurate if the varying dead time is dominantly caused by a radiation source. Solutions have been offered in several forms: dead time stabilization [14,[24][25][26] solves the problem at the cost of a fixed, perhaps unnecessary, dead time and resulting loss of counting efficiency [17]. However, results of the other deadtime correction models have not been forthcoming for counting losses due to the system dead time.…”