Non-Dispersive X-Ray Spectrometer with High Precision Dead-Time Correcticn

A campact system coupled with high resolution Si(Li) detector and optoelectronic pulsed feedback preamplifier is described. It includes main amplifier, very efficient D. C. level stabilizer, pile-up rejector, detector bias supply, 2000 channels - 100 MHz A.D. C., and dead-time correction unit for high precision quantitative X-Ray analysis. This correction is based on the injection at the input of the preamplifier of a known rate of recurrent generator pulses, which have the same probability than X-Ray pulses to be rejected during the dead-times of the system (optical reset, pile-up rejection, A.D. C. dead-time...). This pulse rate is a function of amplifier time cmstant ¿. Inspection, at the output, of the rate of rejected pulses, by a correlation system, gives the true dead-time. The generator pulses did not appear on the spectrum and their rate is only 1 % of the maximum counting capability of the system without resolution deterioration:120 c/s at ¿ = 15 ¿s for 11 000 c/s counting capability to 1200 c/s at ¿ = 1,5 ¿s for 110 000 c/s counting capability. The precision of the correction is generally within experimental errors (order of 1 %) and the method requires no setting or adjusting from the experimentator.