A Digital Spectrometer Approach to Obtaining Multiple Time-Resolved Gamma-Ray Spectra for Pulsed Spectroscopy

by , , , | Oct 1, 2007 | Papers

Neutron-induced gamma emission and its detection using a pulsed neutron generator system is a recognized analytical technique for quantitative multi-elemental analysis. Traditional gamma-ray spectrometers used for this type of analysis are normally operated in either coincidence mode by counting prompt gamma-rays from inelastic scattering when the neutron generator is ON, or anti-coincidence mode by counting prompt or delayed gamma-rays from thermal neutron capture or delayed activation when the neutron generator is OFF. We have developed a digital gamma-ray spectrometer for concurrently measuring both the inelastic and capture gamma-rays emitted from a sample when activated by 14 MeV neutrons from a pulsed neutron generator. The spectrometer separates the gamma-ray counts into two independent spectra together with two separate sets of counting statistics based on the external gate level. Occasionally there might be a need for multiple time gates to acquire gamma-ray spectra at different time intervals. For that purpose we are developing a multi-gating system that will allow gamma-ray spectra to be acquired concurrently in real time with up to 16 time slots. These 16 time slots will have adjustable width and time delay that can be arbitrarily allocated within the ON and OFF periods. The conceptual system design and considerations for performing gate signal testing and tracking together with pulse height analysis and bin allocation into spectra in real time will be presented.

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