A New Digital Data Acquisition System for Neutron Metrology

Master Thesis


Permanent link to this Item
Journal Title
Link to Journal
Journal ISSN
Volume Title
Within the neutron metrology and spectrometry community digital pulse processing systems are being developed for measurements of Fast neutron fields in a wide variety of contexts, for example at accelerator and medical radiation facilities, around nuclear power plants, in airplanes in flight and space stations. These fields often vary widely with respect to both energy and intensity, which complicates measurements of energy dependent fluence. Investigations have been completed into the suitability of a CAEN DT5730 digitiser unit as a viable alternative to a traditional analogue system for data acquisition for fast neutron metrology. Experiments were completed at the fast neutron facilities of AMANDE (IRSN, Cadarache) using a BC501A scintillation detector and both the DT5730 digitiser and an analogue system based on NIM electronics and an MPA-3 multichannel analyser acquisition unit. Follow-up measurements were made at the n-lab facility at the University of Cape Town. The measurements covered an energy range from 0.5 MeV to 20 MeV, over a large range of intensities. The energy and intensity response for both systems and digital configurations were investigated based on the unfolding of measured light output spectra using an existing neutron response matrix for the detectors. Deadtime behaviour, rate dependent losses and linearity over the energy range were explored. The quality of the measured neutron spectra was compared through both uncertainty budgets and shape comparison analyses. Factors to consider when migrating from analogue signal processing to digital signal processing are discussed for the measured energy and intensity range, including advantages and disadvantages using digital pulse processing for metrology both in the laboratory and in the field. While there is more research required for a thorough bench-marking, the present results indicate that digital data acquisition technology has matured to the point where it can now be considered for use within neutron metrology.