Application of digital signal processing in nuclear spectroscopy (original) (raw)
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Comparison of digital and analogue data acquisition systems for nuclear spectroscopy
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2010
In the present investigation the performance of digital data acquisition (DA) and analogue data acquisition (AA) systems are compared in neutron-induced fission experiments. The DA results are practically identical to the AA results in terms of angular-, energy-and mass-resolution, and both compare very well with literature data. However, major advantages were found with the digital techniques. DA allows for a very efficient a-particle pileup correction. This is important when considering the accurate measurement of fission-fragment characteristics of highly a-active actinide isotopes relevant for the safe operation of Generation IV reactors and the successful reduction of longlived radioactive nuclear waste. In case of a strong a-emitter, when applying the a-particle pileup correction, the peak-to-valley ratio of the energy distribution was significantly improved. In addition, DA offers a very flexible expanded off-line analysis and reduces the number of electronic modules drastically, leading to an increased stability against electronic drifts when long measurement times are required.
On nuclear spectrometry pulses digital shaping and processing
Trapezoidal pulse shaping by a digital technique from nuclear spectrometry preamplifier output is reported. The shaping is especially suitable for time and / or pulse-height spectra measurements from high counting rate sources which commonly implies pulse pile up. In fact, piled up events may be identified and measured rather than rejected as in usual analog systems. Moreover, the amplitude-arrival time measurement of piled up pulses by the trapezoidal shape is simpler than by both maximum likelihood and least squares estimators, or adaptive nonlinear least squares methods which give better results in the case of severe pile up. Comparison with different techniques currently used in fast scanners for nuclear medicine studies is given. The technique utility in high energy semiconductor gamma ray spectrometry is also discussed.
2014
There are 3 errors that are associated with the measurement of nuclear radiations. These are from the noise accompanying an incident radiation pulse, the dead time required for the processing of the incident radiation pulse and the pile-up of pulses. In analogue processing, these errors are often downplayed leading to the obtained results not being as accurate as they should be. Available digital processors can solve these problems to a large extent but their complex natures and high costs make it difficult for most university laboratories to easily acquire them for laboratory experiments. We have designed and implemented a digital nuclear processing system that will significantly solve the 3 problems associated with nuclear radiation pulse processing as well as being less complex and cheap. The analyses of the implemented digital nuclear radiation processing system (DNRPS) showed that the system has progressively more superior energy resolution than a popular analogue system based ...
A Parallel 8-Bit Computer Interface Circuit And Software For A Digital Nuclear Spectroscopy System
Innovative Systems Design and Engineering, 2014
There are 3 errors that are associated with the measurement of nuclear radiations. These are from the noise accompanying an incident radiation pulse, the dead time required for the processing of the incident radiation pulse and the pile-up of pulses. We have designed and implemented a digital nuclear radiation processing system (DNRPS) that significantly solves the 3 problems as well as being less complex and cheap. The interfacing of the digital processing system to a computer has been achieved through a less complex and cheap interface circuit using discrete integrated circuit (IC) chips. The interface circuit accepted parallel 8-bit data which were simultaneously processed. Furthermore, the operation of the digital processing section involved only digital addition and subtraction of the parallel 8-bit data. This approach has removed the need for complex digital operations requiring the use of digital signal processor chips, microprocessors and other complex and expensive devices ...
An optimum digital signal processing for radiation spectroscopy
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1994
When resolution is a primary requirement in high performance spectroscopy systems, the signal pulse filtering should approach the theoretical optimum weighting function . This goal, almost impossible to reach with analog filtering especially when 1/f noise is dominant, is achieved by the presented digital signal processor. It synthesizes the optimum weighting function by exploiting experimentally measured noise. The energy resolution dependence on the experimental settings is reported. Those include the number of samples acquired per pulse, the sampling frequency and the bandwidth of the antialiasing filter . An experimental comparison against the best analog filter shows an improvement of more than 10% in energy resolution .
Characterization of three digital signal processor systems used in gamma ray spectrometry
Applied Radiation and Isotopes, 2002
Various manufacturers have recently introduced digital signal processing systems that allow data acquisition in gamma spectrometry at high-input counting rates (several thousand pulses per second). In these systems, the signal digitization is performed immediately following the preamplification stage. This allows digital shaping and filtering of the signal which increases the number of possible combinations in signal shaping and as a consequence, optimizes the resolution as a function of the detector characteristics and the counting rate.
A DSP equipped digitizer for online analysis of nuclear detector signals
2007
In the framework of the NUCL-EX collaboration, a DSP equipped fast digitizer has been implemented and it has now reached the production stage. Each sampling channel is implemented on a separate daughter-board to be plugged on a VME mother-board. Each channel features a 12-bit, 125 MSamples/s ADC and a Digital Signal Processor (DSP) for online analysis of detector signals. A few algorithms have been written and successfully tested on detectors of different types (scintillators, solid-state, gas-filled), implementing pulse shape discrimination, constant fraction timing, semi-Gaussian shaping, gated integration. r
Experimental testing of the digital multichannel analyzer for gamma spectrometry measurements
Nuclear Technology and Radiation Protection, 2008
The results of experimental testing of the digital multichannel analyzer which digitalizes the signal after a preamplifier are presented. The recordings of some of the characteristics of the spectrometer containing a digital MCA, such as full-peak efficiency, net area ratio of the two peaks and the stability of the peak position, were carried out under different input counting rates, with different radioactive sources. The tested MCA has shown some excellent features, like the stability of the peak position over a long-term period and flexibility in the adjusting of optimum measurement conditions. However, the performed tests have also shown some serious and unexpected disadvantages of the digital MCA when it operates under certain circumstances, one of them having to do with the automatic tuning of live-time correction at low-input counting rates.
An automatic initialization procedure for real-time digital radiation spectrometry
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment - NUCL INSTRUM METH PHYS RES A, 1998
We introduce a method to automatically evaluate the weights of the digital filter used for high-resolution spectroscopy in a mixed analog-digital setup, which operates with minimum human attendance. The optimum filter weighting function WF is obtained from the noise autocorrelation; an ultra-accurate estimate of the singularities of the antialiasing filter is derived from its experimental pulse response. From these data the procedure automatically computes the optimum WF and the digital filter weights. We show that the method provides a much better flatness of the flat top (to within 0.1% of the peak value); a more precise elimination of tails in the WF (to better than 0.1% of the peak value) and a much lower quantization noise (more than a factor 10) at the filter output than other possible methods (DFT or Wiener algorithms). It was successfully tested in the generation of trapezoidal and optimum cusp-like WFs even in presence of non-negligible 1f noise. This calibration procedure ...
A small multiparameter data acquisition system for nuclear spectroscopy
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1988
A small computer-based system for multiparametric data acquisition in nuclear spectroscopic work is described. The system supports up to eight analog-to-digital converters (ADCs) and permits the detection of time correlations between up to eight channels . Single-and two-parameter spectra are generated and displayed on-line, while three-parameter events are recorded on magnetic tape for off-line analysis. Several independent spectra may be generated concurrently . The system can be used in a "stand-alone" configuration, the only external modules needed in this case being the ADCs. All internal modules have been constructed using easily obtainable components only. The system software has been optimized towards small size and fast data processing by coding all routines in Assembly language . The system has been developed on a PDP 11 computer, but system hardware is largely independent of the specific computer bus architecture .