Design of readout electronics based on peak-holding circuit and multiplexer for a fast neutron spectrometer

Background Fast neutron detection is meaningful in many research fields such as space environment monitoring.A scintillating fiber array model for fast neutron detection was proposed and developed in 1980s.Aerospace applications of the model require electronics in small size.Purpose To design a dedicated electronic system to readout and process the 384-channel signals from scintillating fiber array,and to use the designed system to fabricate a neutron detector for aerospace applications.Methods With the method of nuclear recoil,fast neutron is detected by tracking recoil proton of n–p scatter in scintillating plastic fibers.Using the peak-holding circuits and multiplexers,the system size and power consumption were reduced.Results The detector fabricated with the designed system,had 34 cm×34 cm×27 cm mechanical size,20.4 kg weight,and 30.05W power consumption.Comparing to traditional waveform sampling electronics,the designed electronics was highly integrated and had a small size.The readout electronics also gave a better energy resolution of 39%in neutron detection,while the energy resolution was 43%in previous version.Conclusion In this study,a highly integrated readout electronic system was designed and verified.The detector using the system gave good performance.The designed electronics had potential development in fast neutron detection and other high energy physics detection system.

A preliminary study on 3D position reconstruction ofmonolithic crystal readout

Purpose Compared to pixelated crystal detectors,monolithic crystal detectors present more advantages.Without reflective layer between crystal pixel,monolithic crystal detectors provide higher detection efficiency while being cheaper.Another important feature is that monolithic crystal detectors can provide depth of interaction(DOI)information,which can improve image quality in nuclear imaging systems.In this article,we aim to study a new positioning scheme of this kind of detector in order to push its applications in nuclear imaging systems.Methods Fan-beam collimation and convolutional neural network are combined to reconstruct interaction points in crystal.Firstly,we built a monolithic detector model based on Geant4 and validated this positioning scheme with simulation data.Then,we constructed a monolithic GAGG(Ce)detector and evaluated its performance with experimental data.Results With proposed positioning scheme,in experiment,we obtained~1.7 mm FWHM resolution on average in x-/ydirection,while~2.5 mm FWHM resolution on average in DOI direction for a 33×33×10 mm3 monolithic GAGG(Ce)crystal coupled with 8×8 SiPM array.Conclusion Through simulations and experiments,we validated our positioning scheme,i.e.,fan-beam collimation and convolutional neural network.Convolutional neural network can reconstruct 3D positions of gamma-rays interaction points in a high resolution,and fan-beam collimation can provide high calibration efficiency;with combination of them,we established a high position resolution and high calibration efficiency positioning scheme for monolithic crystal detector.