No Arabic abstract
The Lanthanum Halide scintillator detectors have been widely used for nuclear spectroscopy experiments because of their excellent energy and time resolutions. Despite having these advantages, the intrinsic alpha and beta contaminations in these scintillators pose a severe limitation in their usage in rare-event detections. In the present work, pulse shape discrimination (PSD) with a fast digitizer has been shown to be an efficient method to separate the effect of alpha contamination from the spectrum. The shape of the beta spectrum has been generated with the help of Monte Carlo based simulation code, and its contribution has been eliminated from the spectrum. The reduction in the background events generated by both intrinsic beta and alpha activities has been demonstrated. The present study will encourage the application of these detectors in low cross-section measurement experiments relevant to nuclear astrophysics.
We investigate the performance of large area radiation detectors, with high energy- and spatial-resolution, intended for the development of a Total Energy Detector with gamma-ray imaging capability, so-called i-TED. This new development aims for an enhancement in detection sensitivity in time-of-flight neutron capture measurements, versus the commonly used C6D6 liquid scintillation total-energy detectors. In this work, we study in detail the impact of the readout photosensor on the energy response of large area (5050 mm2) monolithic LaCl3(Ce) crystals, in particular when replacing a conventional mono-cathode photomultiplier tube by an 88 pixelated silicon photomultiplier. Using the largest commercially available monolithic SiPM array (25 cm2), with a pixel size of 66 mm2, we have measured an average energy resolution of 3.92% FWHM at 662 keV for crystal thicknesses of 10, 20 and 30 mm. The results are confronted with detailed Monte Carlo (MC) calculations, where both optical processes and properties have been included for the reliable tracking of the scintillation photons. After the experimental validation of the MC model, se use our MC code to explore the impact of different a photosensor segmentation (pixel size and granularity) on the energy resolution. Our optical MC simulations predict only a marginal deterioration of the spectroscopic performance for pixels of 33 mm2.
The new Oslo Scintillator Array (OSCAR) has been commissioned at the Oslo Cyclotron Laboratory (OCL). It consists of 30 large volume (diameter 3.5 x 8 inches) LaBr$_3$(Ce) detectors that are used for $gamma$-ray spectroscopy. The response functions for incident $gamma$-rays up to 20 MeV are simulated with $texttt{Geant4}$. In addition, the resolution, and the total and full-energy peak efficiencies are extracted. The results are in very good agreement with measurements from calibration sources and experimentally obtained mono-energetic in-beam $gamma$-ray spectra.
In this paper we report studies of the Fermi potential and loss per bounce of ultracold neutron (UCN) on a deuterated scintillator (Eljen-299-02D). These UCN properties of the scintillator enables a wide variety of applications in fundamental neutron research.
CeBr3 is emerging as one of the best scintillators having properties almost similar to Cerium doped lanthanum halide scintillators. We have measured, for the first time, the intrinsic energy resolution of Compton electrons in a cylindrical 1x1 CeBr3 detector using the sources, namely, 137Cs, 22Na and 60Co employing Compton Coincidence Technique (CCT). We have used PIXIE-4 data acquisition system which makes the measurement setup quite compact. The results have shown that non-proportionality is the major factor in limiting the overall energy resolution of CeBr3 and the intrinsic resolution in CeBr3 arises due to processes other than the scattering of electrons inside the scintillator. We have also studied the dependence of intrinsic energy resolution on the coincidence window and optimized its value for a given source
A laser calibration system was developed for monitoring and calibrating time of flight (TOF) scintillating detector arrays. The system includes setups for both small- and large-scale scintillator arrays. Following test-bench characterization, the laser system was recently commissioned in experimental Hall B at the Thomas Jefferson National Accelerator Facility for use on the new Backward Angle Neutron Detector (BAND) scintillator array. The system successfully provided time walk corrections, absolute time calibration, and TOF drift correction for the scintillators in BAND. This showcases the general applicability of the system for use on high-precision TOF detectors.