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Precise measurement under high counting rates has been a major challenge for γ -ray spectroscopy, where signals generally pile up with each other and their characteristic values are deeply coupled. An off-line pile-up pulse recovery algorithm based on template matching is developed for LaBr 3 scintillation detectors and has been applied to data from China Spallation Neutron Source (CSNS) Back-n white neutron beamline. As an improvement to the traditional Template Matching methods, the predetermined template shape is associated with pulse amplitudes, which is found crucial to achieve the best fitting results. Moreover, a universal strategy of setting the initial values of fitting allows to resolve signals that are separated in time by less than the characteristic rise time. Processing of simulated pulses demonstrates that the lower limit of interval to distinguish successive events is 10 ns, which is a significant improvement to the previous works. The algorithm performs well under a counting rate of 6 × 1 0 7 s−1, and is still effective up to 1 0 8 s−1. Analysis of experimental data indicates that this algorithm recovers over 98% count yield under a counting rates of no more than 4 × 1 0 6 s−1 in this work, providing a more reliable approach to deduce neutron-induced reaction cross sections. [ABSTRACT FROM AUTHOR]

A 128-channel positron detection system will be constructed at Experimental Muon Source (EMuS) of China Spallation Neutron Source (CSNS) to conduct muon spin rotation/relaxation/resonance ($\mu $ SR) measurements. Each detector channel consists of a scintillator, a light guide, and a photomultiplier tube (PMT). The long light guide is bent to an “L” shape to propagate optical photons from the scintillator to the PMT. A series of Geant4 simulations and experiments has been performed to optimize the light collection performance of the L-bent detector. Geometry deformation induced by the bending process has been well modeled. Simulation results agree with the experimental tests. Accordingly, a novel hybrid wrapping method (scintillator with polytetrafluoroethylene (PTFE) and light guide with aluminum tape) has been developed to improve the amplitude of detector signals greatly. Compared to wrapping the detector with merely PTFE tapes or aluminum tapes, this method leads to an enhancement in light collection efficiency of 73% or 14%, respectively. Two optimally manufactured prototype detectors using the novel wrapping method have been tested at the ISIS Muon Facility. The beam tests demonstrated that the L-bent detectors can precisely measure the behavior of muon spins inside samples. Therefore, the L-bent detector design is competent for $\mu $ SR applications at CSNS/EMuS. [ABSTRACT FROM AUTHOR]

The Circular Electron Positron Collider (CEPC) is a proposing electron–positron collider in China, which aims for generating high center-of-mass energy colliding above 250 GeV. The high-granularity electromagnetic calorimeter (ECAL) is included in a calorimeter system, which is mainly responsible for the measurement of photon. A particle flow algorithm (PFA)-based ECAL solution will utilize about 400k channels/m3. Here, we present the design and development status of readout electronics based on SPIROC2b for the CEPC ECAL with high-granularity scintillants and silicon photomultipliers (SiPMs). The readout electronics consists of front-end electronics (FEE), data interface (DIF) board, and data acquisition (DAQ) board. The front-end board (FEB) carries SiPMs (S12571-010P), scintillants (PSD), and FEB application-specific integrated circuit (ASIC) (SPIROC2b). Two electronics were designed in this paper, one is for ASIC functionality and performance only, and the other is used as a single layer of a further prototype of ECAL. Electronic test and cosmic ray test have been done to electronics. The results indicate that a charge dynamic from 62 fC to 300 pC at S/N = 2 is successfully achieved, and the minimum ionizing particles (MIPs) are separated from the pedestal. [ABSTRACT FROM AUTHOR]

Being the first astronomical scientific satellite of China, Dark Matter Particle Explorer (DAMPE) has been launched on D e c. 17 , 2015. One of scientific objects of DAMPE is studying the acceleration and propagation mechanisms of cosmic rays by measuring the flux of nuclei cosmic rays up to several hundred T e V s. As one of the key detectors of DAMPE, the Plastics Scintillator Detector (PSD) is used for the nuclei identification as well for the photons/electrons separation. After assembly of DAMPE engineering qualified model (EQM), several beam tests were conducted at CERN to study the performance and the reliability of DAMPE. In this paper, design verification and performance of PSD with heavy ion beam tests will be reported in detail. [ABSTRACT FROM AUTHOR]