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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]

The Jiangmen Underground Neutrino Observatory (JUNO) is a state-of-the-art liquid scintillator-based neutrino physics experiment under construction in South China. To reduce the background from external radioactivities, a water Cherenkov detector composed of 35 kton ultra-pure water and 2,400 20-inch photomultiplier tubes is developed. Even after specialized treatment, ultra-pure water still contains trace levels of radioactive elements that can contribute to the detector background. Among which 222Rn is particularly significant. To address this, an online radon removal system based on the JUNO prototype has been developed. By integrating micro-bubble generators to enhance degasser's radon removal efficiency, the radon concentration in water can be reduced to 1 mBq/m3 level, meeting the stringent requirements of JUNO. Additionally, a highly sensitive online radon concentration measurement system capable of detecting concentrations ∼ 1 mBq/m 3 has been developed to monitor the radon concentration in water. In this paper, the details regarding both systems will be presented. [ABSTRACT FROM AUTHOR]

The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose, large size, liquid scintillator experiment under construction in China. JUNO will perform leading measurements detecting neutrinos from different sources (reactor, terrestrial and astrophysical neutrinos) covering a wide energy range (from 200 keV to several GeV). This paper focuses on the design and development of a test protocol for the 20-inch PMT underwater readout electronics. The protocol has been employed for 10 months during the mass production and validation of all the electronics that will be installed in JUNO. A total number of 6950 electronic boards were tested with an acceptance yield of 99.1 %. [ABSTRACT FROM AUTHOR]

Two inorganic scintillator detectors consisting of Yb:YAG scintillators and photomultiplier tubes, and an oscilloscope were used to studied the neutron sensitivities of Yb:YAG scintillators at the China Spallation Neutron Source (CSNS) Back-n white neutron source. The relative neutron sensitivity curves of two Yb:YAG scintillators in the energy region between 0.5 and 20 MeV were obtained for the first time. As the measured relative neutron sensitivity curves of Yb:YAG scintillators cannot be verified by the Monte Carlo method and there was no referable data, the neutron sensitivity curve of a ST401 scintillator was also studied in the same method and a Geant4 simulation of ST401 scintillator was conducted to verify the experiment method in this paper. The result showed that the experimental and simulation results were approximately consistent between 17–20 MeV, and agreed well between 1–17 MeV. A comparison between the experimental result and references of ST401 scintillator was also applied and the result showed that the curve tendency of the experimental result and references was matched. The above results imply that the measured relative neutron sensitivity curves and the experimental method used herein were reliable. It also demonstrated the feasibility of studying the neutron sensitivity of inorganic scintillator based on the white neutron source. [ABSTRACT FROM AUTHOR]

Jiangmen Underground Neutrino Observatory (JUNO) is a next generation liquid scintillator neutrino experiment under construction phase in South China. Thanks to the anti-neutrinos produced by the nearby nuclear power plants, JUNO will be able to study the neutrino mass hierarchy, one of the open key questions in neutrino physics. One key ingredient for a successful measurement is to use high speed, high resolution sampling electronics located very close to the detector signal. Linearity in the response of the electronics is another important ingredient for the success of the experiment. During the initial design phase of the electronics, a custom design with the Front-End and Read-Out electronics located very close to the detector analog signal has been developed and successfully tested. The present paper describes the electronics structure and the first tests performed on the prototypes. The electronics prototypes have been tested and they show good linearity response, with a maximum deviation of 1.3% over the full dynamic range (1-1000 p.e.), fulfilling the JUNO experiment requirements. [ABSTRACT FROM AUTHOR]

Combined photon and neutron radiography can integrate merits of X/gamma-ray radiography and energy-selective neutron radiography and has the potential of simultaneously visualizing objects composed of high-Z materials, low-Z materials and particular isotopes that resonantly absorb neutrons at certain energies. Intense pulsed gamma bursts and wide energy spectrum neutrons at spallation sources provide a unique opportunity to perform such combined radiography research. We present the results of the combined radiography experiments performed at the back-streaming white neutron (back-n) beamline at China Spallation Neutron Source (CSNS). Gamma-ray and energy-selective neutron radiographic images of multi-element samples were taken by an ICCD camera coupled with scintillators using the time of flight (TOF) technique. High-Z (Pb, Au, W, Ta, et al.) components were visualized with the intense gamma-ray bursts. The low-Z (10B) component was confirmed with varied image contrast when neutrons with varied energies were selected. The specific elements ( nat In, 197Au and nat W) were identified with neutrons at corresponding resonant energies. The experimental results prove the potential for simultaneously visualizing and identifying high-Z materials, low-Z materials and particular nuclides via combined X-ray radiography and energy-selective neutron radiography. [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]