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In nuclear astrophysics, the nuclides 151 Eu and 153 Eu are both in the path of the s-process, and their (n, γ ) cross sections are important input parameters for the calculation of the nuclear astrophysics network. According to the EXFOR database, the neutron capture cross section of natural europium in the resonance region has not been fully measured. The (n, γ ) cross section of nat Eu was measured using the time-of-flight (TOF) technique at the Back-n white neutron source facility of the China Spallation Neutron Source (CSNS) in the 1 eV–to 500 keV range. Four C 6 D 6 liquid scintillator detectors and pulse height weighting techniques were used to measure prompt γ rays and analyze the data. The results of the analysis were compared with the evaluated data of ENDF/B-VIII.0 and JENDL-5.0. It shows that there are some differences between the measurement results and different evaluated data libraries. The resonance parameters of 151 Eu and 153 Eu were extracted in the 1 eV–150 eV region using the R-Matrix code SAMMY. The accurate Maxwellian-averaged capture cross section (MACS) is derived over the temperature range of the s-process nucleosynthesis model. The result shows that at kT=30 keV, the MACS value of 151 Eu is 3417 ± 297 mb and the value of 153 Eu is 2718 ± 237 mb. [ABSTRACT FROM AUTHOR]

The Serappis (SEarch for RAre PP-neutrinos In Scintillator) project aims at a precision measurement of the flux of solar pp neutrinos on the few-percent level. Such a measurement will be a relevant contribution to the study of solar neutrino oscillation parameters and a sensitive test of the equilibrium between solar energy output in neutrinos and electromagnetic radiation (solar luminosity constraint). The concept of Serappis relies on a small organic liquid scintillator detector (∼ 20 m 3 ) with excellent energy resolution (∼ 2.5% at 1 MeV), low internal background and sufficient shielding from surrounding radioactivity. This can be achieved by a minor upgrade of the OSIRIS facility at the site of the JUNO neutrino experiment in southern China. To go substantially beyond current accuracy levels for the pp flux, an organic scintillator with ultra-low 14 C levels (below 10 - 18 ) is required. The existing OSIRIS detector and JUNO infrastructure will be instrumental in identifying suitable scintillator materials, offering a unique chance for a low-budget high-precision measurement of a fundamental property of our Sun that will be otherwise hard to access. [ABSTRACT FROM AUTHOR]

The Jiangmen Underground Neutrino Observatory (JUNO) is a multipurpose experiment under construction in southern China; detector completion is expected in 2023. JUNO is a homogeneous calorimeter consisting of a target mass of 20 kt of an organic liquid scintillator, aiming to detect antineutrinos from reactors to investigate the neutrino oscillation mechanism. The scintillation and Cerenkov light emitted after the interaction of antineutrinos with the liquid scintillator is seen by a compound system of 20 inch large PMTs and 3 inch small PMTs, with a total photo-coverage of 78%. A dual-calorimetry technique is developed based on the presence of the two independent photosensor systems which are characterized by different average light level regimes, resulting in different dynamic ranges. Thanks to this novel technique, an unprecedented high light yield, and in combination with a comprehensive multiple-source and multi-position calibration campaign, JUNO is expected to reach energy-related systematic uncertainties below 1% and an effective energy resolution of 3% at 1%, required for the neutrino oscillation analysis. [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]

The FIssion Neutron spectrum Detector Array (FINDA) has been designed for measurement of prompt fission neutron spectrum on the Back-n beam line at the China Spallation Neutron Source (CSNS). In order to test the neutron- γ discrimination performance of the EJ301 scintillator that will be used as a detector unit in the FINDA, a comparative study using three conventional digital pulse shape discrimination (PSD) methods has been carried out. An Am–Be source has been used to generate the mixed neutron- γ radiation and the waveform data has been obtained with a fast digitizer. Pulse interpolation, baseline restoration and pulses pile-up rejection have been applied for digital pulse processing. Charge comparison (CC) method and simplified charge comparison(SCC) method show a better capability of neutron- γ discrimination than rise time comparison(RTC) method over the entire energy range. Rise time comparison method needs a very fast digitizer or pulse interpolation to improve the PSD ability. The analysis of neutron- γ discrimination performance of the EJ301 scintillator provides a strong technical support for fast neutron measurement using the FINDA at CSNS. • The neutron- γ discrimination performance of an EJ301 scintillator that will used as a detector unit in the FINDA spectrometer at CSNS has been characterized. • A comparative study using three conventional digital pulse shape discrimination (PSD) methods has been carried out. • Charge comparison (CC) method and simplified charge comparison (SCC) method show a better capability of neutron- γ discrimination than rise time comparison (RTC) method over the entire energy range. • With the current test we discussed the results in view of applications on the Back-n beam line at CSNS and the analysis provides a strong technical support for fast neutron measurement using the FINDA. [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]