Signal Readout Method For CSNS-WNS BaF₂ Spectrometer

Neutron radiation capture cross section, namely (n, y) cross section, is used to describe the probability of radiation capture reaction between the incident neutron and the target material. (n, γ) cross section is an important nuclear parameter, which plays a very important role in the study of nuclear astrophysics, nuclide origin theory, nuclear energy development and nuclear waste disposal.BaF2 spectrometer is a 4n solid angle detector composed of BaF2 crystal, used to measure the (n, γ) section of the samples. Nowadays, there are four 4π solid angle BaF2 detectors in the world, the barium fluoride detector (BFD) at Karlsruhe, Germany; the detector for advanced neutron capture experiment (DANCE) at Los Alamos National Laboratory in America; the total absorption Calorimeter at CERN and the gamma-ray total absorption facility at China Atomic Energy Science Research Institute.To further strengthen China’s research in the field of nuclear data measurement, based on that China spallation neutron source (CSNS) could provide perfect white neutron source (WNS), we are planning to build a new white neutron source pipe in the opposite direction of the proton beam. And we’ll develop the corresponding neutron nuclear reaction detectors to obtain the data of neutron nuclear reaction. CSNS-WNS BaF2 spectrometer, as one of the neutron nuclear reaction detector, is used to measure (n, γ) cross section. To achieve this scientific goal, we need to study the signal readout method for the CSNS-WNS BaF2 spectrometer. This paper mainly focuses on the study of the signal readout method for the CSNS-WNS BaF2 spectrometer.To carry out the study of signal readout method for CSNS-WNS BaF2 spectrometer, firstly, we summarize the signal readout system architecture of the general physics experiments and then we research the signal readout method of the similar detection system in the world. Based on these, we propose the technique route for the signal readout method of CSNS-WNS BaF2 spectrometer, divide the research task into details and summarize the key technology. Then we study the key technology, design the readout system and test the key performance of it.In this paper, we put forward a method based on high bandwidth, low noise preamplifier, high speed, large dynamic range waveform digitization and PXIe based data readout architecture to obtain the CSNS-WNS BaF2 spectrometer’s signal. The research in this paper can realize the scientific goal of CSNS-WNS BaF2 spectrometer and provide reference of signal readout method for other detectors under CSNS-WNS. Combined with the high bandwidth PCIe data bus, a new data readout architecture is proposed. The system has a good ability for upgrading and the research results can be applied to many other fields in the future.