Speaker
Description
The Back-n white neutron source at CSNS (China Spallation Neutron Source) has been in operation since 2018. As a multidisciplinary research platform, Back-n has its main focus on nuclear data measurements. With its unique beamline using the back-streaming neutrons from a proton beam of 100 kW in beam power impinging on a thick spallation target in tungsten, Back-n owns the highest neutron flux for a given flight path among white neutron sources. The other excellent properties include a wide neutron energy spectrum covering from 0.3 eV to 200 MeV and a good time resolution of a few per mille in most of the energy range. Currently available detector systems or spectrometers are FIXM for fission cross-section measurements, C6D6 detectors and GTAF-II for neutron capture measurements, LPDA for light-particle emission measurements, NTOX for total cross-section measurements, and user-owned HPGe detectors for in-beam gamma spectrum measurements. All the above types of experiments have been carried out regularly at Back-n with an averaged beam time of 3000 hours per year. In addition, the experimental study on the time reversal violation with neutrons is also under way. This presentation will introduce the improvements of the Back-n facility in the last years, including proton beam power ramp-up, enhanced measurements on the neutron energy spectrum, detector systems, and also a summary of the nuclear data measurements.