JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - UNPB AU - Li, L.W. AU - Jiao, T.Y. ED - Zhang, Tianjue ED - Schaa, Volker R.W. ED - An, Shizhong ED - Kiselev, Daniela ED - Liu, Yuntao ED - Li, Pengzhan TI - Neutron Fluence Measurement of 70MeV~100MeV Quausi-Monoenergetic Neutron Reference Field J2 - Proc. of CYCLOTRONS2022, Beijing, China, 05-09 December 2022 CY - Beijing, China T2 - International Conference on Cyclotrons and their Applications T3 - 23 LA - english AB - A 70 MeV~100 MeV Quausi-monoenergetic neutron reference field was developed at China Institute of Atomic Energy, using proton beams extracted from the 100 MeV H⁻ cyclotron of Beijing radioactive ion-beam facility (BRIF). The Quausi-monoenergetic neutron reference field mainly consists of target chamber, collimator, deflecting magnet, two neutron monitors, and one proton monitor. The proton beam is extracted from cyclotron, and then hits the Li target to produce neutrons with ⁷Li(p, n)⁷Be reaction. The neutrons fly forward through a collimator to the experimental area. A 238U fission chamber is located beside the target chamber as a neutron monitor, and will be used in the large beam current experiment. Another neutron monitor is a plastic scintillation located in the end of experiment area, and will be used in the small beam current experiment. The proton monitor is a Faraday cup behind the deflecting magnet, and it also works as a proton beam dump. The Quausi-monoenergetic neutron reference field can produce 70 MeV, 80 MeV, 90 MeV and 100 MeV neutrons. The neutron fluence was simulated by GEANT4 and was measured by proton recoil telescope and 238U fission chamber. The neutron fluence at reference point(0.8 m from collimator) is about (4×10⁴)cm⁻²s⁻¹µA-1 The results of simulation and measurement were met within 16%( normalized with the proton monitor). The neutron spectra were measure by time-of-flight method with two scintillators, as the cyclotron has no pulsed beam yet. The experimental results are in line with expectations. But TOF measurements still can be improved by increasing the distance between the two scintillations and the sampling rate of the digital MCA. PB - JACoW Publishing CP - Geneva, Switzerland ER -