Research Of The ToF Measurement Of Intermediate And High Energy Neutrons Based On The Laser Electron Accelerator

With the rapid development of human manned space technology,more and more countries explore the space environment and space resources.It becomes a problem in space technology that the radiation protection problem of the astronauts and the damage problem of the spacecraft components.Space radiation is mainly from photons,neutrons and heavy ions.Space neutrons are particularly concerned about by human because of their large number,strong penetration and great damage.If we can measure the space neutron energy spectrum and assessment it,it will play an irreplaceable role in the further development of the space technology.This work measured the neutron energy spectrum on the ground by simulating the space.the intermediate and high energy neutrons generated by 150 Me V electron which are from Tsinghua University LPA(laser plasma accelerator,LPA)hitting the target were used to study the time-of-flight neutron energy spectrum and estimation and calibration of intermediate and high-energy neutrons dose.The electron charge and energy distribution of LPA were obtained by experiment analysis.The photons and neutrons distribution characteristics were obtained by Monte Carlo simulation,and the neutron spectrum measurement position of this work was determined.The neutron energy spectrum were measured under different target conditions,and the best lead shielding conditions were determined,and the neutron energy spectrum with high reliability was obtained.The dose conversion factor of neutron fluence was corrected in different ways,and the equivalent dose value of experiment neutron was calculated.This work has done some experiment explores with the LPA which is as neutron source energy driven,and obtains some useful parameters for the detection conditions under the accelerator.It provides the intermediate and high energy neutrons spectrum measurement experiment on the ground,and the preliminary study of the calibration of the ambient dose equivalent is done and obtain neutron ambient dose equivalent.