Investigation Of Measurement Technique Of Neutron Spectra (100 KeV-2 MeV) In Medium

Integral experimental data in low-energy neutron inner medium are essential to theoretical design in nuclear engineering. Experimental data in low energy neutron are very important to structure materials and assemblies for principle design of fission and fusion reactor. At present, evaluated nuclear data are mostly composed of high energy neutron data. High precision data for low energy neutron are scarce. So, some measurement techniques have been developed to measure 100 keV-2 MeV neutron in medium in this paper.Five aspects of the measurement technique for 100 keV-2 MeV neutron in medium were investigated as listed below:1. Taken into account neutron field to be measured in medium and low energy of the neutron, performance of some neutron spectrometry were comprehensively compared and analyzed, spherical proton recoil proportional counter has been candidate as the detector to acquire neutron spectra.2. Based on the further experiment, a spherical proton recoil proportional counter was developed by analyzing distributed data and papers. Energy resolution and volt performance of counter were tested, by using alpha particle emitted by ²³⁵U coated at inner wall of spherical proton recoil proportional counter as calibration.3. Wall effects and non-uniformity electric filed effects were calculated with Srim2003 and ANSYS10.0, respectively. The acquired data were inputted the MC code, which was used to simulate response function of counter for mono-energy neutron.4. Several kinds of low mono-energetic neutrons induced by NS-200 neutron generator and 2.5 MeV proton accelerator were used to verify response function and anisotropy of spherical proton recoil proportional counter. Energy linearity of spectrometry was calibrated by Alpha particle from ²³⁵U and mono-neutron from neutron generator.5 Method of unfolding of pulse height spectra acquired was studied by spherical proton recoil proportional counter. The method of unfolding is based on the Least-squares and reverse-matrix method. The unfolded neutron spectra indicated that the spherical proton recoil proportional counter is capable of neutron measurement of (100 keV-2 MeV) neutron in medium.