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A Frisch-grid Ionization Chamber (FGIC) for the measurement of low activity of alpha-particle emitters has been built. The design and performance are described in this paper. According to the Shockley–Ramo theorem and the experiment, the key parameter grid inefficiency was studied in detail. The experimental and calculated values of the correction factor are shown to be in good agreement. In the measurement of the alpha-activities of a 234,238U sample, the detection efficiency was investigated based on the Monte-Carlo method. Considering this influence, the activity of alpha-particle emitters was identified.

A reliable 235U enrichment uniformity detection system based on a compact D-D neutron generator is developed to detect the 235U enrichment uniformity of different fuel elements in the same nuclear fuel rod. The high-yield compact D-D neutron generator provides 2.45 MeV D-D neutrons, decelerated by a moderator to thermal neutrons or epithermal neutrons, thereby inducing 235U fission to produce highly excited state fission fragments that undergo de-excitation via γ-ray emission. The system detects the 235U enrichment uniformity of a nuclear fuel rod by measuring γ-rays and establishing a relationship between the γ-ray count rate and 235U enrichment in nuclear fuel. The proposed system yields a confidence probability of 99.99% for a relative 235U enrichment deviation of 10% and a neutron yield of 5 × 108 n/s, and the detection accuracy increases with increasing neutron yield. Furthermore, the developed system can satisfy quality control requirements for nuclear fuel production to promote the safe development of nuclear power.

The EJ309 liquid scintillator detector and the developed gamma spectrum unfolding procedure are used to study the complex gamma spectra. The EJ309 liquid scintillator detector is calibrated by using measured response functions of the standard gamma sources 133Ba, 137Cs, and 60Co, which are verified by Monte Carlo simulations for detector calibration accuracy. A gamma spectra unfolding procedure is developed based on the One-fold Gold algorithm, which is used for unfolding simulated complex gamma spectra, experimentally measured response function of 133Ba and 137Cs, and composed complex gamma spectra using measured response function of 133Ba and 137Cs with different relative intensities (RI). The data of unfolded gamma-ray spectra are compared with the standard data. The results show that the EJ309 liquid scintillator detector and the developed gamma spectra unfolding procedure can quantitative and qualitative analysis of complex gamma spectra with reasonable accuracy.

A high-intensity accelerator-based D-D/D-T fusion neutron source (ZF-400) with a thick adsorption target is designed with an intensity of $ 10^{13}$ n/s. A high-current microwave ion source is used to produce a large current deuteron beam, and neutrons are generated by irradiating the deuteron beam on a deuterium-adsorption target or tritium-adsorption target. According to the particle-in-cell (PIC) code, the length of the whole high-current D+ beam transport line is 500cm, the D+ beam transfer efficiency is up to 96%, and various components can match each other. On the rotating target, the D+ beam spot size is about 20.0 mm with energy of 450 keV. Based on the heat conduction theory, the thick adsorption rotating target with water-cooling can withstand the D+ ions beam with 450 kV/50 mA and ensure that the temperature is less than 200 °C. According to the multi-layer computing model, neutron energy spectra, angular distributions and yields for the thick target can be calculated with remarkable precision. The neutron energy spectra are non-mono-energetic neutrons for the ZF-400 neutron generator, the neutron angular distributions are anisotropic distributions, and they can provide neutrons with an intensity of $ 2.8\times 10^{11}$ n/s (D-D) and $ 1.4\times 10^{13}$ n/s (D-T), respectively, with the deuteron of 450 keV/50 mA.

A compact D–D neutron generator, with a peak neutron yield of D–D reactions up to 2.48 × 108 n/s is being developed at Lanzhou University in China for application in real-time neutron activation analysis. During tests, the problem of back acceleration of secondary electrons liberated from the neutron production target by deuterium ions bombardment was encountered. In this study, an electric field method and a magnetic field method for suppressing secondary electrons are designed and experimentally investigated. The experimental results show that the electric field method is superior to the magnetic field method. Effective suppression of the secondary electrons can be achieved via electrostatic suppression when the bias voltage between the target and the extraction-accelerating electrode is > 204 V. Furthermore, the secondary electron emission coefficient for the mixed deuterium ion (D1+, D2+, and D3+) impacting on molybdenum is estimated. In the deuterium energy range of 80–120 keV, the estimated secondary electron emission coefficients are approximately 5–5.5 for the mixed deuterium ion glancing incidence of 45° and approximately 3.5–3.9 for the mixed deuterium ion normal incidence.

Novel measurements of the neutron energy spectra of the 9Be(d,n)10B reaction with a thick beryllium target are performed using a fast neutron time-of-flight (TOF) spectrometer for the neutron emission angles and , and the incident deuteron energies are 250 and 300 keV, respectively. The neutron contributions from the 9Be(d,n)10B reaction are distributed relatively independently for the ground state and the first, second, and third excited states of 10B. The branching ratios of the 9Be(d,n)10B reaction for the different excited states of 10B are obtained for the neutron emission angles and , and the incident deuteron energies are 250 and 300 keV, respectively. The branching ratio of the 9Be(d,n)10B reaction for the third excited state decreases with increase in the incident deuteron energy, and the branching ratios for the ground state and the second excited state increase with increase in the neutron emission angle.

The potential-driving model is used to describe the driving potential distribution and to calculate the pre-neutron emission mass distributions for different incident energies in the reaction. The potential-driving model is implemented in Geant4 and used to calculate the fission-fragment yield distributions, kinetic energy distributions, fission neutron spectrum and the total nubar for the reaction. Compared with the built-in G4ParaFissionModel, the calculated results from the potential-driving model are in better agreement with the experimental data and evaluated data. Given the good agreement with the experimental data, the potential-driving model in Geant4 can describe well the neutron-induced fission of actinide nuclei, which is very important for the study of neutron transmutation physics and the design of a transmutation system.