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An inelastic neutron scattering system was developed to determine the elemental composition of large metallic materials. The geometrical size of the system was optimized by using Monte Carlo simulation. An experimental setup consisted of a DT neutron generator and a HPGe detector was built based on the optimized configuration and applied to analyze titanium samples. The net peak areas of titanium versus sample mass showed a linear dependence and the mass detection limit was 64 g. The prompt gamma spectra were compared to simulation data. The results demonstrated a good agreement for the signal-to-background ratio of titanium peak between measurements and simulations.

252Cf neutron source has been widely used in biological effects of neutron radiation, neutron activation analysis and nuclear data acquisition. A seed irradiation device based on 252Cf fission neutron source was designed in this paper to study mutation breeding induced by neutron irradiation and biological effects of radiation. Based on the Monte Carlo method, neutron absorbed dose of pea seed samples in the designed irradiation region was simulated and calculated by MCNP. Results demonstrated that the relative standard deviation of the absorbed dose of pea seed samples in the three-layer partition is controlled lower than 10%, indicating the high dose uniformity in designed irradiation region. The experiment verified that the design of shield in this device meet the irradiation protection requirements.

Irradiation breeding is an important technique in the effort to solve food shortages and improve the quality of agricultural products. In this study, a field test was implemented on the M3 generation of two mutant pea plants gained from previous neutron radiation of pea seeds. The relationship between agronomic characteristics and yields of the mutants was investigated. Moreover, differences in physiological and biochemical properties and seed nutrients were analyzed. The results demonstrated that the plant height, effective pods per plant, and yield per plant of mutant Leaf-M1 were 45.0%, 43.2%, and 50.9% higher than those of the control group. Further analysis attributed the increase in yield per plant to the increased branching number. The yield per plant of mutant Leaf-M2 was 7.8% higher than that of the control group, which could be related with the increased chlorophyll content in the leaves. There was a significant difference between the two mutants in the increase of yield per plant owing to morphological variation between the two mutants. There were significant differences in SOD activity and MDA content between the two mutants and the control, indicating that the physiological regulation of the two mutants also changed. In addition, the iron element content of seeds of the two mutants were about 10.9% lower than in the seeds of the control group, a significant difference. These findings indicate that the mutants Leaf-M1 and Leaf-M2 have breeding value and material value for molecular biological studies., Comment: 13 pages,3 figures

In our previous research, a new detection method was proposed to measure Hg and Pb simultaneously by combining Prompt Gamma-ray Neutron Activation Analysis (PGNAA) and X-ray Fluorescence (XRF) and proved by the Monte Carlo N-Particle (MCNP) simulation code. For further experimental verification, a combined measurement experimental facility, comprising an 241Am–Be neutron source, SAINT-GOBAIN Bismuth Germanate (BGO) as the γ-ray detector, and an NaI detector with 25 μm Be window as the X-ray detector, was presented. Specifically, the characteristic X-ray fluorescence of the Hg directly induced in this experimental facility was utilized to improve the limits of detection (LOD) of Hg instead of traditional excitation sources. The simulation and experiment results indicated that LOD for Hg by the combined measurement instrument was 19.4 mg kg−1. The empirical formula of the calibration curve in this method was given based on the aforementioned calculations.

The design of a compact D–D neutron generator with a neutron yield greater than 1 × 1 0 8 n/s is presented in this paper. A duoplasmatron ion source is used to supply the deuteron beam. Deuterium ions are extracted and accelerated by a single-gap accelerating column and then bombard onto a drive-in molybdenum target where neutrons are produced through D–D fusion reactions. The target is cooled by the circulating deionized water. The extraction-accelerating electrode and the target system are enclosed inside a stainless steel vacuum vessel. The ion source is at ground potential, and the target is biased to a negative potential. The electric field distribution inside the vacuum vessel, the ion beam optic, the thermal analysis of the target and the effect of secondary electron suppression are calculated. And these calculation results are used to optimize and evaluate the designed scheme. Calculation results show that the design of the neutron generator satisfies necessary engineering requirements.

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 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.

A Secondary Electrons Profile Monitor (SEPM) is developed as part of the beam dose delivery system in a clinical gantry of the Heavy Ion Medical Machine (HIMM). With the purpose of less disturbance to the beam, a thin foil with a thickness of 0 . 7 μ m and an accelerating grid with a diameter of 15 μ m are employed to produce and accelerate the secondary electrons, and two microchannel plates (MCPs) are used to multiply the electrons. Providing the real-time information of beam size, position, flatness, and symmetry in front of the scanning magnet, the beam monitor features an active area of 989 mm 2 , beam intensities between 1.0 × 1 0 3 to 1.0 × 1 0 8 particles per pulse (ppp) and a wide range of beam energies. A prototype is tested at the horizontal treatment room of the HIMM. Using different beam positions, sizes, and energies of 12C 6 + beams, test experiments show that the beam monitor maintains good consistency with a Multi-Strip Ionization Chamber (MSIC). Compared to the MSIC, the SEPM shows a better signal-to-noise ratio (SNR) and higher sensitivity to the variation of the beam.

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.

An intense D-T/D-D neutron generator is currently being developed at the Lanzhou University. The Cockcroft–Walton accelerator, as a part of the neutron generator, will be used to accelerate and transport the high-current low-energy beam from the duoplasmatron ion source to the rotating target. The design of a high-current low-energy beam transport (LEBT) line and the dynamics simulations of the mixed beam were carried out using the TRACK code. The results illustrate that the designed beam line facilitates smooth transportation of a deuteron beam of 40 mA, and the number of undesired ions can be reduced effectively using two apertures.

Si@SiO2@C core double-shell nanocomposites are successfully synthesized by a facile method. The inside shell of SiO2 with a stable mechanical structure can completely limit the volume expansion of Si during charge/discharge cycles and beneficial for a dense carbon shell formation on the surface of SiO2. The outside carbon shell serves as an effective electron conductor to enhance the electronic conductivity of the nanocomposite. This mechanical constraining double-shell protection is good for the electrode to form a stable solid electrolyte film during cycling. The Si@SiO2@C nanocomposites achieve outstanding long-term cycling stability and high rate performance. High capacity of 775 mAh g−1 is obtained after 1000 cycles at 1.0 A g−1 and 617 mAh g−1 after 400 cycles at 2.0 A g−1. The full-cell coupled with LiNi0.8Mn0.1Co0.1O2 cathode exhibits good cycling ability. This excellent electrochemical performance is much improved when compared with other Si/SiOx based anode materials. These structural features make the Si@SiO2@C as promising anode materials for high energy storage lithium-ion batteries.

The micro-channel plate based particle tracking detector described here is part of the detector system used in a series of measurements of astrophysical ( α , p) reactions, which will be studied at the Radioactive Ion Beam Line in Lanzhou, China. This detector will provide on a particle-by-particle basis tracking information and arrival time of radioactive beams with intensities up to 1 0 5 particles per second. The key requirements of the experiments to the detector are that the spatial resolution is below 1 mm, the time resolution is better than 1 ns and the energy loss is less than for a parallel plate avalanche counter. The current prototype is composed of two micro-channel plate detectors with a compact electrostatic field construction and a delay-line readout. Based on the results of α -particle tests, one micro-channel detector can achieve a position resolution of 552 μ m full width at half maximum on the x axis and 735 μ m on the y axis. The tracking system can achieve 705 ps time resolution and can cope with a beam intensity of up to 5 × 1 0 6 particles per second.

The transport characteristics of a space charge-dominated multi-species deuterium beam consisting of $$ D_{1}^{ + } $$ , $$ D_{2}^{ + } $$ , and $$ D_{3}^{ + } $$ particles in an electrostatic low-energy beam line are studied. First, the envelope equations of the primary $$ D_{1}^{ + } $$ beam are derived considering the space charge effects caused by all particles. Second, the evolution of the envelope of the multi-species deuterium beam is simulated using the PIC code TRACK, with the results showing a significant effect of the unwanted beam on the transport of the primary beam. Finally, different injected beam parameters are used to study beam matching, and a new beam extraction system for the existing duoplasmatron source is designed to obtain the ideal injected beam parameters that allow a $$ D_{1}^{ + } $$ beam of up to 50 mA to pass unobstructed through the electrostatic low-energy beam transport line in the presence of an unwanted ( $$ D_{2}^{ + } $$ , $$ D_{3}^{ + } $$ ) beam of 20 mA; at the same time, distortions of the beam emittance and particle distributions are observed.

The secondary neutron emission differential and double-differential cross sections (DX and DDXs) of n + 9Be have been measured at the neutron energy of 21.94MeV using the multi-detector fast neutron time-of-flight (TOF) spectrometer. The data was derived by comparing the measured TOF spectra with detailed Monte Carlo simulation, and corrected with n-p scattering cross section. Meanwhile, theoretical calculations based on the Hauser-Feshbach and exciton model have been performed to compare with experimental data. Measured differential cross sections were also compared with other measurements. It was found that the experimental results were in agreement with other measurements and theoretical calculations, while discrepancies were also present in the whole energy region and at some angles.

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.

Knowledge of actinides (n,f) fission process induced by neutron is of importance in the field of nuclear power and nuclear engineering, especially for reactor applications. In this work, fission characteristics of 238U(n,f) reaction induced by D-T neutron source were simulated with Geant4 code from multiple perspectives, including the fission production yields, total nubar, kinetic energy distribution, fission neutron spectrum and cumulative γ-ray spectrum of the fission products. The simulation results agree well with the experimental nuclear reaction data (EXFOR) and evaluated nuclear data (ENDF). Mainly, this work was to examine the rationality of the parametric nuclear fission model in Geant4 and to direct our future experimental measurements for the cumulative fission yields of 238U(n,f) reaction.

The 232Th(n,{\gamma})233Th neutron capture reaction cross sections were measured at average neutron energies of 14.1 MeV and 14.8 MeV using the activation method. The neutron flux was determined using the monitor reaction 27Al(n,{\alpha})24Na. The induced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. The experimentally determined cross sections were compared with the literatures data, evaluated data of ENDF/B-VII, JENDL-4.0, and CENDL-3.1. The Excitation functions of 232Th(n,{\gamma}) reaction were also calculated theoretically using the TALYS 1.6 computer code., Comment: 8 pages,1 figures and 2 tables

A fast neutron detector, consisting of a high-density polyethylene sheet, a micro-channel plate, a phosphor screen, a reflection mirror and a CCD camera, is proposed for fast neutron radiography purpose. To optimize the design of the detector, a series of simulations are performed by using Geant4 code. Simulation results indicate that the maximum conversion efficiency of the high-density polyethylene is about 0.38% when its thickness is 2 mm. To ensure the spatial resolution of the detector, the distance between high-density polyethylene and micro-channel plate should be as small as possible. The gap between MCP and PS is selected as 2 mm with a bias voltage of −4 kV to balance the luminescence efficiency and the spatial resolution of the PS. With the optimized structure, the detection efficiency of the detector is calculated to be 0.14% and the spatial resolution is possibly better than 500 μm.

A compact D-D neutron generator was developed at Lanzhou University, China. A duoplasmatron ion source was used to produce a higher-current deuteron beam. The deuteron beam could be accelerated up to 150 keV by a single accelerating gap, and bombarded on a pure molybdenum drive-in target to produce D-D fast neutron. A bias voltage between the target and the extraction-accelerating electrode was produced by a resistance to suppress the secondary electron from the target. The neutron generator has been operated for several hundred hours, and the performances were investigated. The available range of the deuteron beam current was 1.0–4.0 mA. EJ410 scintillator detector system was used to measure the fast neutron yields. D-D neutron yield could reach 2.48×108 n/s under the deuteron beam of 3 mA and 150 keV.

The front-end digitization electronics for thin-Resistive Plate Chambers to be installed as part of the ATLAS Muon Spectrometer Phase-I upgrade project is described. The design is based on the CERN HPTDC and GOL chips. In this paper, the design of the digitization system is presented, including power, connection interfaces to front-end amplifier-shaper-discriminator board and to the low level trigger processor board. System performance tests were conducted and validated with a prototype which includes one HPTDC/GOL pair.

A wide field of view (FOV) is an important feature of a detector in the gamma ray observation of sporadic, extended, and transient sources. In this work, we discuss an atmospheric Cherenkov telescope (ACT) with a refractive water convex lens as its light collector, and we test the feasibility of this new approach. We determine the optical properties of a water lens with a diameter of 0.9 m, such as focal length, spot size, and transmittance. The first detection of cosmic rays (CRs) observed in coincidence with a scintillator extensive air shower (EAS) array is presented and discussed.

A 400 kV 80 mA Cockcroft-Walton power supply driven by 2.5 kHz frequency, and 12 kW isolation transformer systems are developed for an intense DD/DT neutron generator. The design, construction, and testing of the high voltage (HV) power supply and isolation transformer systems are detailed reported. The structure of step-up transformers can make the potential distribution uniform, and auxiliary coils of the isolation transformers can improve the power transmission efficiency significantly. The testing results show that the HV power supply can reach 400 kV, and the isolation transformer systems can withstand 400 kV voltages and its power transmission efficiency is about 98.1%.

The High Performance Time to Digital Converter (HPTDC), a multi-channel ASIC designed by the CERN Microelectronics group, has been proposed for the digitization of the thin-Resistive Plate Chambers (tRPC) in the ATLAS Muon Spectrometer Phase-1 upgrade project. These chambers, to be staged for higher luminosity LHC operation, will increase trigger acceptance and reduce or eliminate the fake muon trigger rates in the barrel-endcap transition region, corresponding to pseudo-rapidity range 1

A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm. Test results indicate that the maximum output voltage of the power supply is 282 kV, and the stability of the output voltage is better than 0.63% when the high voltage power supply is operated at 250 kV, 6.9 mA with the input voltage varying ±10%.