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The basic principle of neutron detection was proposed in the twentieth century, especially G.F.Knoll compiled Radiation Detection And Measurement in 1979, including detailed in principles and methods of radiation detection and measurement on a variety of hot and fast neutrons. In recent decades there is not have a big breakthrough on the principle of neutron detection development, but there is a great improvement in the performance and scope of neutron detectors. Depending on the working principle of neutron detector, it is roughly divided into the following three: Gas detectors, Semiconductor detectors and Scintillator detector.

Gallium nitride (GaN) is the third generation of semiconductor material; it has a large band gap, high thermal conductivity, low dielectric constant, high drift speed, etc. Radiation detectors based on GaN material have small volume, high radiation resistance, and fast response, can be used to replace the existing Large Hadron Collider vertex detector and track detector. Energy deposition characteristic of GaN detectors to radiation beam is an important factor for detection efficiency, and there are many factors that affect the energy deposition characteristics of the detector, like the detection mechanism, the impact of material properties, the type of incident ray, radiation energy, and many other factors. This paper studies the physical properties of GaN detector by calculation based on Monte Carlo simulation. Energy deposition characteristics are discussed respectively for incident γ-ray with different energy, in the front-end and back-end add PTFE material. The results of our study present the theoretical properties of GaN radiation detectors.

Boron-containing plastic scintillator detectors have a high detection efficiency for low-intensity thermal neutrons and fast neutrons which is currently the preferred types of neutron detector. This article is based on Monte Carlo method, studied boron-containing plastic scintillator for neutron detection performance, and analysis the energy deposition flux characteristics and detection efficiency when low intensity fission neutron incident to the boron plastic scintillator. We obtain the low-flux neutron detector performance in a variety of neutron source energy, boron-containing plastic scintillator diameter and length. Results showed that, when the boron-containing plastic scintillator lengths increase, the energy deposition flux will increase. When the length and diameter is constant, increasing source strength can increase the energy deposition flux brought by the recoil proton to a certain extent. When the source intensity over after thermal neutrons, due to the decrease of the cross section, the energy deposition fluxes brought by the react of neutrons and will decrease. The results provide help for low intensity fission neutron radiation detection technology with high sensitivity.

Electrode jump motion strategy was adopted to fabricate noncircular tool using wire electrical discharge grinding (WEDG). The machining procedure and electrode jump motion strategy for noncircular tool fabrication were determined through experiments. This approach has been verified by successfully machining of rectangular electrode (38μm×38μm, 700μm length) and D-shaped electrode (diameter 45μm, height 42μm, 500μm length). D-shaped array holes of 6×6 matrix were drilled using corresponding single noncircular tool which was manufactured by the adopted machining approach. The array holes have tight diameter tolerance and height tolerance which are both less than 2μm, and positioning errors are both less than 1μm in the direction of the X, Y-axes.

The inkjet template is an important part of digital printing equipment. The diameter of hole arrays on the template determines the consistency of the ink droplet and thus affects print quality. To improve the printing performance of digital printing equipment, this study investigated the effect of micro-electrical discharge machining (micro-EDM) on the diameter consistency of micro-hole arrays on an inkjet template. Combining block electrical discharge grinding and wire electrical discharge grinding enabled the online processing of the fine tool electrode, whose diameter can be stably controlled at less than 45 μm, whose maximum diameter deviation was about 1 μm. The tool electrode can also be used to process micro-hole arrays. Subsequently, the relationship between the discharge energy of micro-EDM and the erosion material was theoretically analyzed, as was the effects of the diameter consistency of the micro-electrode itself on that of the micro-hole array processed by the micro-electrode and the relationship between processing parameters and the discharge gap between the micro-electrode and the workpiece. Experimentations were conducted on the effect of the flow rate, flush angle, and rotation speed of the electrode and the resistivity of de-ionized water to the diameter consistency of the micro-hole arrays. On the optimized parameters, a 16×16 micro-hole array with a diameter deviation of less than 2 μm was successfully processed, and the average diameter of the holes, about 44 μm, was used for the inkjet template. Beside, an electrode with a diameter of 14μm is also machined and it was used to process a 8×8 micro-hole array, whose diameter deviation is 0.9μm and average diameter is less than 20μm. Large number of experiments show that by the proposed method, one electrode can stably machined 800 holes with diameter less than 50μm, and their diameter deviation is less than 3μm. ​The digital printing equipment with these holes can meet the current demand for components with micro-hole arrays.

As demands for the micro array holes in modern industry and the characteristics of micro Electrical Discharge Machining (micro EDM), a new type micro EDM machine tool used to machine micro array holes was designed and manufactured. The machine tool contains following systems: the mechanism system, the control system, the pulse generator system and other auxiliary systems. Each system was studied respectively. Base on a large number of experiments, finally, a sample with 256 array holes was processed by the machine tool. The diameter of single hole is 45µm and precision of the holes is ±1µm. The sample has been successfully applied to R & D test of micro nozzle components

Experiments of micro-EDM in gas (dry MEDM) were conducted on the conditions of an external supplying gas mode based on a RC pulse generator. The objective of the work is to optimize machining parameters of the dry MEDM and investigate the machining performance of the ultrasonic induced workpiece vibration. Micro solid copper electrodes were fabricated on line by the block grinding method. Range analysis results of the Taguchi approach indicate that capacitance, servo feed speed have great effect on the material remove rate (MRR); and capacitance and open voltage are main influencing factors on the tool relative wear ratio (TWR). An optimal parameters combination was obtained under the experimental conditions. The experimental results of the ultrasonic induced workpiece vibration demonstrate that high frequency workpiece vibration with a suitable input current could improve MRR and TWR of the dry MEDM.

Micro-EDM technology has the advantages of no-contact and no-cutting force, it has been used in many fields. In order to use micro-EDM to machine proprietary micro array holes, which needs high precise of hole spacing and consistent hole diameter, a new macro-micro dual-drive system of micro-EDM have been made. It uses macro drive to move to a place, measures the error with the high precise grating, and uses micro drive to compensate the error. Online measurement proved that this method has important value if it will be used in micro-EDM.