Four refrigerator cooled cryopumps (DN1250 LN₂) were designed and manufactured by BISEE. The pumps were used in space environment simulation system to meet the demand of the high vacuum in thermal vacuum test. The design and test method for pumping speed, cool down time and crossover were introduced in this paper. A test system was built to test the main performance of the cryopumps. The experimental results show that the pumping speed for N₂ of the pump is up to 57000 L/s, the cool down time is about 330min, and the crossover is over than 3.0 ×10⁵Pa·L.

In the development process of the microwave tubes, the main purpose of vacuum degassing system for the electron gun is to obtain the data between current/voltage and temperature, to test the quick start parameter, to measure thermal expansion and to minimize the material evapotranspiration and outgassing. According to the relation between structure and property of the electron gun, two operating station vacuum degassing system was designed and developed with the function of temperature, thermal expansion and other measure property. The final system pressure is better than  2×10^-7 Pa. In the vacuum degassing system, mechanical pump is used as the backing up pump, while the molecular pump and the ion pump are the main pumps. Each operating station can work simultaneously to improve the quality and to save time for increasing the efficiency. Indicator lights are equiped with the system to prevent the potential problems for the electron guns or the vacuum system that is caused by misoperation. A large amount of data obtained from experiments verifies the working principal, structure design and good properties of the system. It is applicable to different types of electron guns for microwave tubes, which has important significance in the small amount production of klystrons.

T he mechanical performance of the high -speed shafting of compound and greased molecular pump was analyzed, and thus the design optimization was carried out. In this paper, the CG-250/1600 pump was used as the prototype, and the bearing span and shaft stiffness were optimized and improved. The dynamic and static mechanical properties of the high -speed shaft were calculated before and after optimization design of the high -speed shafting. All the critical speed and mode formation of the rotor system were obtained, and two kinds of structures were tested and verified. The results show that the experimental results are basically the same as the theoretical analysis. After optimization, the critical speed of the rotor system varied slightly; the amplitude-frequency characteristic was basically unchanged; the start and stop process was more stable; the initial unbalance response decreased obviously, the hidden danger caused by the resonance was reduced, and the difficulty of the dynamic balancing debugging was reduced greatly.

Ion getter pumps (IGPs) are particularly appropriate for use in modern accelerator facilities because of their high reliability, cleanliness and the absence of vibration that could disturb the trajectory of the beam. Normally, T-pieces are used to connect the pumps to the beam tube. These reduce the effective pumping speed and require the use of radiofrequency (RF) shielding which is complicated and expensive. Moreover, very often the accelerated particles are sensitive to stray magnetic fields and the impedance of the surrounding vacuum tube. Magnetic fields generated by the ion pump magnets, which are asymmetrically oriented to the beam tube, can be a major drawback. To overcome these problems, we have developed, in collaboration with the Deutsche Elektronen -Synchrotron (DESY), an innovative in -line ion getter pump which can be mounted directly into a beam line without a T -piece and which has a symmetrical arrangement of the magnets around the beam tube. Additionally, RF shielding can be easily integrated inside the in-line pump. Using this innovative in-line concept (Patent EP2 431996A1) ion pumps will become an integral part of the beam tube for the first time when installed on the X -FEL system at DESY. The arrangement of the magnets and the geometry of the pole piece, used to guide the magnetic field lines, were designed to minimize any disturbance on the beam trajectory. Moreover, the element location inside the pump has been optimized to“selfshield”the beam, without requiring the addition of expensive and complex optical shields. Finally, thanks to the in-line solution, a simple RF shield (a copper coated tube with pumping slits) can now be easily installed directly inside the pump at the accelerator site installed directly inside the pump at the accelerator site.

In this article, the selection of thin film materials, failure mechanism, mechanical properties test method and fatigue failure are reviewed. The influence of tensile bending on the microstructure of the film and the initiation, electrical properties, expansion and saturation of microcracks were analyzed. The effects of film material, grain size and film thickness on the fatigue life of thin film were summarized. On membrane surface, along the thickness direction and control of fatigue crack was discussed. It is shown that the future studies on mathematical modeling and film fatigue experiment need to be combined together for better results.

The cleaning sources with argon ions using vacuum arc discharge technology are new methods to improve the adhesive strength between top layer and substrate, where electrons coming from arc discharge plasma by hollow cathode gun, heater filament gun and vacuum cathode arc sources produce argon ions and then the argon ions were used to clean the samples before coating process. With the help of this technology, bias currents on substrate holder can reach between 10A and 30A under the condition of bias voltages of only 200V. This new clean method has great advantage, since it brings the high ion density. The article also gives a brief introduction on the vacuum arc deposition systems and magnetron sputtering system with this advanced Ar ⁺ cleaning sources.

Numeric simulation of the three-layer hot-wall metal-organic chemical vapor deposition（MOCVD）vacuum reactor was performed, including the design and the final flow field distribution. In this article, on the basis of the optimization array of the nozzles, the substrates susceptor, the near ceiling wall around the susceptor and the wall above the susceptor were all heated and the partial hot-wall reactor was formed. Furthermore, the design of the vacuum reactor, the flowing speed of the top layer and the bottom layer were all investigated in detail. As a result, we can ensure that in the material growth region, the precursors and the carrier gases were all kept in a stable flow states without swirls and the precursors were concentrated on the position of the substrates, which increased the utilization of the reactive materials effectively and the reaction on the other wall was reduced largely. At last, materials was grown in this hot-wall MOCVD reactor and the thickness of the film was averaged. The FWHM of XRD rocking curves for the wafer is 149.8 arcsecond, indicating that good materials quality was gained.

TiO2 films were prepared by electron beam evaporation deposition technique with different deposition rates. Based on transmittance spectrums of the samples, the optical band gaps of films were obtained. The refractive index, extinction coefficient and thickness of the films were investigated by using an ellipsometer. The electric field intensity of the film was analyzed and the laser damage characteristics were studied. It was found that the optical band gap of TiO₂ film was relatively stable in the range of process factors, and the change corresponding to the deposition rate was not significant, among 3.95eV -3.97eV. The ellipsometry test results showed that the refractive index increased from 1.9782, 1.9928, to 2.0021 (at the wavelength of 1064 nm) with the increasing of deposition rate from 0.088nm/s，0.128nm/s to 0.18 nm/s, whereas decreased to 1.9663 at the deposition rate of 0.327nm/s. The extinction coefficient of the film increased with the enhancement of deposition rate. Broken by the same high energy laser, the sizes of the laser damage spots of the films which deposited at the low deposition rate were almost the same. However, the spot size was significantly enlarged when the film was prepared at the deposition rate of 0.327nm/s. The films with low absorption and high laser-induced damage threshold can be obtained at low deposition rates.

The Al -doped ZnO (AZO) thin films were deposited by DC -RF coupled magnetron sputtering system on glass substrates at room temperature. The RF sputtering power increased from 0 to 200W. The structure, surface morphology, optical and electrical properties of the AZO films were investigated by using X -ray diffractometer, scanning electronic microscope, ultraviolet-visible spectrophotometer and hall effect test system as a function of different RF sputtering power, respectively. The results indicate that AZO thin films with excellent performance can be prepared by DC-RF coupled magnetron sputtering at room temperature. Meanwhile, the RF sputtering power has a significant impact on the optical and electrical properties of the AZO thin films. With the increase of RF sputtering power, the compactness of AZO films and the grains size were increased, the surface morphology and growth form of the AZO films change greatly. Under RF sputtering power of 200W, the lowest resistivity of the AZO film is  5.39×10 ^-4 Ω·cm. The average optical transmittance of the AZO film prepared at room temperature is approximately 82.6% in the visible wavelength.

Leakage is one of the most frequent failures of high-pressure heater in nuclear power plants. As an important part of CI, high -pressure heater plays a key role in determining the smooth and stable operation of the equipment. This paper mainly introduces the application of helium leak detection and vacuum differential pressure leak detection in heat transfer pipe and seal welding of high-pressure heater, which can largely improve the efficiency of testing and repairing.

In this paper, the principle of the leak detection technology of helium mass spectrometer and blowing leak detection method are briefly described. Taking the vacuum furnace as an example, several common leakage problems in practical production were analyzed in detail and corresponding solutions were made.

In this paper, a three dimensional model of DC arc thermal plasma torch was established. The CFD software FLUENT was then used to simulate the spatial distribution of temperature and velocity for nitrogen thermal plasma, and the influence of the working gas flow on the spatial distribution of temperature were studied base on the model. The results show that the highest plasma temperature occurs near the cathode and decreases with increasing the axial distance, while the situations will reverse for plasma velocity and it reaches the maximum at the torch exit. There was no significant effect on the spatial distribution of plasma temperature by increasing the working gas flow rate, while the plasma temperature tends to decrease as increasing the working gas flow rate.

Vacuum heat treatment is widely used by more and more enterprises because of its advantages such as non-oxidation and decarbonization, good comprehensive mechanical properties, high degree of automation, and green and pollution -free. However, due to its high degree of automation and the requirements for sealing the chamber, high requirements are placed on the operator's skills, daily maintenance and the cleanliness of the furnace; this paper studied the causes and harm of pollution in the chamber of gas quenching vacuum furnace. The measures to prevent the pollution of chamber during using the equipment and the daily maintenance were discussed.

With the wide application of high -power magnetron, people are paying much attention to the heat -dissipation performance of high -power magnetron, because the heat -dissipation performance of magnetron directly affects the lifespan and stability of magnetron. Referring to the working characteristics of air -cooled magnetron, we optimize the existing magnetron technology in this paper. Firstly we decide the designing direction of analysis and optimization theoretically, and then simulate it by the software Icepak, and obtain a feasible plan. Samples are made to test the actual heat -dissipation performance. We find that increasing the superficial area of the heat -dissipation system of the magnetron and improving the Reynolds number of the heat-dissipation system could obviously improve the heat- dissipation performance.

At present, some enterprises can not deal with the dangerous industrial wastewater in a cheap and easy way. In view of this problem, we introduced a new method to deal with the wastewater. The Double -way Phase Change Heat Exchanger (DPCHE) has a single vacuum -compression pump as the power source. Due to the vacuum effect, the wastewater is evaporated into vapour under low temperature and low pressure conditions. Then, the vapour is turned into an overheating steam under high temperature and high pressure because of the compression. The overheating steam is recirculated in the DPCHE for heat transfer, so the heat is passed from the overheating steam to the wastewater, and overheating steam will condense into clean water. We carried out the parameter design for the DPCHE, preheater and vacuum-compression pump. The corresponding calculation formula and working parameters were also given. A set of system design parameters were selected according to the analysis results as the reference for production design.

This article briefly describes the effects of low -orbit space environmental factors such as atomic oxygen, ultraviolet radiation, charged particle irradiation and thermal cycling on material properties. The synergistic effects of ultraviolet radiation, charged particle irradiation and temperature cycling on the interaction of atomic oxygen with materials are reviewed. It provides a reference for ground simulation experiments of material space environmental effects, and also provides a basis for the study of multi-factor synergistic effects of materials.