[en] We constructed a simple prototype model based on the geometry of the 56 MHz superconducting cavity for RHIC. We studied the formation, in this prototype, of bubbles of liquid helium and their thermal effects on the cavity. We found that due to the low viscosity of the liquid helium, and its small surface tension, no large bubbles formed. The tiny bubbles, generated from most of the area, behaved like light gas travelling in a free space and escaped from the trapping region. The bubbles that were generated in the trapping area, due to its descending geometry, are much bigger than the other bubbles, but due to the liquid flow generated by heating, they still are negligible compared to the size of the trapping region. We expected that the effects of bubbles in our 56 MHz cavity during operation might well be negligible.

[en] It has been proved by practice that nuclear power is a safe, clean and reliable energy source for optimizing the energy supply structure and guaranteeing the national energy safety, economic safety and environmental safety. Nuclear power has developed for over 20 years in China, to satisfy the increasing energy demand for rapid economic growth and optimize the energy supply structure for maintaining the sustainable development, China's government has changed the strategy of developing nuclear power to 'actively boosting nuclear power construction' and established a 'Long- and Medium-term Development Plan of Nuclear Power (2005-2020)' which planned out the installed nuclear power capacity of 40 million kilowatts by 2020, about four percent of the country's total. This lecture shows the current status and future prospect of the nuclear power development in China. (authors)

[en] Diamond amplifiers demonstrably are an electron source with the potential to support high-brightness, high-average-current emission into a vacuum. We recently developed a reliable hydrogenation procedure for the diamond amplifier. The systematic study of hydrogenation resulted in the reproducible fabrication of high gain diamond amplifier. Furthermore, we measured the emission probability of diamond amplifier as a function of the external field and modelled the process with resulting changes in the vacuum level due to the Schottky effect. We demonstrated that the decrease in the secondary electrons average emission gain was a function of the pulse width and related this to the trapping of electrons by the effective NEA surface. The findings from the model agree well with our experimental measurements. As an application of the model, the energy spread of secondary electrons inside the diamond was estimated from the measured emission.

[en] Plasma treatments can be utilized to upgrade the value and utility of fibrous materials for a variety of applications. In this work, the authors have utilized inductively coupled cold plasmas for modification of both lignocellulosic and synthetic materials. ESR was used to monitor the effect of the plasma parameters on the production of free radicals in the substrate and ESCA, wetting techniques, FTIR and wet chemical approaches were used to evaluate changes in the chemical composition of the surfaces. Argon and oxygen plasmas were used for both direct surface modification of the substrates as well as for plasma induced polymerization with conventional vinyl monomers. The plasma modified substrates exhibit improved compatibility, bonding and adhesion as measured by pull-out and T-peel tests. Hydrophobic surfaces were also created at the surfaces of cellulosics with carbon tetrafluoride plasmas. Attempts were made to correlate the plasma reaction parameters with the characteristics of the modified substrates

[en] We recently developed a reliable hydrogenation procedure for the diamond amplifier that assures the generation of a high-current, high-brightness beam. In this paper, we compare room-temperature hydrogenation with that at high temperatures. We identified the factors leading to the decay of quantum efficiency. The optimum temperature for heat treatment ranged from 400-450 C; its superiority was proven in the gain test. Hydrogenated diamond amplifiers exposed to N₂ and air exhibited a good emission after being heated to 350 C; the highest gain we registered in emission scanning was 178. Our systematic study of hydrogenation resulted in the reproducible fabrication of diamond amplifiers.

[en] A 112 MHz superconducting quarter-wave resonator electron gun will be used as the injector of the Coherent Electron Cooling (CEC) proof-of-principle experiment at BNL. Furthermore, this electron gun can be used for testing of the performance of various high quantum efficiency photocathodes. In a previous paper, we presented the design of the cathode stalks and a Fundamental Power Coupler (FPC). In this paper we present updated designs of the cathode stalk and FPC. Multipacting in the cathode stalk and FPC was simulated using three different codes. All simulation results show no serious multipacting in the cathode stalk and FPC.

[en] A 112 MHz superconducting quarter-wave resonator electron gun will be used as the injector of the Coherent Electron Cooling (CEC) proof-of-principle experiment at BNL. Furthermore, this electron gun can be the testing cavity for various photocathodes. In this paper, we present the design of the cathode stalks and a Fundamental Power Coupler (FPC) designated to the future experiments. Two types of cathode stalks are discussed. Special shape of the stalk is applied in order to minimize the RF power loss. The location of cathode plane is also optimized to enable the extraction of low emittance beam. The coaxial waveguide structure FPC has the properties of tunable coupling factor and small interference to the electron beam output. The optimization of the coupling factor and the location of the FPC are discussed in detail. Based on the transmission line theory, we designed a half wavelength cathode stalk which significantly brings down the voltage drop between the cavity and the stalk from more than 5.6 kV to 0.1 kV. The transverse field distribution on cathode has been optimized by carefully choosing the position of cathode stalk inside the cavity. Moreover, in order to decrease the RF power loss, a variable diameter design of cathode stalk has been applied. Compared to the uniform shape of stalk, this design gives us much smaller power losses in important locations. Besides that, we also proposed a fundamental power coupler based on the designed beam parameters for the future proof-of-principle CEC experiment. This FPC should give a strong enough coupling which has the Q external range from 1.5e7 to 2.6e8.

[en] Two years ago, we obtained an emission gain of 40 from the Diamond Amplifier Cathode (DAC) in our test system. In our current systematic study of hydrogenation, the highest gain we registered in emission scanning was 178. We proved that our treatments for improving the diamond amplifiers are reproducible. Upcoming tests planned include testing DAC in a RF cavity. Already, we have designed a system for these tests using our 112 MHz superconducting cavity, wherein we will measure DAC parameters, such as the limit, if any, on emission current density, the bunch charge, and the bunch length. The diamond-amplified photocathode, that promises to support a high average current, low emittance, and a highly stable electron beam with a long lifetime, is under development for an electron source. The diamond, functioning as a secondary emitter amplifies the primary current, with a few KeV energy, that comes from the traditional cathode. Earlier, our group recorded a maximum gain of 40 in the secondary electron emission from a diamond amplifier. In this article, we detail our optimization of the hydrogenation process for a diamond amplifier that resulted in a stable emission gain of 140. We proved that these characteristics are reproducible. We now are designing a system to test the diamond amplifier cathode using an 112MHz SRF gun to measure the limits of the emission current's density, and on the bunch charge and bunch length.

[en] The future electron-ion collider eRHIC requires a high average current (∼50 mA), short bunch (∼3 mm), low emittance (∼20 (micro)m) polarized electron source. The maximum average current of a polarized electron source so far is more than 1 mA, but much less than 50 mA, from a GaAs:Cs cathode. One possible approach to overcome the average current limit and to achieve the required 50 mA beam for eRHIC, is to combine beamlets from multiple cathodes to one beam. In this paper, we present the feasibility studies of this technique. The future eRHIC project, next upgrade of RHIC, will be the first electron-heavy ion collider in the world. It requires polarized electron source with a high average current (∼50 mA), short bunch (∼3 mm), emittance of about 20 (micro)m and energy spread of ∼1% at 10 MeV. The state-of-art polarized electron cathode can generate average current of about more than 1 mA, but much less than 50 mA. The current is limited by the low quantum efficiency, space charge and ultra-high vacuum requirement of the polarized cathode. A possible approach to achieve the 50 mA beam is to employ multiple cathodes, such as 20 cathodes, and funnel the multiple bunched beams from cathodes to the same axis. Fig.1 illustrates schematically the concept of combining the multiple beams. We name it as 'Gatling gun' because it bears functional similarity to a Gatling gun. Laser beams strike the cathodes sequentially with revolution frequency of 700 kHz. Each beam bunch is focused by a solenoid and is bent toward the combiner. The combiner with rotating bending field bends all bunches arriving the combiner with a rotational pattern to the same axis. The energy of each bunch is modified by a bunching cavity (112MHz) and a 3rd harmonic cavity (336MHz). The bunch length is compressed ballistically in the drift space and is frozen after energy has been boosted to 10 MeV by the Booster linac. Each beam bunch contains 3.5 nC charge. The space charge is very strong at energy of 200 keV. A long bunch, σ of 250 ps, is adopted to reduce the space charge on cathode. To compress the beam to final length of 3 mm (10 ps) can be achieved by ballistic compression with a 3rd harmonic cavity.

[en] Objective was to investigate the relationship between survivingexpression and invasiveness of pituitary adenoma. A total of 66 patients, onwhom transphenoidal surgery had been performed between July 2006 and March2008, were enrolled in our study at the Department of Neurosurgery inShandong Provincial Hospital and Jinan Central Hospital, Shandong, P. R.China. All patients were divided into the invasion group (n=39) and thenon-invasion group (n=27) by assessment of preoperative MRI andintraoperative inspection. Survivin expression was determined byimmunohistochemistry. Statistical analysis of surviving expression betweenthe 2 sample groups was accomplished using the chi-square test. Survivin wasexpressed in 46 (69.7%) of the investigated pituitary adenomas. For invasivepituitary adenoma, surviving staining was positive in 35 (89.7%), only 11(40.7%) specimens were positive in noninvasive tumors. The chi-square testdemonstrated a statistically significant difference in surviving expressionbetween invasive and noninvasive pituitary adenoma (X2=14.30, p=0.0002).Survivin was highly associated with invasive pituitary adenoma, it is likelyto serve as a useful tool for confirmation of invasive pituitary adenoma andthe gene could be an effective target for pituitary adenoma gene therapy.(author)