A study of low-energy ion induced radiolysis of thiol-containing amino acid cysteine in the solid and aqueous solution states

The radiolysis of cysteine under plasma discharge and irradiation of low-energy Ion beam was investigated. The damage of cysteine in aqueous solution under discharge was assessed via the acid ninhydrin reagent and the yield of cystine produced from the reaction was analyzed by FTIR In addition, the generation of hydrogen sulfide was also identified The destruction of solid cysteine under low-energy ion beam irradiation was estimated via monitoring IR bands of different functional groups (-SH, -NH3, -COO-) of cysteine. and the production of cystine from ion-irradiated solid cysteine after dissolution in water was also verified These results may help us to understand the inactivation of sulphydryl enzymes under direct and indirect interaction with the low-energy ion irradiation (C) 2010 Elsevier B V All rights reserved.

Ultrahigh compression of water using intense heavy ion beams: laboratory planetary physics

Intense heavy ion beams offer a unique tool for generating samples of high energy density matter with extreme conditions of density and pressure that are believed to exist in the interiors of giant planets. An international accelerator facility named FAIR (Facility for Antiprotons and Ion Research) is being constructed at Darmstadt, which will be completed around the year 2015. It is expected that this accelerator facility will deliver a bunched uranium beam with an intensity of 5x10(11) ions per spill with a bunch length of 50-100 ns. An experiment named LAPLAS (Laboratory Planetary Sciences) has been proposed to achieve a low-entropy compression of a sample material like hydrogen or water (which are believed to be abundant in giant planets) that is imploded in a multi-layered target by the ion beam. Detailed numerical simulations have shown that using parameters of the heavy ion beam that will be available at FAIR, one can generate physical conditions that have been predicted to exist in the interior of giant planets. In the present paper, we report simulations of compression of water that show that one can generate a plasma phase as well as a superionic phase of water in the LAPLAS experiments.

Emittance estimation by an ion optical element with variable focusing strength and a viewing target

The emittance of an extracted ion beam can be estimated to first order by a series of three linear independent profile measurements. This estimation is restricted to the evaluation of an upper limit of the emittance value for a homogeneous, nonfilamented beam. The beam is assumed to be round, respectively elliptical, without any structure of the intensity distribution, no space charge has been assumed for the drifting beam, and the optics is assumed to be linear. Instead of using three different drift sections, a linear focusing element with three different focusing strengths can be used. Plotting the beam radius as function of focusing strength, three independent solutions can be used to calculate the Twiss parameters alpha, beta, and gamma and furthermore the emittance epsilon. Here we describe the measurements which have been performed with the SECRAL ion source at Institute of Modern Physics Lanzhou.

New development of advanced superconducting electron cyclotron resonance ion source SECRAL (invited)

Superconducting electron cyclotron resonance ion source with advance design in Lanzhou (SECRAL) is an 18-28 GHz fully superconducting electron cyclotron resonance (ECR) ion source dedicated for highly charged heavy ion beam production. SECRAL, with an innovative superconducting magnet structure of solenoid-inside-sextupole and at lower frequency and lower rf power operation, may open a new way for developing compact and reliable high performance superconducting ECR ion source. One of the recent highlights achieved at SECRAL is that some new record beam currents for very high charge states were produced by 18 GHz or 18+14.5 GHz double frequency heating, such as 1 e mu A of Xe-129(43+), 22 e mu A of Bi-209(41+), and 1.5 e mu A of Bi-209(50+). To further enhance the performance of SECRAL, a 24 GHz/7 kW gyrotron microwave generator was installed and SECRAL was tested at 24 GHz. Some promising and exciting results at 24 GHz with new record highly charged ion beam intensities were produced, such as 455 e mu A of Xe-129(27+) and 152 e mu A of Xe-129(30+), although the commissioning time was limited within 3-4 weeks and rf power only 3-4 kW. Bremsstrahlung measurements at 24 GHz show that x-ray is much stronger with higher rf frequency, higher rf power. and higher minimum mirror magnetic field (minimum B). Preliminary emittance measurements indicate that SECRAL emittance at 24 GHz is slightly higher that at 18 GHz. SECRAL has been put into routine operation at 18 GHz for heavy ion research facility in Lanzhou (HIRFL) accelerator complex since May 2007. The total operation beam time from SECRAL for HIRFL accelerator has been more than 2000 h, and Xe-129(27+), Kr-78(19+), Bi-209(31+), and Ni-58(19+) beams were delivered. All of these new developments, the latest results, and long-term operation for the accelerator have again demonstrated that SECRAL is one of the best in the performance of ECR ion source for highly charged heavy ion beam production. Finally the future development of SECRAL will be presented.

Thermal Properties Measurement of Micro-Electromechanical System Sensors by Digital Moire Method

The thermal properties of a micro-electromechanical system sensor were analysed by a novel digital moire method. A double-layer micro-cantilever sensor (60 mu m long, 10 mu m width and 2 mu dm thick) was prepared by focused ion beam milling. A grating with frequency of 5000 lines mm- I was etched on the cantilever. The sensor was placed into a scanning electron microscope system with a high temperature device. The observation and recording of the thermal deformation of the grating were realised in real-time as the temperature rose from room temperature to 300 degrees C at intervals of 50 degrees C. Digital moire was generated by interference of the deformed grating and a digital virtual grating. The thermal properties including strain distribution of the sensor and the linear expansion coefficient of polysilicon were accurately measured by the phase-shifted moire patterns.

Cu原子簇触发形核下的深过冷Ag-Ge合金组织演变研究

采用玻璃包覆的方法获得具有较大过冷度的亚共晶、共晶以及过共晶Ag-Ge合金熔体,并通过高能离子束轰击Cu箔产生Cu原子团簇溅射到过冷合金熔体中来触发非均质形核过程.凝固后合金显微组织的分析结果表明:在深过冷合金熔体中引入Cu原子团簇,它对亚共晶、共晶以及过共晶Ag-Ge合金的显微组织演变有着不同的影响效果,分析了显微组织的演变规律与形成机制. The Ag-Ge alloy melts with deeply undercooled hypoeutectic, eutectic and hypereutectic were obtained via glass fluxing technique. The nucleation of the deeply undercooled alloy melts were triggered by atoms cluster sputtering on the surface of the melts. The atoms clusters were generated by an ion beam bombarding on the Cu foil fixed above the alloy melts. The resultant microstructure reveals that the induced atom clusters exert great influence on the microstructural evolution of the highly undercooled eutectic and hypereutectic Ag-Ge alloys, but no obvious influence on the highly undercooled hypoeutectic alloy. The microstructural evolution and formation mechanism were analyzed and discussed.

The magnetic and structure properties of room-temperature ferromagnetic semiconductor (Ga,Mn)N

Diluted magnetic semiconductor (Ga,Mn)N were prepared by the implantation of Mn ions into GaN/Al2O3 substrate. Clear X-ray diffraction peak from (Ga,Mn)N is observed. It indicates that the solid solution (Ga,Mn)N phase was formed with the same lattice structure as GaN and different lattice constant. Magnetic hysteresis-loops of the (Ga,Mn)N were obtained at room temperature (293 K) with the coercivity of about 2496.97 A m(-1). (C) 2003 Elsevier B.V. All rights reserved.

Characteristics of the interface of a laser-quenched steel substrate and chromium electroplate

The interface of a laser-discrete-quenched steel substrate and as-deposited chromium electroplate was investigated by ion beam etching, dissolving-substrate-away and using a Vickers microhardness tester, in an attempt to reveal the mechanism that the service life of the chromium-coated parts is increased by the duplex technique of laser pre-quenching plus chromium post-depositing. The laser quenching of the steel substrate can reduce the steep hardness gradient at the substrate/chromium interface and improve the load-bearing capacity of chromium electroplate. Moreover, the laser quenching prior to plating has an extremely great effect on the morphologies and microstructure of the substrate/chromium interface: there is a transient interlayer at the original substrate/chromium interface while there is not at the laser-quenchedzone/chromium interface; the near-substrate surface microstructure and morphologies of the free-standing chromium electrodeposits, whose substrate was dissolved away with nital 30% in volume, inherit the periodically gradient characteristics of the laser-discrete-quenched substrate surface. (c) 2006 Elsevier B.V. All rights reserved.

离子束溅射法薄膜生长中结瘤微缺陷的生长机理

用离子束溅射法制备了锆单层薄膜．用设计新型夹具和预置种子方法，对薄膜中结瘤微缺陷的生长过程进行了研究．在高分辨率光学显微镜和扫描电子显微镜下观察发现，结瘤在其生长初期呈现出分形的特征．用分子动力学和薄膜生长的扩散限制聚集模型，薄膜中结瘤微缺陷成核时的分形现象得到了很好的解释．

Subsurface damage in optical substrates

The origin, character, analysis and treatment of subsurface damage (SSD) were summarized in this paper. SSD, which was introduced to substrates by manufacture processes, may bring about the decrease of laser-induced damage threshold (LIDT) of substrates and thin films. Nondestructive evaluation (NDE) methods for the measurement of SSD were used extensively because of their conveniences and reliabilities. The principle, experimental setup and some other technological details were given for total internal reflection microscopy (TIRM), high-frequency scanning acoustic microscopy (HFSAM) and laser-modulated scattering (LMS). However, the spatial resolution, probing depth and theoretic models of these NDE methods demanded further studies. Furthermore, effective surface treatments for minimizing or eliminating SSD were also presented in this paper. Both advantages and disadvantages of ion beam etching (IBE) and magnetorheological finishing (MRF) were discussed. Finally, the key problems and research directions of SSD were summarized. (c) 2005 Elsevier GmbH. All rights reserved.

Design and properties analysis of multi-layer dielectric used in pulse compressor gratings

Used in chirped-pulse amplification system and based on multi-layer thin film stack, pulse compressor gratings (PCG) are etched by ion-beam and holographic techniques. Diffraction efficiency and laser-induced damage threshold rely on the structural parameters of gratings. On the other hand, they depend greatly on the design of multi-layer. A theoretic design is given for dielectric multi-layer, which is exposed at 413.1 nm and used at 1053 nm. The influences of coating design on optical characters are described in detail. The analysis shows that a coating stack of H3L (H2L) (boolean AND) 9H0.5L2.01H meets the specifications of PCG well. And there is good agreement of transmission between experimental and the theoretic design. (c) 2005 Elsevier GmbH. All rights reserved.

脉宽压缩光栅用的多层膜设计和性能分析

应用于啁啾脉冲放大技术中的脉宽压缩光栅是基于多层膜作为基底，利用全息干涉技术和离子束技术刻蚀而成。脉宽压缩光栅的衍射效率和抗激光损伤阈值一方面依赖于光栅结构的设计，另一方面很大程度上取决于作为基底的多层膜的设计。给出了以413．1nm作为写入波长，1053nm作为使用波长的多层介质光栅膜的设计．样品在ZZS-800F、型真空镀膜机上采用电子束蒸发方式沉积而成，并给出了膜系结构对光学性能影响因素的详细分析，结果表明膜系H3L(H2L)^9H0．5L2．03H满足光栅膜的指标。给出了样品光学特性测试，其使用波

Negative dispersion mirrors in Ta2O5/: SiO2 for femtosecond Ti : Sapphire lasers by using gires-tournois interferometers

We design and experimentally demonstrate some negative dispersion mirrors with optimized Gires-Tournois interferometers. The mirror structure is composed of 38 alternating Ta2O5 and SiO2 layers and could be regarded as two sections: high-reflectivity section consisting of a series of quarter-wavelength optical thickness stacks and negative-dispersion section consisting of only 13 layers. The designed mirrors exhibit the expected performance. These mirrors were fabricated by using ion beam sputtering. By adopting such mirrors, dispersion of a mode-locked femtosecond Ti:sapphire laser has been compensated for mostly. With two series of the mirrors, 32 fs and 15 fs pulses have been obtained respectively.

Influence of different post-treatments on the structure and optical properties of zinc oxide thin films

Zinc oxide (ZnO) films with c-oriented were grown on fused quartz glass substrates at room temperature using dc reactive magnetron sputtering. The as-grown films were annealed at 700 degrees C in air and bombarded by ion beam, respectively. The effects of post-treatments on the structural and optical properties of the ZnO films were investigated by X-ray diffraction (XRD), photoluminescence (PL), optical transmittance and absorption measurements. The XRD spectra indicate that the crystal quality of ZnO films has been improved by both the post-treatments. Compared with the as-grown sample, both annealed and bombarded samples exhibited blueshift in the UV emission peaks, and a strong green emission was found in the annealed ZnO film. In both optical transmittance and absorption spectra, a blueshift of the band-gap edge was observed in the bombarded film, while a redshift was observed in the annealed film. (c) 2004 Elsevier B.V. All rights reserved.

离子束清洗在激光薄膜中的应用

介绍了在激光薄膜中End—Hall型离子源离子柬清洗的应用。通过实验验证了基片的二次污染和离子柬的清洗效果，观测了离子柬清洗前后基片的表面形貌变化。研究了用离子柬清洗基片时对薄膜抗激光损伤阈值的作用。分析了用离子束清洗基片时其基片表面的性质，如清洁度、表面能、接触角、表面形貌的变化机理。指出了杂质微粒的去除和附着力的增加是如何使薄膜抗激光损伤阈值显著提高的。