Solid State Phenomena Vol. 107

Abstract: In this note, we describe the upgrade effort to convert the SIAM Photon source into an Xray synchrotron radiation facility with photon energies up to some 15 keV. This conversion of SIAM Photon into a third generation light source can be achieved through an increase of the electron beam energy and the addition of recently available superconducting wavelength shifter and multipole wiggler magnets. A gradual retrofit of vacuum chambers aiming at a reduction of electron beam instabilities as well as a modification of the focusing structure are expected to greatly increase the brightness of the photon beam. These upgrades will be implemented gradually over a few years to minimize the interruption of ongoing experimental activities. As an ultimate upgrade, a study has been started which shows the feasibility to implement a 2 GeV storage ring replacing the present ring in the same foot print. This new ring is configured to provide double the number of insertion device photon beam lines.

Abstract: Soft X-ray Contact Microscopy (SXCM) of Caenorhabditis elegans nematodes wit typical length 800 μm and diameter 30 μm has been performed using the PALS laser source of wavelength λ = 1.314 μm and pulse duration τ (FWHM) = 400 ps. Pulsed soft X-rays were generated using molybdenum and gold targets with laser intensities I ≥ 1014 W/cm2. Images have been recorded on PMMA photo resists and analyzed using an atomic force microscope operating in contact mode. Cuticle features and several internal organs have been identified in the SXCM images including lateral field, cuticle annuli, pharynx, and hypodermal and neuronal cell nuclei.

Abstract: Femtosecond electron bunches can be generated from a system consisting of an RF gun with a thermionic cathode, an alpha magnet, and a linear accelerator and can be used to produce femtosecond (fs) electromagnetic radiation pulses. At the Fast Neutron Research Facility (FNRF), Thailand, we are especially interested in production in Far-infrared (FIR) and x-radiation. In the far-infrared, radiation is emitted coherently for wavelengths which are longer than the electron bunch length, yielding intense radiation. Although, the x-rays emitted are incoherent, its femtosecond time scale is crucial for development of a femtosecond x-ray source.

Abstract: The SURIYA project is designed to generate femtosecond (fs) electron pulses at the Fast Neutron Research Facility (FNRF), Thailand. The fs electron pulses production system consists mainly of a thermionic cathode RF-gun, a magnetic bunch compressor in form of an alpha magnet (α-magnet), a linear accelerator (linac), a beam transport line, and various electron beam diagnostic instruments. This system aims to produce a 20-25 MeV electron beam with micropulses of less than 100 fs in length. Theses pulses can be used either for direct experimentation or to produce fs pulses of intense coherent far infrared radiation (FIR) and/or x-ray. In this paper, an overview of the system and characteristics of its major components will be presented.

Abstract: A 13.56 MHz radio-frequency (rf) driven multicusp ion source has been constructed [1] to produce a high argon ion current density. Milliampere-range argon ion current can be extracted from the source. An in-waveguide microwave plasma source has been utilized as the ion beam neutralizer [2]. The neutralization source was placed 20 cm downstream from the extraction system. With the former extraction system, comprised of extraction electrodes and an Einzel lens, the electrons from the neutralizer were attracted to the high positive potential of the lens. Consequently, the potential of the lens drops and the beam is diverged. To suppress electrons from being accelerated to the Einzel lens a negatively biased electrode was placed before the last electrode, which is grounded, to produce a retarding electric field for electrons. The hole of the electrode was made small to make sure that the potential at the center is negative enough to suppress electrons. All simulations have been performed with the KOBRA3-INP simulation software. The results of the beam shape from the simulation will be presented.

Abstract: Low-energy ion beam has widely been applied in the field of research on genetic modification since the 1980’s in China. It has been shown, in principle and practice, that ion beam, as a new mutagenic source, has many outstanding advantages: lower damage rate, higher mutation and wider mutational spectrum. Many new varieties of crops and microbes have been bred using these techniques and used in agricultural and industrial production. Meanwhile the method of transferring genes assisted by ion beam has also been developed. Scientists in China have begun to pay a big attention to study on ion beam biology. Up to now there have been seven key laboratories of ion beam bioengineering of Chinese Academy of Sciences and Chinese Provinces to be in succession created. Recent advances in research on ion beam biology have opened new areas of study in the field of life sciences, such as the role of low energy ions in the chemical origin and the interplanetary molecules forming, the health risk of low-energy particle radiation in the environment.

Abstract: Industrially relevant PIII conditions were applied to H13 and CrNiMo 316 steel as well as in CrCoMo and Ti6Al4V metal alloys. Typically, nitrogen ions were implanted at peak voltages of 10 to 15 kV, 50 to 80 (s pulse durations, and 1 to 2 kHz frequencies, for treatment times of 1 to12h. Case thicknesses of more than 20 μm were achieved in treated H13 steel which resulted in reduced friction and wear. For CrNiMo steel, a wear reduction of as high as 160 times was obtained besides a significant reduction of the coefficient of friction. Much thinner modified layer was obtained for Ti6Al4V but sufficient for an important improvement of the surface hardness.

Abstract: This paper summarizes the development of the research and application of ion implantation biotechnology on plant, animal and microorganism varieties Improvement, and it also includes the contemporary effects and utilization of ion implantation, and the application of ion implantation on trans-gene plant. In 1980s, cooperated with Anhui Academy of Agriculture Sciences, the ion implantation was applied for crops’ improvement by Plasma Physics Research Institute of the Chinese Academy of Sciences, and made greater progress in both practice and theory, which attracted many scholars inside and outside. By using ion implantation, extensive researches had been made in different materials including plant, animal and microorganism on different levels. With combination of physics and biology, as a new cross subject and a unique technology system, the ion implantation biotechnology came into being, and created more dramatically economic and social benefit in crops improvement by transferring exogenous gene. This paper summarizes the development of the research and application of ion implantation biotechnology.

Abstract: An aluminum nitride (AlN) target for Al-Kα X-ray source with high power and long service life has been developed by N2 + ions assisted Al vapor deposition method (IBAD). The AlN film formations were carried out at the Al deposition rate varied from 2.0 nm/s to 0.15 nm/s with a fixed low-energy N2 + ion of 1 keV. The films were deposited on Cu substrate at room temperature. The AlN films were characterized by an X-ray diffraction, an electron probe X-ray microanalysis and a Knoop-hardness measurement. The AlN deposited at the Al deposition rate of 0.5 nm has a N/Al ratio of 0.4, a Knoop-hardness of ~1500 and a low resistance of ~0.2 . Comparison of durability test between the AlN target and a conventional Al target was performed. It has been revealed, after 500 hours under an electron bombardment of 300 mA at 20 kV, that there were no change of morphology and X-ray intensity on the AlN-surface whilst cracks due to the heat-cycle fatigue covered the Al-surface.

Abstract: The interaction between ion beam and biological cells has been studied to apply ionbeam- induced mutation to breeding of crops and gene transfer in cells. Formation of micro-craters has been observed after ion bombardment of plant cells and they are suspected to act as pathways for exogenous macromolecule transfer in the cells. A technique of in-situ atomic force microscopy (AFM) in the ion beam line is being developed to observe ion bombardment effects on cell surface morphology during ion bombardment. A commercial AFM is designed to place inside the target chamber of the bioengineering ion beam line at Chiang Mai University. In order to allow the ion beam to properly bombard the sample without the risk of damaging the scanning tip and affecting normal operation of AFM, geometrical factors have been calculated for tilting the AFM with 35 degree from the normal. In order to avoid vibrations from external sources, mechanical designs have been done for a vibration isolation system. Construction and installation of the in-situ AFM facility to the beam line have been completed and are reported in details.