08 Applications of Accelerators, Technology Transfer and Industrial Relations

U02 Materials Analysis and Modification

Paper Title Page
MOPEA030 Material Recognition System using 950 keV X-band Linac with Dual Energy X-ray Scintillator Array 130
 
  • K. Lee, S. Hirai, M. Uesaka, T. Yamamoto
    The University of Tokyo, Nuclear Professional School, Ibaraki-ken
  • E. Hashimoto
    JAEA, Ibaraki-ken
  • T. Natsui
    UTNL, Ibaraki
 
 

Dual energy X-ray system using high energy X-ray from linear accelerator (Linac) applies two times X-ray irradiation which have different energy spectrum each other in many cases. Two different X-rays yield two tomography images which is analyzed through numerical calculation with pixel values for material recognition of a object. However if the X-ray generation is not stable, the results of numerical calculation shows irregular tendency during the inspection. We propose the scintillator array in detection part, because two tomography images are obtained by just one irradiation. That leads to the time saving during inspection and the cost down for additional facilities. The optimal condition is researched to increase the ability of material recognition in interesting materials designing the detector with CsI and CdWO4 scintillators. We focus on the discrimination between heavy materials and light materials with the system in the research. X-ray source is 950 keV X-band Linac we developed for industrial application, which produce pulsed X-ray, 10 pps with around 400 mA beam current.

 
MOPEA031 Application of Liquid Cluster Ion Beams in Surface Processing 133
 
  • H. Ryuto, G.H. Takaoka, M. Takeuchi
    Kyoto University, Photonics and Electronics Science and Engineering Center, Kyoto
 
 

A liquid cluster ion beam irradiation system has been developed for surface processing and modification of solid materials used in the semiconductor industry. The liquid clusters are produced by the adiabatic expansion method. The vapor pressure of the source materials such as water or ethanol is increased by heating, and ejected to a vacuum chamber through a supersonic nozzle. The ionized clusters by the electron impact ionization are accelerated to typically 3-9 kV after the elimination of monomers by the retarding voltage method, and irradiated on the solid surfaces. The sputtering yield of silicon by the ethanol cluster ion beam irradiation was more than 100 times larger than that by an argon monomer ion beam. On the other hand, the radiation damage and surface roughness caused by the ethanol cluster ion beam irradiation decreased when the mean cluster size was increased by increasing the retarding voltage. Irradiation effects of liquid cluster ion beams on polymers are also discussed.

 
MOPEA033 Characteristics of the Electron Linac Based Coherent Radiation Light Source at OPU 139
 
  • S. Okuda, T. Kojima, R. Taniguchi
    Osaka Prefecture University, Sakai
 
 

The coherent synchrotron and transition radiation from the bunched electron beams of a linear accelerator (linac) has continuous spectra in a submillimeter to millimeter wavelength range at relatively high peak-intensity. The coherent radiation has been applied to absorption spectroscopy for various kinds of matters. However, the number of such light sources are very small. A new pulsed coherent transition radiation light source has been established by using the electron beams of a 18 MeV S-band electron linac at Osaka Prefecture University (OPU). In the linac pulsed electron beams are injected from a thermionic triode gun with a cathode-grid assembly at pulse lengths of 5 ns-4 μs at a pulse repetition rate of 500 pulses/s in maximum. The light source will be also applied to the pump-probe experiment using the pulsed electron beam or the pulsed coherent radiation as a beam for pumping matters and the coherent radiation for probing them. The transient properties of the matters excited with the electron beams or the coherent radiation will be investigated. The characteristics of the light source are reported.

 
MOPEA034 Study of Positron Production System using Superconducting Electron Linac 142
 
  • N. Hayashizaki
    RLNR, Tokyo
  • R. Kuroda, B.E. O'Rourke, N. Oshima, R. Suzuki
    AIST, Tsukuba, Ibaraki
  • E.J. Minehara
    WERC, Tsuruga , Fukui
 
 

Positron that is the antiparticle of the electron, by the specific character, can evaluate vacant spaces in microstructure from atomic level to nanometer level, which is difficult in other measurement methods. In the case of high functional material, this structure often relates directly to the performance, and the evaluation method that uses the positron beam is expected as a useful measurement tool to develop a new material. If it is able to produce more high-intense and low-energy positron beam with an accelerator, the microstructure evaluation is carried out in prompt and high accuracy for various demands of the material analysis. We have studied a positron production system using a superconducting electron linac instead of normal conducting one. Electron beam accelerated with the superconducting linac is irradiated on tantalum and converted to bremstrahlung photons, and positron beam is produced by pair creation of them. The designed acceleration energy of the superconducting electron linac is 15-40 MeV and the maximum beam power is 10 kW. The system configuration and the progress status will be presented.

 
MOPEA035 Pulse Radiolysis with Supercontinuum Probe Generated by PCF 145
 
  • Y. Hosaka, R. Betto, A. Fujita, K. Sakaue, M. Washio
    RISE, Tokyo
  • S. Kashiwagi
    ISIR, Osaka
  • R. Kuroda
    AIST, Tsukuba, Ibaraki
  • K. Ushida
    RIKEN, Saitama
 
 

We have been studying a pump-probe pulse radiolysis as an application of the S-band photo cathode RF-Gun. Pump-probe spectroscopy is well-known method of pulse radiolysis measurement. We had used 5MeV electron beam obtained from the photo cathode RF-Gun as a pump beam, and used the white light emitted from Xe flash lamp or generated by self-phase modulation in the water cell as a probe light. However, the white probe light with high intensity, good stability and broad spectrum is a key issue for pump-probe pulse radiolysis. Supercontinuum light with photonic crystal fiber (PCF) is a new technique of white light generation. Short pulse laser through PCF spreads its spectrum by nonlinear optical effect. Supercontinuum light has very continuous spectrum, and it is studied for various applications recently. For applying supercontinuum light as a probe of pulse radiolysis experiment, we have generated a supercontinuum radiation with 7 picoseconds pulse width IR (1064nm) laser and PCF, and measured its properties. The experimental results of supercontinuum generation and design of a supercontinuum based pulse radiolysis system will be presented.

 
MOPEA036 Design of High Brightness Light Source based on Laser-Compton Undulator for EUV Lithography Mask Inspection 148
 
  • K. Sakaue, A. Endo, M. Washio
    RISE, Tokyo
 
 

We will present a design of high brightness light source for EUV lithography mask inspection. The required system parameters are minimum brightness of 2500W/mm2/Sr at 13.5nm/2% bandwidth. Our design consists of super-conducting DC RF-gun as a radiator and 10.74nm CO2 laser stacked in an optical cavity as a laser undulator. Recent achievements of each component technologies, which is 1.3GHz SC-RF-gun, 10kW average power short pulse CO2 laser, and laser storage optical super-cavity, indicate the feasibility of producing required brightness based on laser Compton undulator. Design parameters of high brightness EUV source, the technological gap of the present component technologies and required further developments will be resented at the conference.

 
MOPEA037 Activation and Discoloration of Polymer by Proton Beam 151
 
  • S.J. Ra, M.H. Jung, K. R. Kim
    KAERI, Daejon
 
 

During the beam irradiation experiments with more than a few MeV energetic protons, nuclear reactions are occurred in sample materials. Because of these nuclear reactions, the samples are activated so many kinds of additional problems for the post-processing of the samples are caused; such as time-loss, inconvenience of sample handling, personal radiation safety, etc. For in-vitro experiments, we observe death of tumor cells by proton irradiation. The use of large activated container material can cause erroneous results in this case. To solve these problems, we studied why the samples are activated and how the level of the activation can be reduced. In our proton beam irradiation experiments, the target materials can be defined as the container and sample itself. We could easily reduce activation of container material comparing to activation of sample itself. Therefore, we tried to find less activated container material by irradiating proton beam in PS (Polystyrene), PMP (Polymethypenten), and PMMA (Poly methacrylate). We used 45 MeV proton beams (MC-50 Cyclotron, KIRAM) with 10 nA.

 
MOPEA038 Gamma-Ray Source for Nuclear Resonance Fluorescence Based on Compton Storage Ring 154
 
  • P. Gladkikh, E.V. Bulyak, V.A. Skomorokhov
    NSC/KIPT, Kharkov
  • T. Omori, J. Urakawa
    KEK, Ibaraki
 
 

Nuclear resonance fluorescence (NRF) is the one of the most promising methods of the nuclear waste management and of the modern technologies of the nonproliferation of nuclear weapons. There are a few proposals of the usage of NRF *,**. Yet linac and energy recovery linac are suggested as the electron source for the Compton scattering (CS) of the laser photons. The storage ring is capable to produce sufficiently higher beam intensity and is more effective since the electrons interact with the laser pulse many times. The storage ring with the electron energy from 240 to 530 MeV is proposed for the CS of 1.16 eV laser photons in the report. Maximal energy of the scattered gamma rays lies within range from 1 MeV to 5 MeV. It allows detecting of practically any isotope in analyzed objects. The specificity of the proposed storage ring is usage of the crab-crossing of the electron and laser beams. Due to crab-crossing we expect to obtain the gamma beam intensity approximately 5*1013 gammas/s for laser flash energy 5 mJ stored in the optical cavity. Both electron beam and gamma beam parameters are studied analytically and by simulation of the CS in the designed ring lattice.


* J. Pruet et al. Detecting clandestine material with nuclear resonance fluorescence. J. Appl. Phys., 99, 123102-1-11 (2006).
** R. Hajima et al. J. Nucl. Sci. Tech., vol. 45, pp. 441-451, 2008.

 
TUOCRA02 HIGS - A High-intensity, Mono-energetic, and Tunable Source of Polarized Gamma-rays
 
  • Y.K. Wu
    FEL/Duke University, Durham, North Carolina
 
 

After years of development, High Intensity Gamma-ray Source (HIGS) at Duke University, the most powerful Compton gamma-ray source in the 1 to 100 MeV region, has recently become a dedicate light source facility for scientific research. Driven by the kW power of a storage ring FEL, the HIGS produces high-intensity gamma-ray beams with an exceptionally high flux, a total flux up to few 1010 g/s and a spectral flux of more than 103 g/s/eV, in the few MeV to 10 MeV region. With the present configuration, the HIGS has a wide energy tuning range from 1 to 100 MeV, a high degree of polarization (nearly 100%) switchable among linear, left-, and right-circular polarizations, and a high energy-resolution as low as 0.8% (FWHM). The planned future upgrades will enable the HIGS to produce high-energy gamma-ray beams up to 160 MeV, providing a precision tool for the photo-pion physics research. With these outstanding capabilities, the HIGS is a world-class Compton gamma-ray source for frontier research in a wide range of scientific areas from nuclear physics to astrophysics, from medicine to industry.

 

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