HOMEトピックス一覧2010年のトピックス＿Kwang-Je Kim博士をお迎えしてのXFEL-Oに関するセミナー

topic_2010.01.13

Kwang-Je Kim博士をお迎えしてのセミナー ：　XFEL-Oに関するセミナー　

12月２１日に4号館セミナーホールで、ＸＦＥＬ−Ｏの提案者であるKwang-Je Kim博士(APS/ANL)を招く機会が実現しました。また同時に、その詳細なシミュレーション解析の結果に関して日本原子力研究開発機構の西森信行博士、そしてＸＦＥＬ−Ｏの実現によって飛躍的に更なる発展が期待されるＸ線非弾性散乱の第一人者の日本原子力研究開発機構・量子ビーム研究開発部門・副部門長の水木純一郎博士にも講演を頂き、ＸＦＥＬ−Ｏに関する光源と利用研究のセミナーが行われました。半日のセミナーにもかかわらず多くの聴衆が参加し、その新しい光源の可能性への期待を膨らませました。 　　　　　　　　　　　　

 XFEL-Oseminar

PROGRAM

13:30-13:35 Welcome & Opening address (O. Shimomura/IMSS)
13:35 - 14:35
 An X-ray Free Electron Laser Oscillator: Promises and Challenges
(Dr. Kwang-Je Kim/ANL)
【Abstract】Having seen proof that FEL principles work for hard x-rays for lCLS, it is time to seriously consider more advanced hard x-ray sources. An x-ray FEL oscillator (XFELO) promises to provide an extremely narrow bandwidth of a few meV (corresponding to 10-7 in relative bandwidth) with an average brightness higher by several orders of magnitude than, and peak brightness comparable to, the SASE XFEL. These capabilities will provide breakthrough opportunities in areas complementary to SASE XFELs as well as drastically enhance the capabilities of techniques developed at third-generation synchrotron radiation facilities-particularly those requiring high coherence and high spectral purity. The main technological challenges for XFELO are: an injector providing a continuous sequence of ultralow emittance, low intensity electron bunches at a few MHz repetition rate; high quality diamond crystals serving as the main mirrors for x-ray cavity; high-reflectivity grazing incidence, curved mirrors for controlling the transverse mode profile; tight tolerances for angular stability of the optical elements. We will present progresses in conceptual and experimental efforts to advance the state-of-the-arts in these topics.
Presentation file（PDF)

14:35 - 15:05 A simulation of XFELO operating in a scheme of velocity bunching
(Dr. Nobuyuki Nishimori /JAEA)
【Abstract】 An X-ray synchrotron light source, a multi-GeV ERL, is one of the targets of our Japanese collaboration　towards future ERL light sources. As an option of the multi-GeV ERL, we consider an X-ray FEL oscillator (XFEL-O) to produce hard X-ray pulses with excellent temporal coherence. In this study, we present simulation results of the XFEL-O such as FEL lasing including spectral narrowing and nonlinear phase shift at Bragg reflectors. We also propose a scheme of velocity bunching in an ERL main linac for X-FELO operation. The velocity bunching brings significant enhancement of the small-signal gain and an X-FELO at 0.1 nm is feasible with a 5-GeV electron beam from the ERL light source planned in Japan.　
Presenation file(PDF)

15:05 - 15:20

Coffee break
15:20 - 16:20
 The idea how to measure dynamical charge susceptibility combined with X-ray and Neutron inelastic scattering
(Dr. Jun-ichiro Mizuki /JAEA)
【Abstract】It is well-known that the inelastic X-ray scattering (IXS)intensity is directly related to the dynamical charge susceptibility. Thespectrum of IXS in the energy between meV and a few 100meV, which is important energy range to investigate the physical properties in materials, has been explained so far with a contribution of oscillatingions, "phonons". Of course this is not correct. The spectrum should have the information on dynamical dielectric function which consists of not only phonons, but also polarization properties of electrons in a field of rigid lattice. The talk is addressed to the idea how to get the information on dynamical electric function by a combination of x-ray and neutron inelastic scattering methods.
Presentation file(PDF)
16:20 - 16:30
 General Discussion

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