Cavity optimization for compact accelerator-based free-electron maser
In previous works [1] we have successfully commissioned pre-bunched beam pumped free electron maser based on Stimulated Coherent Diffraction Radiation (SCDR) generated in an open resonator. An ultra-fast Schottky Barrier Diode (SBD) detector has enabled us to investigate the properties of the radiation in the range from 3 to 5 mm of wavelengths among broad frequencies stored in the cavity as well as the intrinsic properties of the cavity itself. We observed a turn-by-turn SCDR generated by a multibunch electron beam and directly measured the opened cavity quality factor of 11.4. In this report we represent the work directly related to optimization of both the maser system to achieve higher quality factor of the cavity essential to gain soft X-ray production via Thomson scattering in the next stage of the experiment and measurement system for better characterization of the maser light. One way of optimization is to minimize losses of energy due to transmission through resonator mirrors. For this purpose we have designed and constructed a test setup to investigate reflection and transmission properties of different mirror materials. Theoretical calculations have been performed using optical constants and theoretical models of electrical permittivity to compare with experimental results. In this report we summarize the experimental activity, represent new experimental results and represent steps undertaken to achieve the new resonator mirror design. For better understanding of the resonator performance a test of the SBD detector linearity is also demonstrated.
Development of microwave and soft X-ray sources based on coherent radiation and Thomson scattering
Compact, high-brightness and reliable sources in the VUV and the soft X-ray region may be used for numerous applications in medicine and biochemistry. We propose a new approach to produce the intense beams of X-rays in the range of ≤ 500 eV based on compact electron accelerator. We present our first experimental results obtained in the Laser Undulator Compact X-ray facility (LUCX) at KEK: High Energy Accelerator Research Organization devoted to the development of a compact microwave and soft X-ray source based on coherent diffraction radiation and Thompson scattering processes.
Reexamining and Extending the Dual Mediation Hypothesis in an On-line Advertising Context
The relationship between attitude toward the advertisement (A_ad) and intentions to buy (I_b) is a controversial one. The present research examines the potential for a direct relationship between A_ad and I_b within an on-line advertising context, substituting A_site (attitude toward the Web site) for A_ad. The article replicates previous findings with respect to the four competing A_ad models they tested. The article then predicts and finds a significant A_site → I_b path based on an opportunity and motivation perspective. In terms of opportunity, Web sites contain nonproduct information that is independent of traditional measures of brand attitude (A_b), such as security, ease of use, transactional capabilities, which are likely to affect I_b. Further, on-line consumers are motivated to process this information when they visit a Web site because they cannot directly examine the products they are considering. Evidence for the opportunity and motivation perspective is provided by the decomposition of A_site into its claim and non-claim components and assessment of the A_site → I_b path across levels of motivation to process. Implications for on-line advertisers are discussed.