| Paper | Title | Page |
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| MOPOW017 | Generation of GeV Photons from X-ray Free Electron Laser Oscillators | 751 |
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| We propose generation of narrow-bandwidth GeV photons, gamma-rays, via Compton scattering of hard X-ray photons in X-ray free-electron laser oscillators. The gamma-rays have a narrow-bandwidth spectrum with a sharp peak, ~0.1% (FWHM), due to the nature of Compton scattering in relativistic regime. Such gamma-rays will be a unique probe for studying hadron physics. We discuss features of the gamma-ray source, flux, spectrum, polarization, tunability and energy resolution. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW017 | |
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| WEPMB018 | Multipactor Simulations in 650 MHz Superconducting Spoke Cavity for an Electron Accelerator | 2161 |
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Funding: The work is supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan. In order to realize a compact industrial-use X-ray source based on the laser-Compton scattering, a superconducting spoke cavity for an electron accelerator operated at 4K is under development. While the initially proposed operating frequency was 325MHz considering the 4K operation, we decided to start from the half scale model at 650MHz to accumulate our production experience of spoke cavity within our limited resources. In the present contribution, procedures and results of multipactor simulations for 650MHz spoke cavities are briefly introduced. |
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| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB018 | |
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| WEPMB024 | Study on Nondestructive Inspections for Super-conducting Cavity | 2174 |
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Funding: The work is supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan. We have been studying nondestructive inspections for super-conducting spoke cavities. The temperature mapping (T-map) and X-ray mapping (X-map) are powerful inspection methods to locate a hot spot during the vertical RF tests. There would be a defect under the hot spot and the defect may be the cause of a quench. Our XT-map system (a combined system of T-map and X-map) has a high resolution in space. Because the huge amount of sensor signals are multiplexed at a hi-speed scanning rate in the vicinity of the sensors, the small number of signal lines makes the installation process easy and reduces the system complexity. Our XT-map got useful results on finding a defect in vertical RF tests of International Linear collider super-conducting cavity. The XT-map system is useful as low cost nondestructive inspections for superconducting spoke cavity. The study will be reported. progresses will be reported. |
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| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB024 | |
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| THPMB013 | Proposal of 6 GeV Energy Recovery Linac Hybrid Machine | 3254 |
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We proposed 6 GeV Energy Recovery Linac (ERL) as an intense gamma-ray source for the polarized positron source of International Linear Collider (ILC)*. In this scheme, Coherent Synchrotron Radiation from quasi-CW 6 GeV electron beam is stacked in optical cavity at middle infrared region, and it is used for inverse Compton scattering to generate 10 MeV polarized gamma-ray. The same 6 GeV superconducting linac accelerates both the electron and positron beams up to 5 GeV for injection to the dumping ring. Furthermore, it is available for X-ray light source by adding another recirculation loop. It can be expected as a diffraction limit light source at 10 keV, and the target of the brilliance is 1022-23 ph/s/mm2/mrad2/b.w.0.1%.
* M. Shimada, Proceedings of IPAC'13 |
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| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB013 | |
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| THPOW008 | DC Photoemission Gun Upgrade at the Compact ERL | 3944 |
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Funding: This work is partially supported by a JSPS Grant-in-Aid for Scientific Research in Japan (15H03594). The DC photoemission gun at the compact ERL (cERL) has stably provided beam for ERL commissioning and laser Compton scattering experiments since April 2013. The operational voltage has however been limited to 390 kV due to failures of two segments out of the ten segmented insulator. In order to recover 500 kV operation, we installed an additional two segmented insulator on the existing ten segmented insulator during summer shutdown in 2015. The details of the gun upgrade and the operational experience of the upgraded cERL gun will be presented. |
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| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW008 | |
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| TUPOW036 | Recent Developments and Operational Status of the Compact ERL at KEK | 1835 |
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| The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW036 | |
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| WEPMB025 | Fabrication of Superconducting Spoke Cavity for Laser Compton Scattered Photon Sources | 2177 |
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Funding: The work is supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan. We have launched a 5-year research program to develop superconducting spoke cavity for laser Compton scattered (LCS) photon sources. For realizing a wide use of LCS X-ray and γ-ray sources in academic and industrial applications, we adopt the super-conducting spoke cavity to electron beam drivers. The spoke cavity has advantages such as relative compactness in comparison with an elliptical cavity of the same frequency, robustness with respect to manufacturing inaccuracy due to its strong cell-to-cell coupling, the better packing in a linac to install couplers on outer conductor. On the other hand the spoke cavity has disadvantage of more complicated structure than an elliptical cavity. Though our proposal design for the photon source consists of the 325 MHz spoke cavities in 4K operation, we have begun to fabricate the half scale model of 650 MHz spoke cavity in order to accumulate our cavity production experience by effective utilization of our limited resources. In this paper, we present our fabrication status. |
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| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB025 | |
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