| Paper | Title | Page |
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WG1007 |
Status of 500-kV DC Gun at JAEA | |
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| We have developed a 500-kV DC gun at JAEA. It is difficult to apply DC high voltage on a ceramic insulator with a stem electrode because of field emission from the electrode. By employing a segmented insulator with rings which guard the ceramics from the field emission, we succeeded in applying 500-kV on the ceramics for eight hours without any discharge in Dec. 2009. This high voltage testing was performed with a simple configuration without NEG pumps and electrodes. In Jul. 2009, we reached 380kV with electrodes in place before we suffered field emission problem from the cathode electrode. Then we generated beam at 300kV in Nov. 2010. After beam generation we have continued high voltage testing with electrodes in place. In Jul. 2011, we reached 510kV, before suffering another field emission problem from cathode electrodes. The problem may be attributed to small dust inside our gun chamber. We are trying to reach 550kV by solving the small dust problem. Our current status of development will be presented in the workshop. | ||
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Slides WG1007 [6.486 MB] | |
WG2010 |
Strategy of the Lattice and Optics Design of 2 loop Compact ERL and Multi-GeV ERL | |
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| Multi-GeV class energy recovery linac (ERL) is considered as a successor of X-ray light source, Photon Factory. As an optional light source, XFEL-O is planned to be operated by utilizing the ERL loop as a recirculating linac to accelerate an electron beam twice. In both ERL and XFEL-O projects, the extreme low emittance is necessary to achieve the high performance. Therefore, an emittance growth induced by space charge (SC) effects and coherent synchrotron radiation (CSR) wake is the critical issue in an optics design. The SC effects are remarkable in non-relativistic energy region such as an injector and after energy recovering. CSR wake affect an electron bunch in the bending magnets. To evaluate the beam quality including the effects, we utilize the 6D tracking codes, General Particle Tracer (GPT) and 'elegant'. The codes are switched at the reasonable electron energy: it is named self-consistent start-to-end simulation (S2E). The S2E simulation has been demonstrated for the 200 MeV class Compact ERL (cERL) with a double loop circulation. We report the strategy of lattice design and S2E simulation for the multi-GeV ERL as well as cERL. | ||
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Slides WG2010 [2.290 MB] | |
| WG2012 | Generation of High-Brightness Gamma-Rays from Energy-Recovery Linac | 56 |
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| Energy recovery linacs (ERL) is an ideal device for laser Compton scattered gamma-ray source, because a fresh electron bunch of ultra-small emittance interacts with laser pulse for LCS. The property of LCS gamma-rays, monochromaticity, flux and brightness can be significantly improved by using an ERL. We discuss beam dynamics issues in ERL-LCS gamma-ray sources. | ||
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Slides WG2012 [1.294 MB] | |
WG2022 |
Envelope Matching from Injector to Main Linac for ERL | |
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| Since the brilliance of electron beams in Energy Recovery Linac (ERL) is primarily determined by the performance of its injector, the improvement of the injector performance is essential issue. After the injector, the electron beams are accelerated by a main linac to relativistic energy region, in which an emittance growth due to space charge force can be ignored. Because an injected beam with lower energy and a returned beam with higher energy pass through the same main linac, the beam optics in the main linac is restricted to design a reasonable optics throughout the return loop. Therefore, minimization of the emittance, and matching of beam optics to that of the return loop have to be carried out during the injector optimization. The injector parameters have been optimized using multi-objective method with genetic algorithm and a particle tracking code GPT. However, the optimized emittance was far larger than a target emittance, so that some conflict between the minimization of emittance and the restriction of beam optics have been found in the optimization. We report the optimization results, and the strategy to avoid the conflict and to produce a reasonable beam performance. | ||
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Slides WG2022 [2.786 MB] | |
| PSP021 | Design of ERL Spoke Cavity for Non-destructive Assay Research | 140 |
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| We are proposing non-destructive assay system of nuclear materials with laser Compton scattering combined with an energy-recovery linac and a laser. To construct this system for nuclear safeguards and security purpose, it is important to make the accelerating cavity small. The spoke cavity has advantages over the elliptical cavity to adopt for our proposing system. We are designing a spoke cavity favorable to compact cavity. Design optimization calculation of the spoke cavity shape is being carried out using 3D electro-magnetic field simulation code with multi-objective genetic algorithm. The results will be presented. | ||