| Paper | Title | Page |
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| TUPE083 | Effects of Alignment Error of Main Superconducting Cavities on ERLs and their Correction | 2314 |
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In ERLs, superconducting cavities accelerate low-emittance beams with high-gradient standing-wave RF fields. If alignment error of the cavities is considerable, they can harmfully affect the beam trajectory and quality because the cavities have strong transverse focusing. Achieving high alignment accuracy of the cavities is difficult compared with the other ERL elements such as magnets because the cavities are contained in cryomodules. Therefore we studied effects of the alignment error of main superconducting cavities with analytical approaches and simulations, using a one-loop model of the compact ERL as an example. In this paper, we present the effects of alignment error of main superconducting cavities on ERLs and their correction. |
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| TUPE085 | Application of the Eigenvector Method with Constraints to Orbit Correction for ERLs | 2320 |
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Orbit correction in an ERL is more complicated than those of an ordinary linac and a transport line, because the ERL beam passes a straight section containing main superconducting cavities at least two times with different energies. A corrector in this section gives a different kick angle to the beam in a different turn. Therefore a sophisticated orbit correction method is required for ERLs and ERL-based light sources. The eigenvector method with constraints (EVC)* can perform global orbit correction under constraint conditions and has been proposed and used for uniting global and exact local orbit corrections mainly in storage-ring based SR sources**. We applied this EVC method to orbit correction in an ERL. In this paper, we present how to use the EVC method for an ERL and simulation results of orbit correction for the compact ERL. * N. Nakamura et al., Nucl. Instr. Meth. A 556 (2006) 421-432. |
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| TUPE090 | Progress in Construction of Gun Test Facility for Compact ERL | 2335 |
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Compact ERL (cERL) is a test accelerator to establish accelerator technologies for GeV-class synchrotron light source based on ERL (Energy Recovery Linac), and will be constructed in KEK. It consists of an injector with photo cathode 500 kV DC gun, a merger section, super conducting RF cavities for acceleration and energy recovery, return loops, and a beam dump. To operate and test the photo cathode gun before installing it in the cERL injector, Gun Test Facility is constructing in KEK, AR south experimental hall. The Gun Test Facility has two photo cathode guns, 200 kV gun developed by Nagoya University and new 500 kV gun which is being developed, laser system to be emitted electrons from photo cathode surface, beam transport lines, and a beam diagnostics system. The diagnostics system consists of a double slit emittance measurement system, beam position monitors, transverse profile monitors, and a deflecting cavity to measure the bunch length and the longitudinal profile. In this presentation, the progress in the construction of the Gun Test Facility and the beam dynamics simulation will be presented. |
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| WEPEA034 | Development and Operational Status of PF-Ring and PF-AR | 2561 |
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KEK manages two synchrotron radiation sources, Photon Factory storage ring (PF-ring) of 2.5 GeV and Photon Factory advanced ring (PF-AR) of 6.5 GeV. These rings share an injector linac with the two main rings of KEK B-factory, 8-GeV HER and 3.5-GeV LER. Recently, the linac has succeeded in a pulse by pulse multi-energy acceleration. A top-up operation of PF-ring has been realized as the simultaneous continuous injection to the 3 rings, PF-ring, HER and LER. Development of new injection scheme using a pulsed sextupole magnet continues aiming at practical use in the top-up operation. A rapid-polarization-switching device consisting of tandem two APPLE-II type undulators has been developed at PF-ring. The first undulator was installed in 2008, and the second one will be installed in 2010 summer. PF-AR, operated in a single-bunch mode at all times, has been suffered from sudden lifetime drop phenomena attributed to dust trapping for many years. Using the movable electrodes installed for experiment, we confirmed that the discharge created by the electrode was followed by the dust trapping, and succeeded in a visual observation of luminous dust streaking in front of CCD cameras. |
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| TUPE091 | Recent Progress in the Energy Recovery Linac Project in Japan | 2338 |
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Future synchrotron light source using a 5-GeV-class energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting active R&D efforts for that. We are developing super-brilliant DC photocathode guns, two types of cryomodules for both injector and main superconducting linacs, 1.3 GHz high CW-power rf sources, and other important components. We are also constructing a compact ERL for demonstrating the recirculation of low-emittance, high-current beams using those key components. We present our recent progress in this project. |
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| WEPD027 | Tuning of the Fast Local Bump System for Helicity Switching at the Photon Factory | 3150 |
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The fast local bump system for the helicity switching of variably polarizing undulators has been developed at the Photon Factory ring. The system consists of two APPLE-II type variably polarizing undulators and five identical horizontal kicker magnets for local bump with four small corrector magnets to prevent the leakage of the bump. At present, one undulator and the local bump system with corrector magnets are installed. For beam test, the system was operated with frequency up to 50 Hz with feed forward correction. In this presentation, after brief description of the system configuration, the results of the test operation and fine tunings of the fast local bump system are shown. |
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| WEPD060 | Update of Main Magnet Power Supplies at Pf-Ar | 3233 |
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At PF-AR, a bending magnet power supply was updated in 2007. The converter works in the 3 pulsed PWM. A trouble caused by higher harmonics above 40th had occurred. We manufactured filters and installed in 6.6kV ac lines in 2008. Furthermore, a QF magnet power supply was updated in 2009. This paper reports on the update of PF-AR main magnet power supplies. |