| Paper | Title | Page |
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| WG2000 | ERL2011 Summary of Working Group 2 Beam Dynamics | 36 |
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Slides WG2000 [0.800 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] | |
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] | |
| WG3006 | Development of Input Coupler for Compact ERL Main Linac | 91 |
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| We fabricated the prototype of an input coupler, which has two ceramic windows to keep the inside of the superconducting cavity clean, for ERL main linac and performed the high power test. Required input power is about 20kW with standing wave condition for the cavity acceleration field of 20MV/m. In this high power test, the one ceramic window, named as a cold window, was installed into the vacuum insulating chamber and cooled by liquid Nitrogen. First, the multipacting at 10kW level prevented the power increasing. By using the pulse processing method for 8 hours, power finally reached the 25kW with standing wave condition. We could also keep feeding 20kW power into coupler for 16 hours. From these results of high power test, this prototype coupler satisfied our thermal and RF requirements. | ||
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Slides WG3006 [5.352 MB] | |
| PSP020 | Recent Progress of an Yb-doped Fiber Laser System for an ERL-based Light Source | 137 |
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| We have been developing an Yb fiber laser system for an ERL photocathode gun. The Yb fiber laser system is expected to have both high stability and high output power required for the drive laser. We have improved the output power of Yb fiber laser system up to 31 W at 85 MHz by installing a preamplifier, and demonstrated wavelength conversion from 1 μm to 800 nm with a conversion efficiency of 9.5% by generating a supercontinuum light, which is planned to be amplified by optical parametric amplification(OPA) in future. In addition, we are developing a Nd:YVO4-based mode-locked oscillator that can operate at the same frequency as the RF frequency of a superconducting accelerating cavity. We report our recent progress in this development. | ||