02 Synchrotron Light Sources and FELs

A16 Energy Recovery Linacs (ERLs)

Paper	Title	Page
MOZBPA02	A Review of ERL Prototype Experience and Light Source Design Challenges	39
	S.L. Smith CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	The presentation will review the status of commissioning of ERL light source prototype projects drawing on experience from the JLab IR FEL, UK's ERL prototype ring and the Cornell injector project. State of the art design for future light source based on ERLs and FELs will be illustrated using the concept for the UK's 4GLS project.
	Transparencies
MOPCH064	The Specification, Design and Measurement of Magnets for the Energy Recovery Linac Prototype (ERLP) at Daresbury Laboratory	175
	F. Bødker Danfysik A/S, Jyllinge N. Marks, N. Thompson CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	The Energy Recovery Linac Prototype (ERLP) is currently under construction at Daresbury Laboratory in the UK and will serve as a test bed for the investigation of technologies and beam physics issues necessary for the development of Daresbury Laboratory's Fourth Generation Light Source (4GLS) proposal. A number of new ERLP beam transport system magnets have been procured for the project. The magnets have been designed, manufactured and measured by Danfysik following a stringent magnetic field specification produced by Daresbury Laboratory. In this paper we summarise the magnet specification. We then present details of the magnetic and mechanical design of the magnets and finally discuss the measurement techniques used to demonstrate that the field quality of the magnets satisfied the specification.
MOPCH065	Fabrication and Installation of Superconducting Accelerator Modules for the ERL Prototype (ERLP) at Daresbury	178
	P. vom Stein, S. Bauer, M. Pekeler, H. Vogel ACCEL, Bergisch Gladbach R. Bate, C.D. Beard, D.M. Dykes, P.A. McIntosh, B. Todd CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	Installation and commissioning of the superconducting energy recovery linac(ERL) prototype is under way at Daresbury Laboratory. ACCEL have manufactured two superconducting accelerator modules for the injector and the linac, operating at 2K with 1.3 GHz TESLA type cavities. Each module contains two cavities and is designed to provide an accelerating voltage of 25 MV in cw mode. This paper presents details of the module fabrication, cavity preparation and performance results. An overview of the cryogenic installations for the modules is given and status results of the commissioning are discussed.
MOPCH066	The Conceptual Design of 4GLS at Daresbury Laboratory	181
	J.A. Clarke CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	4GLS is a novel next generation proposal for a UK national light source to be sited at Daresbury Laboratory, based on a superconducting energy recovery linac (ERL) with both high average current photon sources (undulators and bending magnets) and three high peak current free electron lasers. Key features are a high gain, seeded FEL amplifier to generate XUV radiation and the prospect of advanced research arising from unique combinations of sources with femtosecond pulse structure. The conceptual design is now completed and a CDR recently published. The 4GLS concept is summarised, highlighting how the significant design challenges have been addressed, and the project status and plans explained.
MOPCH069	Lattice Design for the Fourth Generation Light Source at Daresbury Laboratory	184
	B.D. Muratori, M.A. Bowler, H.L. Owen, S.L. Smith CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire S.V. Miginsky BINP SB RAS, Novosibirsk
	The proposed Fourth Generation Light Source (4GLS) has three electron transport paths, an energy recovery loop containing the main linac, IDs and a VUV-FEL, a separate branch after the main linac for an XUV-FEL and a transport path for an IR-FEL. The first two present major challenges in lattice design. The energy recovery loop will be fed by a high average current gun, with bunches of charge of about 80 pC. High charge (1nC) bunches from a high brightness gun will be accelerated prior to the main linac and split into the XUV-FEL branch using energy separation after the main linac. We present a lattice design and results from numerical modelling of the electron bunch transport. The requirements of the machine are short bunches, a small emittance for both branches and an overall topology which gives a reasonable dimension for the building. Different transport and compression schemes were assessed to meet these requirements whilst balancing the disruptive effects of longitudinal and transverse space charge, CSR, wakefields and BBU. Investigations into all of these instabilities are summarized together with other transport issues and the resulting requirements on all IDs.
MOPCH070	The Status of the Daresbury Energy Recovery Prototype Project	187
	D.J. Holder, J.A. Clarke, P.A. McIntosh, M.W. Poole, S.L. Smith CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire N. Bliss CCLRC/DL, Daresbury, Warrington, Cheshire E.A. Seddon CCLRC/DL/SRD, Daresbury, Warrington, Cheshire
	The major component of the UK's R&D programme towards an advanced energy recovery linac-based light source facility is a 35 MeV technology demonstrator called the energy recovery linac prototype (ERLP). This is based on a combination of a DC photocathode electron gun, a superconducting linac operated in energy recovery mode and an IR FEL. The current status of the of this project is presented, including the construction and commissioning progress and plans for the future exploitation of this scientific and technical R&D facility.
MOPCH071	Optimization of Optics at 200 MeV KEK-ERL Test Facility for Suppression of Emittance Growth Induced by CSR	190
	M. Shimada, A. Enomoto, T. Suwada, K. Yokoya KEK, Ibaraki
	Energy Recovery Linac (ERL) gets a lot of attention as a next period light source instrument. To produce high-brightness and short pulse synchrotoron lights, it is necessary to pass through high current and short bunch electron beams to the insertion part of ERL with keeping the low emittance and the low energy spread. However, it is challenging because Coherent Synchrotorn Radiation (CSR) generated at bending magnets is potential sources of the emittance growth which is enomous especially for high current, short bunch and a low energy beam. Therefore, it is benefit to a gradual bunch compression in the arc after accelerating the beam up to the full energy. The beam optics and lattice design of 200MeV ERL Test Facility is optimized to suppress the emittance growth caused by CSR at the arc section on two conditions, high-current mode (100mA, 1psec) and short bunch mode (0.1psec) similar to 5GeV ERL facility proposed by Cornell University.
MOPCH072	Adjustable Input Coupler Development for Superconducting Accelerating Cavity	193
	M.V. Lalayan, M.A. Gusarova, V.I. Kaminsky, A.A. Krasnov, V.A. Makarov, N.P. Sobenin MEPhI, Moscow A.A. Zavadtsev, D.A. Zavadtsev Introscan, Moscow
	The waveguide and coaxial-type input couplers for Energy Recovery Linac type injector cavity electrodynamical and thermal simulation results are presented. The devices are designed to feed the superconducting cavity with up to 500 kW RF power in continuous wave regime at 1.3 GHz operating frequency. The cavity external quality factor adjustment is provided. The heat load to the cryogenic system was lowered to a tolerable level by coupler design optimization.
MOPCH073	A Project of a High-power FEL Driven by an SC ERL at KAERI	196
	A.V. Bondarenko, S.V. Miginsky BINP SB RAS, Novosibirsk Y.H. Han, Y.U. Jeong, B.C. Lee, S. H. Park KAERI, Daejon
	A project of a high-power FEL at Korea Atomic Energy Research Institute is described. The FEL is driven by a superconducting energy recovery linac. The future ERL will be connected to the existing machine without any modification. It consists of two 180-degree bents and two straight sections: one is for the FEL, another for a Compton X-rays source. One can choose the regime controlling the lenses. The total ERL is isochronous to avoid any problems with longitudinal beam instability. The total relative emittance degradation through the whole machine is ? 1.5. The FEL will be based on a 2 m helical in-vacuum undulator made of permanent magnets. One mirror of the optical cavity is blind and made of copper; the other one, the outcoupler, is semi-transparent and made of CVD diamond. The expected average power is a few kW and the tuning range 35…70 ?m.