Belomestnykh S.

Paper	Title	Page
MO202	Status of the Cornell ERL injector cryomodule	9
	M. Liepe, S. Belomestnykh, E. Chojnacki, V. Medjidzade, H. Padamsee, P. Quigley, J. Sears, V. Shemelin, V. Veshcherevich CLASSE, Cornell University
	Cornell University is developing and fabricating a SRF injector cryomodule for the acceleration of the high current (100 mA) beam in the Cornell ERL prototype and ERL light source. Major challenges include emittance preservation of the low energy, ultra low emittance beam, cw cavity operation, and strong HOM damping with efficient HOM power extraction. Axial symmetry of HOM absorbers, together with two symmetrically placed input couplers per cavity, avoid transverse on-axis fields, which would cause emittance growth. Fabrication of five 2-cell niobium cavities and coaxial blade tuners, ten twin high power input couplers, and six beam line HOM absorbers has finished. The injector cryomodule is presently under assembly at Cornell University with beam test planned for early 2008. In this paper we report on the cryomodule fabrication and assembly status.
	Slides(PDF)
MO302	Superconducting RF in storage-ring-based light sources	19
	S. Belomestnykh CLASSE, Cornell University
	Third generation synchrotron light sources are small storage rings operating in the energy range of 1.5 to 3.5 GeV. These machines require relatively low total accelerating voltage and high RF power to compensate particle beam energy losses to X-rays. Strong damping of Higher-Order Modes (HOMs) is also necessary for stable operation of high-current multi-bunch beams. Superconducting HOM-damped single-cell cavities are ideal for such applications. Their ability to transfer almost all RF power to the beam and to operate at high accelerating gap voltages reduces the number of installed cavities thus improving overall efficiency of the RF systems. In the past many laboratories were reluctant to use superconducting RF (SRF) technology as it was considered more complex than conventional copper accelerating structures. Proliferation of superconducting insertion devices made having a cryogenic plant the necessity for every contemporary light source thus providing infrastructure for SRF as well. With the successful and reliable operation of HOM-damped cavities at CESR and KEKB, technological developments at CERN and other laboratories and the technology transfer to industry, SRF has become the readily available technology of choice for new and small labs with no prior experience in the field. In this paper we will describe the use of superconducting cavities in fundamental RF systems and as passive structures for bunch lengthening. Operating experience and recent achievements from light sources around the world will be discussed.
	Slides(PDF)
WE305	Overview of input power coupler developments,pulsed and CW	419
	S. Belomestnykh CLASSE, Cornell University
	While many successful high power fundamental input couplers have been developed over years for superconducting cavities, projects like the International Linear Collider (ILC), Energy Recovery Linacs (ERLs), Free Electron Lasers (FELs), and Superconducting RF (SRF) guns bring new challenges. As a result, a number of new coupler designs, both for pulsed and CW operation, was proposed and developed recently. In this paper a brief discussion of design options and technical issues associated with R&D, testing and operation of the high power couplers will be given first. Then we will review existing designs with an emphasis on new developments and summarize operational experience accumulated in different laboratories around the world.
	Slides(PDF)
WEP26	High power tests of input couplers for Cornell ERL injector	517
	V. Veshcherevich, S. Belomestnykh, P. Quigley, J. Reilly, J. Sears Cornell University
	RF power couplers for the ERL injector, currently under construction at Cornell University, have been fabricated. The couplers were assembled in pairs in the liquid nitrogen cryostat, built for their tests. First two prototype couplers were tested using an IOT transmitter and a resonant ring for additional power amplification. They were tested up to the goal power level of 50 kW CW and used later for tests of the first injector cavity. However, the first pair of couplers showed excessive temperature rise in some points. Therefore, minor changes in the design have been done to improve cooling. The couplers of updated design were successfully tested from a klystron up to the power level of 60 kW CW. In situ baking was implemented for coupler installed in the cryostat.
WEP33	Realisation of a prototype superconducting CW cavity and cryomodule for energy recovery	545
	P. A. McIntosh, R. Bate, C. D. Beard, M. Cordwell, D. M. Dykes, S. Pattalwar, J. Strachan, E. Wooldridge STFC Daresbury Laboratory S. Belomestnykh, M. Liepe, H. Padamsee Cornell University A. Buechner, F. Gabriel, P. Michel FZR Rossendorf T. Kimura, T. I. Smith Stanford University J. Byrd, J. N. Corlett, D. Li, S. Lidia LBNL
	For Energy Recovery applications, the requirement for high-Q accelerating structures, operating in CW mode, at large beam currents, with precise phase & amplitude stability and modest accelerating gradients are all fundamental in achieving intense photon fluxes from the synchronised FEL insertion devices. Both Daresbury Laboratory and Cornell University are developing designs for advanced Energy Recovery Linac (ERL) facilities which require accelerating Linacs which meet such demanding criteria. The specification for the main ERL accelerator for both facilities dictates a modest accelerating gradient of 20 MV/m, at a Qo of better than 10^10, with a Qext of up to 10^8. A collaborative R&D program has been set-up to design and fabricate a 'proof-of- principle' cryomodule (which is well underway) that can be tested on ERLP at Daresbury and also on the Cornell ERL injector. This paper details the new cryomodule design, provides an insight to the design solutions employed and reports on the present status of the project.