> Working Group 3 - Superconducting RF

Working Group Convenor: Todd Smith; Todd.Smith@Stanford.edu
Co-convenors:  Bob Rimmer; RARimmer@jlab.org, Stefan Simrock; Stefan.Simrock@desy.de

Working Group Charge

The overall charge to Working Group 3 on superconducting RF and RF control is to identify critical SRF related items for the construction of ERLs, evaluate the readiness of the related science and technology, and to lay out an R&D path for solving remaining open issues. In particular the following questions will be explored: 

• What parameter space is covered by ERLs presently under discussion? A template/questionnaire will be distributed in advance to participants of the WG, which should be submitted prior to the workshop.
  
  
• What are the SRF-related ERL-specific challenges? A questionnaire will be distributed in advance to participants.
  
  
• What optimization criteria should be used in designing the main linac? Where is the optimum? This will be discussed using a generic machine as an example.
  
  
• What solutions have already been developed for the SRF-specific challenges? Participants are invited to propose contributed talks discussing their recent R&D work.
  
  
• What components/areas need more R&D work? All sub-components will be classified on a 1 to 3 scale according to their complexity, readiness for future ERLs, required R&D effort and time schedule to perform required R&D.
  
  
• How can the R&D effort be organized internationally? A detailed R&D roadmap will be developed including a list of specific tests with a ranking of importance, timeframe estimate and potential test place. Participants will be asked to make a list in advance of specific activities they plan on doing the next few years.

Working Group Sessions (DRAFT)

Session 1 - Cryomodules (Tuesday 09:00-13:00)

Time	Title	Presenter
09:00 (25+5q)	Cryomodule overview	Ali Nassiri
09:30 (25+5q)	The CW ERL Cryomodule Collaboration Project	Peter McIntosh
10:00 (25+5q)	JLab High Current Cryomodule	Bob Rimmer
10:30 - 11:00	Coffee
11:00 (25+5q)	Low loss cryomodules intended for the main linac of an ERL	Georg Hoffstaetter
11:30 (25 +5q)	BNL Cryomodule	Andrew Burrill

Session 2 - Cavities (Tuesday 14:00-17:30)

Time	Title	Presenter
14:00 (25+5q)	SRF Cavity Shape Design Optimization for High Current ERL	Haipang Wang
14:30 (25+5)	LBL Cavity modeling	Steve Lidia
15:00 (25+5)	Development of a 1.3GHz superconducting cavity for the ERL main linac in Japan	Takaaki Furuya
15:30-16:00	Coffee
16:00 (25+5)	Experience with the TESLA cavities in CW-operation at ELBE	Peter Michel

Session 3 - Tuners, Microphonics and RF Control (Wednesday 09:00-13:00)

Time	Title	Presenter
09:00 (25+5q)	Selection of Loaded-Q Values for SRF Cavities Used in Energy Recovered Linacs.	Tom Powers
09:30 (25+5q)	Concept of Vector-Sum Control for CW-operation	Christian Schmidt
10:00 (25+5q)	Measurement and compensation of microphonics in CW operated TESLA-type cavities	Oliver Kugeler
10:30 - 11:00	Coffee
11:00 (25+5q)	Microphonics Measurements at ELBE	Gerald Staats
11:30 (25 +5q)	Energy recovery linac gradient and phase tolerance calculations	Nick Sereno

Session 4 - (Joint with WG1) RF Sources and Couplers (Wednesday 14:00-17:30)

Time	Title	Presenter
14:00 (25+5q)	Review of RF Sources	Mike Dykes
14:30 (25+5)	Review of RF Couplers	Carl Beard
15:00 (25+5)	Design of the input coupler for the ERL main linac in Japan	Hiroshi Sakai
15:30-16:00	Coffee
16:00	Joint Session with WG1

Session 5 - (Joint with WG2) SRF and Beam Optics Issues (Thursday 09:00-13:00)

Time	Title	Presenter
09:00 (15 +15q)	Suppression of the quadrupole mode BBU by using the eccentric fluted beam pipe	Hiroshi Sakai
09:30 (15 +15q)	HOM Damping Simulation and Measurement of JLab Ampere Class Cavity	Haipang Wang
10:00 (15 +15q)	Coupler-kick emittance increase for ultra low emittance beams in linacs	Georg Hoffstaetter
10:30-11:00	Coffee
11:00 (15 +15q)	ERL-related HOM measurements at ELBE	Graeme Burt
11:30 (15 +15q)	Dual-axis Energy Recovery Linac	Chun-Xi Wang
12:00 (15 +15q)	Analysis of HOM-BBU with newly designed cavities	Ryoichi Hajima

Session 6 - (Thursday 14:00-15:30)

Session 7 - (Thursday 16:30-18:00)

Session 8 - (Friday 09:00-10:30)

Time	Title	Presenter
90	Writing WG reports	All