> Working Group 2 - Optics

Working Group Convenor: Ryoichi Hajima hajima.ryoichi@jaea.go.jp
Co-Convenor: Hywel Owen h.owen@dl.ac.uk

Working Group Charge

Review of progress made since ERL'05 - issues which have been solved and which are unsolved. Specific issues to be raised are:

ERL merger design compatible with emittance compensation
ERL optics for high energy ratio
ERL lattices for magnetized beams
Bunch flattening schemes
Practical multi-turn configurations

Issues from ERL'05:

Linear optics design for the main linac section, linear optics for different ERL applications, nonlinear optics, current dependent effects like BBU and CSR, other sources of emittance growth, halo development and collimation, instrumentation and commissioning techniques. Identification of new and promising ideas. Finally, the group should summarize in a brief report (a few pages) the highest priority research topics for beam transport in ERLs.

Working Group Sessions

Session 1 (Joint WG2/WG4) - Optics Issues for Ongoing ERL Projects (Tue 09:00 - 13:00)

Time	Title	Presenter
09:00 (15 +15q)	Optics Design of 4GLS	Hywel Owen
09:30 (15 +15q)	Lattice and Optics Design of the Test ERL in Japan	Shogo Sakanaka
10:00 (15 +15q)	Concepts, simulation, and performance for an energy recovery linac upgrade of the Advanced Photon Source	Michael Borland
10:30-11:00	Coffee
11:00 (15 +15q)	Analysis and mitigation of Touschek scattering effects for an energy recovery linac upgrade of the Advanced Photon Source	Michael Borland
11:30 (15 +15q)	Optics Issues for ERL-based electron cooler	Vladimir Litvinenko
12:00 (15 +15q)	Optics Issues for ERL-FEL	Presenter/Discussion

Session 2 (Joint WG2/WG4) - Beam Loss and Stability Issues (Tue 14:00 - 17:30)

Time	Title	Presenter
14:00 (15 +15q)	Ions in ERLs	George Hoffstaetter
14:30 (15+15q)	Investigation of the Bunch Gap Effect on Ion Trapping	Shogo Sakanaka
15:00 (15+15q)	Study of Resistive-Wall Beam Breakup	Norio Nakamura
15:30-16:00	Coffee
16:00 (25+5q)	Beam Instrumentation at the Jefferson Lab FEL	Kevin Jordan
16:30 (25+5q)	Beam Instrumentation for the KEK ERL Test Facility	Makoto Tobiyama
17:00 (25+5q)	Beam Loss Issues for an ERL Upgrade to APS	CY Yao

Session 3 (Joint WG1/WG2) - Computational Aspects (Wed 09:00 - 13:00)

Time	Title	Presenter
09:00 (25 +5q)	Emittance evolution far from invariant envelope in photoinjectors	Chun-Xi Wang (Argonne)
09:30 (25 +5q)	Beam parameter simulation of the Rossendorf SRF gun and comparison with other RF photoinjectors	F. Staufenbiel (Rossendorf)
10:00 (25 +5q)	Cell length optimisation of photocathode RF gun cavity	Jang-Hui Han (DESY)
10:30-11:00	Coffee
11:00 (25+5q)	Simulation and Optimisation of the JLab/AES DC Photo-injector	Fay Hannon (JLab)
11:30 (25+5q)	Parallelization and other new features in elegant	Michael Borland (Argonne/APS)
12:00 (25+5q)	Design and Simulation of the 4GLS High Average Current Loop DC Photoinjector	Julian McKenzie

Session 4 - Optics Developments (Wed 14:00 - 17:30)

Time	Title	Presenter
14:00 (15 +15q)	An X-Ray FEL Oscillator using ERL Beams	Kwang-Je Kim
14:30 (15+15q)	CSR in ERLs	George Hoffstaetter
15:00 (15+15q)	A Modular Path Length Correction System	Peter Williams
15:30-16:00	Coffee
16:00 (15+15q)	Laser power limit in an ERL	Hywel Owen
16:30 (15+15q)	Bunch Compression and Emittance Growth due to CSR	Miho Shimada
17:00 (15+15q)	Beam Dynamics in the high gain ring FEL based on energy recovery linac	Oleg Shevchenko

Session 5 (Joint WG2/WG3) - BBU and Cavity Optics (Thu 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
12:30 (15 +15q)	4GLS Cavity Considerations for BBU	Emma Wooldridge