Working Group 4 Terry Garvey LAL and Patric

Working Group 4: Terry Garvey (LAL) and Patric Muggli (USC) Goals: -Where are plasmas most efficient? -Mixed techniques (injection) -Case study: how to obtain using plasmas CLIC beam properties?

Session 4 a:

Beam quality:

Short bunch production: 4 methods

Example: UCLA photo-injector, ≈0. 390 ps

With rf harmonic section to correct for nonlinearities, reach 1. 1 ps

Our conclusion: RF guns achieve short bunches, high charge, low emittace, small ∆E/E, but not necessarily all at the same time Well understood and rather stable.

Mixed system:

Tagging of events to deal with jitter: electro-optical sampling Also: laser/particle beam synchronization using focusing/defocusing of LWFA

Shorter bunches from rf gun cathode shaping (5 th method)

Minumum emittance limited by crossing of bubble front, Minimum value? To be tested soon …

Session 4 b:

Goal Parameters for plasma accelerators?

If so …

Plasma accelerators? THz and Ge. V/m? Let’s begin the discussion …

Getting the PWFA to look like a “ 2 -beam” accelerator!

Summary and conclusions for WG 4: Mixed techniques: -Photo-injectors are relevant for injection into plasma accelerators -Proposal for “in front of the pulse injection” looks interesting -Proposal for injection of rf gun beam into LWFA and FEL Timing and synchronization: -Use the same laser beam to drive plasma wave and produce bunched electron beam is still the best solution -When jitter is present (fs scale), monitor the jitter It would be interesting to “compare” rf and plasma injectors It would be interesting to “seed” a plasma injectorbem into an rf linac, or into another plasma accelerator

-Review of rf approach to multi Te. V, high-luminosity collider -Attempts to establish consistent sets of plasma accelerator parameters (multi-Te. V beams) -Presentations triggered discussions -Room for cross-fertilization of ideas and methods -Further interaction much needed, the discussion has just begun