BES R&D Plasma Processing for LCLS-II Cryomodule

BES R&D – Plasma Processing for LCLS-II Cryomodule

Link for group website (public)

https://portal.slac.stanford.edu/sites/ad_public/ppr_d/shared_docs/

Questions from BES Proposal Review:

1)  What did not come through clearly in the proposal for this project was what information was to be gained from the dressed as opposed to bare cavity cryotests. For example, are the bare cavity tests performed with a different coupler geometry, or are they for some other reason materially different?

2)  A substantial caveat is that the reviewer has reservations …proposing to use ACE3P to study the plasma discharge and possible damage to the coupler (mostly the SLAC scope of work). The reviewer is not aware that ACE3P contains the proper physics to model the glow discharge …

Visit to ORNL:

26-28 October to visit SNS. Anticipate to set up with a single cavity – multi-cell SNS cavity. Also have an offline CM and try to position the hardware around and to see the practical application. (There is more monitoring hardware to help when the cavity is out.) From Marc D: Thursday is the best. Paperwork includes that date. One full day should be enough. Giulia, Dan, Martina, Paolo, Sasha? Send information to Marc Doleans ASAP. Dan will arrive 26 evening and leave 28 morning.

I don’t have Martina’s slides from 19 September meeting

Cho’s slides:

1)  Plasma ignition depends fairly strongly on Sey/surface condition

2)  Implementation may be do-able.

3)  Does it make sense to compare SNS / LCLS-II cavity simulation?

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-Paolo presented first thoughts at FNAL (see slides attached) – 12 September 2016 ignition via FPC maybe problematic because lowest possible Qext1 in the mid e6 range (one order of magnitude higher compared to SNS scheme), alternative idea presented- maybe use HOMs?

-buy FPC from DESY? Marc will ask Jacek – evaluate what is more cost effective

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M. Ross / A. Grassellino / M. Doleans (SLAC / Fermilab / ORNL) 03 October 2016