[FFA_CEBAF_Collab] [EXTERNAL] Re: FFA at CEBAF WG mtg. this Friday, Jan. 5

[Brooks, Stephen]

The main determining factor of this is the minimum linac energy.  So the FFA energy ranges start at about 9 times that (four turns, two arcs each, so eight arcs, so nine linac passes).

If the users want energy tunability, there will have to be a range of linac energies anyway.  I pointed out if we could make that range 1100MeV but tune upwards to 1210MeV, with five turns in the FFA instead of six then everything seems fine.

If you tune downwards from 1100MeV, you lose the upper end of the FFA energy range because you have to accommodate more energies at the lower end, hence machine energy can only be 20GeV not 22GeV.  Having missing RF modules is the same as tuning the energy downwards.

Making the energy ratio wider comes at quite a big cost in terms of magnet volume, even if you include sextupole (although sextupole seems to help on the 10% level in terms of volume).  My attempt at making a 9-22GeV energy range, with sextupole, requires 46.36% more magnet volume than our current baseline 10.5-21GeV for the east arc.

I'm currently running a 9-21GeV optimisation but it's not yet any better (will let it run overnight).

     -Stephen

________________________________________
From: FFA_CEBAF_Collab <ffa_cebaf_collab-bounces at jlab.org> on behalf of Roger Ruber via FFA_CEBAF_Collab <ffa_cebaf_collab at jlab.org>
Sent: 05 January 2024 14:35
To: Ryan Bodenstein; ffa_cebaf_collab at jlab.org
Cc: Planche Thomas
Subject: Re: [FFA_CEBAF_Collab] FFA at CEBAF WG mtg. this Friday, Jan. 5

Hi,

Apologies I missed the discussion this morning. I see in the minutes there
was a discussion about the CEBAF energy (20 or 22 GeV) and required SRF cryomodule
upgrades to keep the energy.

Probably this was already discussed earlier, so apologies for my question:

What are the approximate energy acceptance windows for the FFA arcs?

That would determine how many cavities/cryomodules we can afford to lose
before we have to stop operation. Also, it would strongly point to how much
gradient headroom we want for acceptable operation.

With best regards,
Roger.

-----Original Message-----
From: FFA_CEBAF_Collab <ffa_cebaf_collab-bounces at jlab.org> On Behalf Of Ryan Bodenstein via FFA_CEBAF_Collab
Sent: Friday, 5 January, 2024 13:04
To: Alex Bogacz via FFA_CEBAF_Collab <ffa_cebaf_collab at jlab.org>
Cc: Planche Thomas <tplanche at triumf.ca>
Subject: Re: [FFA_CEBAF_Collab] FFA at CEBAF WG mtg. this Friday, Jan. 5

Dear Colleagues,



Attached, you’ll find the minutes from today’s meeting. Everyone have a great weekend!



Cheers!

Ryan



From: FFA_CEBAF_Collab <ffa_cebaf_collab-bounces at jlab.org> on behalf of Alex Bogacz via FFA_CEBAF_Collab <ffa_cebaf_collab at jlab.org>
Date: Tuesday, January 2, 2024 at 5:31 PM
To: Alex Bogacz via FFA_CEBAF_Collab <ffa_cebaf_collab at jlab.org>
Cc: Planche Thomas <tplanche at triumf.ca>
Subject: [FFA_CEBAF_Collab] FFA at CEBAF WG mtg. this Friday, Jan. 5


Dear Colleagues,

Happy New Year!

We will continue our design efforts this Friday, Jan. 5, at 11:00 am.

* Emittance dilution for 5-pass FFA scenario with 1200 MeV linacs - Kirsten

* Update on Transition design - Vasiliy

* AOB - ALL

Please, follow a ZOOM invitation below.

Cheers,

Alex

 ___________________________________

S. Alex Bogacz,

Accelerator Physics Group Leader

Center for Advanced Studies of Accelerators

Jefferson Lab

12000 Jefferson Avenue,





ZOOM connection:

The link is here: https://urldefense.com/v3/__https://jlab-org.zoomgov.com/j/1614898082?pwd=TnUzMS81M2sxbDZIbERJU01tYkJCQT09__;!!P4SdNyxKAPE!A3wgmlgH_WXzaHCqN_oeRYP-37-MumbQNcIxYFt9k2CaooWEYBFp2H44oCeuxKE1glFbvF-QpKGvOMOnFMkgiY_VdJo$

In case of problems, the zoom room is below:

Meeting ID: 161 489 8082

Passcode: 123456

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