Next Meeting

Date: June 10, 1997

Time: 3:00 - 4:00

Place: Test Lab Conference Room

Attendees

Addenda/Errata to Previous Minutes
-------------------------------

• none Items of Discussion
  ----------------------
  

• B. Yunn presented his simulations of the 350 keV 'long gun' His results can be viewed on the www at URL, www.cebaf.gov/ ~legg/060397_comm. The highlights of the discussion were a question about whether the 0.5 mm bunch length in the 10 MeV region is too long for the CSR or Hapek bunch length diagnostic. These devices are limited by diffraction at long wavelengths and Philippe was going to calculate the effect.

• Steve pointed out that if this was indeed a problem, we could use the dispersed region and cross phasing which works well at longer bunchlengths.

• There was also a question about the setting of solenoid #1 for transverse properties. At the 280 G level specified we have seen scraping in the ITS at 135 pC/bunch. There was also a question about the spot size used and Byung said the emittance is dominated by the bunching/acceleration process. Byung also said the transverse phase space will need more development. To that end, it was agreed to start passing harp scans showing real beam envelopes at known solenoid settings to Byung from the ITS for cross correlation.

• Philippe presented results from the multislit. The data supported the plan to use the multislits on the FEL, but there were still many unresolved issues and more beam time was requested.

  Interested parties can get a copy of the paper presented at PAC from Philippe.

  New Issues
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• George Biallas brought up a question about the high aspect correctors using mu metal in the arcs. He is concerned about hysteresis and crosstalk with the mu metal, but thinks the field profiles will suffer badly if only aircores are used.

• Steve says they tried this at Duke and mu metal saturated and vanished. If hysteresis is a problem though, we have the synchro- tron monitor, and the cavity after the cryomodule for pathlength. Conclusion was until we have more data about how bad the problems with the mu metal were, that George should go ahead with the design.

• We did decide to relax the corrector strengths to 4sigma or around 7 milliRad. This should make the design easier without impacting the setup of the machine, although to compensate, a slightly tighter tolerance on vertical alignment will be looked at by Dave Douglas (?).

  Action Items
  ------------
  

• none.

   
Action Priority  Items (assigned)
----------------------------------

A-15   1  Commissioning Procedure                       Legg, Krafft    5/16/96
A-19   0  Web Documentation                                             weekly
A-24  1,2 Beam loss                                     Bohn
A-30   1  Burnthrough/Conflat Expansion                 Denard, Kloppel
A-34   2  Consistent Linac phasing plan                 Yunn
A-42   2  2nd gun for long term tests			Bohn		10/1/96
A-44  1,2 Start Rui on emittance code                   Bohn            8/13/96
A-47   1  OTR beam interaction number by 		Denard		9/11
A-55   1  Laser Diagnostic Proc				Benson		11/1/96

Action Items (pending)
------------

P-05  1   Devise fine-tuning procedure for buncher gradient		Krafft/Kehne
P-08 1,2  How do we change energy? What is the energy range?		Benson
P-14  1   How is the gun/laser operated?				Benson
P-15      Discussion on robustness of controls				Legg
P-19  2   Consistent linac/bunching phase sets				Yunn
P-20  1   Lock plans (who in particular)				Johannes?
P-21  1   Save/restore plans						Benesch
P-25 1,2  RF control sensitivities/					Merminga
	    Microphonics Diff for FEL/
	    Pathlength effect
P-29  2   FEL/linac interaction						Merminga
P-30  2   Tracking including realistic wiggler fields			Douglas
P-37  1   42 MeV dump design and interlocking				Wiseman

Agenda for Next Meeting
-----------------------

                Item                              Person Responsible     Time
                ----                              ------------------     ----
    *	Review agenda/corrections to minutes	        Legg	         5 min.
    *	CSR experimental plan				Douglas		 30 min
    *   Magnetic probes					Terrell		 10 min	
    *	Agenda for next meeting		                All		 5 min.