Next Meeting

Date: April 8, 1997

Time: 3:00 - 4:00

Place: Test Lab Conference Room

Attendees

None.

Items of Discussion
----------------------

• B. Yunn presented his simulation results from 350 kV gun up to the wiggler. He has considered a "long gun" (spacer in place) for first light (60 pC), and a "short gun" (spacer removed, as in the new gun configuration now in the ITS) for full-power operation (135 pC). He needs to run the second cryounit cavity off-crest to get the target transverse emittance. There are two puzzling results. First, there is large emittance growth in the cryomodule for unknown reasons (but the target emittance of 13 mm-mrad for full-power operation is achieved). The degradation seems to be sensitively dependent on the beam shape at the entrance to the cryomodule. Skew quads were ignored; including them may help. Second, PARMELA doesn't seem to simulate transport through bending magnets correctly. Its results with space charge turned off disagree significantly with DIMAD, again for unknown reasons. Byung plans to examine other machine settings that give a more favorable beam shape entering the cryomodule and reduce emittance degradation.

• J. Boyce went through his "webification plans" for the ARR process. He proposes just one ARR sometime around Jan 98. The web pages include input from line managers (usually WBS managers) concerning whether all required resources, both hardware and people, are available. It will take about a month to get the material on the web. Boyce will now formally approach the DOE site office for approval of these ideas. He already has done so informally.

• B. Terrell discussed magnetic-field probes. Rotating-coil probes were the best candidates for measurements of fields in the FEL dipoles. They are insensitive to temperature changes and to radiation, and they are self-calibrating (reading "zero" when coil current is off). After some discussion, Terrell was advised to procure half-inch coil probes. The basic plan is to use them to map the full field profile in each dipole prior to their installation on the beamline, then after installation, position probes outside the vacuum chamber, and thus perhaps outside the "good field" regions of the magnets, for in-situ measurements. The bench measurements will provide the rosetta stone for interpreting the data taken in-situ.

  New Issues
  ----------

• None

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

• J. Boyce will meet with our DOE site office to solicit approval of his ARR process.

     
  Action Priority  Items (assigned)
  ----------------------------------
  
  A-05   2  Injector energy precision                     Douglas
  A-15   1  Commissioning Procedure                       Legg, Krafft
  5/16/96
  A-19   0  Web Documentation                                             weekly
  A-20   1  10->42 MeV dump                               Douglas
  A-24  1,2 Beam loss                                     Bohn
  A-29   1  Software Planning for Longer Term             Bohn, et al.
  A-30   1  Burnthrough/Conflat Expansion                 Denard, Kloppel
  A-34   2  Consistent Linac phasing plan                 Yunn
  A-35   1  simultaneous transverse and longitudinal      Kehne/Engwall	8/6/96 
  A-39   1  report on ARR plan 				Legg		8/23.
  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-54   1  FEL Turn-On Proc				S. Benson	11/1/96
  A-55   1  Laser Diagnostic Proc				Benson		11/1/96
  
  Action Items (pending)
  ------------
  
  P-02  1   Laser phase modulator						Jordan
  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.
      *	Commissioning process				Bohn		10 min	
      *   Discussion					all		 10 min
      *   New Issues 					ALL    		 10 min
      *	Agenda for next meeting		                All		 5 min.