Free Electron Laser Commissioning/Diagnostic Meeting
Tuesday, August 6, 1996
Recorder: R. Legg
Next Meeting
- Date: August 13, 1996
- Time: 3:00 - 4:00
- Place: Test Lab Conference Room
Attendees
P. Piot, D. Engwall, R. Ursic, D. Kehne, S. Benson, G. Neil
R. Legg, G. Biallas, K. Jordan, C. Bohn, E. Feldl and G. Krafft
Addenda/Errata to Previous Minutes
- 10/42 MeV dipole: Leigh responded that he would prefer alternate crest/anti-
crest phasing or a new magnet to overpowering the existing magnet. He also
said he'll know more on magnet performance after he tests the prototype.
C. Sinclair also said that focusing issues of the crest/anti-crest phasing
system will make the task very difficult operationally and a new magnet
should be investigated. The magnet will be replaced for the 1 um machine
however, and the IR FEL is only slotted to run 3 months after commissioning,
so living with the magnets is my proposal for this machine with a commitment
to replace them with a design capable of operating up to 110 MeV (UV) when
the 1 um upgrade is done. G. Biallas has suggested a pair of magnets only
used to tune the cryomodule be placed around the extraction magnet. They
would be an existing design on an individual power supply. The suggestion
will be considered by D. Douglas when he returns.
More comment is welcome.
- The 2" BPM's were reported as a "done deal". The only question presently is
on the BPM in the 180 bend. They are in place for Autosteer capability.
The proposal is to use the video digitizer on the synchrotron light port
to report a beam position for use by Autosteer. K. Jordan guarantees a 0.1 Hz
update rate on the video digitizer generated position. This is more than
adequate for Autosteer. To close the BPM issue out entirely Court, Jean Claude,
Kevin and Roc will meet.
Items of Discussion
- The 10 MeV line is now consistent with the DIMAD deck.
- A strawman ARR schedule is attached with these minutes. The dates
and phaseing are open to discussion, but remember we want to be consistent
in our commissioning startegy and the ARR scheduling. Legg will try to post
the graphs from an ARR workshop given for CEBA for WBS managers to get
familiar with the paper work required by DOE. WBS managers also will
want to talk with their subcontractors about their ARR responsibilities.
- A summary of the meeting on the 350 keV gun tests was given (see minutes on
www minutes page). Discussion of staffing of the tests was delayed until
next week, but on a show of hands of who was interested it is clear we
will need to schedule a laser safety course with P. Hunt for several people.
New Issues
- The straight ahead dump needs to be upgraded to handle 50 kW for the
increased current which was suggested by the commissioning workshop. M.
Wiseman will get back to us on the increase in cost.
The increased rf may also be a problem for the circulators.
- S. Benson reported that the central trajectory for the wiggler was better
at k squared =1, but we still don't know if the wiggler orbit will be straight.
He also reported that the error in alignment between the magnetic center
and the external fiducials was about 100 um, primarily due to uncertainty in
the absolute position of the Hall probe. This should be good enough to make
moving the wiggler remotely unnecessary.
- K. Jordan has an action item to find at what point the firewall on the web
starts so future company sensitive documents (like the wiggler's magnetic
review) can be posted. 8/13/96
- C. Bohn wanted to know if we had configured the bend as a good
diagnostic to map emittance growth vs. CSR? The result of the ensuing
discussion was, yes, the diagnostics are in place and Court will ask Rui
to look at the matrices to plug into her emittance calculator code for the
backleg. And to look at the error analysis.
Action Items
A-43 Where is the firewall? Jordan 8/13/96
A-44 Start Rui on emittance code Bohn 8/13/96
Action Items (assigned)
A-01 Update Drawing Bohn weekly
A-02 Magnet Specifications Webbed Douglas
A-04 Unit gradient precision Bohn, Liu
A-05 Injector energy precision Douglas
A-06 10 MeV dump optics Douglas
A-09 Dump Instrumentation Legg 6/04/96
A-10 Back leg diagnostic placement Douglas
A-11 Multifrequency CSR Measurements Krafft 6/04/96
A-12 How should the path length be checked? Krafft, Jordan 6/11/96
A-15 Commissioning Procedure Legg, Krafft 5/16/96
A-19 Web Documentation Krafft weekly
A-20 10->42 MeV dump Biallas
A-21 Diagnostics reviews Jordan 6/11/96
A-22 Beam dump and scaper design Wiseman 6/18/96
A-24 Beam loss Bohn
A-25 Synchrotron Light Monitors Krafft
A-26 IR Camera Plan Neil
A-27 Autosteer Plan Bohn
A-28 Transverse Effects in CSR Li
A-29 Software Planning for Longer Term Bohn
A-30 Burnthrough/Conflat Expansion Denard, Kloppel
A-32 10 MeV emittance Plan Bohn
A-33 FSD Plan Mahoney, Legg
A-34 Consistent Linac phasing plan Yunn
A-35 simultaneous transverse and longitudinal Kehne/Engwall 8/6/96
A-36 'bad' injection dipole/dump geometry. Douglas 7/30/96
A-39 report on ARR plan Legg 8/23.
A-40 post tentative commissioning strategy Legg I.P.
A-41 Modeling of lower than 10 MeV injector kehne, Liu 10/1/96
A-42 2nd gun for long term tests Bohn 10/1/96
Action Items (pending)
P-01 Determine Beam Pulse structure for setup
P-02 Laser phase modulator
P-03 Slit emittance measurement
P-04 Is an energy compression scheme needed?
P-05 Devise fine-tuning procedure for buncher gradient
P-07 Diagnostics "Freeze"
P-08 How do we change energy? What is the energy range?
P-09 Do we need bunching after the module
P-10 Will the SLM monitor work to center the large beam
P-11 Calculate from Hall C data how much scatter the BPMs can take
P-12 FEL/OTR interaction question
P-13 Do we have sufficient diagnostics for emittance degradation measurements
P-14 How is the gun/laser operated?
P-15 Discussion on robustness of controls??????
P-16 Injector diagnostics in the main machine
P-18 Technote by Yunn summarizing machine impedance
P-19 Consistent linac/bunching phase sets
P-20 Lock plans (who in particular)
P-21 Save/restore plans
P-24 FEL Commissioning review
P-25 RF control sensitivities/Microphonics Diff for FEL/Pathlength effect
P-26 What if studies
P-27 Plan to measure beam loss
P-28 Scrapers: Where and How?
P-29 FEL/linac interaction
P-30 Tracking including realistic wiggler fields
P-31 What drives the vacuum spec.
P-32 Are two sextupole families enough to tune M56
P-33 Is path length feedback needed?
P-35 Coordinated ITS beam running/SRF commissioning plan
P-36 Beam power robust BPMs
P-37 42 MeV dump design and interlocking
Agenda for Next Meeting
Item Person Responsible Time
---- ------------------ ----
* Review agenda/corrections to minutes Legg 5 min.
* New issues All 10 min
* 500 keV staffing Bohn/Engwall 10 min
* Setup Arc procedure Legg 20 min
* Agenda for next meeting All 5 min.