Free Electron Laser Commissioning/Diagnostic Meeting

Tuesday, Jan 28, 1997
Recorder: R. Legg

Next Meeting

Date: Feb 4, 1997

Time: 3:00 - 4:00

Place: Test Lab Conference Room

Attendees

G. Neil, J.C. Denard, D. Kehne, J. Bennett, R. Legg, C. Bohn, S. Benson, R. Walker, D. Douglas, G. Biallas

Addenda/Errata to Previous Minutes
-------------------------------: None.

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

We discussed a change to the commissioning strategy. The strategy was modified because of Byung's revelation that it would require changes to the phases of the rf cavities and probably the quads to maintain the beam properties as the charge per bunch was increased, no matter what initial quad/ phase setup was chosen. This was deemed too many knobs to simultaneously adjust. The new strategy is to run first light and commission the hardware of the backleg at 60 pC/bunch on alternating shifts.
During energy recovery the beam will be increased to 135 pC/ bunch at 9 MHz for setup to preserve the average current for MPS and SRF purposes, but this will allow a careful setup of the injector match and phasing with the charge per bunch to be used for the energy recovery experiment. This may be a strain on the diagnostics, but should allow a more rapid switch to high currents during the actual experiment.

G. Neil presented data on a cooled CCD and a Gated camera. Both had nice features and good resolution, but the cooled CCD from Pegasus had better response at longer wavelengths and may be compatible with the Datacube. Bothe cameras need to be tested under high rad conditions to determine compati- bility.

After some discussion, four conditions were suggested to bound the problem of initial setup to get the desired wiggler beam.
1 - Fix accel/decel vectors on SRF at 12.5 degrees off crest. 2 - Upright distribution at wiggler. <1 psec RMS, 160 keV RMS 3 - Solutions at both 60 and 135 pC charge per bunch 4 - Target bunchlength, emittance, alpha and beta at entrance to the wiggler. This assumes that Byung is right and a simultaneous solution for 135 and 60 pC/bunch cannot be found.

The discussion of the arc setup procedure was a wash - I tried to explain what my thoughts are, and there was some handwaving and discussion. The result was that the group agreed to talk about it again after looking at the procedure on the www and some thought.

G. Biallas told us that the 10/42 MeV phasing dipole(s) could be accomplished using one dipole, but it might only reach 40 MeV or so. We discussed the techniques for resetting the fields briefly. I asked about the "Must, should, like" goals for the dipole I'd set out and he said he hadn't recieved them yet. I promised to re-mail them to him, but in the mean time it was decided we should go with the one dipole design
.
New Issues

----------

Action Items

------------
Items of Discussion -------------------: We discussed a change to the commissioning strategy. The strategy was modified because of Byung's revelation that it would require changes to the phases of the rf cavities and probably the quads to maintain the beam properties as the charge per bunch was increased, no matter what initial quad/ phase setup was chosen. This was deemed too many knobs to simultaneously adjust. The new strategy is to run first light and commission the hardware of the backleg at 60 pC/bunch on alternating shifts.
During energy recovery the beam will be increased to 135 pC/ bunch at 9 MHz for setup to preserve the average current for MPS and SRF purposes, but this will allow a careful setup of the injector match and phasing with the charge per bunch to be used for the energy recovery experiment. This may be a strain on the diagnostics, but should allow a more rapid switch to high currents during the actual experiment.

G. Neil presented data on a cooled CCD and a Gated camera. Both had nice features and good resolution, but the cooled CCD from Pegasus had better response at longer wavelengths and may be compatible with the Datacube. Bothe cameras need to be tested under high rad conditions to determine compati- bility.

After some discussion, four conditions were suggested to bound the problem of initial setup to get the desired wiggler beam.
1 - Fix accel/decel vectors on SRF at 12.5 degrees off crest. 2 - Upright distribution at wiggler. <1 psec RMS, 160 keV RMS 3 - Solutions at both 60 and 135 pC charge per bunch 4 - Target bunchlength, emittance, alpha and beta at entrance to the wiggler. This assumes that Byung is right and a simultaneous solution for 135 and 60 pC/bunch cannot be found.

The discussion of the arc setup procedure was a wash - I tried to explain what my thoughts are, and there was some handwaving and discussion. The result was that the group agreed to talk about it again after looking at the procedure on the www and some thought.

G. Biallas told us that the 10/42 MeV phasing dipole(s) could be accomplished using one dipole, but it might only reach 40 MeV or so. We discussed the techniques for resetting the fields briefly. I asked about the "Must, should, like" goals for the dipole I'd set out and he said he hadn't recieved them yet. I promised to re-mail them to him, but in the mean time it was decided we should go with the one dipole design
.
New Issues

----------

Action Items

------------; G. Neil presented data on a cooled CCD and a Gated camera. Both had nice features and good resolution, but the cooled CCD from Pegasus had better response at longer wavelengths and may be compatible with the Datacube. Bothe cameras need to be tested under high rad conditions to determine compati- bility.

After some discussion, four conditions were suggested to bound the problem of initial setup to get the desired wiggler beam.
1 - Fix accel/decel vectors on SRF at 12.5 degrees off crest. 2 - Upright distribution at wiggler. <1 psec RMS, 160 keV RMS 3 - Solutions at both 60 and 135 pC charge per bunch 4 - Target bunchlength, emittance, alpha and beta at entrance to the wiggler. This assumes that Byung is right and a simultaneous solution for 135 and 60 pC/bunch cannot be found.

The discussion of the arc setup procedure was a wash - I tried to explain what my thoughts are, and there was some handwaving and discussion. The result was that the group agreed to talk about it again after looking at the procedure on the www and some thought.

G. Biallas told us that the 10/42 MeV phasing dipole(s) could be accomplished using one dipole, but it might only reach 40 MeV or so. We discussed the techniques for resetting the fields briefly. I asked about the "Must, should, like" goals for the dipole I'd set out and he said he hadn't recieved them yet. I promised to re-mail them to him, but in the mean time it was decided we should go with the one dipole design
.
New Issues

----------

Action Items

------------; After some discussion, four conditions were suggested to bound the problem of initial setup to get the desired wiggler beam.
1 - Fix accel/decel vectors on SRF at 12.5 degrees off crest. 2 - Upright distribution at wiggler. <1 psec RMS, 160 keV RMS 3 - Solutions at both 60 and 135 pC charge per bunch 4 - Target bunchlength, emittance, alpha and beta at entrance to the wiggler. This assumes that Byung is right and a simultaneous solution for 135 and 60 pC/bunch cannot be found.

The discussion of the arc setup procedure was a wash - I tried to explain what my thoughts are, and there was some handwaving and discussion. The result was that the group agreed to talk about it again after looking at the procedure on the www and some thought.

G. Biallas told us that the 10/42 MeV phasing dipole(s) could be accomplished using one dipole, but it might only reach 40 MeV or so. We discussed the techniques for resetting the fields briefly. I asked about the "Must, should, like" goals for the dipole I'd set out and he said he hadn't recieved them yet. I promised to re-mail them to him, but in the mean time it was decided we should go with the one dipole design
.
New Issues

----------

Action Items

------------; The discussion of the arc setup procedure was a wash - I tried to explain what my thoughts are, and there was some handwaving and discussion. The result was that the group agreed to talk about it again after looking at the procedure on the www and some thought.

G. Biallas told us that the 10/42 MeV phasing dipole(s) could be accomplished using one dipole, but it might only reach 40 MeV or so. We discussed the techniques for resetting the fields briefly. I asked about the "Must, should, like" goals for the dipole I'd set out and he said he hadn't recieved them yet. I promised to re-mail them to him, but in the mean time it was decided we should go with the one dipole design
.
New Issues

----------

Action Items

------------; G. Biallas told us that the 10/42 MeV phasing dipole(s) could be accomplished using one dipole, but it might only reach 40 MeV or so. We discussed the techniques for resetting the fields briefly. I asked about the "Must, should, like" goals for the dipole I'd set out and he said he hadn't recieved them yet. I promised to re-mail them to him, but in the mean time it was decided we should go with the one dipole design
.
New Issues

----------

Action Items

------------
New Issues
----------
Action Items
------------

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

A-05 2 Injector energy precision Douglas A-06 1 10 MeV dump optics Douglas A-09 1 Dump Instrumentation Legg 6/04/96 A-10 2 Back leg diagnostic placement 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-41 2 Modeling of lower than 10 MeV injector kehne, Liu 10/1/96 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-45 1 decide on dump diagnostics Legg/Krafft 9/4 A-46 1 specify the field quality in the dipole shut off to run straight ahead Douglas 9/11 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-18 1,2 Technote by Yunn summarizing machine impedance Yunn 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-28 1,2 Scrapers: Where and How? Bohn, Li P-29 2 FEL/linac interaction Merminga P-30 2 Tracking including realistic wiggler fields Douglas P-35 1 Coordinated ITS beam running/SRF commissioning plan Legg/Bohn/Harwood 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. * Control room layout and signals All 30 min * New Issues ALL 10 min * Agenda for next meeting All 5 min.

Free Electron Laser Commissioning/Diagnostic Meeting

Tuesday, Jan 28, 1997 Recorder: R. Legg

Tuesday, Jan 28, 1997
Recorder: R. Legg