Free Electron Laser Commissioning/Diagnostic Meeting

Tuesday, June 25, 1996
Recorder: G. Krafft

Next Meeting


Date: July 2, 1996
Time: 3:00 - 4:00
Place: Test Lab Conference Room

Attendees


D. Douglas, J. Denard, C. Bohn, P. Piot, K. Mahoney, R. Li, R. Legg, S. Benson, G. Neil, K. Jordan, G. Biallas, and G. Krafft

Items of Discussion


New Issues


Possible Upgrade: Court related that it is seeming more likely that there might be so-called follow-on money to support an energy upgrade in the next budget cycle. This has an immediate effect on Douglas, Biallas, and Bohn in the vien of planning an upgrade to the 80 MeV level (essentially an additional cryomodule and additional magnet capability). A detailed policy proposal will be developed over the coming weeks so stay tuned. Until it's stated otherwise, we will continue to work on the 42 MeV machine. The information did cause some additional discussion about the purpose of the FEL for the longer term, and it was pointed out that the two critical issues, injector performance and beam recirculation performance, are just as well studied at 42 MeV, and perhaps we should concentrate on them. Jordan also related that getting an additional HPA is liable to be an issue. One agreement that was reached is that the two designs should be called the 42 MeV design, and the 75 MeV design in future discussions.

Synchrotron Light Monitor plans: again no meeting occurred. A meeting with Denard, Piot, Jordan, Benson, Krafft, and Bohn should be scheduled.

Action Items


A-03 No documentation confirmation as of 4/9/96.

A-19 A preliminary version of the documentation tree (hierarchy) is finally posted! The upper level laser requirements are also posted! Take a look and make comments.

A-26 Neil reported further progress on the IR camera. He presented a list of potential applications and preliminary estimates of signal to noise issues. The list seemed complete (no-one objected that their application was missed) and Jean Claude and Phillipe, who have been looking at this issue independently, agreed with George's general conclusion that from a signal to noise point of view, shorter wavelengths are preferred. His guess was that we would concentrate in the 1-5 mum range, and that we would have several cameras for different applications. He agreed to schedule a coordination meeting on Thursday or Friday, so we can solidify the plans.

A-27 Douglas presented more findings on Autosteering. He summarized the current dignostic plan and said that it could be steered (automatically if the OTRs could be made automatic), the restore could be verified, the emittance measured, and the optics verified with the complement of 6 BPMs and 6 OTRs. However, there will be some blind spots to a BPM-based Autosteer. Adding BPM cans to every quad, and redistributing electronics channels to high beta BPMs could provide BPM-based autosteer capability. Since all back-leg quads could be integrated into a modular quad-BPM girder, and potential savings accrue, it was felt that the additional expense for having the cans was "in the noise" and there was general agreement that we should procede with 12 BPM cans on the back-leg. This discussion, aside from documentation, also closes the back-leg diagnostic placement active issue.

A-28 R. Li presented results on her initial attempts on the transverse problem in CSR. The approach is a generalization of the calculation she has recently published, only including potential transverse offsets. Ultimately, a complicated integral over the (evolving) bunch distribution will have to be done. She was a bit uncertain as to when she could have some testable predictions, but was encouraged to think in those terms so that diagnostics planning could include a significant test.
Action Items (assigned)

A-01	Update Drawing                                Bohn                weekly
A-02    Magnet Specifications Webbed                  Douglas
A-03    Stray fields in test stand                    Legg              complete
A-04    Unit gradient precision                       Bohn, Liu
A-05    Injector energy precision                     Douglas
A-06    10 MeV dump optics                            Douglas
A-07    Bypass optics                                 Douglas
A-08    M56/RF phasing and beam load issues           Yunn, Neil, Douglas, Liu
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-13    Impedance Layout for Wiggler                  Yunn, Neil        complete
A-14    Reduce M56 to under 30 cm                     Douglas           complete
A-15    Commissioning Procedure                       Legg, Krafft       5/16/96
A-16    Average Current Measurement/Assess Far. Cup   Legg
A-17    4-Channel BPM on the IRFEL                    Bohn, Denard
A-18    Trombones                                     Douglas, Krafft
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-23    Ganged powering schemes                       Douglas
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-31    S/N for SR to blackbody                       Piot
A-32    10 MeV emittance Plan                         Bohn
A-33    FSD Plan                                      Mahoney, Legg
A-34    Consistent Linac phasing plan                 Yunn

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	        Krafft	         5 min.
*   New drawing                                         Bohn             5 min.
*   Web documentation                                   Krafft           10 min.
*   New issues

 
*   IR Camera Plan                                      Neil             s15 min.
*   Active item discussion                              All              10 min.
*   Agenda for next meeting		                All		 5 min.