Next Meeting

Date: June 4, 1996

Time: 3:00 - 4:00

Place: Test Lab Conference Room

Attendees

D. Douglas, G. Biallas, J. Denard, C. Bohn, S. Benson, K. Jordan, and G. Krafft

Items of Discussion

• There were no changes to the minutes from last meeting. During the discussion on the new drawing, it was mentioned by D. Douglas that there is a substantial amount of steering possibility for path length adjustment in the bend regions. Various discussions on the path length occured, leading to the conclusion that probably the trombones were not necessary. However, until a firm plan exists and is documented I will leave an action here. Resolution awaits a commissioning plan. The numbers quoted were 2 and 5 mm path length changes for 1 mrad steering changes.
• There was a wide BPM meeting. The results of the meeting were not discussed. Next week.

New Items

BPM burnthrough calculations: Kloeppel has calculated that the tuneup mode for the BPMs, namely 625 muA, might possibly cause melting problems for our pulse length of 250 musec. Thus it seems clear that we will need some sort of initial threading mode with relaxed current and pulse length requirements. Measurements and beam delivery in pulsed mode should only occur with beam-on-dump guaranteed. Benson objected that his experience was that this requirement was conservative, but until better guidance is available, it makes no sense to push our luck. Denard suggested a controlled test during the ITS. The idea has merit; we need someone to see it through.

Coupler kick measurements: Sinclair has requested that it might be worthwhile for someone to take a look at this in detail. The consensus of the meeting was that this had been beaten to death in the FEL context by Hongxiu. Charlie is also interested because of emittance growth discrepencies in the main machine. Since the sign is positive (less emittance growth than expected!) there was a feeling that this item should not be revisited by this group. No Action.

Synchrotron Light Monitor plans: It was pointed out by Krafft that the SLM power is MUCH lower at 42 MeV and asked how thorough the planning an testing of this idea had been done. It seems that an off-line meeting on this topic is appropriate. Denard, Piot, Jordan, Benson, Krafft, and Bohn agreed to participate.

Ganging magnets: this item is becoming more pressing. Dave will have final approval of any plan. Merz, Jordan, Harwood, and Douglas will meet soon in order to come up with a final plan.

The lion's share of the meeting consisted of continuing going through the pending task list in order to get items promoted to active status. Wiseman has agreed to design the 30 kW dumps and make a preliminary on scrapers. He has also agreed to present his current thinking in three weeks.

On the theoretical side of the beam loss problem, Bohn and Douglas agreed to start thinking about the problem in terms of available aperture. The task is promoted to active status under Court's name.

Based on new item 4 above, I promoted P-17 to active under David's name.

Action Items

A-02 Agreed to report 6/4/96

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

A-11 Krafft will try to report something in two weeks.

A-19 We hope to have a preliminary version of the documentation tree (hierarchy) posted next week. Please take pot shots at it as appropriate.

A-21 Jordan agreed to present a plan for diagnostics reviews on 6/11/96.

Finally, Dave presented a schedule for his work over the next six months. There were no objections to his proposed due dates. He suggested that once the design is frozen, the detailed studies are largely parallel items, if we can find some useful labor to help Dave.

First Cut List of Commissioning Tasks

The following list was started for commissioning the Injector Test Stand by D. Kehne and G. Krafft. It is only a first cut and should be added to and modified through e-mail to G. Krafft. The list is a partial answer to the question: what does it mean for the Injector Test Stand to be done?

C-1     RF gradients verified
C-2     Operational RF phases determined
C-3     Drifts (of phases if like main machine) quantified
C-4     Gun current verified/operational procedure complete
C-5     Beam jitters determined
C-6     Cryounit Focussing/Convergence determined
C-7     High power CW beam is delivered for ``awhile''
C-8     Cathode lifetime studied
C-9     Engwall/Kehne studies on gun transverse/longitudinal emittance complete
C-10    PARMELA ``verified''

After the move to the FEL building the following tasks must be completed to prepare the beam for injection into the linac.

C-11    Transverse phase space at injection verified
C-12    E-beam matched at injection point
C-13    Longitudinal phase space verified
C-14    Longitudinal tilt checked at injection
C-15    Above determined at high power

Action Items (assigned)

A-01	Update Drawing                                Bohn                weekly
A-02    Viewer light photocurrent                     Benson, Jordan     6/04/96
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           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

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-22    FSD plans
P-23    Transverse Effects in CSR
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.
*   New issues
 	Wide BPMs                                Krafft        5 min.
   	Photocurrents                            Benson        5 min.
   	Dump instrumentation                     Legg         10 min.
*   Web documentation                            Krafft        5 min.
*   Pending Task List Discussions                 All         20 min.
*   Agenda for next meeting	                  All	       5 min.