Next Meeting
Attendees
D. Douglas, G. Biallas, J. Denard, C. Bohn, S. Benson, K. Jordan, and G. Krafft
Items of Discussion
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
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.