Next Meeting

Date: June 18, 1996

Time: 3:00 - 4:00

Place: Test Lab Conference Room

Attendees

D. Douglas, J. Denard, C. Bohn, P. Piot S. Benson, G. Neil, and G. Krafft

Items of Discussion

• There was one change in the minutes from last meeting. J. Denard pointed out that I incorrectly summarized his concern, it had more to do with the survivability of the camera than the survivability of the window. Sorry for the error.

New Items

IR Camera Plan: many threads are converging on the need for an IR camera. Legg needs one for the dump instrumentation. The SLMs don't work very well at light frequencies (see below), and one would be useful for wiggler commissioning. After a bit of discussion it was decided that the best way to procede was to have a coordination meeting to gather all the potential users to focus on particular devices, and to start planning for procurement, installation, etc. G. Neil will take the lead and will report back frequently, until the decision is made.

Magnet Specifications: there seems to be continued ``bargaining'' over magnet specifications. Douglas has published a June 6 technote regarding the specs. (this starting point should be WEBBED). Harwood and Douglas will interact until a satisfactory compromise is obtained.

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

A-25 P. Piot presented his calculations of expected light out the SLM ports. It ain't much, about 1 nW at 625 muA over the range of a typical SONY camera. CW is probably doable but pulsed is probably not doable. Since the critical wavelength is about 7.5 mum, it was proposed that the IR camera be investigated for this application also. As such it is added to Neil's planning meeting on camera usage above.

A-27 Bohn presented his current findings on Autosteering. The arguments for were related to have the ability to change setups rapidly, e.g. when the energy of the machine changes. Arguments against were related to the machine being relatively short and of the sort that once the lasing occurs, autosteering is not useful. It was pointed out that if the machine energy is changed substantially, it would on occassion necessitate a change of the optical cavity mirrors, a process that will take several hours. The question was asked whether the users really need energy scanning capability and whether autosteering would help. A compromise suggestion was floated to install BPM hardware needed and get additional electronics channels in the future if we think we need it. The bottom line, given the uncertainties, is that more work needs to be done.

A-30 Denard presented a burnthrough calculation proposal to resolve the issue of a safe threading mode (beam threading can procede without fear of burnthrough). He presented normal incidence calculations that showed good behavior as a function of spot size. To tackle the grazing incidence problem he proposed that EGS be used to find the worst case angle of incidence, which he suspected being around 5 or 6 radiation lengths within the beam pipe. After the worst case is determined, a safe mode will be determined. There were no strong objections to this plan, although it was pointed out that an additional problem, heating of the conflat flanges, should be investigated given the experience on the main machine. I've added this topic to the burnthrough task.

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    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                                Legg
A-27    Autosteer Plan                                Bohn
A-28    Cavity Coupling                               Yunn
A-29    Software Planning for Longer Term             Bohn
A-30    Burnthrough/Conflat Expansion                 Denard, Kloppel

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.
 *   Web documentation                           Krafft         10 min.
 *   New issues
        IR Camera Plan

 *   Autosteering                                 Bohn           5 min.
 *   Burnthrough                                 Denard         15 min.
 *   SLM Power and Cameras                        Piot          15 min.
 *   Diagnostic Planning                         Jordan         10 min.
 *   Active item discussion                        All          10 min.
 *   Agenda for next meeting		           All		 5 min.