Free Electron Laser Commissioning/Diagnostic Meeting
Tuesday, April 17, 1997
Recorder: R. Legg
Next Meeting
- Date: April 22, 1997
- Time: 3:00 - 4:00
- Place: Test Lab Conference Room
Attendees
Attendees
---------------
R. Legg, C. L. Bohn, Q. S. Shu, K. Jordan,
J. Bennett, L. Merminga, G. Neil,
G.A. Krafft, B. Yunn, D. Douglas
Addenda/Errata to Previous Minutes
-------------------------------
none
Items of Discussion
----------------------
B. Yunn presented his latest PARMELA runs simulating
0, 60, and 135 pC/bunch cases transported through a
lattice optimized for the 135 pC case. The slides are
available on the www at:
www.cebaf.gov/~legg/041897_comm
The first .gif shows the numbers for the 60 and 135 pC cases.
The second .gif shows how the betatron functions evolve for
the 0 pC case in the 135 pC lattice. The horizontal units are
element numbers and the end of the unit is at about 16, the
start of the module at about 34 and the end of the module
about 55. The plot goes to the front of the wiggler. The betatron
functions for the low charge case are the worst raising
concerns about where the ghost pulses are going to go.
The third .gif file shows the 60 pC case. It looks like good
news in that the beam should be transportable in CW with this lattice.
The fourth .gif file shows the 135 pC case. Note that the
peak in beta Y occurs in the "X" region of the injector.
This could be a problem depending on the height of the
chamber.
The fifth .gif file shows a table of the sigmas, emittances and dp/p
for the three charge per bunch settings at various spots along
the lattice.
The last .gif file shows a table of the alphas and betas at the
three charge settings along the machine.
B. Yunn agreed to pass his numbers to D. Douglas to get
DIMAD tracking around the rest of the machine to look for
other problems.
We discussed the OTR size issue. The problem was that there
was a requirement to run CW beam through the OTR foil
while trying to lase. This set constraints on the size
of the foil. G. Krafft set he would talk to S. Benson and
E. Feldl and settle the issue if the CW vs. pulsed issue
could be settled. He subsequent to the meeting
talked to all parties and settled on a 0.75 by 1.5" OTR.
New Issues
----------
D. Douglas says that the multipole field in the air core
Haimson coils is higher than that in the fast corrector
magnets. George Biallas has suggestted that we add some
of the high mu material to the correctors to bring them
within the 1% field flatness specification. Dave agreed
to verify that adding the iron would indeed solve the problem.
Action Items
------------
None
Action Priority Items (assigned)
----------------------------------
A-05 2 Injector energy precision 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-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-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-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-29 2 FEL/linac interaction Merminga
P-30 2 Tracking including realistic wiggler fields Douglas
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.
* Optics issues Douglas 20 min
* Milestones for ER test plans Legg 20 min
* New issues All 10 min
* Agenda for next meeting All 5 min.