Free Electron Laser Commissioning Meeting
Friday, 24 Oct 97
Recorder: C. Bohn
Next Meeting
- Date: 31 Oct 97
- Time: 0830-0930
- Place: FEL Facility Break Room
Agenda for Next Meeting
Item Person Responsible Time
---- ------------------ --------
Review of Minutes/Errata All 5 min
Scheduling Update Bohn 10 min
Progress Report on Injector Commissioning Legg 5 min
Setup Procedure for First-Light Dump Legg 20 min
New Issues All 10 min
Agenda for next week All 5 min
This Week's Attendees
S. Benson, J. Bisognano, C. Bohn, J. Boyce, L. Doolittle, D. Douglas, D.
Engwall, J. Fugitt, A. Hofler, K. Jordan, G. Krafft, R. Legg, R. Li, , P.
Piot, Q.-S. Shu, B. Yunn
Addenda/Errata to Previous Minutes
None.
Items of Discussion
C. Bohn presented pertinent guidance from last Friday's Quarterly
Scheduling Meeting of the Director's Council and from his presentation at
last Monday's M7 Meeting. Highlights include:
- Director's Council and M7 both have directed that we get, at minimum,
tune-up beam to the 42 MeV dump before Christmas to irradiate targets that
will be used in the Nuclear Physics Program as part of the Gen experiment.
The electron beam polarizes nuclei in the target, and polarized targets are
required for the experiment. (Walker is updating the existing top-level
commissioning schedule to reflect this direction.)
- The Director's Council promoted "First User Experiment" (with
FEL-generated photon beam!) from Priority 2 (SHOULD) to Priority 1 (MUST).
- M7 approved the list of Principal Investigators and teamlets, but
advised that the team as a whole work together across all tasks to get the
job of commissioning the FEL done expeditiously.
- The list of System Owners and their responsibilities need revision and
augmentation to make explicit provisions for system maintenance, AES
involvement, and escalation policy. (Bohn is in process of working this
with C. Leemann and C. Rode.)
- The list of Performance Integrators needs augmenting to include, for
example, FEL Injector and FEL Systems. (Bohn will augment. He is
presently inclined to add only these two categories.)
- The FEL Department must have a sufficient number of trained people to
supply one ARM per shift. (Bohn is having most of the FEL Department so
trained expressedly for this purpose.)
R. Legg provided highlights of this week's injector commissioning:
- Reassembly and installation of the high-voltage transmission line for
the photocathode was completed.
- Preparations are underway to start operating the photocathode with the
drive laser next week. Goals for next week include: testing the
photocathode with the buncher cavity powered, verifying operation of the
drive laser, and training people on the respective controls and locations
of the hardware.
- The PSS for the cryounit was certified.
- Low-level srf commissioning of the cryounit commenced.
L. Merminga provided an overview of test results for the
magnetostrictive tuners. Conclusions from these tests are:
- Their range is 350 Hz, with an approximate bandwidth of 20 Hz.
- For linac cavities with Q_ext~4x10^6, the available detuning range is
expected to be approximately 62 degrees.
- Given their range and frequency response, the magnetostrictive tuners
can be used during beam start-up in the energy-recovery mode if
simultaneous detuning of the linac cavities is required.
P. Piot reported on progress toward developing the capability
(specifically, the software) for using the quad-scan technique for
tomographic maps of the transverse phase space at the first- light dump
line and in the back leg. The basic idea is the following: A horizontal
beam-profile measurement (projection along y) can also be viewed as a
projection along the x'-axis (integration axis) in the (x,x') phase space
versus position (sample axis). If one chooses a "treaty" point downstream
of the profile monitor station, one can see the effect of the beam profile
on the downstream phase space by back-propagating the sample and
integration axis. It is in fact a projection of this distribution at an
angle theta=-R12/R11 (R being the first-order transfer matrix). Therefore,
by varying the transfer matrix (e.g., changing the quad-scan strength), one
can vary the angle of view. Doing so provides enough information (if the
angle is varied by 180 degrees) to obtain all possible projections of the
phase-space distribution.
The distribution can be reconstructed from the set of projections
using now-standard techniques based on inverting the Radon transform.
Several ready-to-use codes for doing so are available from the public
domain. One complication is that this inversion is usually done using a 2-D
FFT method which requires 2^n samples, i.e., 2^n quad scans. Duke
nevertheless successfully implemented the technique on the Mark III. Their
results suggest that we will need to try to get 32 points (of course 64
would be even better). Implementation reduces to developing software that
automates the process. Piot will consult with J. Song to estimate the
necessary resources and schedule, then report back to Bohn.
New Issues
In view of recent schedule slips in injector installation and
commissioning, confusion seemed to reign concerning shift schedules of
individuals. Several people intimated that Principal Investigators, the
daily 1145 scheduling meeting and the white board outside the FEL restrooms
reflecting the running two-week schedule constituting the product thereof,
the weekly installation meeting, the telephone, and the open-cubicle
policies of the Scheduling Coordinator (R. Walker) and the Commissioning
Coordinator were collectively insufficient for ascertaining this
information. As a result, two additional administrative services will be
provided. First, a scheduling board like that used in the MCC will be
procured and mounted in the FEL Break Room to keep a running update on
detailed plans for the upcoming two weeks, including staffing of shifts.
Second, on Monday (27 Oct 97) the Scheduling Coordinator will e-mail an
updated month-long shift schedule to the appropriate parties and will
follow by e-mailing changes as they arise. This will be repeated at
one-month intervals. Despite these efforts, it is still incumbent on the
individual routinely to perambulate in the vicinity of the new scheduling
board and/or read the e-mail and/or call the cognizant Principal
Investigator or Commissioning Coordinator to take advantage of this
collection of services. Rickshaws and personnel to operate them are both
unavailable.
New Action Items
- Bohn: Work with M7 to identify system owners and their
responsibilities, maintenance provisions, and escalation policy. (due 7 Nov
97)
- Walker: E-mail one-month shift schedule and staffing on 27 Oct 97.
E-mail updates as they arise. (due 27 Oct 97, with appropriate follow-up)
Jordan: Procure MCC-style scheduling board and mount it in the FEL Break
Room. (due 30 Oct 97)
- Piot: Estimate resource requirements for developing software for
automating acquisition of phase-space-tomographic maps. (due 27 Oct 97)
Old Action Items
- Bohn: Work with M7 to establish criteria for transferring the FEL as a
user facility to the Operations Department. (due 30 Jan 98)
Procedures in Work
Cryomodule Setup
- Set Cavities to Nominal Gradient Merminga, finalize
First Light Setup
- Thread to Straight-Ahead Dump Douglas, 1 Dec 97
- Dump Setup Legg, 1 Dec 97
- CW Setup Legg, 1 Dec 97
Emittance Growth from CSR
- Tomographic Phase-Space Map Piot, 1 Dec 97?
- Back Leg Thread Douglas, 1 Dec 97
Thread Beam around Machine, Top-Level Douglas, 1 Dec 97