MEMORANDUM
To: J. Albertine, D. Helms, W. Skinner
cc: Division (M7), FEL Coordination Group
From: F. Dylla
Subject: IRFEL Weekly Report, July 14-18, 1997
Date: July 18, 1997
Management
The week's highlights included successful cool down of the cryogenic
lines in the injector quarter cryomodule. On Monday the cooldown
to 2 K was accomplished. This milestone completes WBS 6.
Ten of sixteen identified pre-proposals for initial use of the
IR FEL are in-house and undergoing internal review before sending
feedback to the authors and transfer to the DOE-BES Program Office.
Discussions were held with Vice Provost (Calvin Lowe) of Hampton
University concerning relocation of molecular beam epitaxy and
materials analysis equipment to the FEL and ARC Building laboratories.
Our LPC representative from IBM (Jake Pacansky) has arranged for
shipment of IBM surplus vacuum chambers and optical tables for
use in the FEL User Lab.
F. Dylla visited the Vanderbilt Free Electron Laser Facility on
Friday to continue discussions on research collaborations. Vanderbilt
is currently testing one of our diagnostic systems and discussions
were initiated last year on joint research proposals on laser
materials interactions in the infrared.
Arlene Serber and Jim Palmer, Vice Presidents of Newport News
Shipbuilding's subsidiary, Newport News Nuclear, visited the lab
Monday to discuss continued FEL collaborations between Newport
News Shipbuilding and Jefferson Lab.
Injector drive laser
The drive laser was not operated this week, as interface cabling
was being installed, and we were trying to iron out problems with
cooling water and the Clean Room's HVAC. There has been a lot
of progress, so we plan some tests over the weekend.
Accelerator Systems
Regarding the beam-transport system:
Work continued toward the completion of the modifications to the
magnet measurement apparatus to achieve 1 part in 10,000 resolution
between members of a family. Because a designer was freed up,
design started on the apparatus to measure the 180 Degree Dipoles.
Meanwhile, Everson Electric glued mu metal to two more DW cores
and completed painting with the goal of shipping four magnets
early next week.
The finished ground back legs for reverse bend cores and all water jet cut brass shims were received from other vendors by Process Equipment Co. this week. They will pin the reverse bend cores and ship to Everson for assembly late next week. Winding of the first 180 degree dipole coil is complete. Machining of its large pole tips is nearly complete while the back legs were sent to the grinder to receive their final height dimension. Master Machine sent the remainder of the core and parts sets for a DU and a DV dipoles to Everson Electric for assembly as we extended their assembly contract to include those two styles.
The Panofsky trim quad manufacture continued at Magnet Enterprises
International. Sextupole cores were shipped from Process Equipment.
The three quads for the recirculation dump line are on schedule
at New England Technicoil.
In the corrector area, the phasing dipoles went out for bid.
Details of the coils for the two, 8 inch mu metal correctors neared
completion. The design of the constant perimeter, air core corrector
horizontal coil is nearly complete while S. Lassiter has about
a day and a half of analysis to firm up the vertical corrector
nesting coil set configuration.
Welding of the bodies for optical chicane chambers is nearly complete
with beautiful welding technique being shown by the shop. Procurement
and fabrication of the reverse bend chamber parts continued.
Detailing of the last remaining short lengths of vacuum pipe and
detailing of the stands necessary for dump lines and the quad
telescope after the second arc are both nearing completion. Arc
dipole stands and girders were sent out for bid.
Delivery of the two power supplies necessary for injection/extraction
dipole strings was moved up to mid August from an early September
date.
Regarding RF systems:
Hipotronics has modified and tested the second 225 kW Variable
Power Supply. It is nearly ready for our acceptance tests. If
all goes well, we could receive this unit by 8/1/97. The first
unit which suffered a high power arc is being repaired and should
be ready for testing again in 2 weeks.
The second spare 50 kW klystron failed its acceptance test last
week. The vendor has been contacted for any additional tests
they would like us to perform before it is returned.
Regarding cryomodule fabrication:
Completed fabrication and alignment of the full cryomodule. The
team will conduct final leak check of the cryomodule next week.
It is on schedule for delivery to the FEL building the first
week of August.
Regarding electron-beam instrumentation and controls (I&C):
All control and patch cables have been installed in the drive
laser clean room. We are in the process of recommisioning the
ITS servers.
Design work continues on the Analog Monitoring System (AMS).
Installation for all of the systems continues fast and furious!
All of the Ion Pump Power Supply (IPPS) control cards have been
delivered and are being tested.
Progress is also being made on the software requirements.
FEL Systems
The wiggler tube mounting structure was modified to fit over the
existing cap screws and reassembled. It is now ready to accept
the wiggler tube. The tube was released to a local machine shop
for initial welding procedure validation. Alignment fixtures
for bore-sighting the wiggler were released and the alignment
team began final adjustment of the wiggler quads before moving
the wiggler table into position on the linac line.
Optics
We spent the week working on the optical transport system in the
accelerator enclosure. All but one mirror can remains to be hung
on its support, that should be completed later today (7/18).
We mounted a He-Ne on the downstream optical table to facilitate
alignment of the entire beamline. We also mounted picomotors
in the mirror mounts that will go in the mirror cans. We also
began assembly of the optical cavity assemblies in one of the
facility clean rooms.
Commissioning/Operations
The energy recovery meta procedure for the IR-FEL was presented
in the Commissioning meeting by Bob Legg and Dave Douglas. Several
good suggestions came out of the talk concerning how to measure
dispersion and the variation of pathlength with momentum from
the wiggler to the energy recovery beam dump. This parameter
is key to operation of the FEL with energy recovery. Several
pieces of hardware and software which had not been sufficiently
specified were identified and the two principals met after the
meeting to discuss them.
A potential problem with the QJ centering was identified. It
appears that the modeling wants the electron beam centered in
the quads individually. This is not possible with the beam transport
presently designed, and the wobble in magnetic centers of the
quads is large enough to be a problem. This issue will be addressed
at the next Commissioning meeting.
There is an outstanding question concerning the maximum field
that the dipole at the entrance to the energy recovery beam dump
line can attain. It was discussed but the implementation has
slipped through the cracks. This field specification is necessary
to write the procedure for high precision phasing of the cryomodule.
Phasing to the 3 to 5 degree precision can be accomplished by
using the transients induced by the beam on the control system.
Facility
Work continued on punch list items for the facility. A texture coat was put on the exterior porch ceilings. Asphalt was put in the parking areas, graded to the loading dock, added to the west loading road, and then the street out front was resurfaced. Final site cleanup is underway. Punch
list work continued for the elevator. Electricians hooked up many more racks, power supplies, etc. in the gallery and tunnel. Balancing and calibration continued on the HVAC. The chilled water system was flushed but still needs additional cleaning and addition of rust proofing. The
laser clean room HVAC was brought into operation; there is some question about adequacy of air flow and humidity but the temperature appears stable. We will be making measurements and test runs next week to resolve these questions. All phone lines are complete upstairs and are 50% done in the tunnel.
The clean hood for injector assembly activities was moved from
the ITS to the FEL tunnel and mounted. The lightbox was positioned
on its stand and surveyed into place. A small modification to
the stop block was machined to improve fit up. The buncher cavity
was remounted and prepared for installation. Interlocks are being
installed on the HVPS in preparation for an air test: initial
voltage on the stack inside the tank. Layout drawings of the
photogun laser light transport system were produced. Optical
transport stand drawings were marked up for signoff. The cryounit
sat stable at 2K all week. Operation of the cryosystem is uncomplicated
as expected.