MEMORANDUM
To: J. Albertine, D. Helms, W. Skinner
cc: Division (M7), FEL Coordination Group
From: F. Dylla
Subject: IRFEL Weekly Report, September 2-5, 1997
Date: September 5, 1997
Management
This was a productive week for both FEL installation activities
and progress with the FEL user community. Installation highlights
include release of the first optical chicane dipole magnets and
chicane vacuum chambers for fit-up tests, pump down of the injection
beam line, and installation of the first two segments of the return
leg beam line.
On Thursday, Sept. 4, F. Dylla met with BES Chemical Sciences
Program Management, Bob Marianelli and Andrew DePristo, at DOE-BES
headquarters. The first nine IR FEL pre-proposals were delivered
for review for BES. Bob Marianelli and Dan Lehman (DOE Construction
Project Management) are planning to visit Jefferson Lab next Thursday
(Sept. 11) to review the progress and DOE interactions.
Jim Cox, Chairman of the ODU Physics Dept. visited this week to
discuss interactions with the FEL program, particularly new members
of the ODU atomic physics faculty.
Data was gathered this week on the earned value achieved during
August in preparation for August monthly report.
Accelerator Systems
Regarding the beam-transport system:
Three outlyer optical chicane dipoles (DWs) had a rise to 2.6
parts per ten thousand integral field difference from the central
field at one edge of the 9 cm wide good field region when powered
to 100 A. They should be in the order of one part per ten thousand
over the whole region. By changing their field clamp positions
in the order of +-.002 to .004 inch from the pole faces , we brought
these values to an acceptable rise 1.6 parts per ten thousand,
joining the remaining population of DWs. We are pinning these
plates into these positions. At week's end though, all optical
chicane magnets meet all specifications including the measurements
to quantify changes in the field integral when moving vertically
off the median plane. Sign-off of 7 magnets thus occurred and
three of these magnets will be released for installation on Monday,
the remainder will follow shortly. At the same time the vacuum
group is trying one of the vacuum chambers in one magnet in the
Measurement Area, doing an early fit-up to catch any problems.
The first two Injection/Extraction DU/DV magnets were delivered
and are undergoing inspection. Mechanical assembly of the remaining
seven magnets of this series is in process (gluing of all cores
and mu metal shims is complete) now that some critical commercial
parts have been delivered. The first of eight reverse bend dipoles
had its mu metal and brass shim sets glued at Everson Electric
in anticipation of assembly next week as George Biallas visited
them to observe the state of the supplied parts and keep watch
on the assembly quality.
One set of 180 degree dipole coils is complete at Magnet Enterprises International, as are all the cores and parts at Process Equipment Co. The assembly process has to be worked out next week. The vendor has extensive extra money in the bid to cover risk. After some discussion, they are willing to assemble on a time and materials basis with a price not to exceed the bid. We will take this up with D. Lloyd upon his return on Monday. At the same time, the Jefferson Lab shop is evaluating taking on the assembly of these magnets in-house. Contracts for the remaining parts of the magnet measurement apparatus for these magnets were let with local vendors for delivery in three to four weeks.
In the quadrupole and sextupole area, winding of coils and manufacture
of the cores for the eight Panofsky trim quads continued (with
about 60% of the task done) at Magnet Enterprises International
(MEI). The three quadrupole magnets for the energy-recovery dump
line (QIs) were shipped from New England Technicoil. The design
for the skew quads (four sets of simple coils required) was completed
and arrangements made with the shop to wind the first in-house.
In the corrector area, manufacture of the eight coils for the
phasing dipoles (DGs) continued at MEI. An acceptable bid on
their mu metal cores as well as the cores for the other reverse
bend correctors (DF&DCs) was received from the mu metal supplier
with the contract ready to be placed for a four week delivery.
Bids for the 8 coils for the DFs and 8 coils for the DCs were
received and in evaluation.
Drawings and specifications for the air core corrector half coil
sub assemblies were signed and packages sent out for a quick bid.
We want to get these coils on order before the 15th. In-house
manufacture of one additional prototype horizontal air core corrector
(DB) and two inner vertical correctors (DH) started in order to
validate the design further and have two nested sets ready for
extraction to the Injection Line Dump. At the same time, the
pivotal test that duplicated the intended proximity to nearby
quadrupole's iron proved that no cross talk from the air core
coil to the quadrupole exists. We will be able to mount the coils
in their intended position on the BPMs.
Welding the eight curved reverse bend chamber bodies continued
with completion slated for September 15. We plan to subject the
five bolted-up pieces of the chambers of the first branch of the
first arc to a trial fit-up in-situ, taking advantage of an existing
survey control network and comparing the survey of the reference
spots on their top surfaces with the corresponding theoretical
positions. This will give us a heads-up on how much we will have
to take advantage of the deflection of the diaphragm flanges and
change the length of pieces to obtain a good fit to the magnets.
Note that no bellows are used in these assemblies.
There is continued progress in installation, the beam line in
the injector dump region is purged, pumped and undergoing leak
check. At the other end of the linac cryomodule, the line for
the Recirculation Dump is started with the dump and its instrumentation
vessel made up and the Y chamber mounted in place.
Regarding cryomodule:
The linac cryomodule is sitting at 2k awaiting the completion
of the RF system so commissioning can begin.
Regarding RF systems:
The bellows for the 500 kV High Voltage power supply is being
made by the vendor and is promised for delivery early next week.
The final details for powering the gun are in progress. The
cathode power supply wiring continues for the required PSS interlocks
of the buncher system. The RF system for the buncher is about
60 % complete. The installation of the 50 kW klystron systems
for the quarter cryomodule is about 60 % complete. We are still
waiting for direction from the Russian vendor on what they want
us to do with the 2nd failed spare 50 kW klystron.
AC power was connected to the first 225 kW variable power supply
to allow high voltage testing. Hipotronics will send people back
to repair the second unit after the first unit has been high voltage
tested. The RF system for the linac is about 40 % complete.
Preliminary phase noise testing of the Master Oscillator (MO)
with the drive laser was observed this week to be 0.2 to 0.4 _
p-p. Insulation for the LCW pipe and M.O. distribution cables
was installed through zone 3. The M.O. system is about 95 % complete.
Regarding instrumentation and control systems:
Work continues on installing and connecting the BPMs, beam viewers,
vacuum, and magnets. The trim magnet control software is being
checked out. An interface board is being fabricated for the video
crosspoint switches, the EPICS software is ready for preliminary
system checks.
Control cable for the optical transport and mirror cans is in
place, these are being terminated and tested as the devices arrive.
The access control hardware for the user lab safety systems is
arriving and being checked out. Magnetic locks are being installed
as well as the PLCs.
FEL Systems
Optics
Work continued this week on the drive laser and the optical system.
There were some additional delays in alignment of the drive laser's
delivery optics, due to the need to reset one stand, but we are
making progress. The two mirror cans being built by our Machine
Shop were cleaned and returned for welding. The drive laser was
operated about 43 hrs. this week to check out the new divide-by-40
hardware, and associated electronics. The tentative results of
that test look encouraging. IR lasing performance with the new
flashlamps are in agreement with what we saw in the ITS. We ran
tests to see if the optical cavity mirror holder could be replaced
without disturbing the alignment, and found that we could, within
the accuracy of the measurement (~ 0.5 mrad). The 5.5 in. calcium
fluoride window used for the Brewster window on the output coupler
side of the cavity was clamped in its holder without incident.
Commissioning/Operations
The detailed injector setup procedure is now drafted. It parallels
that of the nuclear physics injector setup, involving a threading
procedure and use of transient phasing and dispersed viewers to
crest cavities and set gradients. The FEL injector however, is
more complicated in that it runs the second cryounit cavity 27.5
degrees off crest and uses a lower injection energy into the cryounit.
Another difficulty is that the cavity gradients and phase loops
will not be characterized initially. Consequently a fine setup
procedure must make use of the existing diagnostics to set the
buncher and two cryounit cavities' phase and gradients to the
required precision. PARMELA simulations of the injector were
run to determine an expedient procedure for setting the injector
parameters.
Facility
This will be the last weekly report for the facility. All major
work is complete. Only two major items remain: a circuit cut-out
for the elevator which is designed to strand you between floors
in case of fire (required by code - go figure); and connection
of all fire and building alarms to remote annunciation. Building
janitorial is on a standard schedule now and things look clean
and professional. Hardware installation and checkout is proceeding
heavily in the facility as reported in other sections of this
report. We are shooting for first beam from the gun before the
end of the month.