MEMORANDUM
To: J. Albertine, D. Helms, W. Skinner
cc: Division (M7), FEL Coordination Group
From: F. Dylla
Subject: IRFEL Weekly Report Jan. 27-31, 1997
Date: January 31, 1997
Management
The December monthly report for the IR Demo project was completed
and distributed on Jan. 29.
A laboratory-wide scheduling and resource planning effort was
completed on Jan. 31 in order to resolve conflicts and optimize
the use of the laboratory's design, fabrication and installation
labor for support of the experimental halls and the IR Demo project
over the next 12 months.
Grunder, Dylla, and Ware met the Under Secretary for Technology
in the US Dept. of Commerce, Dr. Mary Good, at the Virginia Technology
Summit held in Norfolk on January 29. Dr. Good, whose oversight
includes the NIST laboratories, encouraged us to ask potential
users of our FEL facility to submit proposals to NIST's Advanced
Technology Program.
Injector Test Stand
We completed baking the gun and beamline. Plans are to make the
photocathode today (31 Jan 97). The harp and viewer equipment
were installed, and magnet installation has started. Tasks that
remain are to attach the SF_6 tank and align the laser-steering
mirror on the light box leading to the photocathode. We are on
track to turn on the electron beam next week.
Regarding upgrading the photocathode gun:
Coated Cathode-Support Tube - FM Technologies is sole-sourcing
the multilayer coating of the tube instead of sequentially contracting
for each layer. They forecast that acceptance tests of the samples
from the sole source will be complete today. If the results are
satisfactory, delivery will be within the next two weeks.
Ion-Implanted Ceramics - This week Lawrence Berkeley Lab had to
satisfy a number of their other implantation customers and refurbish
their electronics to increase the efficiency of their implanter.
Implantation of our first ceramic should begin on Monday, 3 Feb.,
and be completed by the end of the week.
A new supply of 1/4-inch-diameter platinum rods is required to
complete the implantation of the second improved ceramic. Procuring
the platinum rods from an external source would take an unacceptable
4 weeks. We plan instead to make our own rod, and project completion
by Wednesday, 5 Feb. The necessary materials are in hand.
Cr/V-Oxide-Coated Ceramics - In view of LBL's success, we plan
to remove the Cr/V-oxide coatings with the unacceptably high resistances
on the three other ceramics and substitute the ion- implanted
surface.
Regarding other ITS activities:
We received the third Svetlana klystron this week. It is a spare
klystron for the FEL injector. Svetlana claims to have operated
this klystron to 85 kW cw prior to shipping it. We will try to
duplicate their results as part of our acceptance testing.
Regarding the beam-transport system:
The design drawings for the optical-chicane dipoles were modified
to incorporate a wider configuration that provides the extra width
needed for good end field drop-off. We are in the process of
looking at the design of the entire optical chicane and optical-cavity
mirror to make sure there are no hardware interferences. We plan
to initiate procurement of the optical-chicane magnets based on
the existing drawings, and then follow up with signed-off versions
that will include any necessary corrections.
The design of the reverse-bend dipoles and the 180-degree dipoles
continued at Northrop Grumman.
The method for phasing the beam at 42 MeV using the injection/extraction
dipoles was finalized, which in turn has led to firm guidelines
for the designs of these magnets. In the extraction chicane,
the first wedge dipole will have an extra 150-turn coil that will
permit bending the 42 MeV beam. The third dipole in the chicane
(a mirror image of the first) will be made of the same iron as
the first dipole, but without the extra coil. Hysteresis differences
between the magnets after phasing will be zeroed out by using
the a reversing switch to allow the power supply to zero the remnant
field. Similar wedge magnets in the injection chicane will be
made in the identical mechanical configuration, but less wide,
thus retaining a need for a third style of magnet.
Fabrication of the quadrupoles for transporting the beam along
the back leg of the recirculation loop progressed as the first
four quadrants of laminations were made and 10 coils were potted.
The first article is slated to be shipped to us by air next week.
Regarding cryomodule fabrication:
Two ceramic warm-window assemblies are due to be completed today
(31 Jan 97). The upgrade of the ring-resonator test stand to
improve its vacuum is also due to be finished today. Testing
of the new warm windows in the refurbished test stand is slated
for early next week. In addition, assembly of the first cavity
pair for the cryomodule is scheduled to be completed next Tuesday.
Regarding electron-beam diagnostics:
Fabrication of the modified prototype stripline beam-position
monitor (BPM) was successfully completed. This BPM also successfully
passed its electrical acceptance tests.
We have a flange-mounted design for the button BPMs that are envisioned
for the centers of the 180-degree bends. This provides flexibility
in that we have the option to install a blank-off flange and use
the co-located optical-transition-radiation viewers to monitor
beam position at these locations during commissioning. Having
the BPMs on hand would provide redundancy and the possibility
to incorporate autosteering in the future. The design enables
change-out to be completed within one day.
Twelve of 52 slit arrays have been successfully fabricated for
the multislit transverse-emittance diagnostic. All of these arrays
should be complete within the next two weeks.
A prototype diffraction-transition-radiation (DTR) detector has
been installed on the nuclear- physics machine for experimentation
next week. If successful, DTR detectors will then be used at
various synchrotron light ports along the FEL to nonintrusively
monitor the bunch length.
We received the video-over-fiber distribution system which will
be used to operate the FEL remotely from the Machine Control
Center (MCC). This system will provide 14 channels of real- time
video between the FEL Facility and the MCC.
The "to-build" vacuum-controls drawing is finished,
and the magnet-controls drawings are being updated.
FEL Systems
Wiggler
Purchase requisitions for components of the wiggler support were
prepared. The designs of the vacuum chamber and chamber support
are progressing nicely at Northrop Grumman. Vacuum-chamber drawings
are now ready for checking.
Optics
Design efforts this week were focused on investigating potential
interferences between the new optical chicane dipoles and the
optical cavity assemblies. Changes to the design of the diagnostic
pick off and mirror cans are being incorporated into the drawings.
The sensitivity of an intensified CCD camera was measured, and
it and other cameras that will be used in the FEL accelerator
area have been moved to the main accelerator for tests of their
survivability to radiation. The optical transport system mirrors
were ordered, along with other parts for the optical cavity assemblies,
specifically the custom crosses and some fasteners.
For the ITS, we received the redesigned divide-by-two EO modulator,
and we are installing it into the drive laser for tests. We also
successfully tested the software for remote control of the laser
pulse selection hardware.
Operations/Commissioning
Candidates for charge-coupled-device (CCD) cameras have been identified
for use in conjunction with synchrotron-light monitors. One outstanding
question is their robustness in a radiation environment. Plans
are soon to install and monitor a camera in the nuclear-physics
injector to get an indication of its lifetime.
As described above under "Accelerator Systems", the
method for phasing the beam at 42 MeV using the injection/extraction
dipoles was finalized.
General plans were considered for timing the commissioning of
the energy-recovery loop vis-a-vis obtaining first light. At
this time, we are planning to commission the hardware along the
recirculation loop in parallel to achieving first light, and afterward,
to commission fully the process of energy recovery.
Facility
To date we have received only one bid for the clean room for the
FEL Facility. We are reviewing the proposal and are continuing
to solicit bids from other vendors.
The high-voltage-power-supply tank for the FEL Facility needed
some redesign to accommodate elliptical heads rather than the
hemispherical heads proposed in the initial design. The redesign
was done and sent to the potential vendors.
Regarding Facility construction, the pad for the main power transformer
was poured, and the transformer was set in place. A retaining
wall remains to be poured for the power-distribution pad and the
pad for the HVAC heat exchanger. A substantial amount of steel
framing was craned to the second floor, as were two power distribution
units. Survey teams were surveying the building network throughout
the week. Utility piping was welded in place along the north
wall. Lighting fixtures are 90% complete in the lower level.
An installation-coordination meeting was held to schedule the
next wave of Jefferson Lab activity. Coming up will be installation
of cable trays, cryopiping placement, and blocking out the positions
of the magnet stands.