WBS 2.0 - Beam Physics (Bohn)
A comprehensive technical review of the IRFEL accelerator was held during 23-25 April 1996. The Review Committee, staffed by 5 Jefferson Lab people and 4 highly regarded external consultants, issued a generally favorable report. The weakest (largely missing) top-level areas were the development of detailed commissioning and operations plans and in sensitivity studies
and error analyses. Activities for these areas had been planned
to begin in earnest subsequent to the Review, and beam-physics
efforts in May have strongly focused on them.
In May, the conceptual design of the transport lattice was finalized,
and the sensitivity studies and error analyses were started.
These analyses, coupled with strategies for commissioning and
operations, feed into the requirements for magnet design and beam
diagnostics. Weekly commissioning meetings, which were started
in April, are held to integrate all of the activities related
to the development of the accelerator and the wiggler/optical
systems. Meeting minutes are posted on the World-Wide Web under
TJNAF's FEL Home Page.
Development of an analytic theory of coherent synchrotron radiation
(CSR) in magnetic bending systems and its effect back on the beam
progressed through preparation of a manuscript for submission
to Physical Review Letters. The IRFEL accelerator has been designed
largely to circumvent CSR. Application of the theory to the bunch-compression
chicane preceding the wiggler indicates that the CSR-induced emittance
growth is well within budget.
WBS 3.0 - SRF (Preble)
Work has continued on the designs for beamline components to support the 3 inch cavity pair to cavity pair and 2 inch cavity to cavity interconnections.
- A 3 inch cavity pair isolation valve has been procured and is being evaluated for vacuum and particulate performance.
- Cavity interconnecting niobium beamtube has been procured.
Cold window production has completed two prototype lower loss windows.
Prototypes will be used on the ITS 1/4 cryomodule.
- Twelve metalized ceramics have been received for additional
cold window assemblies.
Discussions with vendors for Higher Order Mode Load production have been
started. Thermacore will provide a budgetary quote.
- Prototype HOM loads have been produced and will be installed
in the ITS 1/4 cryomodule.
WBS 4.0 -- Operations/Commissioning (Bohn)
Jefferson Lab's Operations Department, in conjunction with in-house
experts on wigglers/optical systems, has agreed to commission
the IRFEL. Planning activities for operations/commissioning described
under WBS 2.0 now involve several members of the Operations Department,
and lab-wide interest and involvement continues to grow. Ultimate
plans are to write the commissioning plan and user manual prior
to completion of the machine. These efforts impact current activities
by largely determining the detailed system design. Planning has
begun for a Commissioning Workshop to be held this summer.
WBS 5 - Instrumentation & Controls (Jordan)
The Beam Position Monitor (BPM) and small bore shielded beam viewer
designs are complete, prototyping has been started. The Argonne
controls group is going to send the VME based hardware for our
evaluation of the APS machine protection system for use with the
FEL. The design for the electron beam pulse control and machine
protection interface is 90 % complete and is proceeding to the
first stages of prototyping. The shunts required fro fine control
of the dipole magnet current are identified, procurement packages
are being prepared for production.
WBS 6 - Cryogenics (Kashy)
100K$ pipe procurement awarded. Pipe is due July 12
Design of supports and piers for Quad TL completed.
Detail design of FEL/CHL TL Bayonet Can for CHL in final checking.
Detail design of FEL TL anchor at CHL has been checked and drawings are being corrected.
Preliminary design of CHL Distribution Headers and FEL Quad TL Field Flex Can started.
otal of PR's and PO's is $205,000
*STATUS OF CONTRACT NEGOTIATIONS: Cryogenic group leader has
agreed to sign the contract to provide fabrication and installation
support when two new employee's are hired.
WBS 7 - Beam Transport (Biallas)
The overall schedule was fixed, lattice and powering schemes frozen,
the design of the major dipoles, their design energy and dynamic
range firmed up and the concept for the prototype injector dipole
developed. Work on the vacuum system started. The core for the
prototype main quadrupole was completed. Outstanding major issues
are: (1) increasing the engineering and design personnel available
(2) generating accelerator physics lattices for the dumps and
(3) reducing the cost from the increases in scope.
BCWS 1622 k$
The re-analysis of the schedule during the month moved the major
milestones of receipt of Quadrupoles and sextupoles to April '97
and receipt of the 180° Dipoles to March '97.
WBS 8 - RF (Walker)
The 2nd CPS for the 50 KW klystron was received this month and will be tested in June. Several power resistors were damaged in shipment and must be replaced.
It was determined the E.O. photodiode can produce a -30 dBm signal from the 1µ sample port of the drive laser. This is sufficient for the amplifiers in the Divide by 40 Chassis to drive the RF Module and allow it to phase control the cathode drive laser.
The initial testing of the 5 KW HPA for the Buncher was completed this month. New probes are being made prior to brazing the Buncher Cavity in June.
Waveguides were installed to the top of the cave to drive the Quarter Cryomodules and for the 50 KW Circulator tests in early June.
The optical and electrical design for the arc detectors used in the 50 KW system is complete. The mechanical design of the sensor blocks is in progress.
The Chopper Cavity and Water Skid were delivered and preliminary tests were completed. Minor changes are being made to each unit.
The design was completed and the parts ordered for the Low Pressure
LCW system for the 50 KW klystrons.
WBS 9.2 - Injector move (Benson)
Received budget estimate from vendor for move of injector drive
laser clean room to verify budget estimate for moving cost. It
is only slightly lower than the original cost of the room including
installation. Looking into doing it ourselves or leaving clean
room where it is and getting a new one.
WBS 9.4 - Wiggler (Benson)
Received two bids for IR Demo wiggler from Danfysik and STI
Optoronics. Both look technically acceptable at first glance.
Now doing technical evaluation for award later in June.
Specified diagnostic viewers for wiggler.
WBS 9.6 - Optical System (Shinn)
Work this month centered on determining the effect of thermal
deformations of the cavity mirrors (through bulk absorption) on
the laser output power and beam quality. My role centered on
providing material's properties and from them, calculating some
of the thermal transport coefficients. I also helped plan and
present our plan for the FEL optics (cavity and transport) in
a workshop given 29-30 May to our sponsors. More information
has come from the Accel. Div. managers on support, and I've used
it to refine my budgets. Finally, three (of four) undergraduate
students have begun work on projects related to the IR FEL's commissioning,
operation, and applications.