July 2000 was the second month of activity for the IR Demo FEL Upgrade Project. Design and initial fabrication activities for the IR Demo continued as noted below. Cost and schedule performance for the upgrade project are given in the appended "Performance Assessment Report".
For most of the month of July, the IR Demo was operated for user tests and several experiments that expanded the capability of the FEL. In the latter category, the IR Demo was operated in a third harmonic mode generating 100-watt cw at 1 micron. This makes the IR Demo the highest power sub-picosecond laser operating at this wavelength, which is very useful for laser material processing and scientific research.
In addition, we re-established the generation of short pulse (sub-picosecond) x-rays this week by Compton scattering of the IR Demo IR pulses off of the driver electron beam. The IR Demo is presently the brightness source of sub-picosecond x-rays in existence. The experimental configuration has been enhanced to allow further characterization of the x-ray flux including the energy and angular distributions.
The FEL management team worked with Accelerator Division management to ensure that we had our best labor estimates in hand for all the required work that is necessary when sharing lab design resources (the FEL Upgrade, SNS and the CEBAF Upgrade). We are prioritizing the scheduled work and making sure we maintain flexibility in sharing the available resources.
A paper was submitted and accepted for presentation at the Directed Energy Symposium, which will be held the first week in November in Albuquerque.
We received a number of responsive bids for an RFP to provide engineering services for the design and construction of FEL upgrade hardware. The bids are under evaluation according to advertised selection criteria.
Project Cost Performance
The project budget for the period, June 1, 2000 to Sept. 30, 2001 is $9,029k. The project through the month of July 2000 has a total of $778k of performance scheduled (assuming the project started at the originally planned start date of April 1, 2000). The work performed through the end of July was $246k, which is 3% complete vs. 8% scheduled. The actual cost accrued through July totals $192k. This results in a schedule variance of -$532k and a cost variance of +$54k. We expect to carry the schedule variance for about the first half of the project until we recover from the 2-month delay in the start of the project.
WBS 2 (Facilities)
We made a revised estimate of the total amount of low conductivity cooling water (LCW) that we would need in the FEL facility to accommodate the upgrade. The new estimate (610 gpm for the upgrade) is comfortably within the presently installed capacity (680 gpm) in the building. Design was completed and parts specified for an upgrade of the radiation monitoring system in the FEL vault. It will use local detectors within the vault and eliminate the need for radiation surveys before access to the vault under most operating conditions. This was made possible by the exceptionally clean beam transport.
Beam Physics: (WBS 3)
This week we continued work for documentation for the upcoming FEL and Linac conferences. We have completed a preliminary CSR study for the upgrade based on 1-D longitudinal wake field:
Injector: (WBS 4)
The ceramic insulators, which will be used to construct the upgraded photoemission gun, were successfully ion implanted at Berkeley. This process produces a slight conductivity in the near surface region of the ceramic to allow excessive charge to be bled off the surface in a non-damaging manner. Some small changes in surface resistance were noted after air exposure. The final resistance will be monitored at LBL before shipment to JLab. This effort proceeded well, despite the two-year hiatus since the ceramics for the existing gun were treated. The vacuum vessel for the tests of the apertured cesiator was baked and leak checked. By month’s end it had not yet passed our qualification tests.
SRF: (WBS 5)
The procurement bid process has been completed for the helium vessels, space frames and vacuum vessels for the upgrade cryomodule. Design work continues on remaining cryostat components. Tuner cost redesign has been completed and a prototype tuner is being procured. We completed the fabrication of two 7-cell cavities that will be shipped to KEK (Japan) for test of KEK's electropolishing procedure. One cavity has completed chemistry and has achieved 14 MV/m during cold tests. The second cavity has completed the initial chemistry and is under going tuning prior to final chemistry and installation in the VTA dewar for cold testing.
RF Systems: (WBS 6)
Installation activities have begun for the waveguide in the 3rd cryomodule position through the FEL ceiling penetrations during the weekend shut downs of the July user run. The second High Power Amplifier (HPA) for powering the second cryomodule klystrons was moved into position.
Instrumentation: (WBS 8)
We completed a prototype for the optical BPM, and tested this new diagnostic with beam during the July user run. Orders for beam viewer related items to support upgrade were placed this month. Significant progress was made on the design and drawings for the 3-inch beam viewers. We continued to work on 2" vs. 3" hardware cost/benefit estimates.
Beam Transport: (WBS 9)
We continued layout of the GX Prototype dipole magnet, refining the details of coil winding configuration to avoid asymmetrical bundle configuration in the beam zone of the magnet face. The copper vendor indicated the prototype quantity of custom sized conductor is a viable order.
We quickly completed the 3D magnetic model of the existing H style dipole. The model agreed with magnet test data and hence benchmarked the code. We are now constructing the 3D model of the GX dipole.
Prototype 3-inch quadrupole yoke parts are back from annealing and are being semifinal machined by an outside firm. The finishing cut for the yokes above is the first instance of complete CAD/CAM at Jefferson Lab. After a number of tries, the digital model of the quadrupole yoke became the basis for the program for yoke machining.
Wiggler: (WBS 10)
We continued layout and details of the Optical Klystron on its strong back with all diagnostics, vacuum pipe, dispersion section and water manifolds. We released a drawing for the core modifications for the optical klystron for the shop. We are nearing completion of the dispersion section details with concentration on instrumentation, wiring connections, covers, and support frame.
Optics: (WBS 11)
One upgrade and one new copy of GLAD were purchased and initial trials of axicon pair beam compression were modeled. Conversion of the 2D Optical Transport drawing into a 3D version was completed. This will allow us to identify and fix potential interferences. We started preliminary design of a test stand that will be used to test the mirror mounting, figure control and diagnostic configuration.
As part of this user run we have been utilizing crews from CEBAF Operations. The operators are being trained in not only the linac setup but also in running the laser so that at some point in the future standard user operations can be taken over by the Machine Control Center. The crews are coming up to speed rapidly and having the extra help is proving to be beneficial.
The FEL gun has been running very well with the photocathode providing the required charge for the laser user experiments. Efficiency of the FEL at 3 microns has also been exceptional; at least 1.5% in pulse mode or three times specifications.
We provided FEL light this month to the following user groups:
All information for prospective users of the FEL is now posted on the JLab web site at:http://www.jlab.org/exp_prog/experiments/index.html