MEMORANDUM

To: J. Albertine, D. Helms, W. Skinner

cc: Division (M7), FEL Coordination Group

From: F. Dylla

Subject: IRFEL Weekly Report, July 7 - 11, 1997

Date: July 11, 1997

Management

SURA received the June 9-10 MTAC meeting report from Adm. Baccioco. The committee made recommendations to SURA and Jefferson Laboratory for dealing with the current lack of Navy support for FY 98 funding and optimizing the use of the soon to be released FY 97 funding.

The Navy High Energy Laser Program office, the DOE Site Office and Jefferson Lab have agreed on the final contract version documents for release of the $3.7M of FY 97 funding to support commissioning preparations, commissioning and continuation of upgrade activities through Sept. 30, 1998. The documents are currently in sign-off in the Navy.

The first round of pre-proposals to be forwarded to DOE-BES for initial use of the IR FEL were received this week for review. By week's end, 8 pre-proposals were in hand out of 12 that are known to be in preparation.

Highlights for the week on FEL construction activities include cooldown of the cryogenic transfer lines, injector quarter cryomodule in the FEL Building, the final cryounit for the linac cryomodule was complete, and the injector drive laser was briefly operated in the new clean room.

Injector drive laser

The laser was operated briefly and was found to not be misaligned due to transport so we will now build up the rest of the injection laser system around it. The chiller water and power to the laser has been established. Some problems with water purity still remain and are being resolved. The rest of the equipment from the ITS Clean Room has been moved to the new clean room. Move complete.

Accelerator Systems

Regarding the beam-transport system:

Additional magnetic measurements of the first optical chicane dipole continued. Adjustment of the field clamps allowed us to achieve the required effective length at the centerline to within the specified 0.01%. Determining that the effective length at other positions on the horizontal plane to the one part in 10,000 level awaits completion of the modifications to the magnet measurement apparatus. Meanwhile, Everson Electric glued mu metal to two more DW cores and are going to start final magnet assembly on those cores and continue further core gluing on Monday.

Anticipated receipt of the finish ground back legs and of the water jet cut brass shims early next week will complete all cores and parts for the reverse bends by Process Equipment Co. All coils for these reverse bends have been shipped to Everson Electric for assembly. Winding form mounting and preparation and application of conductor insulation in anticipation of winding the 180 degree coils is complete. Machining of the large pole tips is continuing while a rush torch cut out of existing material, rapid rough machining and a quick, small batch heat treatment is allowing Process Equipment to recover from discovery that the original back legs were torch cut well under specified size. Master Machine sent core and parts sets for a DU and a DV to Everson Electric for assembly.

The modifications to the magnet measurement stand for measuring uniformity within a dipole family remain in fabrication with completion expected in one week. Realistic planning of the magnetic measurement effort, now possible with knowledge of the probable receipt dates for assembled dipoles, indicates that measurement of the 180 degree dipoles will run several weeks beyond October 1. Getting started on the design next week by working in parallel would forestall this schedule overrun. M. Wiseman is working the issue.

The Panofsky trim quad contract was awarded to Magnet Enterprises International. Twelve of the 48 sextupole coils were shipped. Sextupole cores are somewhat delayed with completion now expected next week. The three quads for the recirculation dump line are on schedule at New England Technicoil.

In the corrector area, details of the core and coil drawings and the assembly for the phasing dipoles were signed off. We assured ourselves of minimal fringe field cross talk from the 180 degree dipole field clamps by consulting with the field measurements from the DW dipole at 42 MeV excitation. Details of the two, 8 inch mu metal correctors were in process. The design of the constant perimeter, air core corrector horizontal coil started in earnest. I am investigating inexpensive water jet cut keys are being investigated to locate the coils with respect to themselves such that the assigned conductor placement achieves the required 1% field accuracy.

Welding of the bodies for optical chicane chambers continued with a projected completion date of July 18. Pump down of the 60 inch test piece chamber indicated that contamination from the machining oil that the X Chamber experienced is not significant. We will complete the X and Y chambers as welders become available. The reverse bend chambers were signed off. Procurement was split into two parts-a quick contract with an incentive payment for making the straight pieces. This will get us parts soon enough to our supply of trained welders. A second procurement will follow, with more competitive bidding, for the remainder of the parts that will match the follow-on welder availability. Drawings for the arc dipole stands and girders for the trim quads and sextupoles are in back checking while drawings of the beam pipes and stands for the dump lines are in signature.

LCW was turned on in the header in the enclosure and the volume of water is in clean-up mode.

The remaining two probes to allow zeroing out the dipoles at the switch points to the three dumps were ordered. Design of the mounting bracketry will start next week.

Regarding cryomodule fabrication:

Cryounit

The final cryounit was completed and handed over for cryomodule assembly this week. Post assembly review of special FEL components and procedures is underway.

Cryomodule

The remaining two bridging beam pipes have been installed. This required the venting of the third cavity pair due to a valve leak, see last weeks report. This work was completed with no unexpected actions. The supply side transition beam tube has been installed. Helium circuit interconnecting pipe work is completed and requires leak checking. Assembly and clean-up of helium circuits is on schedule for a 4 August installation into the FEL building.

Regarding electron-beam instrumentation and controls (I&C):

The focus this week was reestablishing remote control of the drive laser. This should be done by 7/15/97.

All three networks are operational; the CHL network for running the cryogenic systems, the Controls LAN for operating the accelerator, and the CEBAF LAN for connection to the main CEBAF computers and printers. The racks and tables have the AC power connected in the control room and most of the RF gallery. Reconnection of the ITS server for drive laser operation is proceeding well, the drive laser controls should be up by Tuesday of next week.

Design work is proceeding for the Analog Monitoring System (AMS), this system and the video distribution system is based on a 16x16 200MHz cross point switch. The assembled printed circuit boards are purchased from Analog Devices for $500 each. They are meant to be a demonstration board but it is a perfect match for multiplexing 128 analog channels to 16 channels (and ultimately to 4 ch.) and for mux'ing 64 video channels to 16 outputs.

The new servers for the FEL control system were installed in their final location. The ITS server will run the drive laser controls and be used for RF commisioning while the new server configuration is tested. When the new servers are proven to be stable, the controls for quarter cryomodule RF and driver laser will be moved.

FEL Systems

Wiggler

More optical equipment was moved to the laser clean room and the laser was run successfully. The clean room is still awaiting certification. The two new drive laser cans were ordered. The light box was place in position and the gun was aligned. Both were grouted. The bakeout cart was also moved to the FEL building.


WBS 9.4 IR Demo wiggler

The wiggler is now in the FEL facility. The wiggler vacuum chamber support was assembled and fit up to the wiggler. A clearance problem was found between the wiggler magbase bolts and the support requiring about one man-day of machining to correct. This will be fixed next week.

Optics

Optical transport stands in the accelerator enclosure have been installed. Optical tables were modified and re-aligned to less than 1 mm of perfect alignment. That meets spec. Design of mirror cassettes have moved into detailing phase. The optical collimator was recleaned and received. We are beginning to align it.

Commissioning/Operations

Analysis of the data collected during the last series of experiments with the photocathode gun is continuing. Regarding longitudinal properties of the 135 pC bunches, the data concerning energy spread versus longitudinal position, as well as the data concerning bunch length, agree remarkably well with code (PARMELA) predictions. However, several issues remain, most notably a disagreement regarding transverse beam size. Specifically, the transverse rms beam size at the gun's aperture appears to be much larger than predicted by PARMELA, and tails are seen to form at the edge of the bunch. Data reduction continues.

Successful tests of the multislit transverse-emittance monitor during experiments with the photocathode gun had led us to consider designing and mounting one of these devices at the gun's light box as an aid in monitoring the gun's performance during commissioning and operations. However, in view of cost and schedule, we are putting this on hold until we can bring it through design, fabrication, and installation without stalling higher-priority projects already programmed. Nonetheless, we are also firming up the projected cost and schedule for the additional instrument. It is not required for commissioning but would be a nice augmentation of the baseline diagnostic suite.

Facility

Work is winding down on the facility. This week there was more work on punch lists. The HVAC balancing continued. The chilled water system was inspected by the contractor and cleanup of the water performed. Grading of the site continued in preparation for asphalt in the parking areas and loading dock next Monday. Concrete was poured for sidewalks around the window areas, near the street, and on the upper level exit stairs. The berms were leveled. Punch list work continued in the elevator. Rubber pads were placed on the stairs and the stairwell painted. General cleanup continues. Jefferson Lab work included a lot of electrical hookup to racks. The LCW was turned on upstairs and mods were completed downstairs to provide better access to the gun. Considerable effort was devoted to getting RF online and during the week the cryomodule low level controls were cycled on a portable computer for the first time. The cryounit was filled with helium and is ready to bring down to 2K. Klystrons were placed in the Zone 1 HPA. Communications networks were expanded around the building and brought online. We now have communication to the server just as was available in the ITS, all programs that were there are now available for hardware checkout. There will be a switchover to the final server configuration around August 1 as that new server facility becomes fully operational. Phones are getting installed in the building we have a number of analog phones now available. The chiller was brought into operation for the drive laser. The mounts for the optical transport lines for the FEL output were mounted on the ceiling. Installation of the cans should begin next week. The gun was surveyed into position then grouted down. The 10 MeV dump, light box, gun controls, etc., etc. got delivered from the ITS into the building. The wiggler with its table and quadrupoles was delivered to the building but awaits alignment before it will go to its final position. Both optical tables were re-positioned and surveyed in. We have now locked that down and can begin installing hardware on them. The remaining back leg quad girders were installed. Survey performed a check of the building matrix and discovered a 1mm expansion in length since February. Whether this is seasonally related or part of the building settling remains to be determined. We intend to monitor this on a quarterly basis until the question is resolved. Progress continued on the gun high voltage power supply installation. The control room is getting set up with the communication cables to the tables, phones, a printer on the net, a scanner, and rack hookup continuing. We continue to work with the vendor in getting the clean room air controls to meet our needs as regards humidity and temperature.