Project Progress Summary
Nov 5, 1991
Accelerator Instrumentation Workshop
- Some 130 people attended the Accelerator Instrumentation Workshop at CEBAF last week (28 to 31 October). The workshop was judged to be quite successful. Participants heard three days of presentations, and toured CEBAF on the fourth day.
FET Operations
- Continued work on bringing beam into full operation'. By Friday had succeeded in getting beam through the first 180-degree bend of the recirculatory to allow for proper phase adjustment of the first cryomodule. Continuing work with RF control and other software.
SRF
Cryomodules:
- The cryounit technicians are working on the alignment strongback fixtures.
- Re-established the vacuum in A' and conducted a second loss-of-vacuum test Both the 2 K and 4 K loss-of-vacuum tests yielded results on heat fluxes and pressures as predicted. Vacuum valves closed rapidly to ensure no deterioration of downstream vacuums. This correlates the results between superfluid and normal fluid.
Cavity Pairs:
- Measuring an additional 10 cavities to gather alignment statistics for the accelerator physics group.
- The alignment fixture was checked after the vertical test. The largest change observed was 0.2 mm on one cell. This is excellent news indicating the cavity pair alignment is repeatable before and after cold test.
- Assembled IA094/IA096 and it was leak tight at room temperature.
- No leak has been found on IA129/IA130 at room temperature. This is the pair where a gate valve was mistakenly closed during the cold test leading to erratic vacuum performance.
- IA90/IA91 has had two leak checks at room temperature. It was tested Wednesday, 30 October, and achieved 7 MeV/m on 90 and 11 MeV/m on 91, or 9 MeV/m net on the pair.
- An additional cavity pair was assembled last Friday and began testing late that day.
- A second fixture has been remodified for the end dish alignment. This gives a total of three fixtures.
HOM Loads:
- To date, 200 HOM flanges have been brazed with copper inserts, of which 130 are undergoing final machining, 40 are being electropolished and 30 are completed loads with 17 delivered to the cavity pair group.
- Drawing package has been revised and released for production.
RF Windows:
- Two windows turned over last Wednesday.
- Drawing package has been revised and released for production.
Nb Pair Parts:
- Two fundamental power coupler extensions with the production dimensions have been completed.
Arcs
Magnets:
- A visit to the common arc dipole core and steel vendors was made to inspect reported filamentary (1/16" diam. x 1/2" deep) holes in iron bars. The average number of holes per bar is eight They are randomly located longitudinally but occur in a plane vertically. Initial evaluation at CEBAF indicates that these holes will have negligible effect on the performance of the magnets since we operate at low fields. They also are consistent with the allowable void's specification in the contract.
- Engineering drawings were begun for the septa.
- Trial installation of a BE dipole at 30 degrees in east arc was done.
Survey/alignment:
- East arc stand alignment rate has increased to about six stands ·a, day.
- Checks of the EA quad stand alignments have found that while most are within tolerance, some have been disturbed at the 1 mm level. The shift is predominantly at the base. The planned grouting will eliminate this in the future.
- Preliminary work for locating Hall A reference points began on Saturday.
DC Power:
- One trim rack placed in the south linac service building. Total is now 28 out of 80.
- Miscellaneous installation activities have been completed. They include north linac P2 panel for RF, rack labels in north linac, and HP A supports in south linac. Instc1Jlation was begun for panel and transformer in service building W3.
Diagnostics:
- Assembly of BPMs, viewers, and harps continues.
RF:
- Held successful design review of the Master Oscillator distribution system. The committee, including two _outside reviewers, endorsed the design.
- Implemented autotuning for the FET superconducting cavities. The algorithm still needs work.
- Machine shop completed-line reactors, and they have been installed.
Ops Electronics:
- Final changes to BPM CAMAC artwork are being made. Modules will be ordered next week.
- Held several sessions at the Accelerator Instrumentation Workshop on CEBAF systems. The workshop was well received.
Software and Controls:
- Prepared new embedded code to allow for automatic (as opposed to expert) operation of RF systems.
- Design of logic macro program completed. First trial slated for December.
- Software for 1500 MHz BPM ready for test.
Cryogenics:
- Purifiers are still being cleaned due to contamination from an oil line failure last week.
- Final flowsheets for the ESR are being released to Physics for comment.
Physics
No report received.
Civil Construction
- Continued working on cleanup, leak repairs and punch-list items in Hall A, the counting house, and the beam switchyard and personnel tunnels.
- Hall B dome concrete is complete, shoring has been removed, and post-tensioning is nearing completion.
- Post-tensioning of the Hall C dome is complete. Installation of the crane support brackets continues.
- Continued working on the storm drain system, site fine grading, roads and parking lot areas.
- MCI continued working on site utilities and the footing, under slab utilities, and floor slabs for SB #1, SB #2 and SB #4. They also continued erecting structural steel for the ESR building.
Support Services
Stockroom:
- Withdrawal activity for the week: $43,267.44.
- Total month expenditures: $133,447.69.
- Received 45 equipment racks.
Machine Shop:
- Fabrication of a rack for cryomodule pump and monitor support has begun (WBS 1).
- Fabrication of three ball holders for the alignment reference fixtures has begun (WBS 2).
- Prototype simulator components being fabricated for Physics.
CEBAF Colloquium
Professor S. Freedman (U.C. Berkeley) will discuss "What Are We Learning from the Beta Decay of Neutrons and Nuclei?" at 4 o'clock Wednesday, 6 November, in the auditorium.