1. Status Report of the Review of Vacuum Systems and Procedures Tug Arkan, Allan Rowe 3/7/2011 1

2. Reviews Completed HTS – Risks identified – Procedure and hardware recommendations – New venting/evacuation hardware ordered VTS – Risks identified – Procedure and hardware recommendations SCSPF @ ANL (followed TB9RI024) – Minor process improvements identified – No hardware changes required

3. Reviews Yet to be Performed MP9 activities (following TB9RI024 + next bare cavity) – Cavity prep. following good vertical test – Cavity helium vessel welding – Cleanroom assembly – Evacuation and venting procedures – Comparison of hardware preparations – Cavity preparation for HTS testing – Cavity preparation for string assembly

4. Update on HTS Review Process Sequence Modification – Eliminate venting/evacuation processes where possible. – Identified two venting/evacuation cycles to eliminate---one at MP9 and one at HTS. – Requires change of cavity preparation work flow at MP9, but no additional steps. Modified vacuum system at HTS for controlled manifold pumping/venting (see current vs. new schematic—slides 12-13)

5. New Cavity Preparation Sequence for HTS Following qualified test, cavity is delivered from VTS to MP9 under vacuum. (change) Vent cavity at MP9 (change) Measure straightness of cavity – If straight, weld-compatible flanges are assembled in class 1000 area, leak checked, and backfilled to 1050 mBar abs. – If not straight, cavity is sent to RF lab, straightened, then sent to SCSPF for HPR, assembly, leak check, transport under vacuum to MP9.

6. New HTS cavity Prep. Sequence Cont. If coming from SCSPF, vent cavity at MP9 and fit to helium vessel. Otherwise, fit to helium vessel. Weld on helium vessel (bellows supported by rods) Leak check AND pressure test helium vessel (change) Transport to ANL for HTS HPR and pre-assembly with leak-check. Transport back to MP9 for cold-coupler installation in CR---requires venting to 1050 mBar abs.

7. New HTS cavity Prep. Sequence Cont. Evacuate and leak check cavity. Leave under vacuum for tuner/mag. shielding installation. (change) Remove cavity from CR. Install tuner and mag. shielding. Tune HOM notch frequency. Transport to HTS under vacuum (change) *MP9 may install HTS gooseneck, limiting clean flange assem. to one at HTS.

8. New HTS cavity Prep. Sequence Cont. Install cavity in HTS cryostat while cavity is under vacuum. (change) Make-up cavity-to-manifold CFF using new assembly procedure. Evacuate and leak check manifold using new pump-down procedure. (change) Take RGA scan of manifold volume. (change) Install warm end of coupler while keeping squirm protection on. (change) – New support fixture required. Evacuate warm end of coupler

9. New HTS cavity Prep. Sequence Cont. Remove squirm protection and support fixture. (change) Slowly open cavity RAV to vacuum manifold and leak check cavity and manifold. Take RGA scan of vacuum volume. (change) Pump on cavity throughout warm coupler processing. *Isolate cavity from pumping station at cryostat isolation RAV right before cool down. (change) – Under evaluation---burst disk must be on cavity vacuum side.

10. New HTS cavity Prep. Sequence Cont. *Test cavity with no-pumping station active pumping---cryo-pumped. (change) – New manifold cold-cathode gauge will monitor cavity pressure. – Need to evaluate whether RF event gas bursts are sufficient to justify pumping. After testing, slowly close cavity isolation RAV to keep cavity under vacuum. (change) Open isolation RAV outside cryostat to allow vacuum line venting. (change)

11. New HTS cavity Prep. Sequence Cont. Install coupler squirm protection and support fixture. (change) Vent vacuum manifold up to cavity RAV. Using new procedure (change) Disconnect gooseneck/manifold CFF and cap for transport inside portable CR. Remove warm end of coupler. Remove cavity from HTS. Transport back to MP9 under vacuum. (change) Prepare cavity for string assembly at MP9. (not yet reviewed)

12. Flange to Cryostat wall Burst Disk Ion Pump Turbo Pump Roughing Pump RAVPressure gauge RGA 0.01 micron filter LN2 supply Ion Gauge Variable Leak Valve Current pump down/backfill system at HTS Pressure relief valve Current HTS Vacuum Manifolds

13. Flange to Cryostat wall Burst Disk Ion Pump Turbo Pump Roughing Pump RAV-1 Pressure gauge RGA 0.01 micron filter LN2 supply (to be used only if needed to backfill the manifold) Ion Gauge Needle Valve -1 Proposed new pump down/backfill system at HTS Pressure relief valve RAV-2 Flange to Backfill Gas Panel Full range Gauge Mini RAV Needle Valve -2 or MFC ¼ inch stainless steel pipe Benefits: 1.Pumping station can remain under vacuum. 2.Slow evacuation and venting can occur in controlled manner. 3.Only manifold from RAV-2 to cavity RAV needs to be vented.

14. HTS Process Improvement Implementation Complete mechanical/RF evaluation to ensure proposals do not risk RF coupler or cavity integrity. Re-write and implement new procedures at MP9 for cavity preparation and at HTS for installation. Assemble new vacuum manifold hardware at HTS.

15. VTS Review Eliminate cavity venting/evacuation where possible. Improve clean assembly process of single PFFA CFF flange. Improve venting/evacuation procedure. Improve hardware preparation prior to and during assembly.

16. VTS Recommendations Cavities sent to MP9 should not be vented. Cavities should not be actively pumped during vertical testing. LHe will do the pumping. Cavity to be isolated after burst disk, not at cavity RAV. Cavities should only be actively pumped during long waiting periods and during 120C baking. Cavities should always arrive under vacuum. 1-cell cavities may be vented. 9-cell cavities destined for optical inspection or the RF tuning lab may be vented. Develop a 120C bake cycle operation separate from VTS hardware.

17. VTS Recommendations Cont. An RGA scan AND leak check of the complete cavity and new CFF connection should be performed before each vertical test with the RGA. Follow standard PFFA procedure on CFF. Obtain individually cleaned and bagged hardware from facility capable of performing activities. Implement use of CFF gasket clips to simplify CFF assembly. Obtain gas panel like MP9 for cavity venting. Verify cavity position on vertical insert before attempting PFFA. Improve cleanroom clothing to make compatible with other areas performing PFFA tasks. (hood and face-mask w-class 10 gloves)

18. VTS Recommendations Cont. Compare RGA of vacuum manifold w/o cavity and with cavity. Install N2 gas flow throttle before ion gun to allow particulate check of N2 source and ion gun. Should be accessible to operator in CR. New vacuum manifold hardware to prevent pressure bursts, especially during venting. – Under discussion. Keep all venting sequences for activities where particulate sensitivity is minimal.

19. VTS Process Improvement Implementation Edit existing procedures to reflect modest changes. Follow assembly/leak check procedures as written. Obtain venting gas-panel like MP9 to ensure proper flow control. – *primary gas panel design will be reviewed to ensure compatibility with all systems. Arrange for prepared hardware to come clean and bagged. VTS does not have an adequate hardware prep. area. Implement PFFA technique and other operational changes to ease operator strain. Assembly is uncomfortable and time performing task can be minimized with modest changes.