Experience Fabricating the Storage Ring Vacuum Chambers for NSLSII Prepared by: Charles Hetzel July 12th, 2011

Facility and Cell Overview. Pumps and Valves. Outline Facility and Cell Overview. Pumps and Valves. Instrumentation and Absorbers. RF bellows. Chamber Cross Sections and Fabrication. Chamber Assembly and Production Status. Vacuum Instrumentation Rack Overview.

30 cells (DBA) in 5 pendants Ring circumference: 792m 6 Facility Overview Nominal energy: 3GeV Nominal current: 500mA 30 cells (DBA) in 5 pendants Ring circumference: 792m 6 5 6 6 4 3 1 1- Accelerator Tunnel 2- Experimental Floor 3 - 200MeV LINAC 4 - Booster (C=158m) 5 - RF Building, liquid He Plant 6 - Service Buildings 5 pendants 30 cells LINAC booster 2 6 6

Short straight section Typical Cell Layout Each section of the cell is composed of girders assemblies. 3 focusing and 2 bending segments (DBA). Alternating long and short straights (9.3m and 6.6m). Photon extraction takes place at S3 and G6. The ring is divided into 60 vacuum sections. Sectors can be isolated with RF gate valves. Design pressure (beam on): 10-9 torr. ID photon extraction Dipole and 3PW photon extraction Extraction points Gate valves S2 Multipole S3 Dipole S4 Multipole S5 Dipole Fast corrector S6 Multipole Long straight section RF gate valve 3 pole wiggler (3PW) Short straight section RF gate valve

100 l/s ion pump TSP cartridge Turbo pump cart 18 units Typical Cell Layout – Pumps 100 l/s ion pump TSP cartridge Turbo pump cart 18 units NEG strips (St707) 1500m Turbo cart rough pump Ion pumps over absorbers (large gas load due 2 sync rad) St707 SAES Getters Distributed NEG pumping 200 l/s ion pump (8” or 6”) TSP cartridge Right angle valve

All metal gate valves used in transport lines and font ends. Typical Cell Layout – Valves All metal RF gate valves isolate cells and ID straights. Double position indicators (to vac PLC and to EPS PLC). Radiation resistant and bakeable. Two first articles received. Additional RF gate valves used to isolate SC cavities. All metal gate valves used in transport lines and font ends. Right angle valves Rough pumping. Instrumentation isolation. RF gate valve 62 units All metal GV - DN100 4mm bow 2mm gap Returned to VAT for investigation All metal gate valve 40 units Right angle valve 270 units

Gauge tree with isolation valve. Typical Cell Layout – Instrumentation Instrumentation located in dipole chambers. CCG and RGA in S3 CCG and TCG in S5 Gauge tree with isolation valve. Typically scan and trend 7 on the 11

Intercepting surfaces are made GlidCop Al15. Typical Cell Layout – Absorbers Absorbers intercept unused dipole fan radiation. Intercepting surfaces are made GlidCop Al15. Stick absorber 20mm, 22mm, 25mm 130 units < 700W (< 5 W/mm2) Glidcop: 130°C, Tube: 119°C Flange absorber 21mm X 64mm 90 units < 200 W (< 16 W/mm2) Most sticks @ 25mm, 20mm for DW and RF Zero opening crotch 90° knife edge Crotch absorber 21mm 60 units < 1800W (< 57 W/mm2) GlidCop: 180°, Tube: 127°C

Angular deviation: +/-10 mrad Low impedance RF Shielded Bellows Water cooled flange Requirements: Misalignment: +/- 2 mm Stroke: +10/-15 mm Angular deviation: +/-10 mrad Low impedance Sleeve (316L) Bellows weldment (316L) RF fingers (GlidCop) Coil spring (Be-Cu) Contact springs (Inconel 718) Outside finger design (SPEAR 3) Weldment purchased Assy @ BNL Finger retainer (316L) Storage ring will require ~ 220 units 100 piece order in process Weldment purchased, assembly @ BNL

Fast corrector section Vacuum Chambers Multipole cross section Dipole cross section Almost all aluminum extrusion with bimetal flanges 3 channels extruded into the profile (cal rod) Fast corrector inconel sheet 1mm thick. Beam channel and the ante chamber extraction slot S4A cross section Fast corrector section

Only 2 vendors were willing and able to produce our extrusion. Extrusion fabrication – Mutlipole and Dipole Only 2 vendors were willing and able to produce our extrusion. 180 multipole extrusions. 140 dipole extrusions. Extrusions were fabricated over ~18 months. Incoming extrusions were inspected. Dipole chambers. Bent into shape. Thermally cycled. Re-measured. Packaged and shipped for machining. Large size (12.5” x upto 240” long) and the weight (~16#/ft) Low volume and the challenging tolerance (features but the straightness and twist requirement) 2 vendors one MP one DP All extrusions have been received. Dipoles required quite a bit more work. Bent using a press brake Thermally cycled to relax the extrusions before machining

Support to prevent collapse Several cycles per extrusion Dipole bending Support to prevent collapse Several cycles per extrusion Everyone bent different Bent to accommodate 6° angle in dipole Success rate improved dramatically (~80%)

2 machine shops were qualified Close vicinity to Argonne Chamber Machining 2 machine shops were qualified Close vicinity to Argonne Mounting feature machined with the rest of the chamber. Hi-Tech used some cleaver fixturing (losing registration) Walco machined the entire part in one setup. (167” [4.2m] x 108” [2.7m] x 56” [1.4m] 33,000#)

Welding of flange-adapter sub assemblies. Out of tolerance flanges. Chamber Welding at Argonne Welding of flange-adapter sub assemblies. Out of tolerance flanges. Sub assemblies to chamber welding. Bake out and vacuum certification. Leaky flanges (21 flanges, 10 chambers) Currently producing 10 chambers per month. All welding done at Argonne National Lab Critical tolerances, problems with Atlas flanges, leaky flanges Flange – transition sub assembly Sub assy to chamber (S6 exit port to chamber) Additional side ports, water fittings After welding, chambers cleaned, instrumentation and pumps. Bakeout and conditioning Vac certification prior to shipment Note: Pictures taken at Argonne National Laboratory

Flange ~ 70°C End adapters ~ 90°C Chamber Welding ~ 8”/min A-joint = 3.5-4 minutes Exit port = 10-11 minutes Flange ~ 70°C End adapters ~ 90°C All welds single pass except for pump ports

Target Avg. Measured Values Dipole Measurements Measurement description Target Avg. Measured Values Absorber flange to beam center 290.6mm 289.0 +/- 1.5mm Flatness of machined surface +/- 1mm +/- .6mm (1.8mm max) Flange angle perpendicular to the orbit plane 9 mrad max +/- 3 mrad (7 mrad max) Transition flange twist +/-3 mrad (7 mrad max) Minimum wall thickness in machined area 3mm 2.5mm (1.9mm min) After the chambers are welded and returned to BNL Measure and confirm that they meet our requirements.

Target Avg. Measured Values Multipole Measurements Measurement description Target Avg. Measured Values Absorber flange to beam center 252.0mm 251.5 +/- 1.4mm Chamber flatness near magnet pole cut outs +/- 1mm +/- .56mm (1.4mm max) Flange angle perpendicular to the orbit plane 9 mrad max +/- 3 mrad (10 mrad max) Transition flange twist +/- 5 mrad (6 mrad max) Exit port survey point X 332.2mm 332.4 +/- 1.5mm Exit port survey point Y 7.1mm 7.1 +/- .5mm

BPM rf shield NEG assembly Bake out and conditioning Cal rod heater Chamber Assembly BPM rf shield NEG assembly Bake out and conditioning Cal rod heater Currently assembling 10 chambers/month Assembly work performed in class 1000 clean room (Clean room picture) Install gauge tree (RGA, CCG) and small 20lps ion pump. Bake out (cal rod): Leak check, bake 150°C for 6 hours Activate NEG (50A for 2 min, 35A for 20 min). Valve off turbo when P <10-8 RGA scan for 12 hours to confirm gas species are stable. (Ozone treatment if necessary) Bleed up with N2 and seal. Ozone 400ppm in oxygen at 70°C for 6 hours. Ultimate pressures of low 10s – high 11s torr.

400ppm ozone in oxygen @ 70°C for 6 hours. Ozone Treatment Removal of surface contamination. 400ppm ozone in oxygen @ 70°C for 6 hours. NEG activation 35 A@120 C. Cool down and reprocess. Treatment performed on 9 out of 90 chambers. P = 1.3 x 10-9 Torr 3X bake 6 h@120 C. P = 8.5 x 10-10 Torr Proven to be very effective

Chamber Ordered Machined Welded Assembled Production Status – Multipole and Dipole Chambers Chamber Ordered Machined Welded Assembled S2 34 32 (94%) 30 (88%) S4 33 18 (54%) 16 (47%) S6 24 (71%) 12 (35%) 35 mm Dipoles 62 62 (100%) 36 (58%) 27 (44%) Totals 163 136 (83%) 98 (60%) 85 (52%)

Install after magnet pre-alignment (100µm). Girder Integration Install after magnet pre-alignment (100µm). BPMs positioned using laser tracker (mechanical center). Adjustment may be required after magnetic alignment (30µm). Pumps and bake out wiring added after final alignment. Final leak check and vacuum signoff. Mechanical centers pre-aligned w Hamar laser Next magnets split so the vac chamber can be installed. Pre installed vibrating wire tube Survey uses laser tracker to position the BPM to mechanical center BPM position did not change when fixtures were removed. Magnets are closed environmental room for magnetic alignment. Depending on adjustments chamber may need to be repositioned Final positions of BPMs stored in survey file. Pumps (ion and TSP), bake out wiring, final leak check and signoff.

Three racks/cell located on mezzanine Vacuum Instrumentation Rack Overview Three racks/cell located on mezzanine IPPS, TSP power supplies Gauge controllers (CCG, Pirani) PLC chassis, MOXA Cables: Low smoke, zero halogen, tray rated Computer system w touch screen

Gao-Yu Hsiung and June-Rong Chen (NSRRC) Acknowledgments Joe Gagliano, George Goeppner (APS) Vacuum techs C. Longo S. Sharma L. Doom V. Ravindranath T. Dilgen B. Kosciuk Gao-Yu Hsiung and June-Rong Chen (NSRRC) Many others in and out of NSLS-II