PEP-II Vacuum p1 New HER IR Vacuum Chambers Machine Advisory Committee Meeting December 14, 2004 Presented by Rodd Pope Machine Advisory Committee Meeting December 14, 2004 Presented by Rodd Pope

PEP-II Vacuum p2 New HER IR Vacuum Chamber Team  Q4R/Q5R – Don Arnett & Albert Sheng  Q4L/Q5L – Ted Osier & Rodd Pope  Q4/Q5 Bellows - Nadine Kurita & Manuel Trigos  Support from Ho Dong  Managed by Nadine Kurita

PEP-II Vacuum p3  Location  BSC & Luminosity Stay Clear  Synchrotron Radiation & Heat Loading  Beam Position Monitors  Supports  HER Q4/Q5 Bellows Module  NEG Antechamber Screen  Design and Fabrication  Milestone Schedule Outline

PEP-II Vacuum p4 HER Q5L – Q4L & Q4R – Q5R

PEP-II Vacuum p5 HER- Downstream, “Forward”, “Right” HER- Upstream, “Backward”, “Left” IPQ2RQ4RQ5RFrangible LinkHigh-Power Dump IPQ2LQ4LQ5LFrangible Link “Luminosity Chamber” 10M Collimator 19.5M 9.4M8.4M 5.7M 3.6M 2.3M 3.6M 5.7M 7.7M8.5M10.1M11.4M 0.0 M e-

PEP-II Vacuum p6 Design Specification Beam Parameters  Maximum HER beam energy/current:  9 GeV at 2.2 Amps “Farther Future” per M. Sullivan  Maximum LER beam energy/current:  3 GeV at 4.5 Amps  Beta *s for HER & LER  Beta x* = 28 cm  Beta y* = 7 mm “Farther Future” per M. Sullivan  Emittances for HER & LER  Emittance x = 60 nm-rad  Emittance y = 24 nm-rad

PEP-II Vacuum p7 Beam Stay Clear  Beam Stay-Clear  HER BSC: +/- 12  x x 9  y  Luminosity Cone: 6.24   BSC through Q2R is  +/- 12  x x 8.5  y Q2L Outboard Flange Looking Toward IP 12  x x 9  y BSC 6.24  Luminosity Cone

PEP-II Vacuum p8 Q4 HER BSC Outboard Magnet End Looking Toward IP Q4LQ4R 12  x x 9  y BSC Luminosity Cone (6.24  ) ~90% Clear

PEP-II Vacuum p9 Q5 HER BSC Outboard Magnet End Looking Toward IP Q5LQ5R 12  x x 9  y BSC Luminosity Cone (6.24  ) ~85% Clear

PEP-II Vacuum p10 Luminosity Clear Ray BSC Luminosity Limiting Aperture is Frangible Link -Green Line Represents Clear Aperture -Green Line Clears Q5L & Q4L Q5L Frangible Link Luminosity Chamber

PEP-II Vacuum p11 SR, I 2 R & HOM Heat Loads  9 GeV at 2.2 Amps  3 GeV at 4.5 Amps  HOM & I 2 R Engineering Guess = 269 W/m  Re-analyze at 1 kW/m (worst case estimate)  10% Reflected SR Power

PEP-II Vacuum p12 Heat Load Summary  Q5R May Intercept B1L & B1R High Power SR During Mis-steer  Actively Safe Chamber (TC Interlocked)  Uniform Heating from HOM and I 2 R Loads  Balanced Cooling to Minimize Dynamic (Thermal) Bowing  Q5L & Q4L Intercepts B3, B2 & BLF HER SR  Distribute SR Power Over H 2 0 Cooled, Aluminum Chamber Wall  Distributed Masks Allow Larger BSC than Discrete Masks  Balanced Cooling to Minimize Dynamic (Thermal) Bowing

PEP-II Vacuum p13 Q4R SR Ray Tracing Looking Toward the IP e- Q4R is clear. Q4R

PEP-II Vacuum p14 Q5R Beam Missteering Location 65 inches e- Q5R B1 SR Looking upbeam Add additional cooling channels to eliminate uncertainty of HOM induced thermal gradient within missteering region. It is the worst case when B1 (R) and B1 (L) SR strike at the same spot. Active safe when using thermocouple to detect transient temperature rise.

PEP-II Vacuum p15 Locations of Thermocouples Possible missteering area Combined 0.5 mrad horizontal and 1 mrad vertical mis-steering. B1(L) B1( R) Looking upbeam Water channel Thermocouples, 1/8” deep, 3/8” equal spacing

PEP-II Vacuum p16 Transient Analysis due to Beam Missteering

PEP-II Vacuum p17 Transient Analysis due to Beam Missteering Trip stress = 25ksi dTmax = 97 C Trip stress = 30ksi dTmax=116 C dT at thermocouple = 14 C dT at thermocouple = 30 C

PEP-II Vacuum p18 LER SR Into Q4L HER Plot Frame Represents Chamber Walls B1L & B1R SR Rays

PEP-II Vacuum p19 LER SR Through Q45L HER Bellows Plot Frame Represents Chamber Walls All B1L & B1R Rays

PEP-II Vacuum p20 LER SR Through Q5L Plot Frame Represents Chamber Walls All B1L & B1R Rays

PEP-II Vacuum p21 Q5L HER Chamber  Chamber analyzed  0 W of LER SR  2560 W of HER SR (B3, B2, BLF)  269 W/m HOM (517 W)   T max = 36 C   max = 13 KSI (combined thermal and mechanical stress).  Re-analyze with 1 kW/m HOM, 10% reflected power and displacement loads from installation and manufacturing tolerances.

PEP-II Vacuum p22 Q4L HER Chamber  Chamber analyzed  0 W of LER SR  591 W of HER SR (B3, B2, BLF)  269 W/m HOM (430 W)   T max = 25 C   max = 3.7 ksi (combined thermal and mechanical stress).  Re-analyze in 3D with 1kW/m HOM, 10% reflected power and displacement loads from installation and manufacturing tolerances.

PEP-II Vacuum p23 Thermal and Mechanical Loading Temperature, thermal induced deformation and stress: Q4RQ5R HOM = 268 w/mHOM = 1 kw/mHOM = 268 w/mHOM = 1 kw/m Max. Temperature (C ) Max. x deformation (inch)0.002(out)0.007(out)0.008(out)0.010(out) Max. y deformation (inch)0.006(in)0.005(in)0.023(in)0.02(in) Overall z deformation (inch) Max. effective stress (psi) Q4R Q5R vacuum HOM + I2R Max. y deform vacuum Max. x deform *On may conclude that overall chamber deformation and stress are vacuum force dominated.

PEP-II Vacuum p24 Beam Position Monitors  2 Sets of 4 PEP LER Arc Type, Bolt-in BPM’s  No Additional Sets are Being Added  Located Immediately Outboard of Q4 and Q5 Magnets  Chamber Geometry to Optimize BPM Signal-to- Noise Ratio  Supporting Chamber at BPM location to the Magnet  Bellows allows locking Q5 BPM’s in Z  Increases accuracy and stability

PEP-II Vacuum p25 Beam Position Monitor (BPM) Q5L looking downbeam Q4R looking downbeam e-

PEP-II Vacuum p26 Old Design Q4R Q5R Q2R Q4R s1 Q5R s1 Supports e - Q4RQ5R 4” bellow Q2R Q4R s1 Q5R s1 Q5R s2 BPM New Design BPM

PEP-II Vacuum p27 Support Degrees of Freedom New Design: 8 free DOF xx yy zz pitchyawroll uxuyuzrotxrotyrotz Q2L/Q4L HER xxxxxx Q4L/Bellows HER xx x Bellows/Q5L HER xx x Q5L/Frangible Link HER xxx x Old Design: 3 free DOF xx yy zz pitchyawroll uxuyuzrotxrotyrotz Q2/Q4 HER xxxxxx Q4/Q5 HER xx xxx Q5L/Frangible Link HER xx xx "x" designates a fixed constraint

PEP-II Vacuum p28 Supports  Addition of Bellows Increases Degrees of Freedom  Fix Q5 HER Chambers in X, Y & Z at BPM  Isolate Any Thermal Induced Loads in Q5  Reduce Any Thermal Induced Loads in Q4

PEP-II Vacuum p29 Q4/Q5 Bellows Module Q4 side, 10” flange Q5 side 12” flange GlidCop Stub Inconel Spring Finger GlidCop RF Shield Finger Welded Bellows Cooling – not shown Absorbing Tile  HER arc bellows concept + absorbing tile in bellows cavity.  Nadine to discuss in detail.

PEP-II Vacuum p30 Q5 HER NEG Anti-chamber Screen  New Screen Design  3 mm diameter holes through 6 mm thick wall on a 4 mm center-to- center square pattern  Isolate NEG Wafers from HOM Power Allowing Net Pump versus Net Outgassing  Effective Pumping 695 L/s

PEP-II Vacuum p31 Basic Chamber Design (Q5L HER Shown) Machined, Welded Aluminum Clamshells PEP LER Arc Type BPM’s NEG Assembly with Heater Rod (Q5R and Q5L HER Only) Variable Wall Thickness to Balance Strength, Magnet Clearance and Beam Clearance Explosion Bonded Al to SST Flanges Machined Pump Screen

PEP-II Vacuum p32 Status  All Chambers through Preliminary Design Review  All Driving Requirements Have Been Identified  Preparing Drawings for Long Lead Items  Preliminary Machined Half Estimates Received  Completing Final Analysis to Support Final Design Review

PEP-II Vacuum p33 Milestone Schedule   Final Design Review – 1/05   Order Long Lead Items – 1/05   Complete Piece Part Drawings - 3/05   Procurements - 3/05   Receive Long Lead Items – 4/05   Receive components, inspection - 6/05   Weld/assemble, Clean and Bake - 7/05   Chambers Ready for Installation - 9/05

End of Presentation

PEP-II Vacuum p35 Q5L BPM Section (looking toward IP)

PEP-II Vacuum p36 Q4/5L Clear Luminosity Ray Q4L Magnet Q5L Magnet Corrector Magnet Limiting Aperture is Frangible Link -Green Line Represents Clear Aperture -Green Line Clears Q5L & Q4L

PEP-II Vacuum p37 Installation and Servicing  Final alignment in tunnel vacuum chamber tolerances are:  Local alignment (4 chambers TBD)  X- and Y-tolerance = ± 125  m (.005").  Z-tolerance = ± 1.5 mm (.098").  Pitch and Yaw = ± 1.0 mrad (.06°).  Global alignment  X- and Y-tolerance = ± 250  m (.009").  Q4 to Q5 chamber X or Y offset across Bellows Module < 0.05".  Absolute accuracy of chamber manufacturing tolerances  ± 2 mm full width in X (TBD)  ± 2 mm full height in Y (TBD)

PEP-II Vacuum p38 Q4 & Q5 Vacuum Chamber Requirements  Improve alignment and thermal motion of chambers.  Maintain gap between chamber and magnet  2 mm minimum between chamber and pole tip,  3 mm minimum between chamber and coil.  Reduce thermal gradient in chambers  Change material to Al with water cooling.  Add bellows  Reduces reaction forces on chamber supports/raft from thermal distortion.  Reduces reaction forces on chamber supports/raft from current design due to manufacturing tolerances (pitch, yaw).  Addition of a flex flange would further reduce load on the raft supports, but space constraints make a new design difficult.  Minimize changes to the raft for support modifications.

Material Properties MaterialAluminum 6061 T6 Stainless Steel (316L) Young’s Modules Poisson Ratio Thermal Expansion Conductivity Yield Stress Tensile Stress

PEP-II Vacuum p40 BPM’s  Beam Position Monitors (BPM’s)  Use spare PEP-II BPMs for Al chambers  One set at the outboard end of Q4 and one set at the outboard end of Q5.  Support the BPM set in x and y. Hold in z only if it doesn’t compromise other requirements.  BPM’s are centered on the beam in the x-direction,  Q5L chamber has a BPM center to BPM center x-direction spacing of 1.875” (R. Johnson, S. Smith (2004).  Q5R & Q4 chambers has a BPM center to BPM center x-direction spacing is TBD.  Place BPM’s on flat surfaces. Avoid transitions.  Keep the BPM’s as far away from any holes and masks (at least 4 to 6”).  Buttons recessed.012” +/-.009”

PEP-II Vacuum p41 BPM (cont.)  Support BPM to Quad magnet  No calibration required – QMS/BBA  BPM electrical centerline positional requirements with respect to quad magnetic centerline:  X- and Y- position absolute offset: ± 0.040".  Z-position absolute accuracy: ± 0.060".  Stability  X- and Y- long-term stability (precision): ± 0.001".  3 hour time span - motion due to beam current, diurnal temperature, cooling water temperature, beam off/on hysterisis. Does NOT include drift of electronics.  Z long-term stability (precision): ± 0.010".  X- and Y- short-term stability (precision): ± ".  1 minute time span - motion due to mechanical vibration of chamber with respect to quad magnet (not of magnet itself). Does NOT include jitter of electronics.  Z short-term stability (precision): ± 0.005"

PEP-II Vacuum p42 Pumping  Pumping  Improve average pressure in the chamber (1 e-9 Torr).  Keep NEG in Q5 HER and maximize pumping conductance within screen dimensions.  Improve the screen to reduce broadband impedance and TE leakage into the pump. New Q5 HER screen dimensions: 3 mm (.118”) diameter holes thru 6 mm thick wall, 4 mm x 4 mm square center-to-center pattern.  Add noble diode ion pump at the outboard end of Q5R (TBD).  Add hot filament gauges, new RGA (TBD).

PEP-II Vacuum p43 Fabrication Tolerance  Chamber length tolerance = ± 0.04"  Roll/Twist of chambers  Max allowable twist flange to flange is 3 mrads. This corresponds to a 0.020" step between Q4 & Q5 chambers.  Pins in bellows will allow for a 3 mrad of roll offset between flange pairs.  Chambers allow for 3 mrad of twist for manufacturing tolerances without applying an excessive load to the supports.

PEP-II Vacuum p44 Supports  Q4 inboard flanges supported in x, yy, z by the Q2 chamber support.  Q4 outboard flange supported in xx, y to the raft or magnet? BPM precision will not be as stable as ones held rigidly.  Q5 inboard flange support in xx, y to the raft or magnet; or supported in xx, y, z.  Q5 outboard flange support in xx, y, z to the raft or magnet; or supported in xx, y. If held rigidly here than BPM stability is improved. Do we need to improve how the BPM is held here? Should we support to the magnet or to the raft or to the concrete pier?  Supports utilize rod ends and are fully adjustable in the field. UNC  Max X or Y deflection under operational loads = ± xxx"  Loading at Base of Support (Technical note, xxxx):

PEP-II Vacuum p45 Vacuum Pressure  Average arc pressure ≤ 3.4 x 10-9 torr (N2 equivalent).  Average arc base pressure ≤ 5 x torr  Peak pressure of any bump in profile = 5 x 10-7 torr (N 2 equivalent).  Operating parameters:  9 GeV on 2.2A HEB (CDR, p308)   crit = 9.8 keV at 9 GeV beam energy (CDR, p309)  Vacuum Calculation Variables  Copper & Aluminum   photo = 2 x 10-6 mol/photon (CDR, p310)   photo = 5 x 10-5 mol/photon (CO, Foerster)   therm = 2 x torr-L/cm2-s, scaled with temperature (CDR, p310):   therm = 4.0 x 35°C (beam off)   therm = 1.04 x 60°C (beam on)  No detectable gas species above mass 44 - measured by RGA.

PEP-II Vacuum p46 Photodesorption Data C. Foerster

PEP-II Vacuum p47 PSD (cont.)

PEP-II Vacuum p48 Running Parameters/Orbit Error  Design Running Parameters:  Fill time = 6 minutes, minimum, (0 to 3 amps HER or 4.5 amps LER).  Full cycles = 10,000 cycles over 20 years, (0 to 3 amps HER or 4.5 amps LER).  Fill cycles = 200,000 cycles, 80% to 100% current (3 Amps HER or 4.5 amps LER), over 20 years.  Max axial beam orbit distortion/steering error (CDR, p 304)  ± 7 mm in X.  ± 3 mm in Y.  Max angle beam orbit distortion/steering error (S. Ecklund).  ± 0.5 mrad in X.  ± 1 mrad in Y.  Design using a safety factor of 2 for the bellows and elsewhere when possible.

PEP-II Vacuum p49 Heat Loading  Synchrotron radiation (SR) power  Chamber ends, SS flange pairs and bellows stubs must be shadowed by a nominal and mis-steer SR strike.  The RF Seal fingers and Bellows Module shield fingers need to be shadowed from a nominal SR strike and a mis-steer strike with a safety factor of 2.  Secondary back-scatter from SR.  Assume 10% of SR power is scattered onto chamber walls.  In HER arc dipole magnet, 11.6 % of SR is back-scattered off main strike surface. Outside of the field 12.2 % is back- scattered (FLUKA calculations summary by Al Lisin).

PEP-II Vacuum p50 Goal of the Review  Approval of chamber design specification.  Approval of chamber design concept and material selection.  Proceed to final design, final design review and detail drawings.  Approval to procure long lead items.  GlidCop  Transition material  Bellows  Tiles

PEP-II Vacuum p51 Vacuum Processing  In-situ bakeout  There are no provisions being made for an in-situ bakeout. If one is necessary a hot water system could be implemented and the chambers will survive a bakeout cycle.  Min chamber temperature during in situ bakeout = 95°C.  Max chamber temperature during in situ bakeout = 100°C.  Chamber lab bake-out temperature 150°C.  Glow discharge or TiN coat aluminum chambers to be determined.  Chambers will be scanned for residual gases using a RGA Mass Spectrometer. When scanning for mass 1 to mass 100 at 150  C, peaks above mass 44 shall be less than 5 x 1-12 Torr, and the sum of all peaks above mass 44 shall be less than 1 x Torr.

Material Properties MaterialAluminum 6061 T6 Stainless Steel (316L) Young’s Modules Poisson Ratio Thermal Expansion Conductivity Yield Stress Tensile Stress

PEP-II Vacuum p53 Water Channels 0.256” square with 0.157” diameter bore cooling channels. 2” Q4R Q5R 2 x 1/16” x 0.25” Skip weld

PEP-II Vacuum p54 Transient Analysis due to Beam Missteering e- Temperature contours at t=1 second SR 0.7 mrad horizontally mis-steered SR 1 mrad vertically mis-steered Power density: 14 W/mm (B1(L) + B1(R)) Beam height: 0.6mm

PEP-II Vacuum p55 Transient Analysis due to Beam Missteering Note that temperature rise within missteering area due to HOM + I2R 16 C (HOM + I2R power density 1Kw/m is used) Place few thermocouples, one of the thermocouple will experience temperature rise during beam missteering 14 C (if max trip stress is 25 ksi, max. temperature rise 97 C ) 30 C (if max trip stress is 30 ksi, max. temperature rise 116 C) Assume water temperature 30 C Due to uncertainty of HOM power density, Nominal trip temperature is set to be 46 C ( ) (=115 F) Maximum trip temperature 60 C ( ) (=140 F) is used.

PEP-II Vacuum p56 Reaction Forces due to Support Scenario Q4R + Q5R Forces (lb)Moments (lb-in) XYZXYZ Caused by 1 mrad yaw 1 mrad pitch Z constraints 1 mrad pitch 1 mrad yaw 1 mrad twist Q2R Q4R s Q5R s1N/A Q5R s Net087* *Body force included. Q2R Q4R S1 Q5R S2 Q4R Q5R Q4R + 4” Bellow + Q5R Reaction Forces (lb)Reaction Moments (lb-in) XYZXYZ Caused by 1 mrad yaw 1 mrad pitch Z constraints 1 mrad pitch 1 mrad yaw 1 mrad twist Q2R Q4R s Q5R s Q5R s Net087* Q2R Q4R S1 Q5R S1 Q5R S2 Q4R Q5R Bellow e- z x y