1. LARP Rotatable Collimators for LHC Phase II Collimation 26 October 2006 LARP Collaboration Meeting – Port Jefferson, NY Tom Markiewicz/SLAC Representing Eric Doyle, Lew Keller & Steve Lundgren BNL - FNAL- LBNL - SLAC US LHC Accelerator Research Program

2. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 2 / 71 Collimator Design as of April 2006 beam 136mm diameter x 950 mm long copper jaws (750 mm effective length + 2 x 100mm tapers) Vacuum tank, jaw support mechanism and support base derived from CERN Phase I

3. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 3 / 71 EXTERNAL COIL PERMITS 1 REV OF JAW CERN PHASE I JAW POSITIONING MECHANISM – USE IF POSSIBLE 25mm thick annular (hollow core) copper jaw backed by continuous helical cooling tube Collimator Design as of April 2006 NLC Jaw Ratchet Mechanism assumed Sheet Metal formed RF transition

4. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 4 / 71 Stop prevents thermal bowing of jaws from intruding on minimum gap. Deal with: Residual swelling into beam External vertical actuator and bellows that also has +/- 5mm transverse float Mid-jaw recess Forces possibly unbalanced front vs. back Leaf springs allow jaw end motion up to 1mm away from beam. Must allow: Thermal motion while minimizing gravity-deflection Axial expansion Adjustable central aperture-defining stop and leaf spring support required to prevent jaws from deforming 1200um into beam

5. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 5 / 71 RF Contact Scheme Blessed by CERN Impedance Police Rigid round-square transition Spring loaded fingers ground two jaws through range of motion Jaw support & gap adjustment borrowed from CERN

6. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 6 / 71 Exceeds 200 Max Cu temp Possible boiling Exceeds 42 max water return temp Exceeds Allowed Deflections All temperature simulations based on 20C supply. For CERN 27C supply add 7 to all temperature results. CERN max water return temp 42C Exceeds spec, or other possible problem as noted Baseline Jaw Performance Baseline: hollow Cu, 25mm wall, helical cooling - 5cm pitch

7. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 7 / 71 Technical Review of Baseline 12-2005 Do not ‘cut metal’ until jaw support, stop and rotation scheme developed Increase engineering effort Response –Full time engineer (Steve Lundgren) & full time designer hired April 2006 –Doyle, Keller, & Markiewicz continue on part time basis Result –New jaw design developed which eliminates central stop & flexible springs –New concept for winding the cooling coil which eliminates the 4 loops per end and permits longer jaw and better RF-compliant jaw support –New scheme for rotating after beam abort damages surface –Test pieces constructed & examined BUT… –Still do not have tested full length jaw or complete RC1 prototype

8. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 8 / 71 Progress since April 2006 Meeting Design & Calculation –Improved and much more complete design –ANSYS calculations to simulate performance of new design –ANSYS calculations to start to look at permanent deformation in case of accidental beam abort –FLUKA model improvements to understand heating/cooling in more elements (shaft, bearings, …) of the collimator Fabrication –Fab, brazing & dissection of short (15cm) section of jaw: cooling coil to mandrel and of coil/mandrel assembly to jaw –Fabrication of short aluminum mandrel to practice coil winding & development of coil winding tooling –Fabrication of 2 nd short (20cm) copper mandrel and jaw pieces test braze techniques required for longer jaw pieces

9. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 9 / 71 Advances since RC1 Baseline solid core more cooling

10. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 10 / 71 New Idea to Eliminate Central Stop Jaw-Hub-Shaft 1.Hub located, in Z, near peak temperature location, which lowers peak temperature, reducing gradient and bending. 2.Max deflection toward beam reduced if the shaft deflection can be minimized 3.Both ends of jaw deflect away from beam. (Note: swelling component of deflection is not corrected.) 4.Cooling coils embedded in I.D. of outer cylinder. shaft jaw hub

11. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 11 / 71 Evaluate jaw-hub-shaft for 750mm jaws 22.5mm deep cooling tubes with solid copper shaft Transient 10sec @12min beam SS 1hr beam Notes: 1.Deflection means deviation from straight (um). 2.Eff length is length of jaw (m) deflected <100 um compared to maximum deflection point. 3.Deflection is combination of swelling and shaft bending 4.Shaft static deflection due to gravity = 68um 5.7  min allowable aperture achieved by setting jaws of first collimator at 8.5 . New Baseline

12. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 12 / 71 First Concept to Eliminate 4-Loop Coils at Ends to allow increased jaw length and realistic jaw holder that is “plug&play” replacement for Phase I jaw Restrain each tube on centerline of bearing 200mm 136mm dia Annealed pre-bent cooling coil and dead recon winding to put U- Bend at exact midpoint of mandrel Model of Coil Winding Test piece 200mm long x 86mm diameter Lundren

13. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 13 / 71 Summary of New Baseline Configuration on 1 Sept 2006 Jaw consists of a tubular jaw with embedded cooling tubes, a concentric inner shaft joined by a hub located at mid-jaw Major thermal jaw deformation away from beam No centrally located aperture-defining stop No spring-mounted jaw end supports Jaw is a 950mm long faceted, 20 sided polygon of Glidcop Shorter end taper: 15mm L at 15 o (effective length 920mm) Cooling tube is square 10mm Cu w/ 7mm square aperture at depth = 24.5 mm Jaw is supported in holder jaw rotate-able within holder jaw/holder is plug-in replacement for Phase I jaw nominal aperture setting as low as 8.5  Results in minimum aperture > 7s in transient 12 min beam lifetime event (interactions with first carbon primary TCPV) absorbed power relatively insensitive to aperture: for 950mm long jaw p=12.7kW (7  ), p=12.4kW (8.23  ) Auto-retraction not available for some jaw orientations Jaw rotation by means of worm gear/ratchet mechanism

14. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 14 / 71 Power Absorption in BOTH Copper Jaws of First Secondary Collimator TCSM.A6L7 Lew Keller

15. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 15 / 71 Collimator Inefficiency when the TCSM.A6L7 collimator only is opened from 7 to 8 or 8.5 sigma for each beam and for each primary collimator orientation HaloLength [mm] Half gap [  ] I max [%] η @ 10σ Lwb.hor.b175765.79  18.969.36  10 -6 Lwb.hor.b175879.05  25.261.24  10 -5 Lwb.vert.b175762.50  17.821.94  10 -5 Lwb.vert.b175835.09  6.192.01  10 -5 Lwb.hor.b275745.66  10.501.61  10 -6 Lwb.hor.b275878.74  23.901.83  10 -6 Lwb.vert.b275781.63  21.815.07  10 -6 Lwb.vert.b275867.11  15.265.42  10 -6 Lwb.skew.b175786.58  43.495.25  10 -6 Lwb.skew.b175857.97  23.697.54  10 -6 Lwb.skew.b195779.51  37.258.59  10 -6 Lwb.skew.b1958.569.44  31.018.14  10 -6 Chiara Bracco / CERN

16. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 16 / 71 Contribution to inefficiency fromeach of several collimators as 1 st secondary is opened from 7 to 8 sigma Chiara Bracco / CERN

17. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 17 / 71 Steps on Path to a Thermal Test of a Full Length Cooled Jaw: #1 Test Pieces Braze Test #1 Wind any available 10mm x 10mm tubing on convenient sized and available copper stock for mandrel and jaws Develop and document braze procedures Section for braze inspection, document results Coil winding Procedure and hardware Develop procedure and tooling to wind available tubing on short 200mm length Aluminum mandrel Test 3-axis CNC milling procedure required to machine U-bend in cooling pattern Braze Test #2 Machine short 200mm copper mandrel Wind annealed available tubing on copper mandrel and stake in place to hold –Braze tubing to mandrel –Machine OD and add groove to hold braze wire Machine 4 quarter 200mm jaws –Braze with wire & foil –Section for braze inspection, document results

18. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 18 / 71 BrazeTest #1 Cooling Tube Jaw Center Mandrel ~100 mm ~70 mm dia ~100 mm dia

19. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 19 / 71 Aluminum Mandrel for Coil Winding Test and to test 3-axis CNC Mill before cutting 200mm and 950mm Copper Mandrels 200mm Cooling Tube aligner

20. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 20 / 71 Test Bends on Square Hollow Copper Tubing Preliminary bends just to get some experience Initial test bend of “Half Turn” wound by hand

21. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 21 / 71 Attempts to Use Tooling for Bending LatheMagnet Coil Winding Instrument

22. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 22 / 71 Development of Winding Tooling Vise-Type Roller-Type Aluminum Mandrel with Coil Wound Test Winding the 200mm Copper Mandrel

23. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 23 / 71 Fabrication of Quarter Jaws for 2 nd Braze Test

24. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 24 / 71 Final Wind of 200mm Copper Mandrel

25. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 25 / 71 Update Cooling Coil Wind Concept Based on 200mm Wind Tests Shifting the u-bend from the midpoint of the Mandrel to near the downstream end gives the following benefits: –The groove in the u-bend area can be eliminated reducing the need for precise initial bend locations. –The u-bend can be made larger in diameter to reduce the internal distortions in the cooling channel and improve water flow. –The groove and relief can be machined on a lathe rather than on a CNC milling machine reducing the overall cost. Result –Mandrel has a groove the appropriate width and depth for the conductor and goes 42.5 turns in the same direction. –Mandrel has one 80mm wide “groove” at downstream end to accommodate the u-bend and a enough conductor wrap around about 1 turn (provides a generous allowance for errors in machining and bending locations). –U-bend can be 20 to 30mm diameter not only 10mm Markiewicz

26. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 26 / 71 Model showing Coil wound on Mandrel with U- Bend at downstream end Note: Braze Test #3 will probably need to be added to step #1 1.Fab 2 nd 200mm mandrel on lathe 2.Test wind coil with downstream U-Bend 3.Under discussion: use 8 quarter round jaw sections to make sure butt brazes pose no problem (as promised)

27. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 27 / 71 Steps on Path to a Thermal Test of a Full Length Cooled Jaw Manufacture Full Length Jaw –Machine 930mm mandrel with new winding pattern Mandrel had been released for fabrication with requested due date 10/27/06 Drawings for full length mandrel modified to put loop at end and resubmitted –Acquire CERN-compliant (Nickel alloyed) copper tubing from Finland –Build tooling using roller concept for full length jaw –Shape & anneal tubing –Wind tubing to mandrel –Machine OD and add groove to hold braze wire –Machine (wire EDM) at least 8 full half length (465mm) quarter jaws from copper (NB: Final jaws will be Glidcop) Released to SLAC shops for fabrication on 1 OCT 2006, –Original promise date 11/08/06 –Cost estimates are very high and we are examining issues involved in designing shorter pieces fabricated by other means –Braze jaws to mandrel assembly –Design & order shaft in MOLYBDENUM Order has been placed with vendor: promise date 11/28/06 –Braze shaft to jaw assembly –Machine 20 facets on jaw face –Machine features required to interface resistive heater packages

28. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 28 / 71 ANSYS Model of Jaw-hub-shaft with hollow Mo shaft Hub region - centered Glidcop Jaw Hollow Mo Shaft Simple supports at both shaft ends Deflection Temp

29. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 29 / 71 Comparison of Hollow Mo shaft and Solid Copper Shaft to same FLUKA secondaries: Improved deflections Solid Cu, 75cm tapered jaw, asymmetric hub Tubular Moly, 95 cm straight jaw, symmetric hub Steady State  =1 hour  = 12 min for 10 sec Steady State  =1 hour  = 12 min for 10 sec Gravity sag200 um67.5 um Power absorbed11.7 kW58.5 kW12.9 kW64.5 kW Peak Temp.66.3 °C197 °C66 °C198 °C Midjaw  x 100 um339 um83.6 um236 um Effective Length51 cm25 cm74 cm39 cm Sagitta221 um881 um197 um781 um

30. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 30 / 71 Molybdenum Shaft Details Relief on I.D. is for roller bearing Slots for tubing extend past bearing and are 180 deg offset Relief on O.D is for stiffening sleeve and worm gear mounting 1mm raised shoulder (Hub) at center

31. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 31 / 71 Single Jaw Thermal Test Hardware Jaw Sections ~450 mm long Jaw sections are manufactured as quarter cylinders for fabrication accuracy and ease of braze assembly Only 4 or 5 flats are planned for the test and for measurement purposes

32. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 32 / 71 Steps on Path to a Thermal Test of a Full Length Cooled Jaw Test Fixture Specify details of test stand Make design drawings Fabricate

33. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 33 / 71 Steps on Path to a Thermal Test of a Full Length Cooled Jaw Test Lab Preparation Clean space with gantry access Basic equipment: Granite table, racks, hand tools Power supplies to drive heaters Chiller & plumbed (?) LCW to cool jaw –480V wiring for heater power supplies required engineering review, safety review, and multiple bids (?!) 23 Nov 2006 promise date –Acquire Heaters 5kW resistive heaters available on short notice from OMEGA PC & Labview Rudimentary software tests only National Instruments DAQ with ADCs Data Acquisition and Control Module 32-Channel Isothermal Terminal Block 32-Channel Amplifier –Thermocouples (?) –Capacitive Sensors (?) –Vacuum or Nitrogen (?) –Safety Authorization (!!!) Collimator Assembly & Test Area in SLAC Bldg.33

34. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 34 / 71 Equipping of Clean Collimator Test Area Granite surface plateAdjacent 16.5 kW Chiller Heater Power Supplies staged for installation in rack Instrumentation rack and computer workstation

35. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 35 / 71 Beginnings of System Schematic for Single Jaw Thermal Test Hardware Test Lab Setup Block Diagram PC with LabView Software Heater #1 Controller Heater #2 Controller Capacitec Signal Amplifier DAC & Signal Processor Jaw thermocouples Jaw deflection sensors Jaw Heater #1 Jaw Heater #2 Over Temperature Control Jaw Internal Cooling Line Chiller LCW Water (Supply) LCW Water (Return) fuse Bldg Power 100 Amp Tap

36. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 36 / 71 Steps on Path to RC1 Successful thermal performance of first full length jaw Complete design of RC1 support, rotation & RF features –Layouts, calculations and models of two Jaw mounting methods as well as a rotation scheme have been explored…. –Detail drawings of the preferred Jaw mounting method and rotation mechanism are in work. –A working model is planned to verify the rotation scheme with respect to Jaw face position accuracy. Acquisition, Fabrication & Assembly cycle of the support, rotation & pieces Fit-up and initial tests on 1 st full length jaw Complete fabrication of second jaw (Glidcop?, Moly??) with full support assembly Remodeling of CERN parts for interface to US parts –Models and assemblies of the various Collimator Mounting Stands are complete –An enlarged vacuum tank has been modeled and some CERN support stand modifications have been identified –No fabrication drawings have been done as yet Acquisition of Phase I support & mover assemblies –Given delivery difficulties of CERN Phase I this has dropped off CERCA/AREAV and CERN event horizon despite promise 1 May 2006 that SLAC quote was “in the mail”

37. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 37 / 71 August 2006 “Plug&Play” Model of Jaw Mounts Lundgren

38. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 38 / 71 August 2006 Jaw mounting details Draws on features from CERN Phase 1 Collimator CERN Contact RF Assy can be used Modified CERN Pivot Tensioning Plate Positioning and Guiding Plates are similar to CERN Design Top and Bottom RF springs (not shown) are identical To CERN part Press here to activate 2 leaf springs producing linear motion to rotate a worm/ratchet shaft Note 20-sided faceted face: Lundgren

39. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 39 / 71 August 2006 Ratchet, Worm and Worm Gear Shaft and Jaw mount details not shown for clarity 100 Tooth Worm Gear (mounts to shaft) Single turn Worm 20 Tooth ratchet Bearing 2X Lundgren

40. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 40 / 71 October 2006 Design Model Replaces Worm Gear with “Geneva Mechanism” for Jaw Rotation and Replaces Needle Bearings with Universal Joint and Angular Contact Bearings and Incorporates Cooling for Support Pieces – A Geneva Mechanism is the key factor in indexing the Jaw. Prevents possible over-run of ratchet. Eliminates step count as determining factor in exact facet positioning. –Universal joints connect Jaw ends to angular contact bearing sets. The stainless steel diaphragm “u-joint” meets required torque, Jaw/shaft sag and end-to-end “slew” offset spec of =/-1.5 mm. ANSYS calculations performed to verify diaphragm thickness & dia. Built-in hard stops prevent damage from potential high accelerations during handling and transport. Maximum stress on diaphragm is 1/2 yield strength of the stainless steel. Lundgren

41. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 41 / 71 Universal Joint required motions –Thermal Expansion of molybdenum Shaft of 0.290mm (transient) causes each diaphragm to distort by 0.145mm. –Shaft sag causes an in plane rotation of the Shaft ends of 0.00025 radians causing an equal distortion of the diaphragm. –Transverse displacement one of the ends of the Shaft relative to the other by +/- 1.5mm causes an angular distortion of 0.0015 radians in the diaphragm. –Worst case is for a Vertical Collimator with maximum “slew” of 0.0015 radians added to the sag component of 0.00025 radians for a total of 0.00175 radians of bending of the diaphragm. Lundgren

42. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 42 / 71 Jaw Mount with Geneva Mechanism 0.5mm thick diaphragm 100 Tooth Worm Gear Geneva Driver Wheel (on ratchet shaft) Geneva Driven Wheel (on Worm shaft) Lundgren

43. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 43 / 71 Jaw Mount section view with safety stop Hard Stop Angular contact bearings 0.5mm thick Diaphragm Shaft mounts here Lundgren

44. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 44 / 71 Upstream end vertical section Jaw Geneva Mechanism Support Bearings Worm Gear Shaft Water Cooling Channel U-Joint Axle Lundgren

45. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 45 / 71 Upstream end horizontal section Support to Support 1000mm Overall length 930mm Facet length ~905mm Lundgren

46. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 46 / 71 Upstream end with actuator and cooling lines Lundgren

47. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 47 / 71 Upstream End looking Downstream Flexible Vane supports each end of Image Current Plate Lundgren

48. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 48 / 71 Image Current Plate Lundgren

49. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 49 / 71 Jaw-Hub-Shaft Key Dimensions

50. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 50 / 71 ceramic bearing Molybdenum shaft: R = 2.2 -3.2 cm bearing axle Copper cylinder + cooling loops: R = 3.3 – 6.8 CM, Z = 95 CM beam axis Extension of SLAC Simple FLUKA Model to include cylinder Copper jaws, Hollow Moly Shaft, Ceramic bearings, Shaft axel, and support blocks for TCSM-A6L7 Alum. image current block Lew Keller

51. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 51 / 71 Results for TCSM-A6L7 at 7 Sigma Total power deposition Copper jaws Molybdenum shaft Axial Al struts Front Al image-current block Rear Al image-current block Front ceramic bearing Rear ceramic bearing Front steel bearing spindle Rear steel bearing spindle 13,500 W 530 W 70 W 35 W 90 W 0.1 W 0.8 W 0.5 W 2.7 W Halo on TCPH, 1 hour beam lifetime Lew Keller

52. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 52 / 71 Axial Power Distribution in TCSM-A6L7 Copper Jaw and Molybdenum Shaft Halo on TCPH, 1 hour beam lifetime Ave. = 13.5 kW/jaw Ave. = 530 W/shaft high energy side - photons from TCPH? Lew Keller

53. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 53 / 71 Azimuthal Power Distribution in TCSM-A6L7 Copper Jaw and Molybdenum Shaft Halo on TCPH, 1 hour beam lifetime FWHM ≈ 20º FWHM ≈ 60º Lew Keller

54. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 54 / 71 Azimuthal Power Distribution in TCSM-A6L7 Ceramic Bearing and Axle (back end) Halo on TCPH, 1 hour beam lifetime Ave. = 0.77 W Ave. = 2.7 W Lew Keller

55. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 55 / 71 Shaft heating SS & Transient Modeling assumptions: -Power concentrated in 120 o of circumference -Power constant in length -No heat transfer at shaft ends -No radiative heat transfer Steady State result: T = 232C, ux = 96 um Transient result: T = 244C, ux = 337 um 28.5 avg Eric Doyle

56. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 56 / 71 Jaw mount – tie rod heating hand calculations FLUKA => 100 W per rod, steady state Assume uniform heating along length Assume conduction only to end mounts at 20C, no radiative heat transfer Peak temperature = 200C,  L =~ 3mm => must cool tie rods Tie rod Eric Doyle

57. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 57 / 71 Hand Calculations for Heating/Cooling of Bearings in Steady State Beam Loss Steel bearings – ball temperature calcs Power density (FLUKA): 40.8e3 W/m^3 Radiation-only heat loss from ball T=113C (upbeam), 285C (downbeam) Si 3 N 4 bearings – ball temperature calcs Power density (FLUKA): 6.5e3 W/m^3 Radiation-only heat loss from ball T=26C (upbeam), 62C (downbeam) => use ceramic bearings Eric Doyle

58. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 58 / 71 Status & Plans for Studies of Phase II Collimators in the case of a 1 MJ Beam Abort Accident 2000um 500 kW 20 GeV e- beam hitting a 30cm Cu block a few mm from edge for 1.3 sec (0.65 MJ) FNAL Collimator with.5 MJ Trying to negotiate 2007 beam test at CERN to study extent of damage

59. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 59 / 71 Cross Section at Shower Maximum Showing Copper Melting and Possible Fracture Regions in a Mis-steering Accident Copper Jaw Melting zone (grey), radius = 3.3 mm Fracture zone, (200 C) radius = 7 mm 2.5 cm ~1MJ Keller, Doyle

60. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 60 / 71 Alum. image current block Accident Energy Deposition in Down-beam Aluminum Image-Current Block should NOT cause damage Total E dep ≈ 3 kJ ΔT max < 100 °C in the image current block Two accident conditions: 1.All bunches hit the front of the collimator: 7 - 10 σ x 2.Grazing angle along collimator edge: at 50 µrad grazing angle and 200µ σ x, only about 15% of the beam hits along the edge 1 MJ of bunches hitting edge, 7-10  Lew Keller

61. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 61 / 71 Quasi-steady state ANSYS analysis to answer question of whether PLASTIC DEFORMATION of ENTIRE JAW will happen after a BEAM ABORT ACCIDENT PRELIMINARY RESULT: –Discrepancy between temperature results using different (coarse vs. fine mesh) models –0.23 MJ dumped in 200 ns into coarse ANSYS model –Molten material removed and model allowed to cool –Result: plastic deformation on order of 100 um after cooling, sagitta ~60um –Jaw ends deflect toward beam Jaw surfaces at 90 to beam impact useable, flat within 5 um CAUTION: WORK VERY NEW Doyle beam side far side 120 um -80 um uxux 60 um

62. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 62 / 71 Modeling Details of Quasi-steady state ANSYS analysis to answer question of whether PLASTIC DEFORMATION of ENTIRE JAW will happen after a BEAM ABORT ACCIDENT Relatively coarse ANSYS model used – same model as steady state & transient simulations Length 95cm, ends not tapered Elements @ O.D.: 2.5 x 8 x 50 (mm r, ,z) Temperature dependent stress-strain (bilinear isotropic hardening) Other properties independent of temperature Steady state energy deposition profile scaled to equal power of high resolution FLUKA accident data 0.23 MJ in 200 ns Axial distribution very similar r,  distribution more diffuse Quasi-steady state analysis of stresses After 200 ns energy deposit, model allowed to cool for 60 sec to ~ steady temperature Doyle

63. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 63 / 71 Jaw-hub-shaft – Hollow Mo Shaft Hub region - centered Glidcop Jaw Hollow Mo Shaft Simple supports at both shaft ends Doyle

64. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 64 / 71 High Resolution and Low Resolution Models High Res Accident model, elements.2 x.16 x 50mm (r, ,z), molten zone in gray: 3 x 5.2 mm (r,  ) at shower max. Permanent deformation simulation: Low resolution accident model, elements 8 x 2.5 x 50 mm (r, ,z). Energy density is well represented in z, coarsely in r & . 5mm melt 8 mm Similarity in z of coarse model (scaled x e8) and fine model. Doyle

65. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 65 / 71 High Resolution and Low Resolution Models – Inconsistent Results 5mm melt 8 mm Tmax = 57 e3 Tmax = 550 Each coarse element corresponds to 40 x 16 fine elements. Factor of 13 difference attributable to element size, peak temperature dilution in large elements. This leaves a factor of 8 apparent inconsistency. Hand calc energy in single bin confirms 550 result. Next: re-check fine model result.

66. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 66 / 71 Permanent Deformation, ux, uy ux uy In plane deformation, ux ~ 100 um Normal deformation (ignoring expansion due to residual axial thermal gradient), uy < 10um Therefore, after hit, rotate jaw 90 o uy 50 um -50 um 27 um thermal expansion bottom top <10 um beam side far side 120 um -80 um ux 60 um  T = 12 o C Doyle

67. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 67 / 71 Energy Deposition in WATER in case of Accidental Beam Abort FLUKA model: 75 cm long cylindrical model cylinder of copper (or carbon) with i.r. = 4.3 cm. o.r. = 6.8 cm. cylinder of water with i.r. = 3.6 cm, o. r. = 4.3 cm inner cylinder of copper (or carbon) with i.r. = 0, o.r. = 3.6 cm For copper the maximum E_dep (at Z = 50 cm) is 0.028 GeV/proton/cm3, which gives about a 1 °C instantaneous temp. rise for 9E11 protons, in that region Using Bulk modulus = 2.07e3 MPa Coeff of vol expansion = 206e-6/K Pressure rise for a sudden 1K temp rise is  P = 2.07e3 x 206e-6 x 1 = 426e-3 MPa = 61.8 psi This is about 4 bar while CERN claims 40bar. How can we check this result? Even at 40 bar (only 600 psi) it doesn't seem catastrophic. It's only about 10% of the yield strength of soft copper. And the copper will get hotter and want to expand even more, which would quickly relieve the pressure. Probably most of the expansion energy would be dissipated in the water up and down stream from the hot spot. Doyle, Keller

68. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 68 / 71 Induced Activation of Secondary Phase II Collimators Issue Raised by DOE/LARPAC Reviews 15 mSv/yr = max dose for rad worker at CERN Work in progress by Mokhov et al

69. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 69 / 71 Longitudinal and Azimuthal Profiles of Remnant Dose after 30 day exposure and 1 day cooldown Mokhov et al

70. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 70 / 71 Inter-Lab Collaboration Good will & cooperation unfortunately limited only by busy work loads –Monthly video meetings –Many technical exchanges via email –Participation in Fall 2006 Phase I testing –Participation in upcoming CERN Phase II brainstorming meeting Areas where CERN help would be extremely valuable to SLAC project –As vendor of collimator jaw assembly is having problems delivering Phase I jaw mechanisms to CERN we have lost our minimal contact. Intervention with vendor or use of CERN prototype hardware would be most appreciated. –Similar comment regarding spare support and mechanism to set gross x, y, u jaw angles –Plans for damage beam tests before final delivery date would remove large and growing risks of damage sufficient to negate entire “rotatable” concept. 2007 tests on first jaws highly desirable from SLAC perspective.

71. LARP Collab. Mtg. - 26 October 2006Rotatable Collimators - T. MarkiewiczSlide n° 71 / 71 Phase II Task Summary There has been fantastic progress in design and good but slow progress on the necessary small scale projects to finalize procedures. Time estimates for thermal test of first jaw and construction of first 2 jaw prototype (RC1) are expanding. In June DOE was told “Expect thermal tests and completely tested RC1 device by end of FY06 and mid-FY07, respectively” We are increasing efforts to find another full time physicist We are starting to change design when it can help schedule and are starting to plan parallel tests for separate technical issues (spend $ to save time). Better project management needed. We hope slippage hopefully consistent with CERN’s newest schedule (admittedly poor excuse)