US LHC Accelerator Research Program BNL FNAL LBNL
US LHC Accelerator Research Program BNL - FNAL- LBNL - SLAC The LARP Collimation Program 05 June 2007 LARP DOE Review - Fermilab Tom Markiewicz/SLAC LARP DOE Review - 05 June 2007 Collimation Tasks - T. Markiewicz
Four LARP Collimation Program Tasks: Address Efficiency, Reliability and Design of Phase I & Prototype a possible solution for Phase II Use RHIC data to benchmark the code used to predict the cleaning efficiency of the LHC collimation system and develop and test algorithms for setting collimator gaps that can be applied at the LHC Responsible: Angelika Drees, BNL TASK ENDS FY 07 Understand improve the design of the tertiary collimation system that protects the LHC final focusing magnets and experiments Responsible: Nikolai Mokhov, FNAL TASK ENDS FY 07 Study, design, prototype and test collimators that can be dropped into 32 reserved lattice locations as a part of the “Phase II Collimation Upgrade” required if the LHC is to reach its nominal 1 E 34 luminosity Responsible: Tom Markiewicz, SLAC Use the facilities and expertise available at BNL to irradiate and then measure the properties of the materials that will be used for phase 1 and phase 2 collimator jaws Responsible: Nick Simos, BNL TASK ENDS FY 07 LARP DOE Review - 05 June 2007 2 Collimation Tasks - T. Markiewicz
Task: Use RHIC Data to Benchmark LHC Tracking Codes Scope: – Install Six. Trackw. Coll particle tracking code at BNL and configure it to simulate RHIC performance for both ions and protons. – Take systematic proton and ion data and compare observed beam loss with predictions – Test (and perhaps help to develop) algorithms proposed for the automatic set up of a large number of collimators Status: Guillaume Robert-Demolaize (ex-CERN) hired January 2007 BNL • The tracking tools developed at CERN are now up and running for RHIC proton beam simulations. • Even though the tracking code itself is portable and can be used for any machine, the aperture model is specific to each machine studied => had to generate one for the RHIC lattice ! • While still in its early stages, it is already fully compatible with the established tools; some effort is still dedicated in refining it (transition regions, local aperture restrictions…). • The events selected so far contained enough data for the first preliminary studies that allowed for debugging of the new functions of the codes LARP DOE Review - 05 June 2007 3 Collimation Tasks - T. Markiewicz
Task 2: Progress Since June 2005 DOE Review (1) (2) (1) Effect on BLM signal Simulating a horizontal jaw movement LARP DOE Review - 05 June 2007 4 Collimation Tasks - T. Markiewicz
Task: Model tertiary collimators at the LHC experimental insertions • Study of betatron collimation and beam-gas debris cleanup by tertiary collimators in IP 1 & IP 5 complete – Peak energy deposition in IRQ is more than two orders of magnitude below the quench limits at normal operation and nominal parameters. • • Tungsten is noticeably better than copper (1 meter). Betatron cleaning contribution dominates over beam-gas, esp. for 0. 22 hr beam life time. – Tertiary collimators noticeably reduce machine backgrounds at small radii (pixels, tracker) and protect these components at beam accidents. • • Backgrounds and radiation levels in the CMS and ATLAS detectors are dominated – at nominal luminosity - by pp-collisions. Tungsten is better. There is only a minor effect of TCTs at radii > 1 m. . Momentum cleaning and an impact of a single bunch loss on TCT still need to be addressed (need someone to help!). LARP DOE Review - 05 June 2007 5 Collimation Tasks - T. Markiewicz
Neutron (bgas & pp) and Muon Fluxes (bgas) in CMS With tertiary collimators in LARP DOE Review - 05 June 2007 6 Collimation Tasks - T. Markiewicz
US LHC Accelerator Research Program BNL - FNAL- LBNL - SLAC LARP Rotatable Collimators for LHC Phase II Collimation Representing Gene Anzalone, Eric Doyle, Lew Keller & Steve Lundgren LARP DOE Review - 05 June 2007 Collimation Tasks - T. Markiewicz
CERN Collimation Plan & Schedule 0) Assume SLAC LARP develops Rotatable Collimator 1) Develop TWO other complementary designs 2) Develop a test stand for the three designs 3) Fabricate 30 Phase II collimators of chosen design & 6 spares The target schedule for phase 2 of LHC collimation: 2005 Start of phase 2 collimator R&D at SLAC (LARP) with CERN support. 2006/7 Start of phase 2 collimator R&D at CERN. 2009 Completion of three full phase 2 collimator prototypes at CERN and SLAC. Prototype qualification in a 450 Ge. V beam test stand at CERN. 2010 Installation of prototypes into the LHC and tests with LHC beam at 7 Te. V. Decision on phase 2 design and production at end of year 2011 Production of 36 phase 2 collimators. 2012 Installation of 30 phase 2 collimators during the 2010/11 shutdown. Commissioning of the phase 2 collimation system. LHC ready for nominal and higher intensities. RED One year slip from recent white paper, “Second Phase LHC Collimators” LARP DOE Review - 05 June 2007 8 Collimation Tasks - T. Markiewicz
June 2006 DOE Review Introduce new jaw-hub-shaft design which eliminates central stop & flexible springs x 5 improvement in thermal deformation 1260 um 236 um (60 k. W/jaw, t=12 min) 426 um 84 um (12 k. W/jaw, t=60 min) LARP DOE Review - 05 June 2007 9 Collimation Tasks - T. Markiewicz
June 2006 DOE Review Introduce new reverse-bend winding concept for the cooling coil which eliminates the 3 end loops, permitting longer jaws and freeing up valuable space for jaw supports, rotation mechanism and RF-features Sheet Metal formed RF transition 4 -1/2 Turns without failure EXTERNAL COIL PERMITS 1 REV OF JAW Restrain each tube on centerline of bearing 136 mm dia 960 mm LARP DOE Review - 05 June 2007 10 Collimation Tasks - T. Markiewicz
Main accomplishments in the last year • Hundreds of 3 -D concept & 2 -D manufacturing drawings made • Rotation & support mechanism fully designed and manufactured • Many test pieces manufactured and examined, tooling developed, and, especially, brazing protocols worked out • All parts for first full length jaw assembly manufactured & in-house • Test lab fully wired, plumbed and equipped LARP DOE Review - 05 June 2007 11 Collimation Tasks - T. Markiewicz
Model showing 42. 5 winds of coil on Mandrel with 80 mm wide space for U-Bend at downstream end LARP DOE Review - 05 June 2007 12 Collimation Tasks - T. Markiewicz
Comparison of Hollow Moly shaft and Solid Copper Shaft to same FLUKA secondaries: Improved deflections Solid Cu, 75 cm tapered jaw, asymmetric hub Steady State t=1 hour Gravity sag t = 12 min for 10 sec Tubular Moly, 95 cm straight jaw, symmetric hub Steady State t=1 hour 200 um t = 12 min for 10 sec 67. 5 um Power absorbed 11. 7 k. W 58. 5 k. W 12. 9 k. W 64. 5 k. W Peak Temp. 66. 3 °C 197 °C 66 °C 198 °C Midjaw Dx 100 um 339 um 83. 6 um 236 um 51 cm 25 cm 74 cm 39 cm 221 um 881 um 197 um 781 um Effective Length Sagitta LARP DOE Review - 05 June 2007 13 Collimation Tasks - T. Markiewicz
Current Upstream end with actuator and cooling lines LARP DOE Review - 05 June 2007 14 Collimation Tasks - T. Markiewicz
Introduce new Internally actuated drive for rotating after beam abort damages surface NLC Jaw Ratchet Mechanism Universal Joint Drive Axle Assembly • Thermal expansion • Gravity sag • Differential transverse displacement LARP DOE Review - 05 June 2007 New rotation drive with “Geneva Mechanism” 15 Collimation Tasks - T. Markiewicz
Upstream end vertical section Lundgren Jaw Geneva Mechanism Worm Gear Shaft 1 -2 mm Gap Water Cooling Channel U-Joint Axle Support Bearings Diaphragm LARP DOE Review - 05 June 2007 16 Collimation Tasks - T. Markiewicz
RF Shielding: ONLY PART THAT REMAINS TO BE DESIGNED Baseline Concept Tie-Rods with Fingers Connect Jaws & Tank Issues: – At a few 10 s of grams per finger (. 1 mΩ/contact) force causes excessive deflection of the tie-rod holding fingers – Cooling required Tie-Rods Discussions with CERN and Pe. P-II experts in progress LARP DOE Review - 05 June 2007 17 Collimation Tasks - T. Markiewicz
Revised RF Spring configuration under consideration Jaw facet RF springs mount on Tank ceiling & floor Double Wedge Adapters mount across Tank ceiling & floor 2 RF springs mount to each Adapter Shorter length springs also mount to Tank ceiling & floor Note: Jaw facet springs are wide enough for line contact thru full transverse travel range LARP DOE Review - 05 June 2007 18 Collimation Tasks - T. Markiewicz
RF Contact Springs for Investigation LARP DOE Review - 05 June 2007 19 Collimation Tasks - T. Markiewicz
Braze. Test #1 (shown June 2006) Cooling Tube Jaw Center Mandrel ~70 mm dia ~100 mm LARP DOE Review - 05 June 2007 20 Collimation Tasks - T. Markiewicz
Aluminum Mandrel for Coil Winding Test and to test 3 -axis CNC Mill before cutting 200 mm and 950 mm Copper Mandrels Cooling Tube aligner 200 mm LARP DOE Review - 05 June 2007 21 Collimation Tasks - T. Markiewicz
Development of Winding Tooling Aluminum Mandrel with Coil Wound Roller-Type Vise-Type Test Winding the 200 mm Copper Mandrel LARP DOE Review - 05 June 2007 22 Collimation Tasks - T. Markiewicz
Fabrication of Quarter Jaws for 2 nd Braze Test LARP DOE Review - 05 June 2007 23 Collimation Tasks - T. Markiewicz
Final Wind of 200 mm Copper Mandrel LARP DOE Review - 05 June 2007 24 Collimation Tasks - T. Markiewicz
First 200 mm Prototype Before-After Brazing Coil to Mandrel 4 braze cycles were required before part deemed good enough to do jaw braze Learned a lot about required tolerances of cooling coil and mandrel grooves Pre-Coil-Braze LARP DOE Review - 05 June 2007 25 Collimation Tasks - T. Markiewicz
More Winding Tooling Developed 1 m winding tooling LARP DOE Review - 05 June 2007 Mill vise as precision bender 26 Collimation Tasks - T. Markiewicz
Full Length Molybdenum Shaft 1 mm raised shoulder (Hub) at center LARP DOE Review - 05 June 2007 27 Collimation Tasks - T. Markiewicz
Braze Test#2 Delivered 19 Dec 2006 LARP DOE Review - 05 June 2007 28 Collimation Tasks - T. Markiewicz
Vacuum Bake Test Results: 4/1/07 ~3 x over LHC Spec 1 st Jaw Braze Test Assembly has been vacuum baked at 300 degrees C for 32 hours. • LHC Requirement = 1 E-7 Pa = 7. 5 E-10 Torr • Baseline pressure of Vacuum Test Chamber: 4. 3 E-7 Pa (3. 2 E-9 Torr) • Pressure w/ 200 mm Jaw Assy. in Test Chamber: 4. 9 E-7 Pa (3. 7 E-9 Torr) • Presumed pressure of 200 mm lg. Jaw Assy. : 6. 0 E-8 Pa (4. 5 E-10 Torr) • Note: above readings were from gauges in the foreline, closer to the pump than to the Test Chamber. Pressures at the part could be higher. SLAC vacuum group has suggested longitudinal grooves be incorporated into the inner length of jaws; incorporated into next prototype Next steps: • Use in Moly-Hub cold press fit Sectioning & examine braze quality LARP DOE Review - 05 June 2007 29 Collimation Tasks - T. Markiewicz
Aluminum Test Mandrel with 80 mm Gap for Downstream U-Bend (11/17/06) LARP DOE Review - 05 June 2007 30 Collimation Tasks - T. Markiewicz
Braze Test #3: 200 mm Cu mandrel with U-Bend Tubing Wound and Tack Welded to Mandrel at the U-Bend Upstream end of mandrel Note stub ends of cooling tube LARP DOE Review - 05 June 2007 31 Collimation Tasks - T. Markiewicz
Braze Test #3: Coil-mandrel brazed & 8 ¼-round jaws prepped After 2 braze cycles, OD & Next steps: braze wire grooves machined -Braze jaws by mid-June NB: experience is indicating 20 cm long full round jaws may be feasible -Vacuum test? -Section & examine braze quality LARP DOE Review - 05 June 2007 32 Collimation Tasks - T. Markiewicz
Fear of Copper-Moly Braze Joint Leads to Mini Devoted R&D Cycle #1 #2 #3 #4 #1 - Mandrel Dummy #2 - Mo Shaft Dummy #3 - Mo Backing Ring #4 - Cu Hub with braze wire grooves LARP DOE Review - 05 June 2007 33 Initial plan to braze one long Mo shaft with raised hub to inner radius of Cu mandrel deemed unworkable Brazing HALF-LENGTH shafts to a COPPER hub piece and THEN brazing the Cu hub to the Cu mandrel deemed possible First test if Mo “backing ring” sufficient to keep Mo and Cu in good enough contact for a strong braze joint Collimation Tasks - T. Markiewicz
Cu-Mo Hub Braze Test Assembly after 3 additional heat cycles (to mimic full assembly procedure) then sectioned. Moly-Cu Joint Declared “Good” by SLAC Braze Shop Experts, but…. . • Grain boundary issues? • Possible fracturing? Samples sliced & polished and sent to Physical Electronics lab for analysis: Fractures evident Cu-Mo joints we care about 1 mm expansion gap Small holes held braze wire LARP DOE Review - 05 June 2007 34 Collimation Tasks - T. Markiewicz
Details of Shaft attachment to the Collimator Interference Fit versus Improved Braze Hub improvement includes a flexible Molybdenum end that prevents the copper Hub stub from pulling away from the Mo. Copper Jaw is constrained on the outside diameter with Carbon and when heated to ~ 900 degrees C is forced to yield so that upon cooling to ~ 500 degrees C the inner diameter begins to shrink onto the Mo Shaft resulting a substantial interference fit. LARP DOE Review - 05 June 2007 35 Collimation Tasks - T. Markiewicz
Full length Mandrel: In-House & Inspected – Most groove widths meet specification except for a few at each end. – Positioning of distorted areas could indicate damage was done by excessive forces imparted by hold down fixturing during machining. – Future Mandrel drawings will include a note warning about potential damage caused by excessive clamping forces. out of specification grooves LARP DOE Review - 05 June 2007 36 Collimation Tasks - T. Markiewicz
Exploded view of CAD model of Flex Mount U-Joint Flexes for Shaft “sag” and “Slewing” Triple Cog Geneva Drive Wheel required for 512 clicks per facet LARP DOE Review - 05 June 2007 Water Cooling Inlet and outlet 37 Collimation Tasks - T. Markiewicz
Up Beam Flex Mount Assembly showing Ratchet and Actuator LARP DOE Review - 05 June 2007 38 Collimation Tasks - T. Markiewicz
Test Lab Preparation ~Finished ü Clean space with gantry access ü Basic equipment: Granite table, racks, hand tools ü Power supplies to drive heaters ü Chiller & plumbed LCW to cool jaw ü 480 V wiring for heater power supplies Adjacent 16. 5 k. W Chiller • required engineering review, safety review, and multiple bids (? !) ü Acquire Heaters • 5 k. W resistive heaters from OMEGA ü PC & Labview ü Rudimentary software tests only ü National Instruments DAQ with ADCs • Data Acquisition and Control Module • 32 -Channel Isothermal Terminal Block • 32 -Channel Amplifier ü Thermocouples ü Capacitive Sensors – Vacuum or Nitrogen (? ) – Safety Authorization (!!!) LARP DOE Review - 05 June 2007 39 Heater Power Supplies staged for installation in rack Collimation Tasks - T. Markiewicz
CONCERN #1: Still have not brazed nor thermally tested a full length jaw assembly Main Steps Still Needed • After 200 mm Jaw tests Completed Satisfactorily Freeze brazing protocol • Jaw 1/4 sections (16 needed of 24 now at SLAC) require slight modifications for braze gap requirements. • Moly shaft (at SLAC) will perhaps need to be cut in two pieces and brazed to copper hub or interference fit made • Drill Cu mandrel for Moly Shaft • Wind coil using in-house SLAC Copper, – Need to order more (Finland 20 week delivery) OFE 10 mm x 10 mm or use CERN order of Ni-Cu alloy, anneal & wind mandrel • Several braze Cycles • Drill jaw to accept resistive heater – Understand (ANSYS) any change to expected performance LARP DOE Review - 05 June 2007 40 Collimation Tasks - T. Markiewicz
Concern#2: Still do not have a complete mechanical (=“RC 1”) prototype • • Successful thermal performance of first full length jaw Complete the design of RC 1 RF features Fit-up and initial tests of support/rotation mechanism on 1 st full length jaw Complete fabrication of second and third jaws (Glidcop? , Moly? ? ) with full support assembly on the four corners • Acquisition of Phase I support & mover assemblies – CERCA/AREVA REFUSES to supply SLAC – Recent (18 APR 07) proposal to sell SLAC a non-functional CERN TCS collimator with damaged tank & bellows • Remodeling of CERN parts for interface to US parts – An enlarged vacuum tank has been modeled and some CERN support stand modifications have been identified • No fabrication drawings have been done as yet • Acquire motors, sensors, . . Not part of CERN TCS purchase LARP DOE Review - 05 June 2007 41 Collimation Tasks - T. Markiewicz
Vacuum tank, jaw positioning mechanism and support base derived from CERN Phase I beam LARP DOE Review - 05 June 2007 42 beam Collimation Tasks - T. Markiewicz
Inter-Lab Collaboration Good will & cooperation limited only by busy work loads – Regular ~monthly video meetings – Many technical exchanges via email – CERN FLUKA team modeling Rotatable Collimator – CERN Engineering team looking at SLAC solid-model of RC and independently doing ANSYS calculations of thermal shock – CERN physicists • investigating effects of Cu jaws at various settings on collimation efficiency • Participating in discussion of RF shielding design – SLAC Participation in upcoming CERN Phase II brainstorming meeting – Ralph Assmann to visit SLAC in summer 2007 LARP DOE Review - 05 June 2007 43 Collimation Tasks - T. Markiewicz
Examples of CERN Collaboration on SLAC Phase II Design Elias Metral Addressing RF Concerns Luisella Lari Collaboration on ANSYS LARP DOE Review - 05 June 2007 44 Collimation Tasks - T. Markiewicz
Collaboration on Tracking Efficiency Studies Chiara Bracco - CERN • Phase II collimators should provide x 2. 5 improvement in global inefficiency • Beam intensity limitations are due to losses in the dispersion suppressor above the quench limit. These losses are not improved by metallic secondary collimators • Solutions must be found to improve performance of primary collimators LARP DOE Review - 05 June 2007 45 Collimation Tasks - T. Markiewicz
Resource Loaded Schedule Showing June 2008 for Full RC 1 LARP DOE Review - 05 June 2007 46 Collimation Tasks - T. Markiewicz
LARP Collimator Delivery Schedule Done Braze test #1 (short piece) & coil winding procedures/hardware Prep heaters, chillers, measurement sensors & fixtures, DAQ & lab Section Braze test #2 (200 mm Cu) and examine –apply lessons Braze test #3 (200 mm Cu) – apply lessons learned Fab/braze 930 mm shaft, mandrel, coil & jaw pieces 2007 -09 -01 1 st full length jaw ready for thermal tests Fab 4 shaft supports with bearings & rotation mechanism Fab 2 nd 930 mm jaw as above with final materials (Glidcop) and equip with rf features, cooling features, motors, etc. Modify 1 st jaw or fab a 3 rd jaw identical to 2 nd jaw, as above Mount 2 jaws in vacuum vessel with external alignment features 2008 -07 -01 2 full length jaws with full motion control in vacuum tank available for mechanical & vacuum tests in all orientations (“RC 1”) Modify RC 1 as required to meet requirements 2009 -01 -01 Final prototype (“RC 2”) fully operational with final materials, LHC control system-compatible, prototype shipped to CERN to beam test LARP DOE Review - 05 June 2007 47 Collimation Tasks - T. Markiewicz
Phase II Task Summary There has been continued progress in design and excellent 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 (RC 1) are expanding. In June 2006 DOE was told “Expect thermal tests and completely tested RC 1 device by end of FY 06 and mid-FY 07, respectively” Now need to say: “Expect thermal tests to begin and completely tested RC 1 device by end of FY 07 and end-FY 08, respectively” Jeff Smith (Ph. D. , Cornell) joins SLAC Collimation team ~July 23, 2007 – 25% ILC, 75% LARP DOE Review - 05 June 2007 48 Collimation Tasks - T. Markiewicz
Task #4: Irradiation Damage Assessment of LHC collimator materials: N. Simos Scope: Irradiate 2 -D weave carbon-carbon and exact graphite used in Phase I jaws plus materials considered viable for Phase II jaws • BNL AGS/BLIP (70 m. A of 117 & 200 Me. V protons) Measure material properties: thermal expansion, mechanical properties, thermal conductivity/diffusivity and thermal shock • BNL “Hot Cell” Sample Measurement Facility Status 2005 -06: Irradiate 2 D-weaved CC composite & measure CTE – DONE 2006 -07: Irradiate Cu & Glidcop & measure CTE - DONE To Do: Measurements of Thermal Conductivity & Mechanical Properties NB 1: 2006 exposure included graphite, super-invar, gum metal, Ti Alloy (6 Al-4 V), Tungsten Tantalum, Al. Be. Met, Graphite bonded to Cu & Ti In Progress: neutron exposure of 2006 Phase II collimator materials Plan: Finish “To Do” & analyze neutron irradiated samples to correlate results with proton irradiated data. In principle will allow for the use of the wealth of radiation data generated from reactor operations NB 2: Nick (not LARP) considers ALL these materials as LHC relevant LARP DOE Review - 05 June 2007 49 Collimation Tasks - T. Markiewicz
CTE Measurements of Irradiated 3 D C-C fluence ~ 1020 protons/cm 2 Irradiation Damage Self Anneals through thermal cycling as seen in 2 -D C-C LARP DOE Review - 05 June 2007 50 Collimation Tasks - T. Markiewicz
CTE Measurements of Irradiated Copper fluence ~ 1021 protons/cm 2 LARP DOE Review - 05 June 2007 51 Collimation Tasks - T. Markiewicz
CTE Measurements of Irradiated Glid. Cop fluence ~ 1021 protons/cm 2 LARP DOE Review - 05 June 2007 52 Collimation Tasks - T. Markiewicz
Carbon Composite & Graphite Damage 3 -D carbon Graphite 2 -D carbon fluence ~ 1021 protons/cm 2 LARP DOE Review - 05 June 2007 53 Collimation Tasks - T. Markiewicz
Conclusions-Platitudes The four LARP Collimation program tasks – Provide R&D results to a key LHC subsystem that will need to perform well from the beginning • Strong support for all tasks from LHC Collimation group – Play to the unique strengths of the US Labs • • RHIC as a testbed BNL irradiation test facilities Fermilab’s simulation strength SLAC’s Linear Collider collimator engineering program LARP DOE Review - 05 June 2007 54 Collimation Tasks - T. Markiewicz
Conclusions-Pessimistic • No real work has happened at BNL to understand RHIC data until recently. Progress may be made soon, but will analysis of existing RHIC data really add anything to LHC design at this point? • FNAL Tertiary collimator simulations too little, too late: Main choice (W vs. Cu) made, collimators fabricated & installed. These studies will never be truly over. Is that so bad? • BNL irradiation studies support 2 -D C-C for Phase I (after the fact) and Cu/GLIDCOP for Phase II (after the fact). Not all measurements of relevant physical properties made yet. Part of an ongoing study of encompassing many materials of general academic but not necessarily LHC-relevant interest. • SLAC team working hard but: – Thermal mechanical tests > 1 year late: what will happen if they do not deliver performance – Need to start construction of “RC 1” at beginning of FY 08 – Need CERN mover assembly as there is no way we can re-manufacture so many parts – Need other improvements (to primaries? ) to improve quench limit – CERN to provide 2 Phase II secondary collimator designs. What then? LARP DOE Review - 05 June 2007 55 Collimation Tasks - T. Markiewicz
Bonus Slides LARP DOE Review - 05 June 2007 Collimation Tasks - T. Markiewicz
Specification Changes Relative to April 2006 Design LARP DOE Review - 05 June 2007 57 Collimation Tasks - T. Markiewicz
Heat deposited in major components (W/m^3) in 1 hr beam lifetime operation LARP DOE Review - 05 June 2007 58 Collimation Tasks - T. Markiewicz
Major jaw dimensions and calculated cooling performance LARP DOE Review - 05 June 2007 59 Collimation Tasks - T. Markiewicz
One Year Later… At June 2006 DOE Review we introduced • New jaw-hub-shaft design which eliminates central stop & flexible springs • New reverse-bend winding concept for the cooling coil which eliminates the 3 end loops, permitting longer jaws and freeing up valuable space for jaw supports, rotation mechanism and RF-features • Internally actuated drive for rotating after beam abort damages surface Main accomplishments in the last year • Many test pieces manufactured and examined, tooling developed, and, especially, brazing protocols worked out • Hundreds of 3 -D concept & 2 -D manufacturing drawings made • Rotation & support mechanism fully designed and manufactured • All parts for first full length jaw assembly manufactured & in-house • Test lab fully wired, plumbed and equipped BUT… – Still have not brazed nor thermally tested a full length jaw assembly – Still do not have a complete mechanical (=“RC 1”) prototype LARP DOE Review - 05 June 2007 60 Collimation Tasks - T. Markiewicz
Summary of New Baseline Configuration 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 930 mm long faceted, 20 sided polygon of Glidcop Shorter end taper: 10 mm L at 15 o (effective length 910 mm) Cooling tube is square 10 mm Cu w/ 7 mm 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 of FIRST COLLIMATOR as low as 8. 5 s – Results in minimum aperture > 7 s in transient 12 min beam lifetime event (interactions with first carbon primary TCPV) – Absorbed power relatively insensitive to aperture: for 950 mm long jaw p=12. 7 k. W (7 s), p=12. 4 k. W (8. 23 s) Auto-retraction not available for some jaw orientations Jaw rotation by means of worm gear/ratchet mechanism “Geneva Mechanism” LARP DOE Review - 05 June 2007 61 Collimation Tasks - T. Markiewicz
Cu-Mo Hub Braze Test parts #2 #1 - Mandrel Dummy (not shown) #2 - Mo Shaft Dummy #3 - Mo Backing Ring #4 - Cu Hub with braze wire grooves LARP DOE Review - 05 June 2007 #3 62 #4 Collimation Tasks - T. Markiewicz
Up Beam Flex Mount – Rotation Assembly Complete Design features that may not be apparent in the photos include: – Integral water cooling channel. – Flexibility for length increase of the Collimator Shaft (proton load). – Compensation for Shaft (in-plane) end angle rotation (sag). – Flexibility for the +/- 1. 5 mm offsets required during “slewing”. – Does not require an extra drive and control (uses existing systems). – 2. 5 mm motions advance the ratchet 1 “click”. – 512 “clicks” advance the Collimator to the next facet. – Facet advancing is ~5% of the lifting load for Vertical Collimator LARP DOE Review - 05 June 2007 63 Collimation Tasks - T. Markiewicz
PLASTIC DEFORMATION of ENTIRE JAW after a BEAM ABORT ACCIDENT? PRELIMINARY RESULT: – 0. 27 MJ dumped in 200 ns into ANSYS model – Quasi steady state temperature dependent stress-strain Doyle • bilinear isotropic hardening – Result: • plastic deformation of 208 um after cooling, sagitta ~130 um – Jaw ends deflect toward beam • Jaw surfaces at 90 to beam impact useable, flat within 5 um 54 um Beam side Melted material removed Far side LARP DOE Review - 05 June 2007 64 Collimation Tasks - T. Markiewicz
Rotatable Collimator Activation & Handling Need dose rate at ~1 m; Mokhov et al LARP DOE Review - 05 June 2007 65 Collimation Tasks - T. Markiewicz
BNL Irradiation (BLIP) and Post-Irradiation Testing Facilities and Set-Up Layout of multi-material irradiation matrix at BNL BLIP Dilatometer Set-up In Hot Cell #1 Remotelyoperated tensile testing system in Hot Cell #2 Test Specimen Assembly LARP DOE Review - 05 June 2007 66 Collimation Tasks - T. Markiewicz
Task #4 Status Completed: • • Phase I Carbon-Carbon irradiation Sample activation measurements (m. Ci, dpa) Thermal Expansion of C-C specimens Preparation of Phase II material samples Specimens highly degraded under dose >> LHC collimator jaws will see. LARP DOE Review - 05 June 2007 67 Collimation Tasks - T. Markiewicz
CTE Measurements of Irradiated 2 D C-C Strong (fiber plane) direction Weak (┴fiber plane) direction 7. 50 m. Ci LHC collimator operating temperature regime Irradiation Damage Self Anneals through thermal cycling in both strong and weak directions LARP DOE Review - 05 June 2007 68 Collimation Tasks - T. Markiewicz
Irradiation damage assessment – to date • While all carbon composites tested (2005 -2007) exhibit stability in their thermal expansion coefficient in the temperature range they are expected to operate normally, they experience a dramatic change in their CTE with increased radiation. However they are able to fully reverse the “damage” with thermal annealing • Carbon composites also showed that with increased proton fluence (> 0. 2 10^21 p/cm 2) they experience serious structural degradation. This finding was confirmed for the family of such composites and not only for the 2 -D composite used in the LHC. • It was also experimentally shown that under similar conditions, graphite also suffers structurally the same way as the carbon composites • Proton radiation was shown to not effect thermal expansion of Copper and Glidcop that are considered for Phase II • Encouraging results were obtained for super-Invar, Ti-6 Al-4 V alloy and Al. Be. Met In Progress: • Set up of existing tensile test apparatus & test of irradiated C-C • Set up of new thermal conductivity apparatus LARP DOE Review - 05 June 2007 69 Collimation Tasks - T. Markiewicz
- Slides: 69