US LHC Accelerator Research Program BNL FNAL LBNL
US LHC Accelerator Research Program BNL - FNAL- LBNL - SLAC LARP Collimator Tasks Summary 28 April 2006 LARP Collaboration Meeting-LBL Tom Markiewicz SLAC LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz
LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 2
Take Home Points Phase II Rotate-able Collimators – Elevated to “Hard Deliverable Status” in eyes of our CERN colleagues – Schedule slippage of ~6 months • Manpower issues • Review committee issues (more complete design before can start) – 400 k$ returned to LARP general fund – Now on track & better staffed – Consensus that we need more effort to understand 1 MJ beam-abort on jaw Communication with CERN slower than ideal (see Nikolai’s comments later) – Should we ask Ralph to appoint a “Point of Contact”? New Task 5 proposed: Crystal Collimation – To be examined by Gang of 5+1: (4 x L 2 + VS) + S • Impact on “baseline” secondary collimator LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 3
Task 2: Progress Since October 2005 Meeting State of affairs Oct. 2005: Ion loss maps in RHIC agree with tracking results, protons do not. Since then, no progress : analysis of proton loss data awaiting manpower – hope is that CERN student who set up Sixtrack with BNL lattice will take BNL postdoc job New work on Collimator efficiency & set up – Heavy Ions and protons very different – positioning procedure for p is slow and tedious and not reproducible – For protons, the effectiveness of the individual collimators changes from store to store and between the IRs Other LARP (not collimation) activities: – LBL luminosity monitor installed in RHIC IR 10 between existing luminosity detectors for calibration later this year – E-cloud studies with LHC style electron detectors installed in IR 10 LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz Electron Detector in RHIC 4
RHIC Tracking Results Ions Agree With “ICOSIM” Protons Data does not agree LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 5
TERTIARY COLLIMATORS- October 2005 Status Tertiary collimators (TCT) at 8. 4 s around IR 1/5 protect SC triplets from tertiary halo coming from particles leaking from 7 s secondary collimators, upstream beam-gas and inefficiency of MPS if unsynchronized beam abort. These must not induce peak energy deposition in the triplets above the quench limit nor induce detector backgrounds. 80 x 25 x 1000 mm Cu jaws at. 4 s 145 m from IP added to MARS 15 Without TCTs LARP Collaboration Meeting. - 28 Apr. 2006 With TCTs Collimator Task Summary - T. Markiewicz 6
Example of New MARS 15 RESULTS after upgrades to Mars code and updates to layout • • Outgoing beam: TCTs are pretty radioactive (especially if made of tungsten) and interfere with the TOTEM first station XRP 1 at 146 m. Incoming beam: preliminary results for beam-gas are encouraging. LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 7
TERTIARY COLLIMATORS PROGRESS & PLANS In October 2005, Nikolai wrote: – File of Beam 1 loss in TCT region calculated by CERN received 2005 -09 • Need similar file for Beam 2 • Need similar files for momentum cleaning insertion IR 3 – Plan to begin updating results using these files beginning mid-October Today Nikolai writes Ø Need input from Ralph ASAP - it’s not the first time – obviously a communication issue Ø As soon as beam loss input files received ~2 mos to finish most work on TCT Ø If no surprises – task can be closed ~1/2 yr 6 months without requested information LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 8
Task #4: Irradiation Damage Assessment of LHC collimator materials 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 (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 October 2005: – Phase I Carbon-Carbon irradiation completed – Sample activation measurements completed – Thermal Expansion of specimens started LARP Collaboration Meeting. - 28 Apr. 2006 Specimens highly degraded under dose >> LHC collimator jaws will see. Collimator Task Summary - T. Markiewicz 9
CTE Measurements of Irradiated C-C Strong (fiber plane) direction Weak (┴fiber plane) direction 7. 50 m. Ci Irradiation Damage Self Anneals through thermal cycling in both strong and weak directions LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 10
Materials for May 2006 BLIP Run are Ready Primary Phase II Materials: • Annealed Copper • Glidcop (0. 15% Al – balance Cu) Other Potential Phase II Materials: • Super Invar • Gum Metal Other Materials to be (re)tested • 2 D Carbon-Carbon • 3 D Carbon-Carbon LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 11
New Measurement Equipment Thermal Conductivity Measurements Using the Laser Flash Method Laser already in the Hot Lab Experimental Safety Review is taking place at BNL Grad Student from SUNY/SB joined the team Tests are planned for summer and fall FY 06 + Mechanical Testing Equipment (Stress vs. Strain) to be reintroduced to the Hot Lab LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 12
Jaw Damage Studies (an increase in scope) Simulations of Extreme Energy Deposition (jaw damage case) Using LS-DYNA Measurements of laser induced ablation of Cu and comparison with LS-DYNA LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 13
Crystal Collimation Proposal • Stages: – Stage 1: feasibility study itself – Stage 2: design of the LHC Phase II Collimation system • Goal: deliver a report (of a mini-review? ) by next LARP collaboration meeting (~ April 2007), be in position to decide whether to proceed to Stage 2 • Plan: – Prepare and perform bent crystal experiments at Tevatron in Fall 2006 – Prepare and perform crystal characterization experiment at SPS H 8 line in Sep’ 06 – Data processing and analysis – Theory work and code development for the LHC LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 14
Status of Phase II Rotating Collimator Project at 10 -06 -2005 Pheasant Run LARP Mtg. SLAC and CERN agree on an initial set of specifications for the first mechanical prototype RC 1 – Put a new vacuum tank with cylinder jaws that fits LHC spatial constraints on a CERN Phase I base and use CERN Phase I scheme for jaw alignment and cooling input – Provide 12 k. W cooling to each 136 mm x 95 cm jaw through flexible tubing – Relax 25 um flatness tolerance but provide flexible jaw support and a central stop mechanism to ensure thermal bowing is AWAY from beam • 400 um sagitta for 1 hr beam lifetime engineering steady state • 1200 um sagitta for 12 min beam lifetime 10 second transient LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 15
FY 06 Goals of Phase II Rotating Collimator Project and Beyond Work Plan outlined 10/6/2006 1. Single jaw thermal test: one jaw with internal helical cooling channels to be thermally loaded for testing the cooling effectiveness and measuring thermal deformations. 2. Full RC 1 prototype: a working prototype for bench top testing of the jaw positioning mechanism, supported to simulate operation in all necessary orientations, but not intended for mounting on actual beamline supports with actual beamline, cooling, control and instrumentation connections. Deliverables listed 10/6/2005 1. Final version of RC 1 CDR: Awaiting support/stopper design 2. External review of RC 1 CDR: √ 3. Construction & Performance report on RC 1: X mid • FY 07 Progress delayed ~6 months due to reviews & manpower issues LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 16
Jaw/Cooling Tube Joint Development Purpose: determine appropriate joint configuration & fabrication methods In process. . target completion date May 9 th Cooling Tube • Square hollow magnet conductor first test ~ 9 mm x 9 mm Jaw Center Mandrel • Copper jaw and mandrel • Cu-Au braze • After first braze, machine coil o. d. for correct fit to jaw i. d. ~70 mm dia ~100 mm dia • After second braze, section assy to inspect coverage • Round tubing with grooved (? ) mandrel is next ~100 mm LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 17
Single Jaw Thermal Test setup Thermocouples measure temperature distribution Reference bar, water cooled to maintain straightness (radiation shield ? ) Standoffs fix jaw distance to reference bar at center Capacitive proximity sensors at ends Flexible end mounts Orientation: may be rotated 90 o, or 180 o or on end Water cooling 2 x 5 k. W heaters, coupled with thermal grease LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 18
Single Jaw Test Thermocouple Locations 2 x 5 k. W Heaters • Thermocouples recessed into Jaw slightly below the surface • Spaced along Heater length and around Jaw circumference • Should yield the Jaw heating profile predicted by the FE analysis 12 x Thermocouples LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 19
IR 7 secondary collimators heat generation, deflection and effective length Deflection and effective length based on ANSYS simulations for TCSM. A 6 L 7. Power scaled from TCSM. A 6 L 7 according to the distribution on secondary collimators provided by CERN. Note: first collimator in the series absorbs the bulk of the energy. Steady State LARP Collaboration Meeting. - 28 Apr. 2006 Transient Collimator Task Summary - T. Markiewicz 20
Unresolved Jaw Support Issues Support needs to: • hold ~100 kg jaw to 5 -10 um accuracy • not sag under gravity for vertical and skew orientations • permit ~1200 um flex for 10 second bursts of 60 k. W energy deposition • work with torque of Phase I stepping motors LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 21
Jaw Positioning Forces – Phase I => Phase II Pull-in headroom expressed as force at nut Upper jaw - shown Jaw deflection = 400 um for 1 hr beam lifetime case, 1200 um for 10 sec transient @12 minute lifetime power level LARP Collaboration Meeting. - 28 Apr. 2006 Lower jaw Jaw end springs will be sized as compromise 1) bending-generated force applied to nut 2) static deflection due to jaw weight Collimator Task Summary - T. Markiewicz 22
Unresolved Central Stop Issues Interplay between alignment scheme • independent motion of each end of each jaw and stop • must be on beam centerline • this can vary ± 5 mm/ store Reproducibility of alignment on successive stores May use two stops to control tilt Slot deep enough to avoid damage in accident Stop far enough from beam to never be damaged & is out of way at injection LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 23
Unresolved Issues with Jaw Rotation Torque required to rotate 360 understood and is substantial; Coil “creep” may alleviate. Details of actuator not yet worked out Interference with RF parts and gross jaw adjustment during injection not studied LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 24
NLC Jaw Indexing Mechanism Reciprocating linear motion advances jaw by one or more ratchet pitches. LHC system will require opposing ratchet to hold jaw position against cooling tube deformation torque. Mechanism probably will be designed to actuate only when jaw fully retracted. LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 25
What is the damage area in a missteering accident? Missteered beam (9 E 11 protons) on secondary Jaw Copper Jaw FNAL Coll with. 5 MJ Cross section at shower max. Copper 2. 5 cm Fracture temp. of copper is about 200 deg C ~1 MJ LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 26
Phase II Task Summary Project has slipped 6 months in 6 months due – Reality of hard deliverables as opposed to softer “design” milestones – Difficulty/cost of acquiring manpower – Understandable design requests by review committee • Nothing we didn’t know about Budget “slipped” 6 months as well After taking this hit we believe we are on-track to deliver on new schedule – Most nervous now about accident condition: begin to discuss beam tests – Believe various steady state requirements are attack-able on an “as good as can be engineered” basis Expect thermal tests and complete design by end of FY 06 and mid-FY 07, respectively Need to get full Phase I mechanism from CERN vendor if we are to make RC 2 deliver schedule. If SLAC can concentrate on jaws and have rest of infrastructure provided RC 2 can meet LHC schedule. LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz 27
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