1. SLAC Phase II Secondary Collimators 6 October 2005 LARP Collaboration Meeting-St. Charles, IL Tom Markiewicz SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator Research Program

2. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 2 / 47 Task#1: Studies of a Rotatable Metallic Collimator for Possible Use in LHC Phase II Collimation System If we ALLOW (rare) ASYNCH. BEAM ABORTS to DAMAGE METAL JAWS, is it possible to build a ROTATING COLLIMATOR –that we can cool to ~<10kW, keeping T<T FRACTURE and P H2O <1 atm. –that has reasonable collimation system efficiency –that satisfies mechanical space & accuracy requirements Scope: –Tracking studies to understand efficiency and loss maps of any proposed configuration (SixTrack) –Energy deposition studies to understand heat load under defined “normal” conditions & damage extent in accident (FLUKA & MARS) –Engineering studies for cooling & deformation –Construct 2 prototypes with eventual beam test at LHC in 2008 –After technical choice by CERN, engineering support –Commissioning support after installation by CERN

3. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 3 / 47 Task#1: Timescale & Manpower FY 2004:Introduction to project FY 2005:Phase II CDR and set up of a collimator lab at SLAC FY 2006:Design, construction & testing of RC1 FY 2007:Design, construction & no-beam testing of RC2 FY 2008:Ship, Install, Beam Tests of RC2 in LHC May-Oct 2008 run FY 2009:Final drawing package for CERN FY 2010:Await production & installation by CERN FY 2011:Commissioning support RC1=Mechanical Prototype; RC2: Beam Test Prototype Engineer#2 Postdoc#1 Active Manpower: Eric Doyle-Engineering Lew Keller-FLUKA Yunhai Cai-Tracking Tom Markiewicz- Integration Meeting/advice: Tor Raubenheimer Andrei Seryi Joe Frisch Planned hires: Mech. Engineer#2 Postdoc#1 Future Effort: Controls Engineer Designer

4. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 4 / 47 2005-06-01 DOE Review of Collimation Program: A+ "The activity in collimation is impressive, with the work being approached in a very professional manner. It is a critical problem, and solving it will have great impact on the ability of the LHC to reach design luminosity. Even the task sheets for this project were done very professionally, lending confidence in a well-managed and well-focused activity. (The synergy with the ILC is clearly evident here.)"

5. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 5 / 47 Status of Phase II Collimator Conceptual Design at 2005-06-01 DOE Review Adequate software in place and MANY studies have been done but … We do NOT yet have a conceptual design for the 1 st of the 11 collimators needed (per beam) in IR7 –28 of 30 Phase II collimators will not have a heating problem No magic design or material which could simultaneously provide good efficiency with combination of energy absorption, thermal conductivity, & thermal expansion to maintain 25 um flatness tolerance over length of jaw during 1hr/12min (90/450kW) beam lifetime transients for nominal jaw length (1m) and gap setting (7  ) Focus on –150mm O.D. 25mm wall Cu jaws with helical cooling tubes –150mm O.D. “solid” Cu jaws cooled with axial flow over 36° of arc

6. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 6 / 47 Copper Similar result was obtained by Ralph A  mann Yunhai Cai Study of Material for Secondary Collimators High Z materials improve system efficiency Copper being considered because its high thermal conductivity Available length is about 1 meter Achievable efficiency is about 3.5x10 -4 at 10  As Sixtrack program adds absorbers/tertiary collimator we expect ~x10 improvement

7. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 7 / 47 Energy Deposition in Metal Phase II Secondary Collimators w/ Carbon Phase I Collimators Open Calculated in FLUKA using CERN-provided input file

8. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 8 / 47 Power absorbed in one TCSH1 jaw at 10  when 80% (5%) of 450kW of primary beam interacts in TCPV (TCSH1)

9. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 9 / 47 Limited cooling arc: free wheeling distributor – orientation controlled by gravity – directs flow to beam-side axial channels. Pro: Far side not cooled, reducing  T and thermal distortion. Con: peak temperature higher; no positive control over flow distributor (could jam); difficult fabrication. 360 o cooling by means of helical (or axial) channels. Pro: Lowers peak temperatures. Con: by cooling back side of jaw, increases net  T through the jaw, and therefore thermal distortion; axial flow wastes cooling capacity on back side of jaw. water beam Helical and axial cooling channels

10. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 10 / 47 ANSYS thermal and structural results for full ID cooling and limited cooling arc showing 64% less distortion with limited cooling 61C  x=221  m Spec: 25  m support 89C  x=79  m Note more swelling than bending Note transverse gradient causes bending Note axial gradient 64% less distortion 360° cooling of I.D. 36° cooling arc

11. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 11 / 47 Material Comparison SS & Transient Thermal Deflection ANSYS simulation results for 150mm OD x 100mm ID x 1.2m L Notes: 1.BeCu is a made-up alloy with 6% Cu. We believe it could be made if warranted 2.2219 Al is an alloy containing 6% Cu 3.Cu/Be is a bimetallic jaw consisting of a 5mm Cu outer layer and a 20mm Be inner layer 4.Cu – 5 mm is a thin walled Cu jaw 5.Super Invar loses its low CTE above 200C, so the 152um deflection is not valid 6.Heat flux to water of 10^6W/m^2 or greater is in regime of possible film boiling

12. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 12 / 47 Material evaluations compared to Cu based on 150mm x 1200mm x25mm wall model MaterialReasons for rejection in favor of Copper BeCu (6% Cu- loaded Be) Beryllium is forbidden by CERN management, low cleaning efficiency due to few particles absorbed; fabrication difficulty Super Invar Poor thermal conductivity  high temperature (866°C), desirable properties (low thermal expansion coefficient) disappear at 200°C Inconel 718 Poor thermal conductivity  high temperature (T mp = 1400°C < 1520°C transient peak) & very high deflection (1039um SS, 1509um transient) Titanium Poor thermal conductivity  deflection 2.7 x Cu (591um, SS) AluminumRelatively poor cleaning efficiency, water channel fabrication difficulty TungstenHigh temperature on water side (240°C - 30bar to suppress boiling); high power density - can't transfer without boiling

13. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 13 / 47 Directions under investigation & negotiation at time of 2005-06-01 DOE Review Redefine secondary hybrid system to treat 1 st collimator as special –Break 1st secondary into two (unequal?) lengths of perhaps different materials –Grooved “expansion slots” to limit deformation –Adjust gaps of the first carbon & metal secondary to reduce heat load while maintaining efficiency with remainder of secondary system –Keep 1 st C-C secondary collimator’s jaws at 7  and leave out 1 st metal secondary collimator –Relax deformation tolerance relaxed to if jaws expand AWAY from beam Begin to deal with LHC infrastructure & operational constraints –45mm jaw gap at injection incompatible with NLC inspired circumferentially mounted gap adjustor Look into adopting Phase I adjustment mechanism –Spatial constraints of LHC beam pipes & tunnel a challenge Jaw dimensions, tank dimension

14. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 14 / 47 IR7 Collimator Layout Beam Direction Primary Collimators Hard Hit Secondary Collimators

15. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 15 / 47 Possible Path to Immediate RC1 Prototype: Leave TCS#1 Carbon-Carbon, Remainder Cu Inefficiency 1C-10CuAll Cu Horizontal2.84x10 -4 3.72x10 -4 Vertical3.63x10 -4 4.36x10 -4 Skew 4.57x10 -4 3.85x10 -4

16. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 16 / 47 Concentrating E_dep in Front Part of Jaw

17. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 17 / 47 Deflections referred to shaft Notes: “Solid” jaws – 150mm OD x ~24mm ID. Basic jaw 120cm L Aperture transition from 10  to 7  7  cases based on CERN ray files for interactions in TCPV pre-radiator not used – Phase I carbon jaw to concentrate energy toward front of Phase II jaw. Effect of: shortened jaws, wider gap, jaw support scheme Deflections referred to edge basic jaw 120cm L

18. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 18 / 47 Circumferential grooves reduce bending deflection by interrupting continuity of thermal strain. CaseTmax °CDeflection (um) Jaw edge refaxis ref Straight 59.533~100 grooved 59.515~74 Parameters 150mm O.D., 25mm wall, 120cm long Grooves: 10mm deep, 50mm spacing 10kW heat, evenly distributed 45 deg cooling arc

19. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 19 / 47 Mechanical Model 2005-06-01 Used NLC Concept of Central Strongback with mid- collimator jaw gap adjuster beam

20. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 20 / 47 June 15-17 CERN/SLAC Collaboration Meeting Attendees –CERN: Ralph Assmann (Project Leader, Tracking), Allesandro Bertarelli (Mechanical Eng.), Markus Brugger (Radiation Issues), Mario Santana (FLUKA) –SLAC: Tom Markiewicz, Eric Doyle (ME), Lew Keller (FLUKA), Yunhai Cai (Tracking), Tor Raubenheimer Radiation Physics Group: Alberto Fasso, Heinz Vincke Results –Agreement on basic design of RC1 (1 st rotatable prototype) –Transfer of many of CERN mechanical CAD files –Lists of Further studies required Outstanding Engineering Issues requiring more design work Project Milestone List & Action Items List –Test Installation of “New FLUKA”

21. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 21 / 47 Conceptual Design of RC1 (1 of 2) Mechanics must fit within CERN Phase I C-C envelope –224mm center-to-center with 88mm OD beampipes –1480mm longitudinal flange-to-flange –25mm adjustment/jaw (22.5mm relative to beam w/±5mm allowed beam center motion and use Phase I alignment and adjustment scheme –Two 75cm Cu cylindrical jaws with 10cm tapered ends, 95cm overall length with axes connected to vertical mover shafts –136mm OD with 9mm taper –Each jaw end independently moved in 10um steps –Vacuum vessel sized to provide 8mm clearance to adjacent beam and allow gross/fine 0°, 45°, 90° positions Relaxed mechanical deformation specifications –<25 um INTO beam guaranteed by adjustable mechanical stop(s) Ride on groove deep enough to not be damaged in accident case Adjustable between ±5 and ±15 sigma (2-6mm) & centered on beam –<325 um (750um) AWAY FROM beam @ 0.8E1p/s loss (4E11p/s) Flexible support on adjustment

22. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 22 / 47 Conceptual Design of RC1 (2 of 2) Assumed worst case heat load (FLUKA) –11.3 kW/jaw steady state, 56.5kW/jaw transient (10 sec) Cooling boundary conditions –200 °C maximum temperature of Cu –27 °C input H2O temperature –42 °C maximum allowed return H2O temperature Two Cooling Schemes under consideration –Helical tube: more secure H2O-vacuum interface –Axial channels w/ diverter: superior thermal mechanical performance –Sufficient pressure (3 atm.) to prevent local boiling in transient –Flexible supply lines to provide 360° rotation Other –Vacuum: <1E-7 Pa (1.3E-5 torr) –RF: shielding scheme has been proposed

23. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 23 / 47 Proposed layout: 136mm diameter x 950mm long jaws, vacuum tank, jaw support mechanism and support base derived from CERN Phase I

24. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 24 / 47 Vacuum tank enlarged to accommodate jaw motion. Relative location of opposing beam pipe – near interference in skew orientations 10° deviation

25. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 25 / 47 Based on CERN’s design – no weld or braze between water & vacuum Tube formed as helix, slightly smaller O.D. than jaw I.D. O.D. of helix wrapped with braze metal shim Helix inserted into bore, two ends twisted wrt each other to expand, ensure contact Fixture (not shown) holds twist during heat cycle Variations: 1.Pitch may vary with length to concentrate cooling 2.Two parallel helixes to double flow 3.Spacer between coils adds thermal mass, strength 4.Electroform jaw body onto coil Helical cooling passages – fabrication concept

26. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 26 / 47 Stop prevents gap closing as jaw bows inward due to heat Jaw ends spring-loaded to the table assemby … move outward in response to bowing 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 Adjustable central gap-defining stop

27. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 27 / 47 Swelling vs. bending deflection Effect depends on jaw support scheme

28. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 28 / 47 Self aligning bearing Leaf springs allow jaw end motion up to 1mm away from beam Adjustable central jaw stops (not shown) define gap Flexible bearing supports allow jaw thermal distortion away from beam CERN’s jaw support/positioning mechanism. Vacuum tank, bellows, steppers not shown. Flexible end supports used in conjunction with central gap-defining mechanism

29. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 29 / 47 Rigid round-square transition Spring loaded fingers ground two jaws through range of motion Jaw support & gap adjustment borrowed from CERN RF Contact Overview

30. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 30 / 47 Flexure – ramp follows jaw motion – sliding contact with jaw and top/bottom walls Step may be detrimental to RF performance Stationary top & bottom walls RF contacts – cutaway view

31. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 31 / 47 RAMP WRAPS 180 o STEP ELIMINATED RF contact variation removes step

32. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 32 / 47 Clearance problems with RF contacts Jaw Support Concept – unresolved issues interferences with RF parts

33. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 33 / 47 CERN design: Jaw supported on individually moveable shaft at each end, controlled by steppers external to tank. Bellows allows full range of jaw motion Continuous one-piece cooling tube brazed to jaw, exits tank at each end through shaft. Unresolved interferences between RF parts and cooling and support parts Jaw rotation mechanism not devised Substantial forces to rotate jaw Mandrel to support coil not shown Flex cooling supply tube concept

34. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 34 / 47 Contiguous with helical tube inside jaw. Formed after assembly-brazing of jaw and installation of bearing on stub-shaft Exits through support shaft per CERN design Material: CuNi10Fe1, 10mm O.D., 8mm I.D. Stub-shaft (bearing not shown) Support shaft Detail of flex cooling supply tube Relaxed (as shown) # coils4 O.D.111mm (4.4in) full 360° rotation# coils5 O.D.91mm (3.6in) torque9.1N-m (81in-lb)

35. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 35 / 47 Primary Collimator (source) TCSM.B6.L7 Jaws at 7  TCSM.B6.L7 Jaws at 10  Copper Al_2219 Copper Al_2219 TCP.D6.L7 (TCPV) 73 26 51 19 TCP.C6.L7 (TCPH) 61 22 49 19 TCP.B6.L7 (TCPS) 92 28 56 20 Power Deposition on First 120cm Secondary Collimator in 12 Min. Lifetime from 20cm C primary hit files (kW per jaw) Notes: 1. Collimator data, ray files, and loss maps from LHC Collimator web page, Feb. 2005. 2. Must add contribution from direct hits on secondary jaws. Sensitivity to aperture and to source of halo: H, V, or S 56.5kW/jaw (11.3kW/jaw for 1 hr beam lifetime) assuming 80%-5% interaction ratio split from 20cm primary hit maps, but adjusting for hadron absorption in back 40cm of C primaries and adjusting for shorter 95cm length

36. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 36 / 47 Continuing evolution of ANSYS model to include realistic cooling channels and cooling water response to heat generated by beam beam 2x 5mm sq channels 136mm x 950mm long “Solid” jaw has less  T across diameter and short cut for heat flow H2O simulation – helical flow shown Fluid pipe elements: Water temperature responds to heat absorbed from jaw More realistic simulation Axial pipes can simulate axial flow Friction can be simulated

37. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 37 / 47 Compact (136x950) jaw variations - performance comparison

38. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 38 / 47 Final Expected Performance of RC1 Design

39. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 39 / 47 Outstanding RC1 Unresolved Issues Jaw positioning –Acceptance of estimated deflection by CERN:281/869um –Design concept for central stop: gap adjust, 5 central position float,.. –Bearings & springs attaching jaws to vertical movers –Load capacity of steppers –Jaw alignment perpendicular to collimation direction Jaw rotation –Specification of mechanism on crowded jaw –Force required to rotate jaws against cooling coil Misc –Spring arrangement for H, V, S orientations –Springs to ensure that device fails open –Motors, cables, temperature sensors, position probes, … Cooling –Possible local boiling in transient condition & need for P~3 atm. H2O system –More flexible yet vacuum safe water supply for helical cooling –Vacuum safe water connection/diverter for axial cooling scheme

40. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 40 / 47 Other Studies Planned Tracking Studies: Hit maps for each of 11 IR7 collimators/beam and efficiency with 60cm C-C primaries and Cylindrical 75cm jaws which includes effect of tertiary collimators and absorbers FLUKA energy deposition with 60cm primaries & cylindrical 75 cm jaws Complete self consistent package of tracking, FLUKA & ANSYS results to support design choices unambiguously Better definition of RC1 thermal tests Remnant & Prompt Dose Rate calculations Engineer damage assessment mechanism into design Thermal shock studies Studies/experiments to verify –assumed extent of damage in accident Where metal slag will wind up –acceptable peak temperature of jaw

41. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 41 / 47 2.5 cm Missteered beam (9E11 protons) on secondary Jaw Copper Jaw Cross section at shower max. Copper Fracture temp. of copper is about 200 deg C What is the damage area in a missteering accident? Assumed Damage threshold seems inconsistent with FNAL experience

42. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 42 / 47 FY2005 Deliverables Collimator Assembly & Test Area (SLAC-ESB) RC1 CDR Draft 9/30/05 32 pages + figures

43. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 43 / 47 FY2006 Work Plan Non-beam Mechanical & Thermal Performance of RC1 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. –Heating by commercial electric resistance heaters coupled to the jaw with thermal grease –Operated in a tank purged with inert gas to protect the copper jaw from oxidation. –Flexible cooling supply that won’t be intended to allow rotation of the jaw. –A FE model of the test jaw will be used as a benchmark to evaluate the response of the test jaw to the test conditions. 2.Full RC1 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. Lidded vacuum tank for easy access. Cooling water feed-throughs and flexible connections as realistic as possible. A reasonable effort will be made to test RC1 under heat loading but this will probably prove to be impractical.

44. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 44 / 47 FY 2006 Deliverables 1.Final version of RC1 CDR Nov. 1, 2005 ? 2.External review of RC1 CDR Nov. 14-18, 2005 ? Dec 12-17, 2005 ? 3.Performance report on RC1 –Sept.30, 2006

45. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 45 / 47 FY2006 Staffing Expect continued involvement of existing collaborators at current level Devoted engineer –negotiations with SLAC “Klystron” shop underway –negotiations with SLAC “Research Division” ME “shop” underway –employment requirements prepared & will be sent to: Fermilab, CERN, etc. Mercury News, etc. Devoted postdoc –Advertisement prepared –People coming through for a “SLAC Postdoc” interviewed In-house & external shop & design work as needed

46. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 46 / 47 Detailed FY2006 Work Plan

47. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 47 / 47 Inter-Lab Collaboration Excellent good will & cooperation limited only by busy work loads on other systems –Exchange of mechanical drawing files –Installation of latest FLUKA at SLAC –Transfer of latest mod to SixTrack –Latest hit maps with 60cm primaries Invaluable 3 day visit by 4 CERN staff Monthly video meetings mostly killed April-present due to visit, other meetings, summer, … Next video meeting Oct 11, 2005 CERN review of SLAC draft CDR CERN participation in RC1 CDR review Exchange of detailed technical information will be crucial to delivering prototypes on time –Drawing of support structures for H, V Skew –Ideally, CERN would send old prototype parts (i.e. everything [support structure with steppers, motors, bellows, LVDTs,…] except for the tank & cylinder jaws) rather than have SLAC re-fab from drawings or from transcriptions of drawings

48. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 48 / 47 Conclusion To meet the Jan.1, 2008 RC2 ship date requirement SLAC and CERN collaborators have agreed on an initial set of specifications for the first mechanical prototype RC1 –based on extensive but incomplete studies done to date –consistent with CERN beam & mechanical constraints & which uses Phase I design to maximum extent RC1 Prototype Conceptual Design, while not 100% complete, has been written up and serves as a start point for construction. –report to be finalized & reviewed in FY2006 Fabrication of RC1 in two main steps in FY2006, with appropriate thermal mechanical tests, should validate most of the design issues Design extension to RC2, a beam-test-capable prototype, will occur in parallel Good (but of course could always be better) communication and exchange of information marks collaboration between labs 100% devoted manpower required to ensure success

49. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 49 / 47 Status of Phase II Efficiency Studies Excellent understanding of the code: –Tracking simulations of 1m metal secondary collimators at 7  show inadequate efficiency (plot shown previously) –CERN provided upgraded code with absorbers & tertiary collimators added will hopefully show adequate performance –Continue to understand playoff between gaps, lengths and materials and provide loss maps for use as FLUKA input for suggested modifications

50. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 50 / 47 Vertical & Skew Collimators Secondary halo in normalized phase space at the end of collimation system Collimators are projected to The end of collimation system Primary collimator This is an independent check of the simulation code, since the collimators are plotted according to the lattice functions calculated using MAD. 6 and 7 sigma contours

51. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 51 / 47 Tertiary Halo: Particles Escaped from the Secondary Collimators TCSG.D4L7.B1 TCSG.E5R7.B1: last skew collimator Number of particles beyond 10  is 73, which is consistent with the efficiency calculation: 73/144446 = 5x10 -4. Tertiary halo at large amplitude is generated by the large-angle Coulomb scattering in the last collimator. If we add a tertiary collimator at 8  in the same phase as the collimator: TCSG.D4L7.B1 after the secondary collimators, the efficiency should be better than 1x10 -4.

52. LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. MarkiewiczSlide n° 52 / 47 Status of Phase II Energy Loss Studies FLUKA with “simple” CERN-provided input file modeling ~40m around primary collimators used for all SLAC studies Let “pencil beam” halo interact in primary vertical carbon collimator and study energy deposition in rectangular 25x80mm jaws at 10  –Assume 80% inelastic int. in primary, 2.5% in each jaw of secondary –Vary jaw material & provide energy deposition grid on jaw to ANSYS 2.5mm x 8mm x 5cm rectangular grid, mapped onto cylinder –Understand secondary particle content, energy & spatial distributions Use CERN provided loss maps for H,V,Skew halo with jaws at 7  and re- calculate energy deposition grids Study accident case: –Transverse extent of damaged region Longer term goal of upgrading to current CERN input structure with much richer description of all devices in tunnel –For the moment, ask CERN for estimates of load on “easier” collimators