Recommendations of 12/16/05 review committee & SLAC response LARP Phase II Secondary Collimator RC1 Prototype Engineering Status 3/28/06 Recommendations of 12/16/05 review committee & SLAC response Double the engineering effort Consider bi-metallic jaw to limit deformation Evaluate plastic deformation More detailed engineering before fabricate test Info needed from CERN Accident Case – damage estimates LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 1/9

Engineering Effort - Manpower FNAL candidate bowed-out Former LBNL engineer interviewed Expect final agreement any day Designer – candidates interviewed, job offered LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 2/9

Review: Baseline and Alternate Jaws BEAM WATER Review Committee: fill in core with SST “strongback” Fabrication Method Strongback not included Alternate configuration - risky mechanically - lower deflection ~ 100 um SS Baseline configuration - lower risk - more deflection ~ 400 um SS LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 3/9

Baseline jaw – added SST and Cu core NOTE: Cu yield strength = 44MPa Conclusions - Yielding is a problem, deformation not evaluated yet, use Glidcop (yield ~ 250MPa) SST core no improvement (same CTE as Cu, lower conductivity) Cu core helps (conductive shortcut – reduces DT across jaw) LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 4/9

Detailed engineering RC1 Concept as presented to reviewers: Flexible end supports with central gap-defining mechanism Stop prevents thermal bowing of jaws from intruding on minimum gap Leaf springs allow jaw end motion up to 1mm away from beam LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 5/9

X Detailed Engineering Review Committee concerns tilt stability of flexible end supports accuracy of jaw placement lack of jaw indexing concept cooling/thermal stability of central stop, springs, etc (implicit) SLAC’s Planned Response - quantitative understanding of CERN positioning mechanism - understand calibration & operation of CERN positioning mechanism - size support springs (force to neutralize 400um deflection ~ 30kN, force to slip stepper ~ 2kN, => need larger stepper and/or softer jaw support springs) - response of springs/stop/positioning mechanism in all operating regimes X LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 6/9

Info Needed from CERN Introduction to fabrication vendor (jaws, vac tank, positioning mechanism) Drawings of support structure for 0o, 90o and skew orientations. We need to know operating clearances for tank/jaw positioning mechanism (scale assembly drawings or part details to make our own assembly) Verbal description of jaw calibration and control algorithms (Aberle Nov 4, 2005 presentation) Standing request New LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 7/9

Accident case: Tevatron collimator damage “The beam groove is probably on the order of a 1/16” (1.5 mm) deep and the main part of the spatter extends 1” (25 mm) or more to either side of the groove. The damaged collimating surface is a vertical surface. The largest of the splatter beads is on the order of 1/16”. “ Estimated energy deposited < 0.5 MJ LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 8/9

Accident case simulation New ANSYS simulation of accident case 8 bunches of 1.1e11, 7 TeV protons 1 MJ in 200 ns bin size .156e-3 in x, .2e-3 in y heat of fusion modeled, not heat of vaporization peak temperature ~ 58e3 C region at shower max exceeding melting point (in gray) 3.3mm deep x 5.2 mm wide LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 9/9

LHC Phase II Collimation BONUS SLIDES LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 10/9

Material Properties LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 11/9

Interesting side trip: 64% less distortion if cooling is limited to a 36o arc centered on beam path. 360o full I.D. cooling 36o arc cooling Note transverse gradient causes bending 89C Note axial gradient 61C dx=221 mm Spec: 25mm support dx=79 mm Note more swelling than bending 64% less distortion LARP LHC PHASE II SECONDARY COLLIMATOR CD1 STATUS - E. Doyle 28 Mar. 2006 12/9