Upgrade phase 1: Energy deposition in the triplet Elena Wildner Francesco Cerutti Marco Mauri 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner Outline Baseline, IR1 and IR5 Some basic considerations The upgrade Phase I scenario Simulation results Continuation Conclusion 24/01/08 Energy deposition, LIUWG, Elena Wildner

Work on the nominal insertion layout Energy deposition studies independently Fermilab, 2002 & CERN, 2007 (LHC report 633 and LHC note to appear) with MARS and FLUKA In addition comparisons have been made on representative toy model Agreement 5 % in coils 20% in iron Studies so far up to D1 24/01/08 Energy deposition, LIUWG, Elena Wildner

Models of baseline IR1 and IR5 Courtesy C. Hoa Liner in Q1 and MCBX of thickness 6.5 mm (stainless steel) Length 31 m Magnet apertures 70 mm Half crossing angle 142.5 mrad 24/01/08 Energy deposition, LIUWG, Elena Wildner

Heat load along the triplet, “nominal” To limit the peaks in the superconducting coils: our first objective Luminosity= L0 (1 *1034 cm-2s-1) Recommended limit Q1 Q2a Q2b Q3 Courtesy C. Hoa 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner The scoring Cable We make the binning for the scoring so that it corresponds to a minimum volume of equilibrium for the heat transport (cable transverse dimensions, with a length corresponding to the twist pitch of the cable) Total power deposited in the magnets Important to know the volume of the magnet (the model has to be realistic) The power deposited per meter of magnet Azimuthal integration of the power in the longitudinal bins Important for results to know how this is calculated and choose correct bin size!!! Scoring volume: A*L Transverse area of cable (A) Length (L) 10 cm (twist pitch) 24/01/08 Energy deposition, LIUWG, Elena Wildner

Effect of Magnetic Field, nominal IR5 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner Effect of the TAS Q1, TAS 40 mm aperture ”Symmetric” upgrade layout Q1, no TAS 24/01/08 Energy deposition, LIUWG, Elena Wildner

Effect of Crossing Angle, nominal IR5 Total Peaks 24/01/08 Energy deposition, LIUWG, Elena Wildner

Basic considerations (summary) Beam Pipe The beam pipe between magnets shields the front face of the downstream magnet The experimental vacuum chamber before the TAS has to be properly integrated We do not include the experimental vacuum chamber before the TAS in our calculations yet TAS The TAS protects essentially the first quadrupole Magnetic field The magnetic field is driving the deposited energy Mask A mask outside the magnet aperture does not affect the energy deposited in the cable Crossing angle The effect of the crossing angle is smaller than 20% 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner The layout, Phase I “Symmetric” TAS Q1 Q2a Q2b Q3 IP1 130mm 130mm 130mm 130mm 9.40m 7.80m 7.80m 9.40m 41 m Positive particle + FDDF Magnet MQXC Configuration “Symmetric” Gradient [T/m] 120 Aperture [mm] 130 Peak Field [T] 8.7 Layers 2 LHC Project Report 1000: “A Solution for Phase-one Upgrade of the LHC Low-beta Quadrupoles Based on Nb-Ti”, J. P. Koutchouk, L. Rossi, E. Todesco Half crossing angle: 220 m rad, vertical For comparison: “Nominal” (L=L0) layout is about 30 m long. 24/01/08 Energy deposition, LIUWG, Elena Wildner

The Magnet/Field Model Cold Mass outer diameter 570 mm 4 X MQXC 130 mm Aperture 270 mm Courtesy: F. Borgnolutti 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner The magnet ends The magnets have in this first study the same length as the magnetic length: mechanical length = magnetic length No coil ends are modeled (the same transverse layout over the whole magnet) No 3D field or hard edge approximation 24/01/08 Energy deposition, LIUWG, Elena Wildner

Beam pipe dimensioning Relation thickness (t) and diameter (D), valid for stainless steel: t = 0.0272D Example for 130 mm aperture quads (3.5 mm is the gap between coil and beam tube): OD = 130 mm - 3.5 mm = 126.5 mm Thickness of beam pipe according to formula: t= 3.45 mm ID = 126.5 mm – 2*3.45 mm = 119.6 mm 24/01/08 Energy deposition, LIUWG, Elena Wildner

“Baseline”or “reference” case, no shielding Peak in coils Luminosity = 2.5 L0 Minimum thicknesses for mechanical considerations: Beam-Pipe 3.45 mm Beam-Screen 2 mm Ref. value for max energy deposition 4.3 mW/cm3 Q1 Q2a Q2b Q3 Continuous beam-screen and pipe, no experimental vacuum pipes 24/01/08 Energy deposition, LIUWG, Elena Wildner

Azimuthal heat deposition pattern, Q2a 24/01/08 Energy deposition, LIUWG, Elena Wildner

Beam-screen, case 3mm W-liner OD = 119.6 mm – 2 * 0.7 mm – 2 * 3 mm = 112.2 mm ID = OD – 2 * 2 mm = 108.2 mm Liner Additional restriction on vertical aperture Necessary Gap 108.2/2 102.61/2 Beam-Screen thickness 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner Liner dimensioning Old Capillary Position Beam-pipe and beam-screen as thin as mechanically possible! Magnet aperture 130 mm same in all 4 magnets. s Liner Space CBT-BS [mm] 0.7 Coil Aperture [mm] 130 CBT Outer Diameter [mm] 126.5 CBT thickness [mm] 3.45 CBT Inner Diameter [mm] 119.6 BS Outer Diameter [mm] 112.2 BS Inner Diameter [mm] 108.2 BS thickness [mm] 2.0 Capillary Outer Diameter [mm] 4.76 hmax [mm] 102.68 w [mm] 11.1 S [mm] 1.1 Liner thickness [mm] 3.0 Width of liner [mm] 17.44 w a hmax = Di,CBT - 2*0.7-2*4.76 - 2*2.0 -2*s= Di,CBT - 14.92 - 2*s Di,BS = Di,CBT - 2*0.7-2*2.0 – 2*3.0= Di,CBT– 11.4 s= (Di,CBT /2 - 4.76/2-0.7)(1-Cos[a]) w= (Di,CBT /2 - 4.76/2-0.7)(Sin[a]) Width of liner: w - outer radius of Capillary = 22.2 mm - 4.76 mm 24/01/08 Energy deposition, LIUWG, Elena Wildner

Adding a liner along the Triplet Recommendation: 3 mm W shield up to Q2 Continuous beam-screen and pipe, liner also between magnets 24/01/08 Energy deposition, LIUWG, Elena Wildner

Liner not covering entirely gap Q1-Q2 Liner 3mm W No shielding, only BS and BP 24/01/08 Energy deposition, LIUWG, Elena Wildner

Liner not covering entirely gap Q1-Q2 Shielding like for “nominal”: Peak due to 1.5 m “gap” Shield needed between magnets 24/01/08 Energy deposition, LIUWG, Elena Wildner

Total heat load in magnets 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner Total heat load Integration over 10 cm longitudinal (z) bins Q1 Q2a Q2b Q3 24/01/08 Energy deposition, LIUWG, Elena Wildner

Between the Q1 and the Q2 magnets Critical region, must be shielded: Coil end BPM aperture 1.4 cm stainless steel (checked case) Nominal Layout 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner TAS opening The TAS opening has been taken as 55 mm 24/01/08 Energy deposition, LIUWG, Elena Wildner

TAS, lateral and backwards scattering Normalization (Lupgrade = 2.5 L0) 24/01/08 Energy deposition, LIUWG, Elena Wildner

TAS, mechanical considerations Fluka - > Ansys Luminosity: 2.5 1034 cm-2 s-1 TAS aperture: 55 cm Total power in TAS: 300 W Peak: 131 mW/cm3 ± 7% 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner Continuation Choice of pipe sizes and absorbers for next iterations Model of the region between Q1 and Q2a to be refined 3D field of coil ends, mechanical lengths Corrector magnets to be implemented Including D1, TAN, D2 and Q4 Detailed experimental pipes also before TAS Mechanical analysis of the TAS Detailed study on the beam particle distributions at the collisions Ions 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner Conclusion The beam-pipe and the beam-screen thicknesses are enlarged (aperture increase): decreases energy deposition in coils! For good coil protection, we propose to add a 3 mm tungsten sheet (or equivalent) around the beam screen up to the entry of the second quadrupole. We need to design detailed shielding in the region close to the beam-pipe between Q1 and Q2a, according to point 2 above (BPM, RF-conncetion, interconnects…) 24/01/08 Energy deposition, LIUWG, Elena Wildner

Energy deposition, LIUWG, Elena Wildner Thanks to Alessio Mereghetti Joined team from 01/01/2008 R. Ostojic V. Baglin S. Fartoukh M. Karppinen S. Sgobba L. Tavian And others… 24/01/08 Energy deposition, LIUWG, Elena Wildner

Comparison, smaller aperture TAS The smaller TAS aperture shields better the entrance of the first quad The effect of 3 mm SS between magnets is important for peak in second quad 24/01/08 Energy deposition, LIUWG, Elena Wildner