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ENERGY DEPOSITION IN HYBRID NbTi/Nb 3 Sn TRIPLET CONFIGURATIONS OF THE LHC PHASE I UPGRADE

Fermilab. Accelerator Physics Center. ENERGY DEPOSITION IN HYBRID NbTi/Nb 3 Sn TRIPLET CONFIGURATIONS OF THE LHC PHASE I UPGRADE. Nikolai Mokhov, Fermilab. CERN March 31 – April 2, 2008. OUTLINE. Introduction Three Upgrade Configurations Studied MARS15 IR and Quad Models

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ENERGY DEPOSITION IN HYBRID NbTi/Nb 3 Sn TRIPLET CONFIGURATIONS OF THE LHC PHASE I UPGRADE

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  1. Fermilab Accelerator Physics Center ENERGY DEPOSITION IN HYBRIDNbTi/Nb3Sn TRIPLET CONFIGURATIONSOF THE LHC PHASE I UPGRADE Nikolai Mokhov, Fermilab CERN March 31 – April 2, 2008

  2. OUTLINE • Introduction • Three Upgrade Configurations Studied • MARS15 IR and Quad Models • Power Density Maps • Peaks w.r.t. Design Limits • Heat Loads • Summary Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  3. INTRODUCTION • JIRS project of the LARP aims at investigation of potential of replacing one (on each side of IP) of the NbTi quadrupoles with a Nb3Sn one in the LHC Phase I upgrade of high-luminosity IRs. Based on realistic energy deposition calculations, we are trying to derive operational margins for the quads in various configurations. Preliminary results are presented here. • Simulations are done with MARS15 (2008), and DPMJET-3 as an event generator for 7x7 TeV pp-collisions at 2.5x1034 cm-2 s-1, using low-betamax and symmetric optics from John Johnstone. • IP5 (R) is considered, with a full crossing angle of 450 mrad, segmented absorbers SS or W (possibly) cooled at LN2-temperature, as proposed in our paper PRSTAB, 9, 10001 (2006) and Proc. WAMDO06 Workshop, CARE-Conf-06-049-HHH, p. 80 (2006). Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  4. 1. LOW-BETAMAX OPTICS: LBM-1 in MARS15 Q1: 90-mm NbTi, 167.2 T/m, L=7.06 m Q2: 130-mm NbTi, 121.4 T/m, L=7.787m x 2 Q3: 110-mm Nb3Sn, 176.2 T/m, L=3m x 2 • TAS aperture: • 42 mm • 55 mm • 3-mm segment absorbers: • W in Q1, SS in Q2, no in Q3 Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  5. 2. LOW-BETAMAX OPTICS: LBM-2 in MARS15 Q1: 90-mm Nb3Sn, 206.1 T/m, L=5.65 m Q2: 130-mm NbTi, 121.1 T/m, L=7.787m x 2 Q3: 130-mm NbTi, 121.1 T/m, L=8.711 m TAS aperture: 55 mm 3-mm segment absorbers: SS in Q1, Q2 & Q3 Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  6. 3. SYMMETRIC OPTICS: SYM-1 in MARS15 Q1: 90-mm Nb3Sn, 203.8 T/m, L=2.75m x 2 Q2: 130-mm NbTi, 121.9 T/m, L=7.8m x 2 Q3: 130-mm NbTi, 121.9 T/m, L=9.2 m TAS aperture: 55 mm 3-mm segment absorbers: SS in Q1, Q2 & Q3 Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  7. 90, 110 and 130-mm Quad Design By Vadim Kashikhin 110-mm 90-mm 130-mm OPERA-calculated 2-D magnetic maps: 200, 180 and 125 T/m, Dx = Dy = 2 mm Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  8. MARS15 IMPLEMENTATION 90-mm Nb3Sn 130-mm NbTi Same scale Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  9. Beam screens, segment absorbers, cold bore, kapton,LHE, coils, collar, yoke and cryostat in MARS15 90-mm Nb3Sn 130-mm NbTi Same scale Cryostat: thermal shield and vessel (R=457 mm) Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  10. CONSISTENCY CHECKS Example: LBM-2 Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  11. Particle Tracks for 1 pp-event at 7x7 TeV Example: SYM-1 Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  12. POWER DENSITY MAP: LBM-1 Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  13. Power Density Profiles at Longitudinal Peaks: LBM-1 Quad ends Q1 non-IP Q3a IP Q2b non-IP Q3b IP Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  14. POWER DENSITY MAP: LBM-2 Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  15. POWER DENSITY MAP: SYM-1 Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  16. Power Density Profiles at Longitudinal Peaks: SYM-1 Q1b non-IP end Q2b non-IP end Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  17. QUENCH LIMITS & DESIGN GOAL Quench Limit Design Goal Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  18. Low-betamax-1: Peak Power Density in Cable-1 vs z LBM-1: 42-mm TAS LBM-1: 55-mm TAS Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  19. LBM-2 & SYM-1: Peak Power Density in Cable-1 vs z 55-mm aperture TAS SYM-1 LBM-2 Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  20. Peak Power Density wrt Design Limits Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  21. HEAT LOADS • At L=2.5x1034 cm-2 s-1, pp-interactions result in power of 2.24 kW per beam carried out from IP1 and IP5. About 1/3 of this power is deposited in the TAS and triplet. • Power dissipation in the TAS scales with the luminosity and decreases with aperture increase thus giving rise to the power deposited in cold components. • TAS: 455W at 34mm, 360W at 42mm, and 283W at 55mm. • Heat loads in low-betamax (LBM-2) optics (Watts): • 109 (Q1), 20 (MCBX), 74 (Q2a), 84 (Q2b), 25 (MQSX), • 7 (TASB), 80 (Q3), 11 (MCBXA), 27 (DFBX), 17 (vessel). Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  22. HEAT LOAD BALANCE (Watts) 55-mm TAS Q1 to MCBXA ~ 40 m ~6.6 W/m ~7.7 W/m ~7.3 W/m LHe+”LN2” ~11 W/m LHe+”LN2” ~10 W/m LHe+”LN2” ~9.9 W/m Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  23. SUMMARY (1) • There are always four pronounced peaks in longitudinal distributions of maximum power density in the first SC cable (averaged over the cable area at the azimuthal maxima): close to Q1 non-IP end, Q2a IP end, Q2b non-IP end and Q3 IP end (see also LHC PR 633, 2003). • For the configurations considered all the peaks are safely below the design limits (for 55-mm TAS). • Increasing TAS aperture from 42 to 55mm, increases first peak by 10% and heat load to the cold components by 75 W. • 3-mm tungsten absorbers in Q1 provides reduction of peaks by a factor of about 3 and 2 in Q1 and Q2, respectively, compared to the stainless steel ones. Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

  24. SUMMARY (2) • Peak in Q3 is practically insensitive to the configuration. • Compared to the nominal case,dynamic heat loads to theSC quads are certainly higher at 2.5x1034 cm-2 s-1 and enlarged TAS aperture, but – because of larger quad apertures and use of absorbers - seem to be manageable, especially with high-Z absorbers cooled at LN2. • Using Nb3Sn for Q1 or Q3 instead of NbTi substantially increases operational margins, frees space for instrumentation between quads, and provides verification of this new technology for Phase II. • Thanks to J. Johnstone for optics, V. Kashikhin for quad geometry and magnetic field maps, I. Rakhno & S. Striganov for enhancement of analysis tools, and A. Zlobin for coordination. Energy Deposition in Hybrid IR Phase I Upgrade - N. Mokhov

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