BusBar Quench Studies Summary of Available Calculations LMC
Bus-Bar Quench Studies Summary of Available Calculations LMC Meeting August 5 th 2009 J. Blanco, M. Brugger, F. Cerutti, A. Ferrari, E. Lebbos, A. Mereghetti, K. Roed, R. Schmidt, V. Vlachoudis, J. Wenninger Input from: A. Verweij Calculations based on the FLUKA Team IR 7 Layout
The Studied Cases: Loss Source General • • Beam-2 case assuming orbit bump at MQ locations Two general cases studied for various locations: (a) Point-like loss in the beam-screen to get peak in the downstream interconnect/empty-cryostat or magnet (b) assuming a distribution (equal) along the element X 250 mrad deflection angle (3) (2) (1) MQ 11 Loss MQ 12 in the Empty Cryostat • aiming to get peak energy deposition in the following empty cryostat interconnect, and the empty downstream magnets cryostat followingand (5 Te. V interconnect magnets only) (5 Te. V and magnets only) • done for both energies 3 Te. V and 5 Te. V MBA 11 MBA 12 Beam 2 August 5 th 2009 MBB 11 MBB 12 Empty Cryostat MBC 12 X Beam 2 Busbar Quench Studies - LMC Meeting MQ 11 MQ 12 X X Beam 2 2
Models: Empty Cryostat n n n August 5 th 2009 Energy deposition on the busbars per unit length Energy deposition on the lyra BLM particles spectra and energy deposition. -> BLM signal Busbar Quench Studies - LMC Meeting 3
Interconnect: FLUKA model Bus Bar Quadrupole Line M 1 & M 2 Linear Heat Exchanger X & Y Beam Line V 1 & V 2 August 5 th 2009 Busbar Quench Studies - LMC Meeting Bus Bar Dipole Line M 3 4
Assumptions for Quench & Heating MB/MQ Quench Limits (for transient case) • 1 m. J/cm 3 (preliminary assumption -> update needed) !!! • peak energy deposition in magnet coils: The Results SCALE cell size (r/f/z): ~1 cm / 2 deg / 10 cm with these Assumptions • 10 m. J/cm (preliminary assumption -> update needed) !!! Busbar Quench Limits (transient) • transversal average over • MQ: 160 mm 2 (M 1, M 2 as shown in layout before) • MB: 280 mm 2 (M 3) • in the moment peak value with: • ~ 1 cm longitudinal average for the busbars • ~ peak value in the Lyra (not averaged!) • adiabatic assumption (Pre)Heating-up 80 K • 80 K: 92 J/cm for the MQ, (c. f. , A. Verweij) (preliminary assumption -> possible update needed) August 5 th 2009 Busbar Quench Studies - LMC Meeting 5
Example: Distributed Loss in MQ 11 Energy density given per simulated primary proton! Empty Cryostat MB. A 11 R 7 MB. B 11 R 7 Bea m. D irect ion MQ 11 R 7 August 5 th 2009 Busbar Quench Studies - LMC Meeting 6
Inter-Connect: Energy deposition Interconnect located after the MQ 11 (point-like loss) Vertical cut Horizontal cut Ge. V/cm 3/primary Beam 2 Peak in the beam-pipe Peak in the busbar Coarse binning for Visualisation only August 5 th 2009 Busbar Quench Studies - LMC Meeting 7
Inter-Connect: Energy Deposition MQ 11 5 Te. V Energy Density / Ge. V/cm 3 Point-Like Loss Distributed Loss Beam 2 Length Along Inter-Connect / cm August 5 th 2009 Busbar Quench Studies - LMC Meeting 8
Energy Per Unit Length / Ge. V/cm Empty Cryostat: Energy deposition August 5 th 2009 Empty Cryostat Loss (Distributed) M 1 (MQ) Get Peak Value (localized) M 2 (MQ) Lyra Peak to be evaluated separately Length Along Empty Cryostat / cm Busbar Quench Studies - LMC Meeting Beam 2 9
Empty Cryostat: Energy deposition Distributed Loss Point-Like Loss Edep Lyra M 2 dist loss M 2 (MQ) Edep Lyra M 2 point loss Factor of ~10 x Edep Lyra M 1 dist loss M 2 (MQ) Distributed Loss Point-Like Loss M 1 (MQ) August 5 th 2009 Edep Lyra M 1 point loss 10 Busbar Quench Studies LMC Meeting
BLM Signal Empty Cryostat BLM Signal (Ideal Pos. ) / m. C/primary Empty Cryostat Loss (Distributed Case) Peak in the beginning of the MB. B 11 Beam 2 Possible BLM Positions Along Beam Elements August 5 th 2009 Busbar Quench Studies - LMC Meeting 11
Analysis, e. g. , MQ 11 - Point-Like Case n n n Magnet quenches ~3 orders of magnitudes earlier than the busbars in the adjacent inter-connect or empty cryostat BLM signal in the order of n. C (if in the optimum position) in the case of the MQ 11 quench Consider important uncertainties due to the loss assumptions and simulation statistics (digits are not significant) August 5 th 2009 Busbar Quench Studies - LMC Meeting 12
Number Of Protons To Quench Both Empty Cryostat 5 Te. V MBA 11 Beam 2 August 5 th 2009 MBB 11 Beam 2 Empty Cryostat Busbar Quench Studies - LMC Meeting MQ 11 Beam 2 13
Number Of Protons To Quench Both MQ 12 5 Te. V MBA 12 Beam 2 August 5 th 2009 MBB 12 MBC 12 Beam 2 Busbar Quench Studies - LMC Meeting MQ 12 Beam 2 14
Quenches: Summary Table n Magnet will quench significantly earlier than adjacent busbars (in interconnects or the empty cryostat) ¨ ¨ n n n (108) 106 protons sufficient to quench the magnets (108) 109 -1010 protons required to quench the busbars Energy dependence between 5 and 3 Te. V is about a factor of two (significantly below the uncertainties due to the loss assumptions) Respective BLM signal is a few n. C for the magnet quench (3 -1000 n. C) Loss (point-like) in the empty cryostat is considered as ‘worst-case’, however direct losses are very unlikely (as compared to the MQs) August 5 th 2009 Busbar Quench Studies - LMC Meeting 15
Pre-Heating to 80 K n Only preliminary assumption for the required energy ¨ n n n 92 J for 80 K (c. f. , A. Verweij) 108 -1010 protons required to quench the busbar` Some 1012 -1013 protons required for >80 K Considered as less of an issue August 5 th 2009 Busbar Quench Studies - LMC Meeting 16
Conclusions n n n Peak values location (and loss scenario) dependent, however general conclusions possible to be drawn within the order of magnitudes (given the assumptions) Combined busbar and magnet quench can not be excluded Magnet will quench at a significantly lower level of beam loss than adjacent bus bars (in inter-connects or the empty cryostat) ¨ ¨ (108) 106 protons sufficient to quench the magnets (108) 109 -1010 protons required to quench the busbars n Applied quench ‘limits’ require an iteration with the magnet experts – results scale accordingly n Energy dependence between 5 and 3 Te. V is about a factor of two According to the present studies it’s very unlikely to quench the busbar only (not observed in these studies) Pre-Heating to 80 K seems less of an issue, but required heat assumptions need to be clarified n n August 5 th 2009 Busbar Quench Studies - LMC Meeting 17
Supporting Material August 5 th 2009 Busbar Quench Studies - LMC Meeting 18
Problem Introduction Motivation “Quantify the likelihood of quenching the busbar with beam. ” “Verify the respective magnet quenches and levels. ” “Analyse the related BLM signal and positions” “Study the probability of rising the temperature of the busbar/Cu over 80 K before discharging. ” The ‘Problem’ Sufficiently ‘realistic’ representation of the geometrical situation Proper implementation in the DS/ARC layout What loss scenario to be condisered Link between loss scenario, energy deposition (quench) and BLM signal - simulation layout follows same layout as damage studies proposed before/after Chamonix 2009 (see V. Kain et al. ) August 5 th 2009 Busbar Quench Studies - LMC Meeting 19
The Required (New) Ingredients Geometry • FLUKA model of the empty cryostat • FLUKA model (different lengths) of the interconnects • BLM ‘dummy’ regions along magnets Technical • Routine allowing for arbitrary losses in beam elements of the DS/ARC • BLM particle energy spectra scoring as a function of ‘Lattice’ • Special LYRA scoring following U-shape and allowing to get only the contribution of the sensitive volume • Check for particles leaving the area (possible use for post-tracking studies) • Longitudinal scoring along bus-bars, as well as 3 D scoring for visualization Loss Assumption • Different cases studied for various loss locations (MQ 12/11/Empty Cryostat) and in some cases also different energies Quench Levels & Preheating: Values and Conditions • Normalization assumptions • Quench conditions to be studied (transient, …) August 5 th 2009 Busbar Quench Studies - LMC Meeting 20
Geometry Models: Empty Cryostat n Details Included ¨ Lyras (complex implementation through angles, …) ¨ Radiation shield (Pb) ¨ Beam screens/pipes ¨ Central part (He/Steel) ¨ Continuous horizontal BLM August 5 th 2009 Busbar Quench Studies - LMC Meeting 21
The Interconnect ‘Challenge’ not in scale MQ 10 MQ 11 MBA 11 MBB 11 Empty Cryostat August 5 th 2009 Busbar Quench Studies - LMC Meeting 22
Interconnect: FLUKA model (2) Beam Line & Bus bar described in detail with respect to the dimensions and materials RF contact development in Cu alloy C 17410 with 5µm Au coating Tube in stainless steel 316 LN Superconducting cables Cu alloy inside Cu outside August 5 th 2009 Transition tube in Cu Busbar Quench Studies - LMC Meeting 23
Different Locations (distributed loss) Empty Cryostat MQ 11 Empty Cryostat MBA 11 MBB 11 MQ 12 Analysis of peak energy depositions in busbars and magnet coils for the different loss locations and distributions (as well as energy for the MQ 12 case) August 5 th 2009 MBA 12 MBB 12 Busbar Quench Studies - LMC Meeting MBC 12 MQ 12 24
Empty Cryostat: Energy deposition Energy Per Unit Length / Ge. V/cm Empty Cryostat Loss (Point-Like) August 5 th 2009 M 1 (MQ) Get Peak Value (localized) M 2 (MQ) Loss Location Lyra Peak to be evaluated seperatedly Quench Studies - Cryostat LMC Meeting / cm Length. Busbar Along Empty Beam 2 25
BLM Signal Empty Cryostat BLM Signal (Ideal Pos. ) / m. C/primary Empty Cryostat Loss (Point-Like Case) Peak in Towards the End of the Empty Cryostat Beam 2 Position Along Beam Elements August 5 th 2009 Busbar Quench Studies - LMC Meeting 26
Analysis, e. g. , MQ 11 - Distributed Case n n Magnet quenches 2 -3 orders of magnitudes earlier than the busbars in the adjacent inter-connect or empty cryostat BLM signal in the order of n. C in the case of the MQ 11 qench August 5 th 2009 Busbar Quench Studies - LMC Meeting 27
Analysis, e. g. , Empty Cryos. Dist. Loss n n Adjacent magnet quenches ‘only’ ten times earlier than the busbars in the empty cryostat significantly higher BLM signal (some 100 n. C) (Note: the BLM signal refers to the BEST possible location, thus not necessarily the one as installed in the machine ) August 5 th 2009 Busbar Quench Studies - LMC Meeting 28
Analysis, e. g. , Empty C. Point Loss n Magnet quenches about at the same time as the busbars in the empty cryostat (Note: the Lyra quench level refers to the peak value) August 5 th 2009 Busbar Quench Studies - LMC Meeting 29
Number Of Protons To Quench Both MQ 11 5 Te. V MBA 11 Beam 2 August 5 th 2009 MBB 11 Empty Cryostat Beam 2 Busbar Quench Studies - LMC Meeting MQ 11 Beam 2 30
Number Of Protons To Quench Both MQ 12 3 Te. V MBA 12 Beam 2 August 5 th 2009 MBB 12 MBC 12 Beam 2 Busbar Quench Studies - LMC Meeting MQ 12 Beam 2 31
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