Update on voltage calculations Tiina Salmi and Antti

Update on voltage calculations Tiina Salmi and Antti Stenvall, Tampere University of Technology (TUT) 11. 3. 2016 With contibution from Janne Ruuskanen and Valtteri Lahtinen, TUT T. Salmi, TUT 1

Status • Last time showed preliminary voltage calculation for Cos. Theta and Block designs. Now have done checks and improvement to the code for more reliable results • Last time the magnet inductive voltage was divided evenly for all coil turns. Now the mutual inductance matrix is computed using a separete software and the inductive voltage is distributed to the turns according to their contribution to the total (differential) inductance. • The inductance calculation is thanks to our student Janne Ruuskanen – Team effort! • Details in appedix • I made a comparison with ROXIE quench module considering the costheta – The temperature and voltage distribution in the turns is in good agreement (inductive + resistive). • Worked together with Susana on this • More details in the appendix • I repeated the voltage analysis for all 3 design options. I will show the resulting voltages – they are smaller than in the presentation last time, not only because new inductance computations but also because of new designs. • Final slide has a summary table of the temperatures and voltages in all desings T. Salmi, TUT 2

Simulation assumptions • Simulations using Coodi • Imag = 105% of Iop • tdelay = 40 ms (all coils quenched uniformly 40 ms after initial quench) • Impact of delay time also studied • Material properties based on NIST data (T and B dependency accounted) • Magnetic field map and inductance vs. Imag from ROXIE • Inductance distribution from ”Janne’s code” • Worst case hotspot in an LF cable with high field • Initial hotspot is small and doesn’t propagate: Negligible effect on the voltage calculation T. Salmi, TUT Effective self-inductance normalized to the maximum one 3

Block, v 26 b Final temperature distribution Worst case hotspot would be here, and reaches 308 K (K) T. Salmi, TUT 4

Block, v 26 b This is for tdelay = 40 ms. But voltages are the same for tdelay = 10 ms. Only THS is lower (208 K). Peak potential to ground ~160 ms 82 V btw adjacent turns -1. 2 k. V to gnd 1. 1 k. V btw layers +1. 2 k. V to gnd (V) T. Salmi, TUT 5

Cos. Theta, 16 T_v 28 b-38 -opt 5 d 2 Final temperature distribution Worst case hotspot would be here, and reach 328 K (K) T. Salmi, TUT 6

Cos. Theta, 16 T_v 28 b-38 -opt 5 d 2 This is for tdelay = 40 ms. But voltages are the same for tdelay = 10 ms. Only THS is lower (232 K). Peak potential to ground ~190 ms 103 V btw adjacent turns -1. 4 k. V to gnd 1. 8 k. V btw layers (V) T. Salmi, TUT 7

Common coil, v 1 h_intragrad_t 2 Final temperature distribution Worst case hotspot would be here, and reach 315 K (K) T. Salmi, TUT 8

Common coil, v 1 h_intragrad_t 2 This is for tdelay = 40 ms. But voltages are the same for tdelay = 10 ms. Only THS is lower (230 K). Potential to ground at ~200 ms -2. 3 k. V to gnd 75 V btw adjacent turns ~3. 3 k. V between layers (V) T. Salmi, TUT 9

Summary (all at 105% of Iop) Tdelay = 40 ms T max (K) V to gnd (V) V turn-to-turn (V) V layer-to-layer (V) CC v 1 h_intragrad_t 2 315 2300 75 3400 Cos. Theta v 28 b_opt 5 d 2 328 1400 103 1900 Block 308 1200 82 1100 Voltages don’t depend on tdelay, but hotspot does: NEXT: Analyze different delay distributions? M Prioli just starting CLIQ simulations and analysis for the circuit T. Salmi, TUT 10

Appendix T. Salmi, TUT 11

Voltage comparison with ROXIE T. Salmi, TUT 12

Coodi @247 ms ROXIE @247 ms Hotspot not shown, but is 203 K At the end of ROXIE simulation (t = 247 ms), MIITs = 14. 4 MAAs and Tmax = 195 K Coodi simulation @247 ms: MIITs = 14. 6 MAAs and Tmax = 203 K T. Salmi, TUT 13

Costheta: Voltages between cables at 190 ms Turn-to-turn (Laterally adjacent turns) T. Salmi, TUT Layer-to-layer (vertically adjacent turns) 14

Common. Coil v 1 h_intragrad_t 2: Layer-to-layer voltages at ~190 ms T. Salmi, TUT 15

Common. Coil v 1 h_intragrad_t 2: Turn-to-turn voltages at ~190 ms T. Salmi, TUT 16

Block_v 26 b: Voltages between cables at ~160 ms Turn-to-turn (Laterally adjacent turns) T. Salmi, TUT Layer-to-layer (vertically adjacent turns) 17

IN OUT T. Salmi, TUT 18

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I in 1 1 6 2 9 4 7 8 I out 1 = I in 2 5 3 T. Salmi, TUT 20

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