1. D1/D2 Circuit Baseline Update Rationales for Baseline Discussion B. Auchmann, F. Rodriguez Mateos, A. Verweij, D. Wollmann CERN, TE-MPE

2. Goal up to HL-LHC Circuit Review  Updated baseline for D1-D2 circuits (and others) taking into account all relevant constraints:  Magnet Protection  Circuit Design + Protection  Powering  Protection Hardware  Cryogenics  Integration  Planning  Testing  Budget  … Daniel Wollmann2

3. Priorities Daniel Wollmann3 Minimal requirement: T peak < ? K, V peak < x kV Protection goals: T peak < ? K, V peak < y kV Risk assessment: failure modes, effects, criticality  Contingency goals for expected faults.  Protection goals for (very) rare faults. Mean Time Before Failure (MTBF) Mean Time To Repair (MTTR)

4. 1 or 2 circuits 1 Circuit2 Circuits CriterionFulfil lmen t CommentsFulfil lmen t Comments Protection11Lower stored energy per circuit Independent protection of each magnet Compatibility0.9Link required between D1 and D2 (powered through different sc. Links) Trim power converter required? 1 Reliability0.7(In case of one CLIQ unit not firing, protection by CLIQ on other magnet) 0.8Reduced # of high current quenches. Availability0.8Less high current power converters & links  less beam aborts 0.8Quicker quench recovery (firing of heaters in less magnets). Maintainability0.7Trim PC required? Additional link required 0.8Two main converters Simplicity0.6Integration of additional link (CLIQ units not to be redundant) 0.8No trim circuits Cost saving0.81 main power converter (but 1 trim?). Reduced operational costs Additional link 0.7 Space Saving0.81 main power converter (but 1 trim?).0.7 Daniel Wollmann4 Judgment of fulfillment [0…1], subjective and open for discussions

5. Illustration example: Radar plot Daniel Wollmann5 CriterionWeighting Protection1 Compatibility1 Reliability1 Availability0.7 Maintainability0.6 Simplicity0.6 Cost saving0.6 Space Saving0.4 Or in two numbers: One Circuit: 3.74 Two Circuits: 4.02 Optimum: 4.9

6. Questions to be addressed (1/2)  Number of circuits (one or two, see above).  Ramp-down speed (  two quadrant PCs?).  Heaters in combination with CLIQ.  # heater strips in active use.  # heater circuits.  # and connections of CLIQ units and their parameters.  Required CLIQ redundancy (capacitance, triggering, … ).  # hot spares.  Lead design (CLIQ, heaters).  Heater & CLIQ polarity assignments. Daniel Wollmann6

7. Questions to be addressed (1/2)  Detection  # and position of (V-) taps (incl. symmetric quench detection)  Logic (voting, redundancy).  Monitoring  Online monitoring, interlocking.  Requirements for post-mortem data.  Test and reception criteria.  … Daniel Wollmann7

8. Conclusion  Numerous questions need to be addressed and decided before the HL-LHC Circuit review (~5 weeks).  Various teams bring different perspectives.  Each decision effects other criteria sometimes conflicting.  What is the most efficient way to come to a  A full list of open questions is needed.  Sharepoint “Team Discussions” can help to continue the discussion outside of meetings. Daniel Wollmann8

9. Thank you for your attention! Daniel Wollmann9