1 / 6

Faster ramps for the LHC magnets?

Faster ramps for the LHC magnets?. Attilio Milanese. 11 Feb. 2014. Faster LHC magnets?. Foreword

zihna
Download Presentation

Faster ramps for the LHC magnets?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Faster ramps for the LHC magnets? Attilio Milanese 11 Feb. 2014

  2. Faster LHC magnets? Foreword • This is a compilation of considerations and possible issues after quick discussions with several colleagues: M. Bajko, L. Bottura, M. Modena, E. Todesco, D. Tommasini, A. Verweij, L. Walckiers. • The focus is on the main bending magnets; the main quadrupoles do not seem more limiting. In the tunnel now • dI/dt = 10 A/s in the linear part, with smoothing at the ends • dI/dt limited by power converter voltage • inductance of a sector (154 magnets in series) Lsector = 15 H • the power converter can take about 190 V when powering • count ≈ 10 V for losses in current leads at nominal conditions • nominal current (11850 A, 8.33 T, 7 TeV) reached in ≈ 19 minutes Attilio Milanese

  3. Faster LHC magnets? Diode • the diode opens at 6 V, that is, 60 A/s Premature quench • overall consensus is that a single magnet can go without premature quenching at 100 A/s (or more) up to nominal Quench protection • already now after a quench the other dipoles in a string start going down at 120 A/s (at the beginning of the exponential) without triggering the QPS, which is still on • this is using 100 mV or 200 mV thresholds on voltage differences (200 mV when the aperture compensation doesn’t work well) • so 100 A/s would seem reasonable for QPS without major upgrades Attilio Milanese

  4. Faster LHC magnets? Cryo load • tentative scaling, from A. Verweij thesis, with Rc = 40 mW • this is one of the physical limits, the cryo upgrades would have to live with the hydraulic / thermal design of the current system • with an injection / ramp up / extraction / ramp down cycle there would be no time to breathe for the cryo Attilio Milanese

  5. Faster LHC magnets? Inductive voltage • maximum voltage per magnet in operating conditions is around 1 kV • the same powering scheme could be used till around 50 A/s • for faster dI/dt extra powering sectorisations of the arcs (jumpers…) seem unavoidable Field quality • ramp rate affects decay and snap-back at injection energy • looking at the measurements, it looks like the dipoles can go to 50 A/s with challenging (but possible) acrobatics to describe the dynamic effects, in particular on the sextupole component • faster than that, some other kind of compensations – is possible – would be required Attilio Milanese

  6. Faster LHC magnets? Other (just on the magnet side) • mechanical lifetime from cycling: fatigue issues? • compensation rates for corrector circuits, faster, with QPS working in an uncompensated mode • electrical lifetime at higher dielectric stress • superconducting magnets for the new transfer lines? Attilio Milanese

More Related