1 / 11

Take worst case

Take worst case. MKI.D5R8.B2:TEMP_MAGNET_DOWN. Analysis of heating. Took all fills (to end September) where in stable beams for longer than 10 h Considered only time from top of ramp onwards Used number of bunches, average bunch current and bunch length as inputs

yahto
Download Presentation

Take worst case

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. Take worst case MKI.D5R8.B2:TEMP_MAGNET_DOWN

  2. Analysis of heating • Took all fills (to end September) where in stable beams for longer than 10 h • Considered only time from top of ramp onwards • Used number of bunches, average bunch current and bunch length as inputs • Fitted initial heating rate (~linear) over first 2 hours as measure of power in • Used cooling after beam off for measure of power out

  3. Analysis (to end September)

  4. Model including cooling • Semi-empirical model makes reasonable predictions • Replicates cooling after about 12 h • Assuming heating from beam power ( Nb, Ib^2, 1/Lb^2), cooling from radiation ( DT^4) and from conduction ( DT)

  5. Cooling coefficients • Used cooldowns at technical stops or MDs

  6. Outlook for 2012 2600 bunches

  7. Longer-term behaviour • Saturation of temperature after a few fills • Assumed 15 h coast, 4h turnaround (to 3.5 TeV) 50 ns, 1.6e11 per bunch

  8. Temperature at injection • Cooling at about 3 deg per hour • Cool to ‘interlock’ level after less than 1 h after dump • Cool to 334 K (61 C) after 2 h 50 ns, 1.6e11 per bunch

  9. Temperature at injection • With 2e11 in 50 ns might be in trouble • 2 h to cool to interlock limit • 4 h to reach 334 K (61 C) 50 ns, 2.0e11 per bunch

  10. Looks better for 25 ns • Cooling at about 3 deg per hour • Cool to ‘interlock’ level after less than 1 h after dump • Cool to 334 K (61 C) after 2 h 50 ns, 1.6e11 per bunch

  11. Conclusions • Worse for 2012 if push 50 ns intensity • Might affect operation at 2e11 per bunch • 25 ns seems to have more margin – looks OK for 1.1e11 per bunch and 2600 b

More Related