47th BLM Thresholds WG Meeting
Minutes from the 47th BLM Threshold Working Group meeting – 18.10.16
Present: B. Auchmann, C. Bahamonde, J. Blomberg Ghini, M. Kalliokoski, A. Lechner, S. Le Naour, A. Mereghetti, E. Skordis, R. Schmidt, C. Xu.
Energy deposition studies for UFO events and quenches at 6.5 TeV (A. Lechner)
Slide 11
Estimating the UFO location from the BLM signal pattern is important to then calculate the energy deposition and the corresponding number of protons lost in that event.
Slide 17
Always 20 to 30 mJ/cm3 for this year UFOs.
Slide 19
This plot shows an event where no quench happened but the energy density and number of collisions recorded were high.
Slide 21
Quench levels are not at 6.5TeV because the energy level that is active is actually 6.39. Further work needs to be done and more quenches should be analysed, but the most crucial thing would be to establish error estimates for energy deposition.
Slide 12
Notice the difference between both red areas in the plot, for UFO and steady state losses.
Rudiger states that he would be highly surprised if the uncertainty would be more than 10% off, the unexplained UFO is 400% off.
Energy deposition studies for UFO events and quenches at 6.5 TeV (E. Felcini)
Dipoles have never shown vertical losses, always horizontal according to Anton.
In the operating condition slides, the peak magnetic field corresponds to the middle plane cable.
MB quench level in transient regime: in the slides the mean value is shown, but the UFO data from Anton does not correspond to the radial average along the cable. It is instead the peak value.
There is a lot of difference between single and multi strand models, therefore the results vary a lot. According to some attendees just modelling a strand should be enough because all of them see the same heat difference. Marco says there are some differences between single and multi strand model depending on the applications or what is the calculation done for. Discussions should be taken offline due to time constraints.
Heat transfer to superfluid helium, as implemented in CUDI/QP3 (J. Blomberg Ghini)
QP3 has a single strand model different from CUDI, which has a multi strand model. However, for this application they should have the same results. This analysis is not QP3.
Slide 9 represents a strand, the different strands are the different cylinders, and the upper cylinder is the upper later of strands with an exaggerated twist.
There is not only a heat distribution but also a current distribution so attention should be paid to plots on slide 20.
Helium infinite bath provides instantaneous cooling which is slightly different from the Helium in voids.