The following results are part of updated studies on material robustness for fast beam failures in the LHC.
One of the most critical failure involves the beam extraction line: if one or all dump kickers (MKDs) fails firing, some of the miskicked bunches may be sent directly into sensitive equipments, like TCTs which are located upstream of the experiments to protect the triplet magnets.
For detailed information about the simulation setup, see ColUSM #45 (E. Quaranta's talk).
Several cases were simulated with different machine optics and collimator settings.
| NOMINAL 7 TeV optics, Beam 1 | NOMINAL 7 TeV optics, Beam 2 |
| 2015 ATS optics, Beam 2 | HL-LHC optics, Beam 2 |
These data were provided for FLUKA energy deposition simulations: the energy maps are now available (see E. Skordis' results) and will be used as input for dynamic simualtions (AUTODYN) of shockwave formation and propagation as consequence of the beam impact.
The main goal of this study is to simulate the shower of secondary particles generating in the TCTs (after the primary beam impact) which may be potentially dangerous for the triplet in front of the experiments.
To have a pessimistic scenario in terms of beam size at the TCT, the considered case is the 2015 ATS optics with beta*=55cm, assuming the the same geometric emittance as at 7 TeV and a 2.5 um normalized emittance, as for HL.
The scenario is thus impacts on the horizontal TCT in IR5 in B2 (most critical case for ATS optics).
| twiss file | contains the optics used for the simulation (beta*=55 cm, ATS 2015, Beam 2). |
| collgaps.dat | contains all the informations about the collimators (type, material, setting, etc). Assumption: 6.5 TeV and 3.5 um emittance. |
The data below contain the coordinates x [mm], x' [mrad], y [mm], y' [mrad] of particles within a bunch impacting the face of TCT. They will be used as input for FLUKA studies.
Two cases are considered:
| Case 1 | the center of the impacting bunch is exactly at the TCT jaw: half of the particles are hitting, the other half escaping and should not hit the triplet. |
| Case 2 | the bunch impacts deeply enough such that 98% of the particles are outside the TCT aperture. |
The coordinates of particles not hitting neither the TCT jaw nor the triplet can be found here for the two cases listed above:
Case 1 Case 2
