MKI failure event 17-April-11 Recall from logbook: MKI D (1st one seen by the beam) had a real flashover between the two sets of 36b during the 3rd 72b injection 2 nd 36 b of the 72b train hitting the TDI with between 75 and maybe 90% of the nominal MKI deflection Dumped ~ 88% of expected beam – nearly all p+ of these 36 b impacted TDI/TCLIB Big injection oscillations of 5 mm for 2 nd 36 b Degraded kicker vacuum already before problem. 20/05/2011W. Bartmann, MKI failure event 17-April-111

20/05/2011W. Bartmann, MKI failure event 17-April-112 Loss pattern compared to optics B2 injection Losses in [Gy/s] Optics functions [m]

Loss pattern compared to optics 20/05/ W. Bartmann, MKI failure event 17-April-11 B2 injection Loss peaks in arc Losses in [Gy/s] Optics functions [m]

TDI grazing tests 8-March-11, B2: MKI scan 7 sig oscillation LHCb triggered even with sunglasses /05/2011W. Bartmann, MKI failure event 17-April-114 Loss peaks in arc ~ 5 mm vertical oscillation

MKI failure vs. TDI grazing test losses 20/05/2011W. Bartmann, MKI failure event 17-April-115 Losses in [Gy/s] Scaled by Intensity (36b nominal/1b probe)

MKI failure with 288 bunches? 20/05/2011W. Bartmann, MKI failure event 17-April-116 To be expected: All ‘peak’ BLMs far in saturation Far-ranging and extensive quenches Damage???

Summary Loss pattern agrees with positions of high horizontal dispersion – Probably by scattering from V-osci into H-osci – If momentum lost should be even enhanced Comparing failure losses with TDI grazing tests – Loss pattern exactly the same – Scaling factor 800 (36 nominal over 1 pilot) shows high agreement also for the loss levels These tests can very likely be used to predict – loss levels for higher intensities (288 b grazing) and – Worst case in terms of grazing angle Scaling for MKI failure with 288 bunches – ‘Peak’ BLMs in arc by far saturated – Extensive quenches to be expected – Damage?? To be checked 20/05/2011W. Bartmann, MKI failure event 17-April-117