MKI failure event 17-April-11

1. 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 • 2nd36 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 2nd 36 b • Degraded kicker vacuum already before problem. W. Bartmann, MKI failure event 17-April-11

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

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

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

5. MKI failure vs. TDI grazing test losses Scaled by Intensity (36b nominal/1b probe) Losses in [Gy/s] W. Bartmann, MKI failure event 17-April-11

6. MKI failure with 288 bunches? • To be expected: • All ‘peak’ BLMs far in saturation • Far-ranging and extensive quenches • Damage??? W. Bartmann, MKI failure event 17-April-11

7. 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 W. Bartmann, MKI failure event 17-April-11