1. News on TMCI in the SPS: Injecting high intensity bunches Benoit for the MD team: T. Bohl, K. Cornelis, H. Damerau, W. Hofle, E. Metral, G. Rumolo, B. Salvant, PSB, PS and SPS OP teams, A. Bullit, Rafaello (SLAC), T. Bogey, J. Albertone, C. Boccard, L. Jensen (BI)

2.  Very preliminary.  Need for discussion and validation!!!!

3. MD summary July 13 th : 2 hours of measurements (recurring MPS problem)  we tried to inject as much intensity (single bunch) as possible in the SPS  results: - “strong” injection losses (TMCI?) - 2.5 10 11 p/b rather stable after injection losses. - intensity after losses pushed to 3.2 10 11 p/b if emittance is blown up with a BTV in transfer line - lowering vertical chromaticity after injection leads to strong losses July 15 th : 3 hours of measurements  we tried to observe the threshold at which the injection losses disappear - injecting 1.5 10 11 p/b lead to injection losses (even when increasing chromaticity)  due to very small transverse emittance? Issues  most limiting issue is the need to disconnect the BPMs (MOPOS) in sextant 1, 2 and 5 for high intensity single bunches. MD is not really parallel any more…  very small transverse emittances  Headtail monitor was not working (it is working now thanks to hard reboot)  issues to read the data from the exponential couplers linked to OASIS  difficulties to match the bunch to the bucket at injection  need for a better control of the bunch parameters before and after injection. Basically blind on the transverse shapes

4. MD Parameters (July 13th) Capture in RF voltage of 1.6 to 1.8 MV injected bunch length =4 ns injected longitudinal emittance ~ 0.38 eVs Beam lost during transverse emittance measurements in the PS… Corrected by Giovanni on 15 th

5. MD Parameters (July 15th) Capture in RF voltage of 1.6 to 1.8 MV injected bunch length =3.6 ns injected longitudinal emittance ~ 0.32 eVs Transverse emittances (at 2.8 10 11 p/b) = 1.3 mm.mrad (normalized 1 sigma)

6. LHCINDIVMDPS Summary of bunch intensity at PS ejection and in the SPS (10 ms after injection and end flat bottom) Tune correction Decreasing  y on flat bottom BTV in TT10 Decreasing  y on flat bottom

7. Intensity in the SPS Without BTV in TT10 With BTV in TT10 Losses at injection ~ 20% to 30% Losses at injection ~ 5% to 10%

8. Transverse emittance on flat bottom (after losses) Without BTV in TT10 With BTV in TT10 HorizontalVertical  H ~3 mm.mrad (norm, 1sig)  V ~4 mm.mrad (norm, 1sig) HorizontalVertical  H ~6 mm.mrad (norm, 1sig)  V ~6 mm.mrad (norm, 1sig)

9. Decreasing chromaticity on flat bottom Decrease vertical chromaticity from 0.28 to 0.12  fast vertical instability with heavy losses

11. Trying to find the stability threshold… Not clear yet… With  y ~ 0.3

12. Very preliminary summary we tried to inject as much intensity (single bunch) as possible in the SPS - “strong” injection losses (TMCI?) - 2.5 10 11 p/b rather stable after injection losses. - intensity after losses pushed to 3.2 10 11 p/b if emittance is blown up with a BTV in transfer line - lowering vertical chromaticity after injection leads to strong losses we tried to observe the threshold at which the injection losses disappear - injecting 1.5 10 11 p/b lead to injection losses (even when increasing chromaticity)  due to very small transverse emittance?

13. Issues for next week Need to disconnect the MOPOS  only possible if the LHC is not running at injection energy.  need BI manpower (disconnection is 20 minutes per sextant). We need transverse bunch shapes measurements (for instability pattern and fast losses) –Headtail monitor should work now –Directional couplers What can we do to increase the transverse emittance before injection on the SPS? Large longitudinal oscillations at injection in the SPS. What about transverse? (we are blind since there is no MOPOS…) Need to control the bunch parameters

15. Headtail simulations Studies still ongoing.

16. Bunch lengthening phi=piBunch shortening phi=0