1. Fast losses at collimators during 16L2 dumps
Arek Gorzawski & Rudiger Schmidt
With a lots of inputs from:
S. Redaelli, N. Fuster Martinez, H. Garcia Morales,
D. Wollman, C. Xu and C. Zamantzas
BLM WG 10/10/2017

2. Fast losses at collimators during 16L2 dumps
Outline
Setup of the dBLMs in IR7
Overview and observations for four loss cases
Conclusions
Fast losses at collimators during 16L2 dumps

3. Fast losses at collimators during 16L2 dumps
System layout
dBLMs in IR7 are installed at four locations:
At the primary collimators (TCP),
9m downstream for B1, 8m downstream for B2
At the crystal collimators,
120m downstream for B1, 49m downstream for B2
dBLMs in 16L2 are installed at two locations,
Beam1 and Beam2
Triggering of the continuous (waveform) data acquisition:
At the primary collimators and 16L2, via PM event (dump trigger)
100e6 of points with 1.6ns (dead time ~1.5min)
Fast losses at collimators during 16L2 dumps

4. Fast losses at collimators during 16L2 dumps
Case studies
Fill 6094, 6.5TeV
Fill 6101, 1.1TeV
Fill 6173, 6.5 TeV, 8b4e
Fill 6256, 6.5 TeV, 8b4e, dBLM in 16L2
Fast losses at collimators during 16L2 dumps

5. Fast losses at collimators during 16L2 dumps
17 Aug TeV Fill 6094
Fast losses at collimators during 16L2 dumps

6. Fast losses at collimators during 16L2 dumps
Fill 6094, 17/08
6.5 TeV,
17-AUG
Fast losses at collimators during 16L2 dumps

7. Fast losses at collimators during 16L2 dumps
Fill 6094, 17/08
6.5 TeV,
Fast losses at collimators during 16L2 dumps

8. Fast losses at collimators during 16L2 dumps
Fill 6094, 17/08
6.5 TeV,
Fast losses at collimators during 16L2 dumps

9. Fast losses at collimators during 16L2 dumps
dBLM overview
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6.5 TeV,
Fast losses at collimators during 16L2 dumps

10. Fast losses at collimators during 16L2 dumps
Integrated Losses
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6.5 TeV,
Rising slope after longer (~AG) gap
Fast losses at collimators during 16L2 dumps

11. Fast losses at collimators during 16L2 dumps
19 Aug TeV Fill 6101
Fast losses at collimators during 16L2 dumps

12. Fast losses at collimators during 16L2 dumps
Fill 6101, 19/08
1.1 TeV,
Losses from UFO Type 2 measured by BLM in 16L2
Fast losses at collimators during 16L2 dumps

13. Fast losses at collimators during 16L2 dumps
Fill 6101, 19/08
1.1 TeV,
Protons become unstable
Losses from UFO Type 2 measured by BLM in 16L2
Fast losses at collimators during 16L2 dumps

14. Fast losses at collimators during 16L2 dumps
Fill 6101, 19/08
1.1 TeV,
Fast losses at collimators during 16L2 dumps

15. Fast losses at collimators during 16L2 dumps
dBLM Loss overview
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1.1 TeV,
10 ms
Protons become unstable
2.4 ms
Fast losses at collimators during 16L2 dumps

16. Fast losses at collimators during 16L2 dumps
Integrated losses
Fill 6101, 19/08
1.1 TeV,
Rising slope after longer (~AG) gap
15 us
Full beam, bunch by bunch
Fast losses at collimators during 16L2 dumps

17. Fast losses at collimators during 16L2 dumps
Fill 6101, 19/08
1.1 TeV,
15 us
48b
First few bunches of each of the 48 batch has higher losses
Fast losses at collimators during 16L2 dumps

18. Fast losses at collimators during 16L2 dumps
8.9 ms
10 ms
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1.1 TeV,
BPM PM DATA
Oscillations in h-plane
Increased oscillation (tune freq) in the concerned plane (Horizontal, up part) during the instability time (10ms).
Fast losses at collimators during 16L2 dumps

19. Fast losses at collimators during 16L2 dumps
6 Sep TeV Fill b4b
Fast losses at collimators during 16L2 dumps

20. Fast losses at collimators during 16L2 dumps
Fill 6173, 6/09
6.5 TeV,
8b4e scheme
Fast losses at collimators during 16L2 dumps

21. Fast losses at collimators during 16L2 dumps
Fill 6173, 6/09
6.5 TeV,
8b4e scheme
Fast losses at collimators during 16L2 dumps

22. Fast losses at collimators during 16L2 dumps
Fill 6173, 6/09
6.5 TeV,
8b4e scheme
Fast losses at collimators during 16L2 dumps

23. Fast losses at collimators during 16L2 dumps
Fill 6173, 6/09
6.5 TeV,
8b4e scheme
3 ms
Fast losses at collimators during 16L2 dumps

24. Fast losses at collimators during 16L2 dumps
dBLMs Overview
Fill 6173, 6/09
6.5 TeV,
8b4e scheme
3 ms
100 us
Fast losses at collimators during 16L2 dumps

25. Fast losses at collimators during 16L2 dumps
dBLMs Overview (2)
Fill 6173, 6/09
6.5 TeV,
8b4e scheme
One turn
100 us
Fast losses at collimators during 16L2 dumps

26. Fast losses at collimators during 16L2 dumps
Integrated losses
Fill 6173, 6/09
6.5 TeV,
8b4e scheme
Rising slope after AG + small after 30b LHC INJ gaps
Full beam, bunch by bunch
Fast losses at collimators during 16L2 dumps

27. Fast losses at collimators during 16L2 dumps
Integrated loss (2)
Fill 6173, 6/09
6.5 TeV,
8b4e scheme
Normalized to the sqrt(emittance)
Fast losses at collimators during 16L2 dumps

28. Fast losses at collimators during 16L2 dumps
30 Sep TeV Fill b4e
Fast losses at collimators during 16L2 dumps

29. Fast losses at collimators during 16L2 dumps
Fill 6256, 30/90
6.5 TeV,
8b4e scheme
Fast losses at collimators during 16L2 dumps

30. Fast losses at collimators during 16L2 dumps
Fill 6256, 30/90
6.5 TeV,
8b4e scheme
Fast losses at collimators during 16L2 dumps

31. Fast losses at collimators during 16L2 dumps
Fill 6256, 30/90
6.5 TeV,
8b4e scheme
Fast losses at collimators during 16L2 dumps

32. Fast losses at collimators during 16L2 dumps
dBLMs Overview
Fill 6256, 30/90
6.5 TeV,
8b4e scheme
Vertical scale to be verified with BE/BI!
Different connection configuration between IR7 and 16L2
Fast losses at collimators during 16L2 dumps

33. Fast losses at collimators during 16L2 dumps
Integrated losses
Fill 6256, 30/90
6.5 TeV,
8b4e scheme
TCP
Rising slope after AG + some 30b LHC INJ gaps
16L2
Fast losses at collimators during 16L2 dumps

34. Fast losses at collimators during 16L2 dumps
Conclusions
Saturation effect in IR7 discards the data after certain threshold but the beginning of the loss reveal some observations:
Observed cleaning effect (when gap > ~300bunches)
Multiple loss peaks
Correlation between TCP and the 16L2 losses require still some action.
Amplification and attenuation difference to be clarified – to get the loss ratio
Loss pattern different – no rising slope!
Fast losses at collimators during 16L2 dumps