1. ATS optics Results from MD3, MD4 and MD5
OP team, Collimation team, OMC team,
RF, ADT, LBDS …
M. Albert, Y. Le Borgne, C. Bracco, R. Bruce, F. Carlier, J. Coello De Portugal, A. Garcia, S. Fartoukh, K. Fuchsberger, R. Giachino, D. Mirarchi, E.H. Maclean, L. Malina, A. Mereghetti, D. Nisbet, L. Normann, G. Papotti, T. Persson, M. Pojer, L. Ponce, S. Redaelli, B. Salvachua, P. Skowronski, M. Solfaroli, R. Suykerbuyk, R. Tomas, D. Valuch, A. Wegscheider, J. Wenninger,..
Acknowledgement for all support and good advices:
MD coordination and (r-)MPP teams
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

2. S. Fartoukh for the ATS optics team, LSWG
Contents
Reminders
Highlights from MD3
Highlights from MD4
Highlights from MD5
Outlook
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

3. Reminders: The basic principles of the ATS
A new injection optics:
~ p/2 FODO lattice  new integer tunes, Q62 with new momentum compaction
A squeeze in 2 steps
1) An “almost” standard squeeze, the Pre-squeeze:
 acting on the matching quads of IR1 and IR5,
 with new matching constraints on the left/right IR phase,
 till reaching some limits (sextupoles, matching section e.g. Q6!).
2) A further reduction of b*, the Telescopic Squeeze:
acting on IR2/8 for squeezing IR1 and IR4/6 for IR5,
inducing b-beating bumps in sectors 81/12/45/56 to boost
the sextupole efficiency at constant strength.
b*= 40 cm
b*= 10 cm
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

4. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD3: mainly collimation oriented
ATS pre-squeezed 40 cm (+/- 140 mrad) with two
nominal bunches (and a few probes)
1st Fill
Establishing a new ref orbit and finding collisions
Studying TCT losses with asynchronous dumps 9 s)
2nd Fill
Loss maps (injection & collision)
IR7 Collimator & TCT alignment in collisions
Studying TCT losses with asynchronous dumps 8 s)
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

5. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD3
Collisions
Found at all IP’s and optimized
~ E30 Lumi in ATLAS and CMS with 1 collision/turn
(should have been ~20% more but the bunch length was 1.5 ns)
i.e E34 (naively) scaling for 2200 bunches
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

6. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD3
More details in Daniele’s presentation at the LHC Collimation Working Group #208
Loss maps in collision (before IR7 collimator re-alignment)
TS1
ATS
TS1
ATS
Example: B1H (no XRP and Totem Bump for the ATS case)
Some differences: no loss for the ATS at TCT_IR8 as expected
But the expected loss spikes at Q10.R8.B1 is missing ??
Hierarchy preserved and very similar inefficiency
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

7. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD4 (essentially optics oriented)
ATS telescopic optics down to 10 cm with probes
Overall mechanics successfully tested down to b*= 10 cm
Optics b*=33 cm/21 cm/14 cm/10 cm
State of the art optics correction b*=21 cm
Chromatic properties fully b*=21 cm
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

8. Combined Ramp & Squeeze (19 optics)
ATS highlights from MD4
The starting point at 40 cm (from MD1)
Combined Ramp & Squeeze (19 optics)
ATS pre-squeeze (3m  40 cm) in 470 s
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

9. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD4
At b*=21 cm
15-20% b-beat before correction corrected to 5-10%
It also works for telescopic optics !
Beam 1
Beam 2
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

10. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD4
At b*=21 cm (cont’d)
The off momentum b-beating is as expected:
one sector of sextupoles compensating one triplet
Beam 1
Beam 2
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

11. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD4
At b*=10 cm
~ 20-25% b-beat but too noisy
ADT-AC dipole may be the 10 cm
Beam 1
Beam 2
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

12. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD4
Spurious dispersion within control even at 10 cm ...
Max m in the triplets
.. but for a bmax of 24 km !
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

13. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD5: mainly collimation oriented
ATS telescopic 33 cm (+/- 140 mrad) with a two
nominal bunches (and a few probes)
1st Fill
IT aperture measurement
TCT losses with asynchronous dumps 9 s): FAILED
2nd Fill
Establishing ref. orbit and collisions
TCT alignment beam separated and in collisions
Loss maps (on and off-momentum with beams separated and in collision)
TCT losses with asynchronous dumps 7 s): FAILED
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

14. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD5
IT 33 cm with +/- 140 mrad half crossing angle
(with “not fully-optimized” 21 cm b-beating correction knob)
Aperture [s]
Bottleneck
B1H
9.7
Q3L1/Q3R5
B1V
Q3L1
B2H
12.6
Q2R5
B2V
9.8
Q3R1
Within reach for 2017, tightening a little bit further the collimation hierarchy !!
(assuming X-angle OK for beam-beam: 9.0 b*=33 cm, ge=2.2 mm & 6.5TeV)
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

15. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD5
Collision found and optimized in all 4 IPs with 6E30 and 8E30 in ATLAS and CMS
(the lumi published by Alice was not correct)
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

16. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD5
Then a series of loss maps with separated and colliding beams, on and off momentum
One example out of ~20 : B1V with delta_f=+30Hz
.. No anomaly detected on-line. Off-line analysis should follow
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

17. S. Fartoukh for the ATS optics team, LSWG
Outlook
A very prolific year for the ATS
Some ‘’details” are still missing, e.g.
Full demonstration of TCT losses with ass. dumps
Optics re-optimization (and test) for the forward physics experiments (AFP, CT-PPS)
But roughly speaking, the main pieces are there
to take a decision for ATS implementation in the LHC, and
continue to push b* … in a “telescopic manner”
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

18. S. Fartoukh for the ATS optics team, LSWG
Reserve
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

19. ATS highlights from MD3 TCT & collimator alignment:
More details in Alessio’s presentation at the LHC Collimation Working Group #208
TCT & collimator alignment:
IR7 collimator centres (beam1):
ATS (collision) vs commissioning (FT)
TCT centres (beam 1):
ATS (collision) vs commissioning
 Some differences, but the optics are different !!
All together looks more than reasonable !
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

20. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD3
More details in Daniele’s presentation at the LHC Collimation Working Group #208
Loss maps at injection: IR3/7 collimator pre-set to TS1 (nominal) settings
TS1
ATS
Inefficiency figures (injection protection out in this case)
Similar as well
Could only improve with collimator alignment at injection
Example: B1H with injection protection in:
 similar features between nominal and ATS optics
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

21. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD3
More details in Roderick’s presentation at the LHC Collimation Working Group #208
TCT losses during asynchronous dump tests
First test with 9 sigma’s but beam2 was in the wrong bucket ..
kicking beam2 too early (at the same moment as beam1), a smaller fraction of beam2 actually escapes from the TCDQ, but this fraction is quite off-momentum (dp<0)
Second test with tighter 8 sigma’s, with correct filling scheme this time, therefore more beam kicked in the AG but less/no losses at TCT5 and TCT8 !
Qualitatively: the key issue seems to be solved, but not fully conclusive (for beam2).
 Was plaaned to be redone in MD5
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

22. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD4
At b*=33 cm
15-20% b-beat (left uncorrected)
Beam 1
Beam 2
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

23. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD4
At b*=21 cm
b* off by 10-20% before correction (from K- modulation)
bx [cm]
by [cm]
Wx [cm]
Wy [cm]
IP1-b1
18.4 ± 0.2
21.4 ± 0.1
0.3 ± 1.6
-1.3 ± 0.9
IP1-b2
21.3 ± 0.6
21.3 ± 0.3
3.9 ± 1.4
3.8 ± 0.7
IP5-b1
22.7 ± 1.8
26.2 ±0.9
8.6 ± 1.8
8.8 ± 1.1
IP5-b2
21.9 ± 0.9
21.4± 0.2
-5.9 ±1.4
2.0 ±1.0
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

24. S. Fartoukh for the ATS optics team, LSWG
ATS highlights from MD4
At b*=14 cm
Back to ~ 15-20% b-beat (left uncorrected)
 .. But noisy (not enough aperture for the AC-dipole amplitude)
Beam 1
Beam 2
9/21/2016
S. Fartoukh for the ATS optics team, LSWG

25. ATS highlights from MD4
The telescopic part is played at (nearly) constant sextupole settings
Pre-squeeze(3m  40 cm):
Only 25% of the circuits are moving
(at quadruple dI/dt)
Combined ramp & squeeze (3m) of
the 32 sextupole families
Tele-squeeze (40 cm  10 cm)
at constant sextupole
9/21/2016
S. Fartoukh for the ATS optics team, LSWG