Cycle at 4 TeV and 7 TeV

LHC Beam Operation WS – Evian December 18th 2012 Matteo Solfaroli

Cycle at 4 TeV and 7 TeV

Many thanks to: the OP team (S.Redaelli and W.Venturini included!), the optic team and the FIDEL

team


outline

Commissioning

Cycle – operation

Cycle @~7 TeV

Conclusions


Commissioning (milestones)

Date Time Milestone Increment (days)

Wed 7.03 PM Powering test completed

Fri 9.03 21:32 BIC loop closed and LBDS armed

Sat 10.03 15:00 Both beams down the TLs

Wed 14.03 15:00 LHC ready for injection 0

23:40 Beam 1 injected

Thu 15.03 01:00 Both beams captured 1

Fri 16.03 22:44 4 TeV 2

Sat 17.03 16:30 Beam 1 at 0.6 m beta* 3

Sun 18.03 11:15 Both beams at 0.6 m beta* 4

Wed 21.03 24:00 Collimators set up @injection 7

Thurs 22.03 20:58 Squeeze with nominal Xing and sep 8

Sun 25.03 15:00 Inj protection setup 11

Tue 27.03 06:40 Pilot through all cycle 13


Commissioning (milestones)

Date Time Milestone Increment (days)

Thurs 29.03 15:00 Collimators aligned @4 Tev 15

Fri 30.03 23:00 Collimators aligned @collisions 16

Sat 31.03 22:00 Collimators aligned @END of squeeze 17

Sun 01.04 16.15 Collisions found in IP5 18

Thurs 05.04 00:38 First Stable Beams @4 TeV (3x3 b)Initial lumi 7.8x1030 cm-2s-1 22

Thurs 05.04 05:39 Stable Beams @4 TeV (47x47) 22


Sat 07.04 02:07 Stable Beams @4 TeV (264x264) 24

Sun 08.04 10:16 Stable Beams @4 TeV (624x624) 25


Fri 13.04 17:52 Stable Beams @4 TeV (1092) 30

Wed 18.04 06:34 Stable Beams @4 TeV (1380) 35


Commissioning (planning)

We are very good at planning!!!J.Wenninger @LBOC on 21st Feb


2012 changes

Ramp at 4 TeVB3 decay compensation at flatop

separated from the rampSqueeze to 0.6m β*Further optimization of optics

distribution in the squeeze

Tilted LHCb collisions


Commissioning (ramp)

First ramp @4TeV after 2 days (beam 2 dumped after a few minutes at flat top due to a glitch in the safe beam flag)

More ramps for tune, orbit and chroma measurements for feed-forward

Most changes around 1 TeV, as in 2011 ORBIT: RT corrections applied (in few steps)

TUNES: RT corrections applied in few steps (FF removed a tune bump between 100 and 200 s)

Snapback correction still not perfect (there are still tune correction spikes), to be analysed during LS1


Commissioning (squeeze)

In 2012, 2 major changes on the squeeze strategy: K function smoothing to reduce orbit spikes of 0.1 mm r.m.s, localized

near the matched points and reproducible from fill to fill The matched point distribution was improved by eliminating some points

above 1.5 m and by allowing different β* values in the IPs

J.Wenninger S. Redaelli

~120 mm


Commissioning (optics)

Optics measurements and corrections @4 TeV Around 20% peak beta-beating at flatop (very similar to 3.5 TeV machine)

Beta beat at 0.6 m reduced from 90/100% to 7% in both beams


40s 100s220s

40s100s 220s

Xing bump IR8: from H to V Xing

H plane

V plane

Separation bumps

Commissioning (collisions)

Before FF

100 mm 100 mm

100 mm100 mm

After FF After FF

Before FF


outline

Commissioning

Cycle – operation

Cycle @~7 TeV

Conclusions


RB.A12RQ6.L1

Cycle @4 TeVCu

rren

t (A)

Time

RAM

PDO

WN

INJE

CTIO

N P

ROBE

INJE

CTIO

N P

HYS

ICS

PREP

ARE

RAM

PRA

MP

FLAT

OP

SQU

EEZE

ADJU

ST

STABLE BEAMS…SETU

P


Analysis method

Homogeneous set of fills (only physics fills with 1092/1380 bunches, 0.6m β* in IP1/5)

‘Rampdown’ & ‘setup’ not taken into account Time calculation for beam modes (tools: logging DB, PM, logbook)

This analysis is not meant to evaluate the efficiency of the machine but rather the performance of operation in the hypothetical case of 100% availability


INJECTIONWHAT WE DO

Inject the pilots and set up the beams Fill the machine

Remove the inj protection COLL Close the injection handshake

Min Mean Mean cut Theoretic

21 min 67 min 52 min n.a.


PREPARE RAMP

WHAT WE DO Set up and switch ON the fbs

Settings incorporation FGC+COLL functions load


140 s 287 s 259 s n.a.


RAMP

WHAT WE DO Ramp

Incorporation (in the shade)Min Mean Mean cut Theoretic

775 s 811 s 791 s 770 s


FLATOP


142 s 409 s 377 s n.a.

WHAT WE DO Tunes check (RQTD/F currents)

Settings incorporation FGC+COLL functions load


SQUEEZE


952 s 1020 s 996 s 925 s

WHAT WE DO Squeeze

Orbit fb OFF


ADJUST


260 s 542 s 513 s 220 s

WHAT WE DO Bring the beams into collisions

(LHCb tilting) IPs optimization (sometimes)


2010 2011 2012

Beam mode Theor Mean Compa

rison* Theor Mean Comparison* Theor Mean Compari

son*

INJPRO n.a.3 h 3 h

n.a. 2205~1.4 h

n.a.52 min ~0.86 h

INJPHYS n.a. n.a. 3034 n.a.

PRERAMP n.a. 504 504 n.a. 270 270 n.a. 259 259

RAMP 1400 1548 148 1020 1088 68 770 791 21

FLATTOP n.a. 468 468 n.a. 130 130 n.a. 377 377

SQUEEZE 1041(3.5 m) 2016 975 548

(1 m) 846 298 925 996 76

ADJUST 108 792 684 60 654 594 220 513 293

RAMPDOWN 4000 2100 2100

TOT 4h29m 2h17 1h41TOT (with

rampdown) 5h36m 2h52m 2h16m

Cycle @4 TeV

Unless differently specified, values are in seconds* length of the BP removed

36 min


outline

Commissioning

Cycle – operation

Cycle @~7 TeV

Conclusions


Cycle @(~)7 TeV

Operational cycle at 6.5 TeV Injection at 11 m Ramp to 6.5 TeV (1250 s) Squeeze to 40/45 cm β* (1473 s –calculated for 55 cm) Collisions (270 s tilting LHCb)

it should be possible to go without the tilting if we have vertical crossing all along

Rampdown (~4200 s)


2010 2011 2012 2015

Beam mode Theor Mean Theor Mean Theor Mean Theor Mean*

INJPRO n.a.3 h

n.a. 2205 n.a.52 min

n.a.~3000

INJPHYS n.a. n.a. 3034 n.a. n.a.

PRERAMP n.a. 504 n.a. 270 n.a. 259 n.a. ~260

RAMP 1400 1548 1020 1088 770 791 1250 1271

FLATTOP n.a. 468 n.a. 130 n.a. 377 n.a. ~375

SQUEEZE 1041 (3.5 m) 2016 548

(1 m) 846 925 996 1473 1544

ADJUST 108 792 56 654 220 513 270 563

RAMPDOWN 4000 2100 2100 4200

TOT 4h29m 2h17m 1h41m 1h57mTOT (with

rampdown) 5h36m 2h52m 2h16m 3h07m

Cycle @(~)7 TeV

Unless differently specified, values are in seconds*calculated by adding replacing the estimated 2015 BP length to the 2012 values

51 min


Cycle @(~)7 TeV

We have many possibility:

some of them would make the cycle shorter: Ramp & Squeeze Beta* levelling Low beta (5/7 m) injection (90 m for highbeta)

Some would have no effect on time Colliding & squeezing ATS vs standard optic Flat beams 25 ns


Cycle @(~)7 TeV

Injection at 5 m (with collision tunes) Ramp & Squeeze to 6.5 TeV / 1 m (1250 s) Collisions without LHCb tilting (~100 s) Beta* levelling from 1 m

MOST AGGRESSIVE SCENARIO:


2010 2011 2012 2015 Most aggressive

Beam mode Theor Mean Theor Mean Theor Mean Theor Mean

INJPRO n.a.3 h

n.a. 2205 n.a.52 min

n.a.~3000 ~3000

INJPHYS n.a. n.a. 3034 n.a. n.a.

PRERAMP n.a. 504 n.a. 270 n.a. 259 n.a. ~250 ~250

RAMP 1400 1548 1020 1088 770 791 1250 1271 1250 1271

FLATTOP n.a. 468 n.a. 130 n.a. 377 n.a. ~375 ~375

SQUEEZE 1041 (3.5 m) 2016 548

(1 m) 846 925 996 1473 1544

ADJUST 108 792 56 654 220 513 270 563 100 393

RAMPDOWN 4000 2100 2100 4200 4200

TOT 4h29m 2h17m 1h41m 1h57m 1h28mTOT (with

rampdown) 5h36m 2h52m 2h16m 3h07m 2h38m

Cycle @(~)7 TeV

Unless differently specified, values are in seconds

29 min


Cycle @(~)7 TeV

Thanks to FIDEL team


Conclusions 2012 commissioning was successful (first SB in 22 days!) – the

machine was very similar to 2011 On OP point of view we are approaching the limit time given by the

settings, but we still can improve (flatop, rampdown,…) Operation in 2012 was efficient and reproducible - despite the

longer settings, the cycle was in average 36 min faster than in 2011 (big gain at injection)

The OP cycle at 6.5 TeV would take ~51 min (37%) more time than at 4 TeV

This can be reduced (up to ~29 min - 15%) In order to properly prepare the 2015 operation we should converge

on a possible scenario by mid 2013 As baseline we propose to start with the same (type of) cycle as 4

TeV (well known!), then have a stop point around mid 2015 to steer the strategy


SPARE SLIDES


Commissioning (450 GeV)

0.47 mm

0.33 mm 0.36 mm

0.39 mm

Orbit of the flat machine was re-corrected, first against 2011 reference, then some absolute corrections were applied:

Orbit was found to be very similar to 2011 ref (0.2 - 0.3 mm rms difference)

Optics measurements and corrections @450 GeV Beta-beating down to 5-10% from 30-40%

Normalized H dispersion beat reduced from 0.04m1/2 to 0.01m1/2

B1 B2


Commissioning (optics)

Optics measurements and corrections @450 GeV Beta-beating down to 5-10% from 30-40%

Normalized H dispersion beat reduced from 0.04m1/2 to 0.01m1/2

B1 B2


SB & turnaround

MEAN = 6 h 34 min

MINIMUM = 2 h 8 min 24 s


Commissioning (squeeze)

Fill 2306 (Nov 2011) - r.m.s wrt first orbit (arc)

50 mm Ex: B1

After feed-forward

With parabolic round-off

The optimization can be further improved during LS1 to get less transient orbit spikes

100 mm

~120 mm

50 mm

Fill 2534


Cycle at 4 TeV

Thanks to FIDEL team


Commissioning (problems)

Glitch on the safe beam flag (noise on BCT2B giving values above the safe beam limit)

Intermittent interlock on BMPSA.4R6.B2 Vacuum gauge outgassing between Q6 and Q5.L5 Issue with generation of the functions for trim

quadrupoles (some points were too close after incorporation)

Problem with the bunch placement on the MKI waveform

FGC: A bug was found in the FCG software that ignored the real-

time correction Tweak on the current reference that was following the

measured current


Rampdown

W.Venturini

RQD.A56RQ4.R2

RQX.R5

4min max

Cycle at 4 TeV and 7 TeV

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