The Large Hadron ColliderContents:

1. The machineII. The beam

III. The interaction regionsIV. First LHC beam

[R. Alemany][CERN AB/OP]

[Engineer In Charge of LHC]Lectures at NIKHEF (12.12.2008)

III. First LHC beamContents:I. Injection test 1II. Injection test IIIII.Injection test IIIIV.10th September

IV.1. Injection Test 1

8 to 10.08.2008

IV.I. Injection Test 1 Achieved

Synchronization SPS – LHC Beam 1 injected IP2 Through to collimators in IP3 first shot Trajectory correction Kick-response measurements Off-energy measurements (dispersion) Explored the aperture First beam induced quench

Discovered Aperture restriction in the injection line

Traced to misaligned vacuum pump Optics problem IP3

Polarity convention QTL

IV.II. Injection Test 2

22-24.08.2008

IV.II. Injection Test 2 Achieved

Beam 2 injected IP8 Through to collimators in IP7 first shot Trajectory correction Kick-response measurements Off-energy measurements (dispersion) Explored the aperture Beam 1 injected IP2 Through to collimators in IP3 Aperture in injection region OK Polarity correction confirmed Interleaved injection

Discovered Optics problem at the end of the TI8 line

I.I. Basic layout of the machine: quadrupole corrector magnets

LHC TDR

Fo

Do

MSCB

MCBM (dipole):Nominal main field strength = 2.93 TInominal = 55 A, 1.9 K, L=78.5 cm, ~143 kg

MSM (sextupole):Nominal main field strength = 4430 T/m2

Inominal = 550 A, 1.9 K, L=45.5 cm, ~83 kg

ChromaticityOrbit

Explore a range of particle angles (=kick strength) with one corrector dipole, then go to the next one

IV.II. Injection Test 2Beam 1 injected IP2Through to collimators in IP3Aperture in injection region OKPolarity correction confirmedInterleaved injection

DiscoveredOptics problem at the end of the

TI8 line

IV.III. Injection Test 3

5 – 7.09.2008

IV.III. Injection Test 3 Achieved

Beam 2 injected IP8 Threaded to dump in IP6 Steered then inject and dump Beam 1 injected IP2 Threaded through to coll in IP5

Discovered Optics problem in IP7

Polarity convention on Q6 Optics problem in IP4

Polarity convention

IV.IV. 10th of September

10.09.2008

IV.IV. 10th of SeptemberAchieved

Beam 1 injected IP2Threaded around the machine in 1hTrajectory steering gave 2 or 3 turns

Beam 2 injected IP8Threaded around the machine in 1h30Trajectory steering gave 2 or 3 turnsQ and Q’ trims gave a few hundred turns

IV.IV. 10th of SeptemberBeam 1 – First turn

trajectory

Each point is a BPM (Beam Position Measurement)

49 mm apertureARC BPMs

Betatron oscillation

IV.IV. 10th of September Beam 1 on TDI screen – 1st and 2nd

turns

ALIC

E

IV.IV. 10th of September Beam 2 – First turn

trajectory

Horizontal position (mm)

Vertical position (mm)

IV.IV. 10th of September Beam 2 – first turn dispersion

measurement

ppsDx x

)(

RF

IV.IV. 10th of September Beam 2: Longitudinal Bunch Profile

~ 200 turns

IV.IV. 10th of September Beam 2 closed orbit

IV.IV. 10th of September Beam 2 beta measurement

QF

QD

IV.IV. 10th of September Beam 2 beta measurement

Reminder from BH lectures

IV.IV. 10th of September Beam 2 integer tunes

Qx = 64

Qy = 59

IV.IV. 10th of September Beam 2 tunes

Qx = .279Qy = .310

BPM pos FFT tune

IV.IV. 10th of September Beam 2 fast BCT (Beam Current Transformer)

FBCT

Inte

nsity

~ 3 109

IV.IV. 10th of September Beam dilution on dump block

~ 8 m

concrete shielding

Beam Dump Block (graphite)

IV.IV. 10th of September Beam 2 captured – mountain range

display

Now RF ON

Bunch length

Turn

num

ber

IV.IV. 10th of September Fast start 10, 11 and 12

All done in 3 days Made possible by

Meticulous preparation Magnetic model data Sophisticated settings generation Dry runs Injection tests

Powerful control system (LSA) Powerful instrumentation working very quickly Logging a multitude of parameters

Allowed early look at several machine parameters systematic check of orbit system

IV.IV. 10th of September