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[R. Alemany] [CERN AB/OP] [Engineer In Charge of LHC ] Lectures at NIKHEF (12.12.2008). The Large Hadron Collider Contents: 1. The machine II. The beam III. The interaction regions IV. First LHC beam. III. First LHC beam. Contents: Injection test 1 Injection test II Injection test III
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[R. Alemany] [CERN AB/OP] [Engineer In Charge of LHC] Lectures at NIKHEF (12.12.2008) The Large Hadron ColliderContents:1. The machineII. The beamIII. The interaction regionsIV. First LHC beam
III. First LHC beam Contents: • Injection test 1 • Injection test II • Injection test III • 10th September
IV.1. Injection Test 1 8 to 10.08.2008
IV.I. Injection Test 1 • Achieved • Synchronization SPS – LHC • Beam 1injected 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 o o F D MSCB Orbit Explore a range of particle angles (=kick strength) with one corrector dipole, then go to the next one LHC TDR Chromaticity MSM (sextupole): Nominal main field strength = 4430 T/m2 Inominal = 550 A, 1.9 K, L=45.5 cm, ~83 kg MCBM (dipole): Nominal main field strength = 2.93 T Inominal = 55 A, 1.9 K, L=78.5 cm, ~143 kg
IV.II. Injection Test 2 • 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
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 September • Achieved • Beam 1 injected IP2 • Threaded around the machine in 1h • Trajectory steering gave 2 or 3 turns • Beam 2 injected IP8 • Threaded around the machine in 1h30 • Trajectory steering gave 2 or 3 turns • Q and Q’ trims gave a few hundred turns
ARC BPMs 49 mm aperture IV.IV. 10th of SeptemberBeam 1 – First turn trajectory Betatron oscillation Each point is a BPM (Beam Position Measurement)
ALICE IV.IV. 10th of September Beam 1 on TDI screen – 1st and 2nd turns
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 RF
IV.IV. 10th of September Beam 2: Longitudinal Bunch Profile ~ 200 turns
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 = .279 Qy = .310 BPM pos FFT tune
FBCT IV.IV. 10th of September Beam 2 fast BCT (Beam Current Transformer) ~ 3 109 Intensity
IV.IV. 10th of September Beam dilution on dump block Beam Dump Block (graphite) ~ 8 m concrete shielding
IV.IV. 10th of September Beam 2 captured – mountain range display Turn number Now RF ON Bunch length
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