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Highlights from the Large Hadron Collider

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Presentation on theme: "Highlights from the Large Hadron Collider"— Presentation transcript:

1 Highlights from the Large Hadron Collider
Physics at the Terascale The LHC: brief overview and status The LHC experiments: brief overview and status Jos Engelen CERN

2 Standard Model and Beyond(?)
x8 gauge H The Higgs sector – ‘the unknown’ The Supersymmetric world? One supersymmetric partner for each ‘standard’ particle – the Higgs sector becomes slightly more complicated: 5 supersymmetric Higgs bosons

3 The ‘Standard Model’ is a wonderful model for describing the fundamental particles and fields and their interactions, it provides a quantitative description of all experimental results so far, but: the model invokes a mechanism for dealing with mass: it is an empirical fact that certain field particles (W, Z bosons) carry mass, incorporating this in the theory is highly non-trivial – it requires the introduction of a new field (Higgs field) and corresponding particle (‘the Higgs’): this particle has never been found by an experiment  it will be at the LHC the model would ‘go wrong’ at high energy without the Higgs particle (or other ‘new physics’) ‘unification of forces’ at very high energy could be revealed by a new trend setting in at LHC energy: ‘supersymmetry’

4 ‘The Terascale’ Based on ‘extrapolations’ from our present
understanding and on quite general theoretical insights we expect the ‘new physics’ to manifest itself at an energy around or below 1 Tera-electronVolt = electronVolt, i.e. at the Terascale accessible at the LHC for the first time (and only at the LHC for years to come!)

5 Quark Gluon Plasma The LHC will also provide Pb Pb collisions at
TeV allowing unique contributions to the study of a quark gluon plasma

6 Accelerator and Experiments
Underground circular tunnel 27 km circum- ference; 100 m underground 4 caverns for experiments () x CMS BD x x RF * x LHCb ALICE ATLAS

7 Accelerator Collisions of 7,000 GeV on 7,000 GeV protons
(for reference: proton mass = 1 GeV) Luminosity 1034 cm-2s-1 (collision rate normalized to cross section) Innovations: ‘2 in 1’ superconducting 8.3 T dipoles (operating temperature 1.9K) focusing s.c. quadrupoles Challenges: collimation (350 MJ stored energy per beam, can melt 800 kg of copper) and furthermore the mere size of the system, e.g. more than 33,000 tonnes of ‘cold mass’, 27 km of cryogenic distribution line, etc.

8 Accelerator complex Biggest ring = 27 km circumference (1959)

9 R&D pre- production industrial 1232 plus spares

10 Van streng tot kabel NiTi filamenten, 7 (geproduceerd via extrusie)

11 In the tunnel Magnet inter- connect Quality control and
Quality assurance

12 Magnet Interconnect 6 superconducting bus bars 13 kA for B, QD, QF quadrupole 20 superconducting bus bars 600 A for corrector magnets (minimise dipole field harmonics) To be connected: Beam tubes Pipes for helium Cryostat Thermal shields Vacuum vessel Superconducting cables 13 kA Protection diode 42 sc bus bars 600 A for corrector magnets (chromaticity, tune, etc….) + 12 sc bus bars for 6 kA (special quadrupoles)

13 In the tunnel Jumper connecting cryogenic distribution line and
magnets (once every ~100 m) (early photo, tunnel practically empty)

14 In the tunnel Beam delivery towards interaction point
Current distribution using High Temperature Supercondutor current leads

15 LHC Status Installation complete Hardware commissioning
cryogenic distribution line injection lines sc dipoles and quadrupoles; interconnect inner triplets preparing beams for collision RF stations (sc) for acceleration 450 GeV  7000 GeV beam dumps collimation beam instrumentation Hardware commissioning cool-down complete pressure tests powering tests Commissioning with beam circulating beams Colliding beams Restart Spring 2009

16 Start of Operations The Large Hadron Collider project saw a wonderful
start of operations on September 10, 2008: LINAC, Booster, PS, SPS were accelerating beam to 450 GeV for injection into the LHC The injection lines (TI8, TI2) transported the beam to the LHC The injection kickers sent the beam(s) into the LHC Circulating beams, in both apertures, were established for the first time, with the whole world looking over our shoulders, in a matter of hours The LHC experiments were ready and operational as planned and recorded beam related (timing!) data immediately The Worldwide LHC Computing Grid was up and running

17 Start of Operations During the days following September 10 some
unreliable (‘old’) elements of the electrical infrastructure (transformers) had to be repaired/replaced, but the preparations for collisions continued, one other very important milestone was passed easily, not because it was easy but because of excellent preparations: the RF system captured the beam the road to first beam-beam collisions was now fully open

18 Final Hardware Commissioning
The magnets in Sector (‘Octant’) 34 had not been commissioned yet to full current for operation at 5 TeV (i.e. commissioning to 5.5 TeV) The 7 other octants of the LHC had been commissioned to 5 TeV (and well above) without problems On September 19 (around 11:18) an incident occurred, leading to a large Helium leak in sector 34 – cold Helium escaped into the tunnel, the insulation vacuum was broken (up to vacuum barriers), the beam vacuum was broken (up to sector valves)

19 Recovery Sector 34 It is now clear that recovery of Sector 34 will take until (‘into’) the planned (and obligatory) Winter shutdown – LHC operations will restart Spring 2009. A precise planning is being worked out. The nature of the incident has been understood – it is due to an electrical fault (resistive splice in interconnect) The loss of the insulation vacuum lead to some collateral damage – the logistics of the repair program are being worked out. Very importantly: diagnostic tools are being designed to avoid such problems in the future

20 Schedule of Experiments
The experiments will now go into ‘long shutdown’ mode, to be ready again in early Spring 2009: a more precise date will be agreed with them as soon as this is possible Most experiments have identified a useful and/or necessary program of work of 4 – 5 months: repairs, refurbishments, improvements, additional installation work Everybody involved in the LHC project is as motivated as ever (or more motivated than ever) to overcome this temporary setback! Everybody has reacted professionally and with determination.

21 The successful start-up
The behavior of the beams was excellent and understood

22 Cross-section of LHC cryodipole

23 Cooldown Status

24 Cooldown Status

25 RF cavities

26 The RF cavities and transverse dampers
Preparation for Beam RF synchronization in place – clocks and timing now going from SR4 to all users. Recent successful dry run tests with all users and OP group, including basic software. Procedures for beam commissioning well defined. Longitudinal diagnostics in good shape to study and commission first beams…. Fibre-optics signal distribution from RF in SR4 to Experiments, BT & BI equipment and to CCC. 40 MHz bunch clocks, revolution frequencies, 40 MHz 7TeV reference. Injection & dump kicker pulses Courtesy Edmond Ciapala

27 Synchronisation Courtesy Roger Bailey

28 Injection Region

29 08 08 08 Friday 15:20 Beam on to TI2 TED MSI etc pulsing
Cycle LHC Sector 23 OP Beam down TI2 first shot Friday 19:00 TI2 TED out, beam to TDI, kickers off Give Alice 20 minute warning before taking TED out INJ Beam on TDI after correction end TI2 Friday 21:00 Kickers on, time in, position checks Resolve timing issues Interesting collaboration between timing and RF Friday 21:40 TDI out - threading - momentum matching - beam to IR3 Jorg & team Beam to IR3 first shot. Tweak SPS. Courtesy Roger Bailey

30 First Trajectory

31 Kick response compared with theoretical optics

32 Dispersion 2-3 The trajectory of the off-momentum (1 per mil) beam. On the far left is the end of TI2 where there are no measurements. It goes through LSS2 and Alice with practically zero dispersion. In the arc there is a slight mismatch which is of no consequence and LSS3 it perfectly maps the large dispersion bump from positive to negative that is designed to stop uncaptured particles (which will be lost as the field rises since they are not accelerated) on the collimators. The vertical dispersion (bottom) is zero as it should be.


34 Beam on turns 1 and 2 Courtesy R. Bailey

35 Few 100 turns Courtesy R. Bailey

36 Dump dilution sweep

37 No RF, debunching in ~ 25*10 turns, i.e. roughly 25 mS
Courtesy E. Ciapala

38 Capture with optimum injection phasing, correct reference
Courtesy E. Ciapala

39 The LHC experiments have seen first ‘man made’ beam


41 Injection tests SPD hits versus bunch intensity (beam through ALICE)
FMD event display (1 bunch through ALICE, > hits) FMD hits versus SPD hits (beam through ALICE) SPD/SSD, Sunday, 15.6 Dump on TED

42 Luminosity monitor (V0)
Double turn, beam 1 back at point 2 ! Single turn

43 Auto-correlation for SPD trigger, with multi-turn correlations
Beam pick-up T0 SPD V0 Auto-correlation for SPD trigger, with multi-turn correlations (3564 bunch crossings) Trigger timing (before alignment) versus bunch number single shot for SPD, V0, beam-pickup BPTX, T0 triggers

44 First interactions 12th September
Circulating beam 2 stray particle causing an interaction in the ITS ITS tracks on

45 Krypton Gain Calibration
TPC Particle Identification Krypton Gain Calibration Momentum Resolution 24/10/ rd RRB J. Schukraft

46 LHCb Spectrometer OT Muon System Magnet RICH1 VELO RICH2 TT
Calo. System

47 LHCb sees tracks from the LHC injection tests
SPD (provided trigger) TED events LHCb sees tracks from the LHC injection tests Muon chambers VELO (Run 30933, Event 14) Silicon tracker

48 Beam1 induced OT tracks originating close to the beam pipe

49 ATLAS 45 m 24 m 7000 Tons Status of ATLAS ATLAS superimposed to
the 5 floors of building 40 24 m 7000 Tons Status of ATLAS LHCC, 24-Sep-2008, PJ

50 Very first beam-splash event seen in ATLAS (as seen online in the
ATLAS Control Room) on 10-Sep-2008 at 10:19

51 A busy beam-halo event with tracks bent in
the Toroids from the start-up day (offline)

52 TRT in the run 22-25 August (a cosmic shower)
Barrel-tracks Shower

53 The CMS Detector

54 Calorimeters: Collimators Closed
Energy in ECAL (EE-, EB, EE+) ECAL: Splash events provided a source for overall internal synchronization. Crystals were time aligned to within 1ns !

55 WLCG Since CCRC08 in May the experiments have continued to run work at very high levels on the grid infrastructure and continued to keep data transfers running at a level consistent with that expected in data taking.   WLCG has seen cosmic data and also the first “events” from LHCb during the second injection test, and data sets from all 4 experiments on Wednesday 9/10.   The transfer rates all summer have been in excess of 1 GB/s more or less continuously with higher peaks (the data taking rate is 650 MB/s, twice that for safety).  This, and the continuous high rate of job submission has been driven by experiment functional testing, and more and more detector-driven stress tests. 

56 Conclusions The LHC experiments have followed the remarkable performance of the LHC machine with an equally remarkable performance: the detectors work with real beam!

57 Conclusions Recovery of Sector 34 has the highest priority Start-up in Spring 2009 is now the target And then: a two phased approach to SLHC

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