Transcript Slide 1
LHC: Status and Plans Partikeldagarna, Göteborg 21 September 2007 Lyn Evans Schematic layout of the LHC L. Evans – EDMS document 867980 2 Main parameters of LHC (p-p) • • • • • • • • • • • • • • • • • Circumference Beam energy at collision Beam energy at injection Dipole field at 7 TeV Luminosity Beam current Protons per bunch Number of bunches Nominal bunch spacing Normalized emittance Total crossing angle Energy loss per turn Critical synchrotron energy Radiated power per beam Stored energy per beam Stored energy in magnets Operating temperature 26.7 7 0.45 8.33 1034 0.56 1.1x1011 2808 24.95 3.75 300 6.7 44.1 3.8 350 11 1.9 L. Evans – EDMS document 867980 km TeV TeV T cm-2.s-1 A ns mm mrad keV eV kW MJ GJ K 3 Descent of the last magnet, 26 April 2007 30’000 km underground at 2 km/h! L. Evans – EDMS document 867980 4 Cross-section of LHC cryodipole L. Evans – EDMS document 867980 5 Dipole magnetic flux plot L. Evans – EDMS document 867980 6 Critical current density of technical superconductors 3000 NbTi @ 4.5 K NbTi @ 1.8 K Nb3Sn @ 4.5 K LHC Spec Cable 1 LHC Spec Cable 2 2500 Jc [A/mm2] 2000 1500 1000 500 0 6 7 8 9 10 11 12 B [T] L. Evans – EDMS document 867980 7 Bending strength of dipoles Cold mass Firm 1 Firm 2 Firm 3 40 upper limit for single magnet (3 sigma) 10.13 20 10.11 0 10.09 -20 Units Int transf func (Tm/kA) 10.15 lower limit for single magnet (3 sigma) -40 10.07 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 Magnet progressive number L. Evans – EDMS document 867980 AT-MAS 8 Field errors in dipole production: b3 5 upper limit for systematic 0 lower limit for systematic Cross-section 2 b3 integral (units) Cold mass Firm 1 Firm 2 Firm 3 10 -5 Cross-section 3 -10 0 100 200 300 400 500 600 700 800 900 Magnet progressive number L. Evans – EDMS document 867980 1000 1100 1200 AT-MAS & MTM 9 Field orientation in dipoles Twist integral of main field angle 0.3 Firm 1 Firm 2 Firm 3 0.2 Cold mass all positions (mrad) upper limit for single magnet 0.1 0.0 -0.1 -0.2 lower limit for single magnet -0.3 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 Collared coil progressive number AT-MAS L. Evans – EDMS document 867980 10 Systematic field errors in dipoles 2 1 9 b3 b5 b7 0 0 -1 -2 -2 -3 -4 a2 a3 a4 a5 -4 -6 AT-MAS -5 b2 aperture 1 0 b4 both apertures 3 2 Measured b4 aperture 2 4 4 b4 aperture 1 Measured Targets Cold mass systematic vs targets 5 b2 both apertures Targets b2 aperture 2 6 AT-MAS L. Evans – EDMS document 867980 11 Random field errors in dipoles Cold mass - random (r.m.s) vs targets 2.0 units/10 units 1.5 Type R Type L Targets 1.0 0.5 0.0 1 L B BdL b2 a2 b3 a3 b4 a4 b5 a5 b7 AT-MAS L. Evans – EDMS document 867980 12 Dipole-dipole interconnect L. Evans – EDMS document 867980 13 Dipole-dipole interconnect: electrical splices L. Evans – EDMS document 867980 14 DFBAO in Sector 7-8 L. Evans – EDMS document 867980 15 Magnet interconnections L. Evans – EDMS document 867980 16 Specific heat of LHe and Cu 100 Specific heat [J/g.K] 10 1 0,1 LHe Cu 0,01 0,001 0,0001 0,00001 0 1 2 3 Temperature [K] L. Evans – EDMS document 867980 4 5 17 Equivalent thermal conductivity of He II 2000 KT,q q 2.4 YT dT q dX Y(T) 1500 Y(T) ± 5% Helium II 3.4 q in W / cm2 1000 T in K X in cm 500 T OFHC copper 0 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 T [K] L. Evans – EDMS document 867980 18 Phase diagram of Helium 10000 SOLID P [kPa] 1000 HeII 100 l line CRITICAL POINT HeI Pressurized He II GAS 10 Saturated He II 1 1 10 T [K] L. Evans – EDMS document 867980 19 Linear heat exchanger L. Evans – EDMS document 867980 20 Sector 7-8 cooldown L. Evans – EDMS document 867980 21 Courtesy F.Bordry L. Evans – EDMS document 867980 22 Tracking between the three main circuits of sector 78 Current [A] 7000 Quadrupole Circuits (RQF, RQD) 6000 5000 2ppm 4000 3000 2000 Dipole Circuit (RB) 1000 0 19:00 19:30 20:00 20:30 L. Evans – EDMS document 867980 21:00 21:30 Courtesy F.Bordry 23 Arc plug-in module at warm temperature L. Evans – EDMS document 867980 24 Arc plug-in module at working temperature L. Evans – EDMS document 867980 25 Module with installation compression tooling L. Evans – EDMS document 867980 26 RF bellows in the 1700 interconnections L. Evans – EDMS document 867980 27 Transmitter prototype L. Evans – EDMS document 867980 28 Transmitter prototype L. Evans – EDMS document 867980 29 The electron cloud effect L. Evans – EDMS document 867980 30 Simulated heat load as a function of SEY L. Evans – EDMS document 867980 31 Beam momentum & stored energy of colliders Energy stored in the accelerator beam, as a function of beam momentum. At less than 1% of nominal intensity LHC enters new territory. Stored energy density as a function of beam momentum. Transverse energy density is a measure of damage potential and is proportional to luminosity. L. Evans – EDMS document 867980 32 Transverse emittances from 3 different bunch intensities (72 bunches) L. Evans – EDMS document 867980 33 Conclusions The LHC design has integrated more than 30 years of accumulated knowledge of the behaviour of beams in hadron storage rings. The various correction systems will be adequate to stabilise the beams up to and beyond design luminosity. The one new effect is the electron cloud which may be the limiting factor in pushing the luminosity well above the design value. This will depend on the efficiency of scrubbing that can be achieved. The rate of increase in luminosity will be governed by our ability to protect the machine and detectors and of the detectors to cope with it. L. Evans – EDMS document 867980 34 CERN accelerator complex L. Evans – EDMS document 867980 35 Upgrade components Proton flux / Beam power 50 MeV 160 MeV Output energy 1.4 GeV 4 GeV 26 GeV 50 GeV 450 GeV 1 TeV 7 TeV ~ 14 TeV Linac2 Linac4 PSB LPSPL PS PS2 SPS LHC / SLHC SPS+ LPSPL: Low Power Superconducting Proton Linac (4 GeV) PS2: High Energy PS (~ 5 to 50 GeV – 0.3 Hz) SPS+: Superconducting SPS (50 to1000 GeV) SLHC: “Superluminosity” LHC (up to 1035 cm-2s-1) DLHC: “Double energy” LHC (1 to ~14 TeV) DLHC L. Evans – EDMS document 867980 36 Layout of the new injectors SPS PS2 SPL PS Linac4 L. Evans – EDMS document 867980 37 Upgrade of LHC insertions Intermediate (2012-2013) upgrade of the two highluminosity insertions using existing NbTi cable from dipole production. Seed money expected from Brussels but construction funds to be found. Possible further upgrade to IE35 (2016-2018) using advanced superconductor. Many ideas but luminosity lifetime will be a problem. L. Evans – EDMS document 867980 38