Transcript SLHC.ppt
LHC & ATLAS UPGRADES Toronto Group Meeting • Physics Case for LHC Upgrade • LHC Issues • General ATLAS Issues • ATLAS Canada R&D R. S. Orr Alors, c’est fini! Et maintenant? ATLAS Detector Systems Diameter Barrel toroid length Endcap end-wall chamber span Overall weight 25 m 26 m 46 m 7000 Tons LHC Prospects • Date for 7 TeV beam commissioning: July 2008 • Initial physics run starts “late” 2008 collect ~10 fb-1 /exp (2.1033cm-2 s-1) by “end of 2009” • Depending on the evolution of the machine… collect 200-300 fb-1 /exp (3.4-10.1033cm-2 s-1 ) in 5-6 years time Already time to think of upgrading the machine Two options initially discussed/studied • Higher luminosity ~1035cm-2 s-1 (SLHC) – Needs changes in machine and particularly in the detectors Start change to SLHC mode some time 2012-2014 Collect ~3000 fb-1/experiment in 3-4 years data taking. • Higher energy? – LHC can reach s = 15 TeV with present magnets (9T field) – s of 28 (25) TeV needs ~17 (15) T magnets R&D + MCHf needed – Don’t discuss today LHC context in 2011 - 2015 SLHC make be only game in town for a LONG time. Physics Case for the SLHC The use/need for for the SLHC will obviously depend on how EWSB and/or the new physics will manifest itself This will only be answered by LHC itself What will the HEP landscape look like in 2012?? Rough expectation for the SLHC versus LHC Improvement of SM/Higgs parameter determination Improvement of New Physics parameter determinations, if discovered Extension of the discovery reach in the high mass region Extension of the sensitivity of rare processes Indicative Physics Reach Ellis, Gianotti, ADR hep-ex/0112004+ updates Units are TeV (except WLWL reach) Ldt correspond to 1 year of running at nominal luminosity for 1 experiment PROCESS LHC 14TeV 100 fb-1 SLHC 14TeV 1000 fb-1 SLHC LinCol 28TeV 0.8 TeV 100 fb-1 500 fb-1 Squarks 2.5 3 4 WLWL 2σ 4σ 4.5σ Z’ 5 6 Extra Dim (δ=2) 9 q* LinCol 5 TeV 100 fb-1 0.4 2.5 8 8† 8† 12 15 5 - 8.5† 30 - 55† 6.5 7.5 9.5 0.8 5 Λcomp 30 40 40 100 400 TGC (λγ) 0.0014 0.0006 0.0008 0.0004 0.00008 † indirect reach (from precision measurements) Approximate mass reach machines: s = 14 TeV, L=1034 (LHC) : up to 6.5 TeV s = 14 TeV, L=1035 (SLHC) : up to 8 TeV s = 28 TeV, L=1034 : up to 10 TeV The Higgs at the LHC • First step – Discover a new Higgs-like particle at the LHC, or exclude its existence • Second step – Measure properties of the new particle to prove it is the Higgs SLHC Statistics Needed • • • • • • • Measure the Higgs mass LHC~1 good year of data Measure the Higgs width Measure (cross sections x branching ratio)s Ratios of couplings to particles (~mparticle) Measure decays with low Branching ratios (e.g H) Measure CP and spin quantum numbers (scalar particle?) Measure the Higgs self-coupling (HHH), in order to reconstruct the Higgs potential Make sure it really is Higgs Higgs Self Coupling Measurements Once the Higgs particle is found, try to reconstruct the Higgs potential ~ v mH2 = 2 v2 Djouadi et al. SM/2 << 3SM/2 Not possible at the LHC Too much backgr. Higgs Self Couplings LHC : (pp HH) < 40 fb mH > 110 GeV + small BR for clean final states no sensitivity SLHC : HH W+ W- W+ W- jj jj studied 6000 fb-1 mH = 170 GeV mH = 200 GeV S 350 220 S/B S/B 8% 7% 5.4 3.8 -- HH production may be observed first at SLHC: ~150 <MH<200 GeV -- may be measured with statistical error ~ 20-25% LC : precision up to 20-25% but for MH < 150 GeV (s 500-800 GeV, 1000 fb-1) Beyond the Standard Model •New physics expected around the TeV scale • Stabilize Higgs mass, Hierarchy problem, • Unification of gauge couplings, Cold Dark Matter,… Supersymmetry Extra dimensions G G Bulk + a lot of other ideas… Split SUSY, Little Higgs models, new gauge bosons, technicolor, compositness,.. +… SUSY : Discovery Reach Discovery reach for squarks/gluinos Time ATLAS 5 discovery curves mass reach 1 month at 1033 1 year at 1033 1 year at 1034 ~ 1.3 TeV ~ 1.8 TeV ~ 2.5 TeV 5 discovery reach m (~ q), m (~ g) LHC SLHC 2.5 TeV 3 TeV SUSY Higgses h,H,A,H Heavy Higgs observable region increased by ~100 GeV at the SLHC. • Green region only SM-like h observable with 300 fb-1/exp • Red line: extension with 3000 fb-1/exp • Blue line: 95% excl. with 3000 fb-1/exp Time Scale of an LHC upgrade Jim Strait, 2003 time to halve error integrated L radiation damage limit ~700 fb-1 L at end of year ultimate luminosity design luminosity •Life expectancy of LHC IR quadrupole magnets is estimated to be <10 years due to high radiation doses • Statistical error halving time exceeds 5 years by 2011-2012 → it is reasonable to plan a machine luminosity upgrade based on new low-b IR magnets around ~2014-2015 Machine Upgrade in Stages • Push LHC performance without new hardware – luminosity →2.3x1034 cm-2s-1, Eb=7→7.54 TeV • LHC IR upgrade – replace low-b quadrupoles after ~7 years peak luminosity →4.6x1034 cm-2s-1 – low-b quadrupoles plus dipoles, plus crab cavities…. peak luminosity →15.5 x 1034 cm-2s-1 • LHC injector upgrade – peak luminosity →9.2x1034 cm-2s-1 • LHC energy upgrade – Eb→13 – 21 TeV (15 → 24 T dipole magnets) Beam-Beam Limit Luminosity Equation injector upgrade L nb LHC + injector changes f rev r b 2 p * Q 2 bb 1 2 2 1 IR upgrade Fprofile LHC+ injector changes Nominal Crossing Angle “at the edge” c z F ; 2 x 1 2 1 luminosity reduction factor nominal LHC Piwinski angle Summary of Luminosity Upgrade Scenarios for L 1035 cm2 s 1 with acceptable heat load and events/crossing 25-ns: push b * to limit • Slim magnets inside detector? • Crab Cavities • High Gradient, Large Aperture Nb3 Sn Quads 50-ns: Fewer bunches, higher charge • Realizable with NbTi • Beam-Beam tune shift due to large Piwinski angle? • Luminosity leveling via bunch length and b * tuning Early Separation (ES) • • • • • ultimate LHC beam (1.7x1011 protons/bunch, 25 spacing) squeeze b* to ~10 cm in ATLAS & CMS add early-separation dipoles in detectors starting at ~ 3 m from IP possibly also add quadrupole-doublet inside detector at ~13 m from IP and add crab cavities (Piwinski~ 0) → new hardware inside ATLAS & CMS detectors, first hadron crab cavities optional D0 dipole Q0 quad’s stronger triplet magnets ultimate bunches + near head-on collision ES Scenario merits: • most long-range collisions negligible, • no geometric luminosity loss, • no increase in beam current beyond ultimate, • could be adapted to crab waist collisions (LNF/FP7) challenges: • D0 dipole deep inside detector (~3 m from IP), • optional Q0 doublet inside detector (~13 m from IP), • strong large-aperture quadrupoles (Nb3Sn) • crab cavity for hadron beams (emittance growth), or shorter bunches (requires much more RF) • 4 parasitic collisions at 4-5 separation, • low beam and luminosity lifetime ~b* Large Piwinski Angle (LPA) • • • double bunch spacing to 50 ns, longer & more intense bunches with Piwinski~ 2 b*~25 cm, do not add any elements inside detectors long-range beam-beam wire compensation → novel operating regime for hadron colliders larger-aperture triplet magnets fewer, long & intense bunches + nonzero crossing angle + wire compensation LPA Scenario merits: • no elements in detector, no crab cavities, • lower chromaticity, • less demand on IR quadrupoles (NbTi expected to be possible), • could be adapted to crab waist collisions (LNF/FP7) challenges: • • • • • • operation with large Piwinski parameter unproven for hadron beams (except for CERN ISR), high bunch charge, beam production and acceleration through SPS, larger beam current, wire compensation (almost established), Principle of Early Separation Stronger focusing with cancellation of the geometrical luminosity loss D0 Full Early Separation (50 ns only if D0 not in inner detector) D0 D0 First encounter First encounter D0 Partial Early Separation (25 or 50 ns) 25ns preferred by We need a residual crossing angle ATLAS D0 is just in front of FCal Possible locations in ATLAS A B C D • Stay out of A • B,C possible location of D0, but need more calculations to avoid to damage the muon system • D possible location of Q0 or D0, probably the least problematic one Detectors: General Considerations s L Bunch spacing t pp (inelastic) N. interactions/x-ing (N=L pp t) dNch/d per x-ing <ET> charg. particles Tracker occupancy Pile-up noise in calo Dose central region LHC SLHC 14 TeV 1034 25 ns 14 TeV 1035 25/50 ns ~ 80 mb ~ 20 ~ 80 mb ~ 300/400 ~ 150 ~ 450 MeV ~ 2000/2500 ~ 450 MeV Normalised to LHC values. 1 1 1 10/20 ~9 10 104 Gy/year R=25 cm In a cone of radius = 0.5 there is ET ~ 200GeV. This will make low Et jet triggering and reconstruction difficult. Detector Upgrade • ATLAS has begun studying what needs to be upgraded for 1035cm-2s-1 instantaneous luminosity – ~10 harsher pileup, radiation environment – Also constrained by existing detector: what can be moved/stored where/when • Major ID overhaul foreseen – TRT replaced by Si Strips – Pixels move to larger radius – New technology for innermost layers • Calorimeters – New FE electronics for HEC – New cold or warm FCAL – Opening endcap cryostat implies a long installation schedule (~2-3 years) • Schedule to fit 2016 timescale – Aim for upgrade TDR in 2010 to allow adequate procurement/construction • Also Trigger, FE in general, etc.. etc.. etc… LAr Calorimeters at sLHC - Overview • Critical issues – ion build up and heat load • The HiLum ATLAS Endcap Project • Radiation hardness: – R&D for HEC cold electronics; FCal - Heatload EMEC HEC FCal Neutron Shielding Pump 300mm V Strickland • Simulation of LAr FCAL beam heating – Maximum temperature 93.8K – recently conclude unlikely that will LAr boil • Improve FCAL cooling (open endcap cryostat)? – ~2-3 year round-trip – big timing challenge • New “warm” FCAL plug? • Main FCAL issue is Voltage drop on protection resistors +ve Ion Buildup – Distorts Electric Field limit r=1 @LHC limit r=0.1 @sLHC •EMEC and HEC OK sLHC •FCAL: may go above 1 close to inner wall •Turn off inner part of FCAL •Instal mini warm FCAL in front – reduce energy deposited in FCAL1 HiLum ATLAS Endcap Project • Goal: establish limitations on the operation of the endcap calorimeters (FCAL, EMEC, HEC) at highest LHC luminosities. • R&D: 'mini modules‘ of FCAL, EMEC and HEC type, each in one separate cryostat; • IHEP Protvino: beam line # 23: from 107 up to 1012 p/spill; E= 60/70 GeV; • Arizona, Dresden, JINR Dubna, Kosice, Mainz, LPI Moscow, MPI Munich, BINP Novosibirsk, IHEP Protvino, TRIUMF, Wuppertal. HiLum Test Modules FCAL module • 4 'standard' HEC gaps (HEC1) • 4 read-out channels • 4 HV lines (one per subgap) Inner Detector Replacement • • • • • Order of magnitude increase in Data rates, Occupancy, Irradiation No TRT – Si strips Pixels moved to larger radius New technology for inner layers R&D required on sensors, readout, and mechanical engineering Tracks silicon TRT P Nevski • Preserve (improve?) tracking performance in SLHC environment • Need to replace TRT: all-silicon ID • Minimize material Strawman Layout of Tracker b layer + 3 pixel layers Semi-projective gaps moderator |η|<2.5 2 long-strip layers (9cm) + stereo 3 short-strip layers (2.5cm) + stereo Pixel-layer Technologies Harshest radiation environment (R~4cm) – investigate new technologies • 3D Si Highest signal - fabrication? Si pixel sensor • Thin silicon + 3D interconnects Conservative – high voltage BiCMOS analogue CMOS digital Cathode (drift) plane Cluster 1 Cluster2 Integrated Grid (InGrid) Input pixel 1mm, 100V Cluster3 • Gas over thin pixel (GOSSIP) Low material – sparks? 50um, 400V Slimmed Silicon Readout chip 50um • Diamond pixels Rad hard, low noise, low current – cost, signal, uniformity? • May test in pre-SLHC b-layer replacement (~2012) Schedule Strawman & options fixed Dec 2006 ID R&D, conceptual design 2007-2009 TDR Feb 2010 ID cooling PRR April 2010 Silicon sensor PRR July 2010 ID FE electronics PRR Oct 2010 b-layer replacement Ready 2012 Procure parts, component assembly 2010-2012 Start surface assembly March 2012 Stop data taking Sep 2014 Remove old detectors, install new 2014-2015 Data April 2016 Tracker Upgrade work in Canada Diamond Sensors – Toronto, Carleton, Montréal, Victoria +….. – Prove radiation tolerance of pCVD diamond pixel prototypes – Industrialize bump-bonding – FE electronics – Mechanical structure – Test beam program 2008-2009 Electronics – Carleton, UBC, York, TRIUMF +….. – FE ASICS – Si FE module controller – Initially FPGA, Move to ASIC – Contribute to system design – develop expertise – Backend (eg RODs) later in upgrade path – TRIUMF Technical manpower LHC Energy Doubler 14*14 TeV Dipoles: Bnom=16.8T, Bdesign=19T • • • • Superconductor Nb3 Sn 16T demonstrated at 4K 10 years for R&D, 10 years production 3G$ LHC Energy Tripler 21*21 TeV Dipoles: Bnom=25T, Bdesign=29T • • • • Superconductor HTS-BSCCO or Nb3 Sn Well above demonstrated Nb3 Sn 20++ years for R&D, ? years production ?G$