The Atlas Spectrometer

P. Kostka, A. Polini

Outline:Experiment requirements and accelerator boundaries(Physics, Machine, Interaction Region and Detector)Present Detector DesignDetector Session and Workshop DiscussionFuture and OutlookThe LHeC Detector(introduction)1

http://cern.ch/lhecP. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis1

New physics, distancescales few . 10-20 mHigh precisionpartons in LHCplateauNuclear Structure & Low x PartonDynamicsHigh Density MatterLarge xpartons High mass (Meq,Q2) frontier

EW & Higgs Q2 lever-arm at moderate & high x PDFs

Low x frontier [ x below 10-6 at Q2 ~ 1 GeV2 ]

novel QCD Kinematics & Motivation (60 GeV x 7 TeV ep)s= 1.4 TeV

P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis3

LHeC KinematicsHigh x and high Q2: few TeV HFS scattered forward: Need forward calorimeter of few TeV energy range down to 10o and below . Mandatory for charged currents where the outgoing electron is missing. Strong variations of cross section at high x demand hadronic energy calibration as good as 1% Scattered electron: Need very bwd angle acceptance for accessing the low Q2 and high y region .

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisDesign ApproachProvide a baseline design which satisfies the Physics requirements along with the constraints from the machine and interaction region for running during the PHASE II of LHC

Having to run along with the LHC, the detector needs to be designed and constructed in about 10 years from now to be able to run concurrently with the other LHC experiments designed for pp and AA studies in the ep/eA mode, respectively.

While avoiding large R&D programs, the final LHeC detector can profit from the technologies used nowadays at the LHC and the related developments and upgrades

Modular and flexible accommodating upgrade programs; Detector assembly above ground; Detector maintenance (shutdown)

Affordable - comparatively reasonable cost.

More refined studies are required and will follow with the TDR and once a LHeC collaboration has been founded4

P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis5Two Alternative DesignsRing-Ringe-p and e-A (A=Pb, Au, ) collisionsMore conventional solution, like HERA, no difficulties of principle - at first sight - but constrained by existing LHC in tunnelpolarization 40% with realistic misalignment assumptionsLinac-Ringe-p and e-A (A=Pb, Au, ) collisions, polarized e from source, somewhat less Luminosity/PowerNew collider type of this scale

10, 30, 50 GeV10 GeV10 GeV

P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis6

LR, RR option - Beam & SRSR Fan growth with zSR Fan growth with z(high luminosity case)Legend : Dipole

RR Option - Beam & Fan Envelopesx [mm]z [mm]e pTriplet Position z= ~22m

LR Option - Beam & Fan Envelopesx [mm]z [mm]e pTriplet Position z= ~10mP. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis7

Special attention is required to the interaction region design, which comprises beam bending (in/out), direct and secondary synchrotron radiation, vacuum and beam pipe

Dipoles around the IP (2 x 9m, 0.3T) for making electrons collide head-on with p-beam 2 & safely extract the disrupted electron beam. Simulation of Synchrotron Radiation (SR) load in the IR and design of absorbers / masks shielding SR from backscattering into the detector & from propagating with e beam. Beam pipe design - space for SR fan - tracking/calorimetry close to the IP / beam line (goal: 1- 179)

SRp-beam 1p-beam 2e-beamPhoton Number Density at the IPx [mm]y [mm]

3 beams, headon collisionsLR Interaction RegionP. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis8

Beam Pipe / Profile - SR FanRing-Ring - Inner dimensions (masks at 6, 5, 4m - primary SR shield)Circular(x)=2.2cm (LHC upgrade); Elliptical(-x)=-5.5, y=2.2cm

beam pipe dimensions reduced - using static / movable masks;

Linac-Ring - Inner DimensionsCircular(x)=2.2cm; Elliptical(-x)=-10., y=2.2cmx=2.2cm

x= -10cmy=2.2cmx=2.2cm

y=2.2cmx= -5.5cmhousing beam/SR envelopes + 1cm safety margin

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisLinac Ring: Favored OptionLinac-Ring:Reduced impact on the LHC scheduleNew Accelerator Design (Energy Recovery Linac)Dipole Field along the whole interaction regionLHC Interaction Point P29

P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis10Requirements from PhysicsHigh resolution tracking system excellent primary vertex resolutionresolution of secondary vertices down to small angles in forward direction for high x heavy flavor physics and searchesprecise pt measurement matching to calorimeter signals (high granularity), calibrated and aligned to 1 mrad accuracy The calorimeterselectron energy to about 10%/ E calibrated using the kinematic peak and double angle method, to permille levelTagging of 's and backward scattered electrons - precise measurement of luminosity and photo-production physicshadronic part 30%/ E calibrated with pt_e /pt_h to 1% accuracy Tagging of forward scattered proton, neutron and deuteron - diffractive and deuteron physics Muon system, very forward detectors, luminosity measurements

P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis11

Dominant forward production of dense jets; backward measurements relaxed

FST - Z= 8. cmmin-inner-R = 3.1 cm; max-inner-R= 10.9 cmouter R = 46.2 cmPlanes 1 - 5: z5-1 = 370. / 330. / 265. / 190. / 130. cmBST - Z= 8. cmmin-inner-R = 3.1 cm; max-inner-R= 10.9 cmouter R = 46.2 cmPlanes 1 - 3: z1-3 = -130. / -170. / -200. cm4 CFT/CBT min-inner-R = 3.1 cm, max-inner-R = 10.9 cmCST - R 3.5cm each1. layer: inner R = 21.2cm2 layer: = 25.6 cm3. layer: = 31.2 cm4. layer: = 36.7 cm 5. layer: = 42.7 cm4 layer CPTmin-inner-R = 3.1 cmmax-inner-R = 10.9 cm

R = 15 cmElectromagnetic CalorimeterCentral Pixel TrackerCentral Si TrackerCentral Forward/Backward TrackerBackward Si Tracker Forward Si Tracker Tracking - High Acceptance P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisTracker SimulationSilicon: compact design, low budget material, radiation hard12

http://wwwhephy.oeaw.ac.at/p3w/ilc/lictoy/UserGuide_20.pdf

LicToy 2.0 Simulation - Simplified Geometry

P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis

Tracker Simulation (ii)Same plots (left) and (small) deterioration in case of innermost barrel layer failure (right)13909090901111

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisGEANT4 - Fluences

Similar studies being done with FLUKAMost critical the forward regionRates far lower than LHC (LHC ~5 x 1014)

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisTracker Detector TechnologyChoose among available technologiesn-in-p ( sLHC ) or n+-in-n (ATLAS/CMS/LHCb)Radiation hardness in LHeC not as challenging as in LHCSilicon Pixel, Strixel, StripsDetailed simulation to best understand the needs and implicationsReadout/Trigger, Services, # silicon layersAnalog/Digital ReadoutModular structure for best replacement / maintenance and detector adoption: RR high luminosity / high acceptance runningPixel Detector*) ( barrel CPT 1-4 and inner forward/backward FST/BST) 15

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisServices and Infrastructure

Detector of very compact design; It might be necessary to open places/grooves/tunnels for services affecting the aperture of the detector; Optimum between costs and detector acceptance needs to be found. Service and Infrastructure need very careful design being the main contributor to Material Budget

Tracker Material Budget

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisSolenoid OptionsLarge CoilLarge Solenoid containing the Calorimeter3.5 T Solenoid of similar to CMS/ILCPrecise Muon measurementLarge return flux either enclosed with Iron orOption of active B shielding with 2nd solenoidSmall CoilSmaller Solenoid placed between EMC and HACCheaper optionConvenient displacement of Solenoid and Dipoles in same cold vacuum vessel (Linac-Ring only)Smaller return flux (less iron required)Muon p, pt measurement compromisedHACEMCEMCEMC

COIL

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisMagnetsBaseline Solution:Solenoid (3.5 T) + dual dipole 0.3 T (Linac-Ring Option)Magnets (may be) embedded into EMC LAr Cryogenic SystemNeed of study the Calorimeter Performance and impact of dead material between EMC and HAC sections; it might be possible placing the magnet system even in front of the EMC - at even lower radius at just outside of the tracking system18

P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis19

Baseline Detector

p/AeP. Kostka, A. PoliniJune14th 2012, Chavannes de BogisBaseline Electromagnetic CalorimeterLAr for barrel EMC calorimetry - ATLAS (~25-30 X0)

Advantage: same cryostat used for solenoid and dipolesGEANT4 simulation (*)Simulation results compatible with ATLASbarrel cryostat being carefully optimized pre-sampler optimal3 different granularity sections longitudinallyElectromagnetic Calorimeter (i)20

ATLASATLAS(*) F. Kocak, I. Tapan Uludag Univ.

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisElectromagnetic Calorimeter (ii)Simulation with simplified design w.r.t.AtlasLAr Calorimeter : good energy resolution, stable performanceSimulation results compatible with ATLASWarm (Pb/Sci) option also investigated30X0 (X0(Pb)=0.56 cm; 20 layers) 21

LHeCF. Kocak, I. Tapan Uludag Univ.

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisHadronic Calorimeter (i)Baseline DesignHAC iron absorber (magnet return flux)scintillating plates (similar to ATLAS TILE CAL)Interaction Length: ~7-9 ISetup:

GEANT4 simulation (*)performance optimization:containment, resolution, combined HAC & EMC responsesolenoid/dipoles/cryostat in between22Tile Rows Height of Tiles in Radial Direction Scintillator Thickness1-397mm3mm4-6127mm3mm7-11147mm3mm

(*) F. Kocak, I. Tapan Uludag Univ.

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisPreliminary studies on impact of the magnet system on calorimetric measurements (GEANT FLUKA)Energy resolutionsShower profiles

Hadronic Calorimeter (ii)23

F.Kocak, I.Tapan, A.Kilic, E.Pilicer Uludag Univ.; E.Arikan, H.Aksakal Nigde Univ. P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis23Forward Energy and Acceptance24

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisEndcap CalorimetersForward/Backward CalorimetersForward FEC + FHC:tungsten high granularitySi (rad-hard)high energy jet resolutionFEC: ~30X0; FHC: ~8-10 IBackward BEC + BHC:need precise electron taggingSi-Pb, Si-Fe/Cu (~25X0, 6-8 I )GEANT4 simulation *containment, multi-track resolution (forward)e tagging/E measurement (backwards)25

* A. Kilic, I. Tapan - Uludag University

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisForward/Backward Calorimeters26Calorimeter ModuleLayerAbsorberThicknessInstrumented GapTotal DepthFEC(W-Si)30x01-2526-501.4 mm2.8 mm16 cm19.5 cm5 mm35.5 cmFHC (W-Si)1-1516-3132-461.2 cm1.6 cm3.8 cm39 cm48 cm78 cm14 mm165 cmFHC (Cu-Si)1-1011-2021-302.5 cm5 cm7.5 cm30 cm55 cm80 cm5 mm165 cmBEC (Pb-Si)1-2526-501.8 mm3.8 mm17 cm22 cm5 mm39 cmBHC(Cu-Si)7.91-1516-2728-392.0 cm3.5 cm4.0 cm39.75 cm49.8 cm55.8 cm6.5 mm145.35cm

Highest energies in forward regionRadiation hardHigh GranularityLinearity

P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis27

Muon System Baseline

p/AdipoledipoleeBaseline Solution:Muon system providing tagging, no independent momentum measurementMomentum measurement done in combination with inner tracking Present technologies in use in LHC exp. sufficient (RPC, MDT, TGC)

P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis28

Muon System Extensionse

p/AExtensions:Independent momentum measurementLarge solenoid (incompatible with LR dipoles)Dual Coil System (homogeneous return field)Forward Toroid System

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisStatus and OutlookA LHeC baseline detector concept has been presentedThe design depends heavily on the constraints from the machine and interaction regionFor all cases a feasible and affordable concept which fulfills the physics requirements has been presentedAs a baseline many improvements available. A more precise design will follow from more detailed simulations, engineering and the knowledge of the machine constraints

This WorkshopStart a new phase in detector designCollect people, experience, informationIdentify and address critical items, discuss the timeline for realization Build a collaboration and move next steps towards a Technical Design29

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisDetector Session AgendaThursday:

Friday:30

P. Kostka, A. PoliniJune14th 2012, Chavannes de BogisOur Thanks to all who contributed, not only within the Detector Group, but also to the Physics, Interaction Region and Accelerator Groups

Many thanks also to the refereesPhilip BlochRoland Horisberger31P. Kostka, A. PoliniJune14th 2012, Chavannes de Bogis