The CLICdp Optimization Process

Transcription

1 ILDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 1/17 The CLICdp Optimization Process André Sailer (CERN-EP-LCD) On Behalf of the CLICdp Collaboration ILD Software and Optimisation Workshop DESY, Hamburg February

2 LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 2/17 Table of Contents 1 Introduction: The CLIC CDR and Beyond 2 Sub-detector Optimisation Studies Vertex Detector Tracking ECal HCal Forward Region Magnetic Field and the Yoke 3 Summary

3 LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 3/17 Studies for the CDR Validated ILC detector models adapted for CLIC background and energy conditions Deeper HCal Larger inner radius of the vertex detector Changes in the very forward region Re-arrangement of the silicon tracker layers Successful physics studies with both detector models and software chains

4 ILDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 4/17 Conclusions from the CDR Studies Some conclusions from the CDR: HCal endcap coverage important for physics processes at small polar angles (e.g., HHH coupling) Move the QD0 outside the detector, 3.5m to 6m L Prefer longer tracker over short detector Too large occupancies for a TPC to work with CLIC timing structure Full Silicon tracker Only one detector model and one software chain To conclude on the layout of the new CLIC detector model made several studies focusing on the issues identified Studies using fast simulation tools (e.g., LicToy), the CDR detector models and software, and with DBD software chain

5 ILDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 5/17 Vertex Detector Studies Studied flavour tagging, occupancy, and resolutions to decide on Material budget Layer positions Spiral geometry Single vs. double layer Misidentification Ratio Dijets at 200 GeV spirals/cdr Charm Background θ= θ=20 θ=30 θ= Beauty eff.

6 LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 6/17 Air Cooling of the Vertex Detector Rationale: Need a way to get cool air into and hot air out of the vertex detector region Use double walled beam-pipe as air-duct Need spiral vertex endcaps to get air to vertex barrel Studies Simulations and full scale mock-up of vertex region

7 LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 7/17 TPC at CLIC? Dedicated study of the TPC at CLIC Simulation of beam and machine induced backgrounds Incoherent electron position pairs γγ hadron events Muons from the beam line The TPC integrates over a full 156 ns bunch train Occupancy deemed too large use all silicon tracker Voxel occupancy [%] Voxel occupancy [%] x1 mm pads All backgrounds γγ hadrons + - e e pairs Beam halo muons Row number x4 mm pads All backgrounds 20 γγ hadrons + - e e pairs Beam halo muons Row number

8 ILDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 8/17 Silicon Tracker The new detector model uses an all-silicon tracker Fast simulation studies of geometry layout and material (support, cabling, cooling) Using p T and d 0 to gauge performance Material budget between 1.6% and 2.2% of X 0 per layer Additional pixelated disk

9 LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 9/17 Silicon Tracker: Radius and B-Field Momentum resolution dependent on B and R max Also impacts particle flow performance Converged on 4 T and R max = 1.5 m Tracker half-length 2.3 m

10 Occupancies in the Tracker Layout Silicon Tracker Occupancy Barrel Endcap Study hit rate and occupancy from Investigatebeam-induced hit rate and occupancy backgrounds of the siliconin the new tracker induced silicon tracker by layout beam-beam interactions Occupancy / train % limit Inner Barrel 1 Inner Barrel 2 Outer Barrel 1 Outer Barrel 2 Outer Barrel 3 Occupancy / train % limit Inner Endcap 1 Inner Endcap 2 Inner Endcap 3 Inner Endcap 4 Inner Endcap 5 Inner Endcap 6 Inner Endcap 7 Outer Endcap 3 Outer Endcap 4 Outer Endcap 5 Outer Endcap 6 Outer Endcap z / mm r / mm Assuming 1 mm long strips, occupancy in the new forward disc Assuming close 1 to mm long % in strips, the inner occupancy parts in the new forward disk (see figure top left) close to % in the inner parts Pixels in first forward disc, also befit to tracking Pixels in the first forward disk, also benefits tracking 7 / Marko Petrič (CERN) The New CLIC Detector Model 7/17 17 ILDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process /17

11 LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 11/17 New Tracker Layout New engineering design Inner and Outer Tracker Support tube for extraction with beam-pipe assembly 3 short and 3 long barrel layers 7 inner and 4 outer endcaps At least 8 hits for θ > 8

12 LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 12/17 ECal Extensive ECal studies together with ILD Studying: Layers, depth, granularity,... Final decision will be taken soon

13 HCal: Iron vs. Tungsten In CDR Studies used tungsten as the absorber in the HCal barrel. This decision was re-evaluated. And due to: Reduced outer radius of the HCal (compared to CLIC ILD) 4 Tesla Field More complicated engineering of a tungsten calorimeter No benefit in terms of energy resolution compared to steel No longer use tungsten in HCal barrel HCal depth of 7.5 λ I will be kept Overlap [%] m W /m Z Fe W Fe, 60 BX overlay W, 60 BX overlay Typical Jet Energies [GeV] WW νljj and ZZ ννjj events LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 13/17

14 LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 14/17 HCal Endcap Coverage Increased hadronic calorimeter coverage needed Studied the jet energy resolution with γγ hadron background and different inner radii of the HCal endcap At 12 cm background rate spoils 0 energy resolution and it is not 50 feasible 0 Can increase the HCal endcap inner radius to 25 cm m JJ [GeV] Entries/2 GeV R in =120 mm R in =240 mm R in =360 mm ZZ s=1 TeV 60 BX γγ s=3 TeV Default Selected PFOs Jets with R=0.5

15 ILDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 15/17 Forward Region HCal endcap coverage extended QD0 L = 6 m, outside the detector Less stringent requirements on stability, less rigid support Anti-solenoid no longer needed Decreased support tube radius to 25 cm

16 Magnetic Field and the Yoke Thinner endcaps Use end coils to compensate for reduced thickness No need for an anti-solenoid (according to beam simulations) Do not fill with iron, better field quality on beam B z component with and without endcoils as a function of z Muon System with 6 equidistant layers LDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 16/17

17 ILDOptWS, Feb, 2016 A. Sailer: The CLICdp Optimization Process 17/17 Summary The new detector model, except that the tracker layout will be different