CEPC Detector R&D Status

Transcription

1 CEPC Detector R&D Status Hongbo Zhu (IHEP, Beijing) KCETA-IHEP-SJTU Symposium "Particles and the Universe 4-7 November 2015, Shanghai Jiao Tong University, Shanghai

2 Outline Introduction to CEPC The CEPC detector R&D status of sub-detectors Summary and outlook 2

3 Introduction The Higgs discovery in 2012 triggered ideas on Higgs Factories, which would be aimed to measure as precise as possible the Higgs properties. Proposal from the Chinese HEP community and presented by Prof. Qing Qin at Accelerators for a Higgs Factory: Linear vs. Circular (HF2012) Prof. Qing Qin 3

4 CEPC-SppC Phase I: Circular Electron-Positron Collider (CEPC) Higgs Factory, center-of-mass energy ~240 GeV, instantaneous luminosity ~ cm -2 s -1, 2 interaction points, ~1 M clean ZH events over 10 years precision measurements of the Higgs boson Operation at Z-pole/WW threshold EW precision measurements Phase II: Super Proton-Proton Collider (SppC) Discovery machine, center-of-mass energy TeV, peak luminosity ~ cm -2 s -1, 2 interaction points energy frontier for New Physics Other possible collisions: ep, ea, pa and AA LEP-LHC Style 4

5 Higgs Couplings Higgs couplings to fermions and gauge bosons predicted by the Standard Model (SM): g(hff;sm) and g(hv V ;SM); deviations from the SM couplings parameterised as: apple f = g(hff) g(hff;sm), apple V = g(hv V ) g(hv V ;SM) Relative Error Model-dependent fit: Precision of Higgs coupling measurement (Contrained Fit) LHC 300/3000 fb -1 CEPC 250 GeV at 5 ab -1 wi/wo HL-LHC Relative Error Model-independent fit: Precision of Higgs coupling measurement (Model-IndependentFit) ILC GeV at fb -1 wi/wo HL-LHC CEPC 250 GeV at 5 ab -1 wi/wo HL-LHC 10-3 κ b κ c κ g κ W κ τ κ Z κ γ 10-3 κ b κ c κ g κ W κ τ κ Z κ γ κ μ Br(inv) κ Γ 5

6 Possible Project Timeline CEPC Pre-studies ( ) R&D Engineering Design ( ) Construction ( ) Data taking ( ) 1 st Milestone: pre-cdr (by the end of 2014) R&D funding request to Chinese government in 2015 (China s 13 th Five-Year Plan ) SppC R&D ( ) Engineering Design ( ) Construction ( ) Data taking ( ) 6

7 CEPC Detector Modified version of the ILD detector for physics feasibility studies, consisting of the following sub-detectors (from inside to outside): Vertex Detector, Silicon Tracker, Time Projection Chamber (TPC), Electromagnetic Calorimeter (ECAL), Hadronic Calorimeter (HCAL), Solenoid + Muon Detector 7

8 Detector Performance Requirements Detector performance mainly driven by Higgs precision measurements 8

9 Vertex Detector (VTX) r =5 10/p sin 3/2 µm Imposing stringent requirements on the Vertex detector Spatial resolution near the interaction point σsp 3 μm high granularity (small pixel size) Material budget 0.15%X0/layer monolithic pixel sensor (sensor + embedded electronics, thinned down to e.g. 50 μm) + air cooling (power dissipation 50 mw/cm 2 ) Low detector occupancy below 0.5% high granularity and short integration time Radiation tolerance (pre.): ~1 MRad (TID) and neq/cm 2 (NIEL) Similar to the ILC vertex detector requirements but without power-pulsing 9

10 Candidate Technologies Monolithic pixel sensor technologies considered: CMOS: Ultimate installed for STAR PXL, ALICE ITS upgrade, Mu3e (HV- CMOS), pursued by ATLAS for Pixel Phase-II upgrade DEPFET: Belle-II pixel detector (attractive feature of self-supporting structure with low material budget in the active volume) SOI: actively pursued for X-ray detection (existing design expertise), remaining issue with radiation tolerance 3D-IC: trials within the 3D consortium, promising (ultimate detector) but technology not mature enough Considering the technology maturity and accessibility, we have chosen CMOS (TJ CIS 0.18 μm) for initial sensor R&D. 10

11 1 st MPW Submission Mainly focused on designs affecting charge collection, e.g. diode geometry and substrate; blocks reserved for analog circuit studies, e.g. amplifiers Sensor layout (incomplete) 1st submission aimed for the TJ CIS MPW shuttle on 30 November; test PCB boards and data acquisition system under development Exploring fast and low power consumption readout architecture 11

12 Silicon Tracker R&D project on CMOS sensor as an alternative solution to conventional silicon micro-strip sensors; possibly not mature enough for the ATLAS Phase-II upgrade but ideal for CEPC silicon tracker digital z-encoded design Original idea from Ivan Peric Already involved in sensor characterisation; stepping into the sensor design and mostly like the full digital readout chip development 12

13 Time Projection Chamber (TPC) Time Projection Chamber as the main tracker: decent spatial resolution, continuous tracking, lower material budget, de/dx, etc. Main components: Rigid and light chamber filled up with working gas Field cage to form uniform electric field MicroPattern Gaseous Detectors (MPGDs) for readout Performance goals: Position resolution: σrφ ~100μm Track momentum resolution: σ1/pt =10-4/GeV (B = 3.5 T) Benefiting from much of the pioneering work by the LC-TPC collaboration 13

14 Readout Module Gating device used for ILD TPC to suppress the ion back-flow effect not applicable for CEPC TPC (different beam structure no power-pulsing) Hybrid structure: GEM + Micromegas GEM as the preamplifier yet to reduce effectively ion back flow originating from Micromegas IBF still accumulating important to understand the detector background 2D GEM imaging results 14

15 Laser Calibration System Precise alignment and calibration to achieve the desired position resolution Laser system to measure precisely time varying drift velocities to correct for the drift field deviations caused by mechanical or electrical imperfections, temperature variations, relative misalignment, etc. Started with a module Litton Nano-150mJ laser Laser profile map Interactions with working mixture gas, interference and reflections with different materials ultimate goal: O(100 um) 15

16 PFA Calorimeters 16

17 Particle Flow Algorithm Measure each object in its most appropriate sub-detectors and combine Enhanced particle identification, improved jet energy resolution Substantial development of Arbor (alternative PFA algorithm to Pandora) 17

18 Electromagnetic Calorimeter (ECAL) ECAL intrinsic energy resolution: 16% p E 1% GeV Ongoing R&D on Tungsten-Scintillator read out with SiPM (cost effective, moderate radiation tolerance but applicable for CEPC), Tungsten-Silicon to be considered in future Super-layer (7mm): Tungsten plate (3mm), 5 45 mm 2 scintillator strips (2mm), readout/service layer (2mm) SiPM performance evaluation and stability against temperature, humidity BNU SiPM Hamamatsu MPPC 18

19 Hadronic Calorimeter (HCAL) HCAL intrinsic energy resolution: 60% p E 1% GeV (Semi-)Digital hadronic calorimeters considered for R&D Low center-of-mass energy for CEPC (up to 250 GeV) jet energy most likely below 100 GeV, which makes DHCAL applicable (decent energy linearity from CALICE studies) RPC or thick GEM (THGEM) as the active material, steel as the absorber 19

20 DHCAL with RPC Large GRPC R&D Negligible dead zone (tiny ceramic spacers) Large area: 1 1 m 2 Cost effective Efficient gas distribution system Homogenous resistive coating Test NCEPU 20

21 SDHCAL with RPC SJTU in collaboration with ANL First step to analyse the test beam data to understand the DHCAL performance Linearity of energy response Hit density Energy composition Energy calibration Energy resolution particle identification 21

22 DHCAL with THGEM WELL-THGEM chosen as the basic structure Advantages: simplicity, robustness, sub-mm spatial resolution, O(ns) time resolution, 1 MHz/mm 2 rate capability Beam tests performed with 8 chambers utilising the beam line (pion/electrons) at IHEP maximum gain:

23 Summary and Outlook Circular Electron Positron Collider (CEPC) proposed by the Chinese HEP community Higgs precision measurements Ongoing R&D efforts on sub-detectors: VTX, Si-Tracker, TPC, ECAL, HCAL Overall detector design/layout yet to be worked out Necessary to explore synergies with other experiments (LHC/ILC/FCC ) Pioneering LC detector R&D efforts Get started with domestic collaboration but will eventually go for internationalisation 23