The UHH Detector Laboratory Universität Hamburg Institut für Experimentalphysik Detektorlabor Doris Eckstein MC-PAD Kick-Off Meeting, CERN, 13./14.1.2009 Outline: Projects Expertise and Infrastructure Examples

The Institute of Experimental Physics has groups working on: Particle Physics and Detector Physics ATLAS, CMS, ZEUS, H1, HESS, ILC, OPERA Accelerator Physics FLASH, PETRA III, XFEL, ILC Laser- and X-Ray Physics DYNAMIX, X-Ray Spectroscopy, STM, SXRD Physics Department

R&D Projects of the Detector Lab Development of radiation hard silicon detectors Marie Curie International Training Network MC-PAD: P2 ‘Hybrid Pixel Detectors’ and P3 ‘Radiation Hard Crystals / 3D Detectors’ RD50 Collaboration: Radiation hard Silicon materials/sensors CMS SLHC upgrade: Central European Consortium – Silicon Sensors for tracking at intermediate to large radii Helmholtz Alliance: Virtual Detector Lab and radiation hard silicon sensors for SLHC HPAD-XFEL

Silicon Detectors for Vertexing and Tracking are used for vertexing, lifetimes, triggering, tracking, even dE/dx are used in all current HEP experiments detect MIPs are fast (~10ns) and precise (~10μm) (crazy geometries, run in vacuum, cover large surface) are radiation tolerant LHC starting 2008: Luminosity L = 1034 cm-2s-1 in 10 years (500 fb-1) F (r=4cm) ~ 3·1015 cm-2 Oxygenated Silicon (ROSE-Collaboration RD48) replacement might be necessary sLHC starting 201x: Luminosity L = 1035 cm-2s-1 in 5 years (2500 fb-1) F (r=4cm) ~ 1.6·1016 cm-2 new materials/technologies under investigation (RD50 Collaboration)

Radiation Damage in Silicon Sensors Two general types of radiation damage: Bulk damage due to Non Ionizing Energy Loss - displacement damage, built up of crystal defects – Change of Effective Doping Concentration Neff type inversion higher depletion voltage  possibly under-depletion  loss of signal, increased noise junction moves from p+ to n+ side influenced by impurities in Si (oxygen, carbon,…)  defect engineering, material dependence! Increase of Leakage Current shot noise  thermal runaway, power consumption  hard to bias  temperature dependent  need cooling Increased carrier Trapping Charge loss  at 1016cm-2 λ≤20μm charge collection distance! Surface damage due to Ionizing Energy Loss accumulation of charge in the oxide (SiO2) and Si/SiO2 interface  inter-strip capacitance (noise factor), breakdown behavior, … CMS MC-PAD RD50 HPAD-XFEL

R&D to develop materials, technologies and simulations for Silicon sensors modules at intermediate to large radii of a new CMS tracker for SLHC Establish a sensor technology valid for the outer radii of the tracker Investigate the maximum durable irradiation fluence  minimum possible radius Stick to planar technology and strixel-like structures, with the possibility of inlcuding a 2nd metal layer for signal routing Provide a single connection technology and minimize material budget by combining sensor and readout

Expertise and Infrastructure Irradiation campaigns (CERN, Ljubljana, Stockholm, Darmstadt, Karlsruhe, DORIS,…) Macroscopic damage vs. time/annealing for different materials Leakage current Ileak  I/V (Probe stations, also cooled) Neff  Vdep  C/V (Probe stations, also cooled) CCE  τe,h  Transient Current Technique Nox, Neff  sensor stability  C/V (Probe station, also cooled) evolution with time  annealing (ovens) overall performance  multi-channel TCT (new) test beam Microscopic damage vs. time/annealing for different materials: Thermally Stimulated Current, Deep Level Transient Spectroscopy characterisation of damage levels (introduction rate, energy level, ) kinetics vs. time/annealing relate to macroscopic damage Overall detector performance Multi-channel TCT Test beam Incorporate results I. and II. into simulation of sensor “static” (ISE TCAD) charge collection

Optimization of Sensor Design - Strategy Study of Macroscopic Properties through IV, CV, TCT Study of Microscopic Defects through DLTS, TSC  Neff, I, e,h depending on Doping, Irradiation, Annealing Sensor Simulation/ Optimization E, I, C as function of Irradiation, Material,... Simulation of Carge Collection in Detector dE/dx  sensor  FE electronics  Efficiency, spatial resolution, … Verification through multi-channel TCT, Testbeam

Example Setup: Multi-Channel TCT TCT (Transient Current Technique) records the time-resolved current of the device under test. Inject laser light  record pulse shape With multiple channels: add sensitivity to position, record neighbouring strips/ pixels Example: 300 V, Spotsize FWHM 5 µm injection of 660 nm light from backside (holes) optics high intensity sub-ns laser 2.5 GHz Scope linear tables defined set-up 32 channels automated control (PC)

Example: Microscopic - Macroscopic Radiation damage – reverse current No known point defects responsible – cluster defects? found a means to measure cluster concetration by using the bistability of E4 and E5 n-irradiated, 3x1011 cm-2 C(T0)-C(Tanneal) vs. I(T0)-I(Tanneal)

Summary Aims: quantitative understanding of Si sensor performance in harsh radiation environment improve sensor performance optimize sensor design (for given material, dose/fluence) Techniques: Measurements macroscopic: I/V, C/V, TCT, multi-TCT microscopic: DLTS, TSC Simulations of sensor ‘static’ and ‘dynamic’ properties