The UHH Detector Laboratory

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

2. 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

3. 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

4. Silicon Detectors for Vertexing and Tracking Silicon detectors: • 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 = 1034cm-2s-1 • in 10 years (500 fb-1) F (r=4cm) ~3·1015cm-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)

5. 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-2λ≤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

6. 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

7. 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

8. Optimization of Sensor Design - Strategy

9. 2.5 GHz Scope automated control (PC) defined set-up optics 32 channels linear tables high intensity sub-ns laser 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)

10. 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 C(T0)-C(Tanneal) vs. I(T0)-I(Tanneal) n-irradiated, 3x1011 cm-2

11. 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