1. Hamburg University: Plans for SLHC Silicon Detector R&D Georg Steinbrück Wien Feb 20, 2008

2. 2 Plans for SLHC Silicon Detector R&D Projects and collaborations of the group Strategies Measurements of material properties Sensor simulation/optimization Simulation of detector performance

3. 3 Projects and Collaborations of the Group The group is involved in the following Projects with respect to Detector R&D: LHC (funded by BMBF) HGF-Alliance (17 German Universities + DESY + FZK) “Physics at the terascale” WP1: The Virtual Laboratory for Detector Technologies WP2: Detector R&D Projects HPAD-XFEL (with Bonn, PSI, DESY) Approved. Project started. PAD-Marie Curie (with CERN, DESY, …) “Marie Curie Training Network on Particle Detectors” Approved in principle. Contract negotiations with EU.

4. 4 Strategies Study of macroscopic properties: IV, CV, TCT (transient current technique) Study of microscopic properties: Defects DLTS: deep level transient spectroscopy, TSC: thermally stimulated current method) N eff, I,  e,h :f(Doping, t, radiation dose, …) Sensor simulation/ optimization: E, I, C as a function of irradiation, material Simulation of charge collection in detector , spatial resolution, reconstruction Monte Carlo simulation experiment: -multi-TCT -testbeam detector = dE/dx x sensor x FE electronics

5. 5 Examples Material Properties SLHC operating scenario, measurement compared to simulation: “Hamburg Model” Thin n-type epi-Silicon. No space charge sign inversion after proton and neutron irradiation. Explanation: Introduction of shallow donors overcompensates creation of acceptors. More pronounced in 25µm Si due to higher oxygen concentration.

6. 6 rad. induced acceptors in lower half of band gap: neg. charged, neg. space charge  hole traps (H).  Increase with annealing time  neg. space charge increases, N eff decreases! conduction band valence band Study of Microscopic Defects: Thermally Stimulated Current (TSC)  N eff TSC results for fully depleted diodes. Goal: Identification of defects responsible for long term annealing (“reverse annealing“) of Neff.  V FD Difference N D -H und Neff: VP

7. 7 Simulation of Detector Performance, Comparison with Test Beam Data Example testbeam measurement for irradiated CMS sensors integrated  (PH(R)/PH(L)+PH(R)) versus  for various incidence angles. Example simulation: Reconstructed position versus reduced incidence position on strip.

8. 8 Simulation of Charge Clouds electron cloud hole cloud Front Backside structure (strip/pixel) Bias-Voltage V bias t2t2 t2t2 t1t1 t1t1 t0t0 I1I1 I0I0 Current is induced to all strips Readout of current allows to investigate charge cloud distribution I 0 current on closest strip I 1 current on neighboring strip black: sum of both strips e collected h collected Goal: Study the effects of trapping.

9. 9 Verification with Multi Channel TCT attenuator + amplifier Laser optics z table x-y stage temporary detector support Goal: Time-resolved measurement of charge collection in Si-pixel and strip detectors in multiple channels up to very high charge densities. fine-grain position and angle scans. Multi-TCT under construction in Hamburg: ps laser (1052 nm and 660 nm), <90ps, W max ~200pJ, spot size <10 µm (red) penetration depth 3 µm (red), 1000µm (IR) fast amplifiers (miteq) data acquisition with fast oscilloscope (500 MHz, 1GS/channel), possible upgrade to digitizer cards with up to 20 ch, synchronized cooled detector support (Peltier) 10 ns

10. 10 People Doris Eckstein (main Hamburg contact person) Robert Klanner Peter Schleper Georg Steinbrück Eckhart Fretwurst (defect engineering) Julian Becker, PhD student (multi-TCT) Volodymyr Khomenkov (starting ~March) (Detector simulation) Ajay Srivastava (just started) (sensor simulation: TCAD,…)

11. 11 Backup

12. 12 Schematic set-up of the Multi-TCT optic fiber and optics working distance optic axis (z) z x y laser and driver Oscilloscope attenuators and amplifiers bias voltage supply, leakage and guardring current measurement PID temperature controller trigger line

13. 13 Laser system (PicoQuant) 660 nm (red) minimum energy:  1 mip  10 x XFEL  /pulse  70 ps pulse width maximum energy:  140 pJ/pulse  4x10 4 XFEL-  /pulse  100 million e-h pairs  4000 mips  800 ps pulse width 1052nm (infrared) minimum energy:  1 mip  10 x XFEL  /pulse  70 ps pulse width maximum energy:  275 pJ/pulse  4x10 4 XFEL-  /pulse  100 million e-h pairs  4000 mips  700 ps pulse width Gaussian beam after single mode fiber

14. 14 Laser system (red) maximum energy:  140 pJ/pulse  800 ps pulse width minimum energy:  22 pJ/pulse  70 ps pulse width

15. 15 Laser system (IR) minimum energy:  44 pJ/pulse  70 ps pulse width maximum energy:  275 pJ/pulse  700 ps pulse width