1. High Dose Irradiation of Possible FCAL Sensors at the S-DALINAC Ch.Grah Physics and Detector Meeting DESY HH, 29.6.2006

2. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 2 Contents  Reminder of FCAL detector systems and motivation  Testbeam at the S-DALINAC of the TU Darmstadt (12.06. -19.06.2006) Preparations Some pictures from the testbeam  Analysis and first results  Summary

3. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 3 FCAL System LumiCal 30 layer Si:W 26 < θ < 155 mrad BeamCal 30 layer CVD diamond:W 5 < θ < 28 mrad Forward region of LDC (V2)

4. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 4 Sensors for FCAL Energy deposition from beamstrahlung pairs in BeamCal. 10-20 TeV and more depending on the beam parameters. Dose of up to 10MGy/a Investigate: pCVD diamond sensors from different manufacturers (E6, IAF, Minsk) Si sensors GaAs sensors pCVD sensor from IAF 12 x 12 mm 2 size, 300-500μm thickness, Ti/Pt/Au metallization IAF: Fraunhofer Institute for Applied Solid-State Physics E6: De Beers Industrial Diamonds rebranded to Element Six in 2002 pCVD: polycrystaline Chemical Vapour Deposition

5. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 5 Radiation Hardness of CVD diamonds In our lab: so far only low dose irradiation diamond response vs. absorbed dose (Sr90) T.Behnke et al., 2001 „pCVD diamonds are radiation hard.“

6. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 6 Testbeam Purpose: High Dose Irradiation  Irradiate different sensor samples to high doses (>1 MGy).  Use rather low energetic electrons similar to secondaries. 2X 0 6X 0 20X 0 V.Drugakov Energy spectrum of particles depositing energy in the BeamCal sensors

7. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 7 S-DALINAC of the TU Darmstadt  Using the injector line of the S-DALINAC: 10 ± 0.015 MeV and beam currents from 10 to 100 nA 3 GHz electron beam energy: 2.5 to 130 MeV intensity: 1 nA to 50 µA Superconducting DArmstadt LInear ACcelerator

8. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 8 Accelerator Hall

9. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 9 S-DALINAC Location CCD setup Periodic Charge Collection Distance measurement Remote control/surveillance of beam area Beam Area see next slide Transport of sensor under HV

10. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 10 Beam Area  Monitor beam current via Faraday cup current to estimate dose.  Monitor high voltage/current and temperatures.  Local DAQ PC is operated remotely. Optimization by G4 simulation

11. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 11 G4 Simulation Optimize distance Optimize collimator and Faraday cup size Reduce distance to exit window

12. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 12 G4 Simulation Energy deposition in the sensorSpatial distribution of sensor hits Statistics (extract R = N FC /N Sensor = 0.98)

13. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 13 Sensor Holder exit window of beam line collimator (I Coll ) sensor box (I Dia, T Dia, HV) Faraday cup (I FC, T FC )

14. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 14 Beam Area: Equipment Power supplies and monitoringSurveillance from control room Sensor holder I-V conversion

15. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 15 Beam Area: Sensor (De-) Installation

16. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 16 CCD Setup Installation

17. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 17 CCD Setup Operation typical spectrum of an E6 sensor Sr90 source Preamplifier Sensor box Trigger box & Gate PA discr delay ADC Sr 90 diamond Scint. PM1 PM2

18. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 18 Program 2 samples from E6 1 MGy 5 MGy 2 samples from IAF 1 MGy 5 MGy 2 Si samples both drew high currents after ~50 kGy. E6_4p after ~5 MGy

19. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 19 Analysis and First Preliminary Results  Tuned the beam to currents in the Faraday cup of:  10, 20, 50 and 100 nA  This corresponds to dose rates of:  59, 118, 296, 591 kGy/h  For now assume an error of 10%.

20. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 20 Conclusion  Investigated the radiation hardness of sensors (silicon and pCVD diamond) for the calorimeters of the FCAL system of the ILC.  The S-DALINAC offers an infrastructure for irradiating with a wide range of intensities and energies up to 10 MeV.  Irradiated 6 samples up to doses of 1-5 MGy (at least for the diamond sensors).  Analysis is ongoing.  Have the opportunity to repeat such a test next year, to irradiate to even higher doses.  There were some issues (beam monitoring during irradiation, sensor box design) which will be improved by then.

21. 29.06.2006 Ch.Grah: FCAL Testbeam 2006 21 The Testbeam Crew not on the photo: W.Lange Thanks to: INTAS and the TU Darmstadt