1. Technical Meeting Diamond Detector Characterization in Frascati F. Burkart F. Burkart, O. Stein

2. Goals of this beam time Characterize three 100 µm, poly-crystalline, high-fluence diamond detectors (H1, H2, H3). –Measure response as a function of bias voltage. –Measure linearity and saturation effects. –Compare the three detectors. (Measure response of standard 500 µm LHC type diamond detector.) (Measure response of a non-irradiated 100 µm diamond detector.) Compare response of different detector types. F. Burkart, O. Stein2

3. Diamond particle detector circuit diagram F. Burkart, O. Stein3 Bias Voltage: 70 – 230 V Corresponds to 0.7 – 2.3 V/µm electric field strength across diamond Diamond Thickness: 100 µm Diameter: 5 mm

4. H3 detector - recorded signals F. Burkart, O. Stein4 Recorded points during voltage and alignment scans. Data taken in two intensity ranges (only H3). Bunch intensity changed by using scrapers. Bias Voltages from 70 – 230 V. During alignment scans: changes in ratio between dBLM and icBLM signal. 8E4 to 5E8 e -

5. Low intensity range F. Burkart, O. Stein5 Linear response for all bias voltages

6. Conversion Factors F. Burkart, O. Stein6 Conversion Factor (e/C) Allows conversion from Coulomb to number of particles at different bias voltages.

7. Detector currents (measured vs. expected) F. Burkart, O. Stein7 Measured signal in the lab: ~ 0.01 µA / MIP for 100 µm diamond detectors. Measured signals a factor 0.68 lower then expected. Differences in diamond material. Variation of 20 - 35 % between detectors.

8. Voltage Scan F. Burkart, O. Stein8 Hysteresis effect expected, when ramping down. Electric field needs time to come to an equilibrium state in the diamond. After that, same response as during ramp up. Timescales varies between tens of seconds and minutes, dependent on diamond. Time between measurements: 10 – 30min Time between measurements: 2 – 3 min Time between measurements: ~ 5 min

9. High intensity range F. Burkart, O. Stein9 Fit curve from low intensity range @ 140V

10. Comparison different detectors F. Burkart, O. Stein10 Variation between H1 and H3 detector between 20% - 35%.

11. Response for a given intensity as a function of bias voltage F. Burkart, O. Stein11 Factor: 2.2 Factor 1.6 in the low intensity range.

12. Limitations Use of 50 Ohm measurement system. Dynamic range limited due to read-out electronics. –High detector current.  High measured voltage.  Decrease of electric field in the diamond. U HV = U diamond + U measurement F. Burkart, O. Stein12  Drift velocity of e - - hole pairs reduced.  Longer dwell time of e - - hole pairs in the diamond (increase of FWHM).  Recombination.  Part of signal lost.

13. FWHM @ high intensity F. Burkart, O. Stein13 ~ 60 % of bias voltage. Signal amplitude saturates. FWHM increases further

14. FWHM F. Burkart, O. Stein14

15. Conclusion Successfully tested 100µm diamond particle detectors in the range ~1E5 to ~1E9 electrons per shot on the detector for the first time. Diamond detector linear in the lower intensity range. Conversion factor for different bias voltages calculated. Non-linear behavior in the higher intensity range. Limitations due to 50 Ohm read-out electronics. Data analysis ongoing. F. Burkart, O. Stein15

16. Outlook – Data Analysis Evaluate efficiency of diamond detectors. Study saturation effects. Comparison of results for the three different diamonds. Study degradation effects due to integrated dose. –Comparison to previous experiments, performed in HiRadMat. Combine with linearity between 1 and 1E4 MIPs F. Burkart, O. Stein16

17. Outlook – Future Plans Re - measure linearity and saturation effects in the high intensity range –Know the limitations of diamond detectors used in high fluence environment (damage experiments in HiRadMat). –Reduce resistance of read-out electronics (1 Ohm shunt built by CIVIDEC) –Study timescales of hysteresis effects. Measure response in the intermediate intensity range (1E5 – 1E7 e - /pulse).  Show linearity within 4 orders of magnitude. Compare response to standard LHC type diamond detectors.  Proposal new measurement time at the BTF. F. Burkart, O. Stein17

18. Thank you for your attention! F. Burkart, O. Stein18

19. Thanks to… Daniel Arjan, Rüdiger, Zinur, PE – section. Erich Griesmayer (CIVIDEC). Paolo Valente, Luca Foggetta, Bruno Buonomo (INFN Frascati). Bernd Dehning, Ewald Effinger, Raymond Tissier, Eduardo Nebot, Mariusz Sapinski (BE-BI). Damien Grenier and team (EN-STI). Loredana Zeni Toberer (Shipment). LINAC team INFN Frascati. … F. Burkart, O. Stein19