Berdermann, GSI Darmstadt. Helmholtz Zentrum für Schwerionenforschung

Transcription

1 Elèni Berdermann, GSI Darmstadt Helmholtz Zentrum für Schwerionenforschung

2 ELECTRICAL CHARACTERIZATION of DIA-ON ON-IR; DoI- DETECTOR CHARACTERISTICS in 2010 INTRODUCTION DESCRIPTION of THE MEASUREMENTS: I IND ; Q C TCT SIGNALS Charge Transport; Internal Field; σ i (t) ALPHA SPECTROSCOPY Crystal Structure; CCE; δe/e SUMMARY and Preliminary Conclusions CHARACTERIZATION Next Steps

3 DETECTOR LABORATORY Mircea Ciobanu Shahinur Rahman Carmen Simons Michael Träger EBe ACCELERATOR HF GROUP Peter Moritz TARGET LABORATORY Willy Hartmann Annett Hübner Birgit Kindler Bettina Lommel UNIVERSITY OF AUGSBURG Stefan Dunst Martin Fischer Stefan Gsell Matthias Schreck Christian Stehl

4 TESTED DOI SAMPLES in 2010 MFDIA , d = 290µm (July 2010) MFDIA , d = 320µm (July 2010) FREESTANDING A = (3.5 x 3.5) mm² both sides polished METALLIZATION Ti/Pt/Au (50/50/100)nm annealed (500 O C) 4Q-motif (growth-s.); solid electrode (nucl.s.) Q4 Q1 Q3 Q2 ground electrode

5 BIREFRINGENCE IMAGES MFDia , d = 290µm, MFDia , d = 320µm, PC: Dia-on-Si Q4 Q1 Q3 Q2 Dia-on-Dia

6 8x10-11 DARK CURRENT [A] IV Characteristics Q1; Q3-2.7 V/µm 2.7 V/µm IV CHARACTERISTICS CS , d = 290µm (2010) -1x x10-11 DARK CURRENT [A] V V Q2; Q4-2.1 V/µm 1 V/µm -2x V 0 BIAS VOLTAGE [V] 500 V ground electrode

7 SINGLE-CARRIER DRIFT MODE; LOW IONIZATION a) IDEAL CASE: CONSTANT E D and COMPLETE DRIFT 12µm d D =300µm 241 Am α s,, 5.5 MeV R bias DSO 6 GHz 20 GS/s v U D - - dr DBAII; inverting h E D =1V/µm t = 0 x = 12µm t TR t = t TR x = 300µm d=100µm 2 ns a) DRIFT VELOCITY and MOBILITY: v dr (E D ) e,h = d D /t TR (E D ) µ dr (E D ) e,h = v dr (E D ) e,h /E D start stop t [ns]

8 SINGLE-CARRIER DRIFT MODE; LOW IONIZATION b) PRESENCE of TRAP CENTRES and FIXED SPACE CHARGE 12µm 241 Am α s,, 5.5 MeV R bias * DSO 6 GHz 20 GS/s * DBA (50 Ω, 2.3 GHz) d D =300µm U D DBAII; inverting h start E D =1V/µm varying stops d = 300µm 4-5 ns b) ESTIMATION of LIMITS LL < v dr (E D ) e,h ; µ dr (E D ) e,h ; τ e,h < UL e t = 0 x = 12µm t i = t itr 0 < x << 300µm t [ns]

9 DUAL-CARRIER DRIFT MODE; HIGH IONISATION traversing ions R bias * DSO 6 GHz 20 GS/s * DBA (50 Ω, 2.3 GHz) d D =300µm E D = V/µm E D = V/µm h h h h h hhh h U D DRIFT VELOCITIES and MOBILITIES 20 h ns h non accessible shorter t TR longer relaxation time

10 SIGNAL PROCESSING: INDUCED CURRENT/COLLECTED CHARGE I tr (t,e) = Q G v dr (E) e,h d D (1 e (t /τ eff t /τ e,h ) (t /RiC) ) = Q C(E) t tr (1 e t /R ic ) Q G E = ; vdr = µ ( E) E ; D ε Dia BROADBAND = µ εε 0 tr bias τ eff 2 ; τ e e, hneff ed Neff t V life ; I = amplitude CHARGE-SENSITIVE 0 I Q C BB-Signal Area: tr ( t, E) = I0 1 0 t t tr ( t / R C ) i e Q c CS-Peak Amplitude: U peak (E) = (t,e) dt = Q C (E) C f I tr C f

11 1.0 ATTENTION max. poss. drift lengths: SC; 390µm PC-DG; 350µm PC-AG; 160µm DOI; 12µm TCT with α-particles Am-α particles, 1.4 AMeV single - carrier drift h - drift signals first indication of DBA (50Ω, 2.3GHz) problems characterizing Diaon-Ir signals! e - drift signals SC, 392µm, 0.9pF DoI, 12µm, 6pF PC-DG, 350µm, 7pF PC-AG, 158µm, 16pF DBA modified for 3.4GHz HP2 CC, Paris Sep DRIFT TIME [ns] CARAT - Advanced Diamond Detectors

12 AMPLITUDE on 50 Ω [mv] HP2 CC, Paris Sep TCT with α-particles Am-α particles, 1.4 AMeV single - carrier drift h - drift signals e - drift signals DoI, 12µm, DBA, 3GHz DSO DoI, 12µm, mod. DBA, 6 GHz DSO DoI CS886-1, 290µm, mod. DBA, 6GHz DSO DRIFT TIME [ns] effect of mod. DBA and 6GHz DSO effect of better DOI CARAT - Advanced Diamond Detectors

13 MFDIA886-2: pumped TCT with α-particles mod. DBA; 6GHz DSO; non-inverting Q4; n640v Q3; p480v Q3; p800v Q3; n480v Q3; n640v Q3; n800v 500ps/div

14 MFDIA886-2; Q1 pumped Positive Bias [V] FWHM [ns] MFDIA886-2; Q2 pumped Negative Bias [V] FWHM [ns]

15 TAKE TCT SIGNALS for SERIOUS and EXTRACT CHARGE DRIFT PARAMETERS VERY-VERY PRELIMINARY!!! M. Pomorski, PhD Thesis v dr = µ 0Ε µ 0Ε 1 + v s

16 TAKE TCT SIGNALS for SERIOUS and EXTRACT CHARGE DRIFT PARAMETERS VERY-VERY PRELIMINARY!!! M. Pomorski PhD Thesis

17 TC signals, traversing ions 2010 mixing of discrete life/drift times? NO! imperfections of the beam-test setup HP2 CC, Paris Sep 2010 CARAT - Advanced Diamond Detectors

18 BEAM TESTwith 40 Ar, 200AMeV; 6MHz/spill=4s ORIGINAL TC SIGNALS RECORDED by REMOTE CONTROLLED DSO, 6GHz BW, 20GS/s without amplifier! Fast uniform rise time; good S/N ratio expecting good σ i = σ N / (dv/dt) FWHM ~ 1.3 ns RateC = 700 MHz/detector channel HP2 CC, Paris Sep 2010 CARAT - Advanced Diamond Detectors

19 BEAM TESTwith 40 Ar, 200AMeV; 6MHz/spill=4s INTRINSIC TIME RESOLUTION of DoI SAMPLES COMPARED TO sc- and pccvdd detectors non corrected for σ N COUNTS / Dia-on-Ir; moddba 40 Ar, 200AMeV σ i = 32 ps DG -PC; FEE1 27 Al, 2AGeV σ i < 25 ps sccvdd; LCBBA 6 Li, 1.8AGeV σ i < 32ps HP2 CC, Paris Sep 2010 TIME DIFFERENCE [ns] CARAT - Advanced Diamond Detectors

20 α SPECTROSCOPY using CSTA2 preamps (U. Bonnes, TUD) 241 Am; E main α-line = 5486 kev MFDIA886-1/2 COUNTS 5486 kev MEASURED ENERGY [kev]

21 MFDia724b, d = 12µm m (2009) MFDia886-1, d= 290µm m (2010) COUNTS 50 CCE % e 40 E a = Am, E α = 5486 kev CCE CCE %; 90.2 E a = % E a =1550 CS886-1, 2010 DoI 724b, MEASURED ENERGY [kev] HP2 CC, Paris Sep 2010 CARAT - Advanced Diamond Detectors

22 MFDia886-1_Q1 (2010)

23 MFDia886-2_Q1,Q3,Q4 (2010)

24 MFDia886-2_Q1,Q3 (2010) comp. to a thick sccvdd (390µm)

25 Low dark conductivity; order of A Narrow TCT signals of fast rt << 80 ps; 0.5 < FWHM < 2.4 ns corresponding to (preliminarily!!) very high v dr values; e-v drmax = 415 µm/ns and e-µ dr (1V/µm) ~ 3080 cm²/vs (!!) CCE α ; ~ 90% - 97% Intrinsic time resolution; σ i = 25 ps Energy resolution; δe/e 3-4% CVD-DOI DOI is a DEFECTIVE SINGLE CRYSTAL DIAMOND MATERIAL THE SHORT CHARGE DRIFT COMBINED WITH A HIGH CCE IS PRESENTLY NOT WELL UNDERSTOOD!!

26 Systematic analysis of TCT signals: FWHM vs. E D CCE(E D ) vs. T TR (E D ) to estimate mean τ e,h NEW MEASUREMENTS applying/removing shortly HV (proposal Christoph Nebel)...any other proposal is also welcome...