SCT Lorentz Angle Measurement and the 1 st Collision ID Plots - PowerPoint PPT Presentation

SCT Lorentz Angle Measurement and the 1 st Collision ID Plots Reisaburo TANAKA ATLAS-LAL Meeting Dec. 17, 2009

ATL-COM-INDET-2009-039 2 2009.12.17 SCT Lorentz angle measurement

Outline 1. SCT Digitization Model 2. Lorentz (Hall) Angle Measurement 3. Under-depleted Detector 4. ID Plots with the 1 st Collision Data 5. After Irradiation 6. Summary 3 2009.12.17 SCT Lorentz angle measurement

1. SCT Digitization Model

ATLAS Inner Detector 内部飛跡検出器 SCT Barrel 2T Solenoid Field SCT  4 barrel, 2x9 disk endcaps, | η |<2.5  2112 barrel SCT modules  80µm strip pitch, 768 strip daisy-chain  2x2 sensors with 40mrad stereo angle 5 2009.12.17

SCT Digitization Threshold 1 fC Radiation damage Amp on ABCD3T (DMILL) Electric noise Trim DAC range/step SiO 2 Threshold non-uniformity Readout Gain drop Strip gap 80µm Al strip Diffusion Radiation damage on sensor Depth p implant Crystal damage 150V 285µm Drift SCT p-in-n n bulk (Pixel n-in-n) Depletion Capacitance Type inversion of Reverse bias voltage bulk material n → p MIP Landau-Vavilov distribution MPV(Median)=72(108) e-h pair/micron → Q=3.28(4.92) fC 6 2009.12.17 SCT Lorentz angle measurement

Ramo (weighting) potential and induced current A B C D  V. Radeka, “Low Noise Techniques in Detectors,” e h Ann.Rev.Nucl.Part.Sci.38 (1988) 217-277.  H. Spieler ”Semiconductor Detector Systems,” Oxford Univ Press, 2005. SCT (p-in-n) Strip detector signal for n-bulk device electron and hole V D =60V, V bias =90V drift in strip detector (Pixel n-in-n) SCT p-in-n e h Electron dominates Hole dominates H. Spieler Total charge is the same. 7 2009.12.17 SCT Lorentz angle measurement

Lorentz (Hall) angle model ATL-INDET-2001-004 tan θ L = µ H B = r µ d B µ H : Hall mobility r : Hall factor ≈ 1 v s / E c 1/ β (drift mobility) µ d = Electrons (n-in-n) [ ] β ( ) 1 + E / E c Holes (p-in-n) Valid for T>250K, E along <111> crystallographic direction Parametrization: C. Jacoboni et al. , Solid-State Electronics 20 (1977) 77-89. T. Lari, ATL-INDET-2001-004 Implemented into SCT Digitization S.Gadomski, ATL-SOFT-2001-005 8 2009.12.17 SCT Lorentz angle measurement

Bias voltage dependence ATL-INDET-2001-004 tan θ L = µ H B = r µ d B v s / E c 1/ β (drift mobility) µ d = [ ] β ( ) 1 + E / E c T.Lari PhD thesis 450V 150V 150V 450V drift velocity saturation at high electric field ( ) ∂θ L V , T → drop of "mobility” = v /E ≈ − 0.005  / V → drop of Lorentz angle ∂ V 150 V ,273 K 9 2009.12.17 SCT Lorentz angle measurement

Doping and Temperature dependence T.Lari PhD thesis tan θ L = µ H B = r µ d B v s / E c 1/ β (drift mobility) µ d = [ ] β ( ) 1 + E / E c  LHC is not supposed to give effects on mobility due to doping concentration increase by radiation. 10 12 cm -3 at the beginning of LHC.  Mobility depends on temperature. ( ) ∂θ L V , T ≈ − 0.027  / K ∂ T 150 V ,273 K 10 2009.12.17 SCT Lorentz angle measurement

2. Lorentz (Hall) Angle Measurement

Lorentz Angle Cosmic rays can traverse SCT module with large Cosmic ray incidence angle. Cosmic ray d SCT Barrel θ L σ a θ B θ : incidence angle y Incident particle d : cluster size θ L : Lorentz (Hall) angle Local incidence angle a : depletion depth b : minimum cluster size σ : charge career diffusion x d = a tan θ − tan θ L + b Cluster SCT module ( θ L =0 when B=0) 2009.12.17 12 SCT Lorentz angle measurement

Incidence angle vs <cluster> width ? Charge sharing #strip(30°,60°,70°)=2.1,6.2,9.8 Q=1.0fC@90° incidence angle (80µm cross) 13 2009.12.17 SCT Lorentz angle measurement

( ) ⊗ Gauss ( θ ) a tan θ − tan θ L + b Wide range plot   2 ( ) 2 πσ exp − θ − ′ 1 θ θ + 5 σ ∫ ( ) a tan ′ θ − tan θ L + b   d ′ = θ   2 σ 2 θ − 5 σ   B=2T B=0T <cluster>_min 1.134 ± 0.004 1.135 ± 0.006 Model prediction Lorentz Angle -3.93 ± 0.03° 0.05 ± 0.05° θ L =-3.69 ± 0.26(syst.)° 14 2009.12.17 SCT Lorentz angle measurement

Systematics Checks  Lorentz angle fitting range  Upper/Lower half of SCT barrel  Axial/Stereo modules  Positive/Negative tracks  Different run period  Module bow effect → No major effects seen 15 2009.12.17 SCT Lorentz angle measurement

Bias voltage dependence ( ) ∂θ L V , T ≈ − 0.005  / V Nominal bias voltage at 150V ∂ V 150 V ,273 K 16 2009.12.17 SCT Lorentz angle measurement

SCT barrel module temperature Graham Beck SCT Software Meeting, Jan. 15, 2009 2008 running Hybrid <T>=+8.67 ℃ Sensor <T>=+5.0±1.0 ℃ 17 2009.12.17 SCT Lorentz angle measurement

Temperature dependence Bias voltage at 150V ( ) ∂θ L V , T ≈ − 0.027  / K ∂ T 150 V ,273 K 18 2009.12.17 SCT Lorentz angle measurement

Magnetic field dependence tan θ L = µ H B = r µ d B Normalized at 150V, 273K. Straight line is the model prediction. 19 2009.12.17 SCT Lorentz angle measurement

Magnetic field dependence Solenoidal field drops by -1.5% at the edge of barrel SCT Lorentz angle can be a Hall probe ! 20 2009.12.17 SCT Lorentz angle measurement

3. Under-depleted Detector

T. Kondo (KEK) 2009.11.27 Field Strength in the bulk V D = 64.8 ± 9.5V NIM A578 (2007)98-118. flat diode model uniform field model SCT Operation with beam 1) "Super safe" : Barrel 5 V, Endcaps 20V 2) "Standby" : Barrel 20 V, Endcaps 20V … still efficiency~80%@1fC Thr. ! 3) "ON" : Barrel 150 V, Endcaps 150V 22 09.12.17

TCAD simulation Mathieu Benoit (LAL), Preliminary result. θ L =4.6° p-implant 2250 θ L =4.15° 2807 4425 θ L =4.5° θ L =3.8° 5263 6600 θ L =4.0° 7719 n-bulk θ L =3.6° Uniform flat diode model − E y = V B + V D − 2 V D ( ) d 2 d − y d Current model agrees with exact calculation θ L within 5% (syst. err.). <60µm from p-implant complicated. Note E-profile change after irradiation (type inversion). 23 2009.12.17 SCT Lorentz angle measurement

Elias Coniavitis, Preliminary SCT bias voltage scan Lorentz angle can be a thermometer ! 24 2009.12.17 SCT Lorentz angle measurement

SCT depletion depth measurement via Lorentz angle slope PDG2009 d 28. Particle Detectors θ L σ a θ B Elias Coniavitis, Preliminary Depletion depth ! partial a ∝ √ V bias depletion Without Gauss. Conv. Why data are not full depletion pointing towards the origin ? With Gauss. Conv. 25 2009.12.17 SCT Lorentz angle measurement

4. ID Plots with the 1 st Collision Data

27 2009.12.17 SCT Lorentz angle measurement

28 2009.12.17 SCT Lorentz angle measurement

Lorentz angle with collision data Pixel SCT θ L ≅ +12 degrees θ L ≅ -4 degrees 29 2009.12.17 SCT Lorentz angle measurement

> 700 dead strips in Disk 2 30 2009.12.17 SCT Lorentz angle measurement

31 2009.12.17 SCT Lorentz angle measurement

32 2009.12.17 SCT Lorentz angle measurement

33 2009.12.17 SCT Lorentz angle measurement

5. After Irradiation

SCT Cooling TF, Taka Kondo 35 2009.12.17 SCT Lorentz angle measurement

SCT Cooling TF, Taka Kondo 36 2009.12.17 SCT Lorentz angle measurement

SCT Cooling TF, Taka Kondo 37 2009.12.17 SCT Lorentz angle measurement

6. Summary Lorentz (Hall) angle  Lorentz angle is powerful tool to study the semiconductor detectors.  θ L can be measured < 0.10° statistical precision.  Studied incidence angle, bias voltage, temperature, B dependence.  Max. 20µm Lorentz shift but clearly visible.  Data agree with the model which is put in SCT digitization.  Needs further investigation for under-depleted detector. To do lists  SCT Digitization Model Tuning (Lorentz angle, cluster width, timing)  Parameter update as functions of bias voltage, sensor temperature and dose of irradiation (important !).  Effect of irradiation for SCT, Pixel (IBL, sLHC). 38 2009.12.17 SCT Lorentz angle measurement

Back up 39 2009.12.17 SCT Lorentz angle measurement

MC (-7°C,150V) Min+-|fit range| fitting range Cosmic (5.0°C,150V) 40 2009.12.17

Elias Coniavitis, Preliminary SCT bias voltage scan [30-300]V 41 2009.12.17 SCT Lorentz angle measurement