Detector Technology, Tips, Tricks Innovation with Integrity
X-Ray Powder Diffraction (XRPD) Bragg-Brentano Geometry 14-15/12/2011 Advanced XRD Workshop 2
X-ray Detector From X-Ray Photon Energy h ν to CPS Photons h ν Counting Signal processing Amplification Preamplification Sensor 14-15/12/2011 Advanced XRD Workshop 3
Commonly Used X-Ray Detectors Point detectors (0-D) Linear detectors (1-D) Area detectors (2-D) Scintillation counter MikroGap detector Proportional counter Compound silicon strip Si(Li) solid state detector detector Ge solid state detectors Single wire proportional counter Silicon pin diodes Image plate detector Silicon drift detectors (IP)* Ionization chambers Linear CCD* Photographic film* * Integrating (analog) detectors, of little use for XRD CCD camera* Multi wire proportional counter (MWPC) MikroGap detector Image plate detector (IP)* Photographic film* Pixel detectors CMOS detectors 14-15/12/2011 Advanced XRD Workshop 4
Point Detectors Point detectors (0-D) Scintillation counter Proportional counter Si(Li) solid state detector Ge solid state detectors Silicon pin diodes Silicon drift detectors Ionization chambers Linear detectors (1-D) MikroGap detector Compound silicon strip detector Single wire proportional counter Image plate detector (IP) Linear CCD Photographic film Area detectors (2-D) CCD camera Multi wire proportional counter (MWPC) MikroGap detector Image plate detector (IP) Photographic film Pixel detectors CMOS detectors 14-15/12/2011 Advanced XRD Workshop 5
Scintillation Counter X-Rays Light Photon Photomultiplier Tube - Pulse Measuring Device Sodium-Iodide Crystal Photocathode Optical Window Dynode Anode 14-15/12/2011 Advanced XRD Workshop 6
Scintillation Counter Active Area: 30 mm Ø Sensitivity: from Cr- to Mo-radiation Energy resolution: 30% - 45% (2.5 kev at 8 kev e.g.) NaI(Tl) scintillation: Maximum count rate >2x10 6 cps Noise: < 0.3 cps Infinite life time Maintenance free Routine detector for all applications Potential angular resolution: no limit! (typical 0.037 for Bragg- Brentano geometry) 14-15/12/2011 Advanced XRD Workshop 7
X-Ray Powder Diffraction with Scintillation Counter D8 ADVANCE diffractometer Cu-radiation 40 kv, 50 ma 0.3 divergence and anti-scatter slit 2.5 axial Soller slits 20µm Ni Cu-Kß filter 0.05mm receiving slit Scintillation counter 0.006 step size 10 seconds per step NIST 1976 Corundum sample FWHM at 100% reflection 0.04 Angular position accuracy certified ±0.01 14-15/12/2011 Advanced XRD Workshop 8
Solid State Detector SOL-XE Detector Active area: 4 x 15 mm 2 Si(Li) solid state energy dispersive detector Energy resolution < 350 ev (4.5%) at 50.000 cps Suppression of e.g. Fefluorescence and Cu-Kß radiation Linearity up to 75.000 cps integral events Wavelength range: 2 kev up to 30 kev (Cr- Mo-radiation) 14-15/12/2011 Advanced XRD Workshop 9
Solid State Detector Functional Principle Au contact ~ 20 nm Pre amplifier Bias voltage X-Rays h Amplifier Signal processing counting e - Au Cathode ~ - 500 V ~ 200 nm Be window P-type Region ~ 0.1µm Lithium drifted depletion region ~ 0.5 3 mm n-type Region ~ 0.1µm 14-15/12/2011 Advanced XRD Workshop 10
X-Ray Powder Diffraction with Energy Dispersive SOL-XE SOL-XE: No Nickel filter, more than 2 times more intensity D8 ADVANCE diffractometer Cu-radiation 40 kv, 50 ma 0.3 divergence and anti-scatter slit 2.5 axial Soller slits No Ni Cu-Kß filter 0.05 receiving slit Sol-XE detector 0.006 step size 2.8 seconds per step NIST 1976 Corundum sample FWHM at 100% reflection 0.04 14-15/12/2011 Advanced XRD Workshop 11
Suppression of Fe-fluorescence Measurement on Hematite/Muscovite composite with Cu-Radiation and scintillation counter Lin (Counts) 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 Ni-Filter 7 10 20 30 40 50 2-Theta - Scale Hematite/Muscovite, 2 Soller, 0,5 slits, 0,2 mm D S, Ni-Filter - Step: 0.020 - Step time: 1. s Hematite Muscovite 14-15/12/2011 Advanced XRD Workshop 12
Suppression of Fe-fluorescence Measurement on Hematite/Muscovite composite with Cu-Radiation, SOL-XE detector 1000 900 800 Sol-X Detector Lin (Counts) 700 600 500 400 300 200 100 0 7 10 20 30 40 50 2-Theta - Scale Hematite/Muscovite, 2 Soller, 0,5 slits, 0,2 mm D S, Solid state Detektor - Step: 0.020 - Step time : 1. s Hematite Muscovite 14-15/12/2011 Advanced XRD Workshop 13
X-Ray Powder Diffraction with SOL-XE Monochromatic Kβ-radiation Energy calibration window of SOL-XE detector Energy dispersive SOL- XE detector can be used with any radiation source, not only Cu. Park the detector on Kβ line of corundum, collect a peak and calibrate with 8.9 KeV for Kβ Very easy and fast way to switch between Kα and Kβ radiation or between different radiation sources 14-15/12/2011 Advanced XRD Workshop 14
X-Ray Powder Diffraction with SOL-XE Monochromatic Kβ-radiation Lin (Cps) 700 600 500 400 300 NIST1976 corundum plate Bragg-Brentano geometry 0.5 divergence 0.1 mm receiving slit Sol-XE detector 200 100 0 46 50 60 2-Theta - Scale File: NIST 1976_1sec kbeta.raw - Step: 0.010 - St ep time: 1. s 00-046-1212 (*) - Corundum, syn - Al2O3 - WL: 1.5406 00-046-1212 (*) - Corundum, syn - Al2O3 - WL: 1.39222 Kβ peaks of corundum Kα peaks of corundum 14-15/12/2011 Advanced XRD Workshop 15
Commonly Used X-Ray Detectors Point detectors (0-D) Scintillation counter Proportional counter Si(Li) solid state detector Ge solid state detectors Silicon pin diodes Silicon drift detectors Ionization chambers Linear detectors (1-D) MikroGap detector Compound silicon strip detector Single wire proportional counter Image plate detector (IP) Linear CCD Photographic film Area detectors (2-D) CCD camera Multi wire proportional counter (MWPC) MikroGap detector Image plate detector (IP) Photographic film Pixel detectors CMOS detectors 14-15/12/2011 Advanced XRD Workshop 16
Compound Si Strip Detector LYNXEYE Detector Active Area: 14.4 x 16 mm Capture angle 3.7 2theta for D8 ADVANCE Compound silicon strip detector technology Maximum global count rate: >100,000,000 cps Maximum local count rate: 700,000 cps Dynamic range >7x10 6 Energy resolution: 25% (2 kev) Wavelength range: from Cr- to Cu-radiation Maintenance free 14-15/12/2011 Advanced XRD Workshop 17
Compound Si Strip Detector How Does it Work Sketch taken from: from Kemmer et al., Phys. Bl., vol. 41, p117 (1985) h + e - LYNXEYE: Compound Silicon Strip Detector 14-15/12/2011 Advanced XRD Workshop 18
High Resolution XRPD in NIST 1976, LYNXEYE vs. Scintillation Counter ~ 150,000 counts D8 ADVANCE 35 kv, 50 ma 0.3 divergence 2.5 Soller 0.3 anti-scatter 2.5 Soller 0.5% Ni-filter 0.1 mm receiving slit 3 opening 0.006 step size 1 sec/step 14-15/12/2011 Advanced XRD Workshop 19
High Resolution XRPD in NIST 1976, LYNXEYE vs. Scintillation Counter 150000 140000 130000 120000 LYNXEYE: 138,000 counts 110000 Intensity [counts] 100000 90000 80000 70000 60000 50000 40000 30000 Scinti: 1100 counts 150000 140000 130000 20000 10000 Intensity [counts] 120000 110000 100000 90000 80000 70000 60000 50000 0 34.71 34.8 34.9 35.0 35.1 35.2 35.3 35.4 35.5 35.6 35.7 2-Theta [deg] 40000 30000 20000 10000 0 25 30 40 50 60 70 2-Theta [deg] 14-15/12/2011 Advanced XRD Workshop 20
High Resolution XRPD in NIST 1976, LYNXEYE vs. Scintillation Counter I rel 100.00 80.00 SRM 660a Scinti LynxEye Normalised Intensity! 60.00 40.00 20.00 0.00 115.50 116.00 116.50 117.00 117.50 2θ deg 14-15/12/2011 Advanced XRD Workshop 21
High-Resolution XRPD on NIST 660a Resolution Counts 100000 SRM 660a LynxEye 80000 60000 40000 FWHM = 0.0365 2 θ With standard slit settings, Using small slits and sollers resolution can be even improved! 20000 0 29.90 30.10 30.30 30.50 30.70 30.90 2θ deg 14-15/12/2011 Advanced XRD Workshop 22
High-Resolution XRPD on NIST 660a: LYNXEYE vs. Scintillation Counter FWHM 0.14 0.12 SRM 660a Scinti LynxEye 0.10 0.08 0.06 0.04 0.02 0.00 0.00 40.00 80.00 120.00 160.00 2θ deg 14-15/12/2011 Advanced XRD Workshop 23
XRPD on NIST 660a Resolution I rel 100 80 SRM 660a Scinti LynxEye 60 40 20 0 20.90 21.10 21.30 21.50 21.70 21.90 2θ deg 14-15/12/2011 Advanced XRD Workshop 24
Bragg-Brentano Geometrie Flat Detector Error the 1-D Detector is tangential to goniometer circle, which causes shifts and asymmetries of the reflections A narrower detector capture angle reduces the drawbacks for the price of smaller intensities 14-15/12/2011 Advanced XRD Workshop 25
XRPD at Low Angles with LYNXEYE Ag-Behenate D8 ADVANCE 35 kv, 50 ma 500 mm Ø 0.1 divergence slit 2.5 Soller slits Anti-scatter screen Ni 0.5 % filter 30 rpm LYNXEYE 1 opening Step size: 0.006 Step time: 0.1 sec/step 2Theta: 0.5 14-15/12/2011 Advanced XRD Workshop 26
Compound Si Strip Detector Optimized for Cu Radiation Sketch taken from: from Kemmer et al., Phys. Bl., vol. 41, p117 (1985) LYNXEYE: Compound Silicon Strip Detector 14-15/12/2011 Advanced XRD Workshop 27
Compound Si Strip Detector Optimized for Cu Radiation Wavelength Linear absorption coefficient for Si (cm -1 ) Efficiency (300µm sensor) Cr 439.3 > 99% Co 216.4 > 99% Cu 139.4 > 98% Mo 14.25 ~ 35% 14-15/12/2011 Advanced XRD Workshop 28
Compound Si Strip Detector For Hard X-rays Sketch taken from: from Kemmer et al., Phys. Bl., vol. 41, p117 (1985) 500 µm LYNXEYE: Compound Silicon Strip Detector 14-15/12/2011 Advanced XRD Workshop 29
Compound Si Strip Detector For Hard X-rays Wavelength Linear absorption coefficient for Si (cm -1 ) Efficiency (500µm sensor) Cr 439.3 > 99% Co 216.4 > 99% Cu 139.4 > 99% Mo 14.25 ~ 50% Ag 7.09 ~ 30% 14-15/12/2011 Advanced XRD Workshop 30
Compound Si Strip Detector Fluorescence Discrimination Optimized discriminator settings Improve peak-to-background ratio Normalized to max.intensity 14-15/12/2011 Advanced XRD Workshop 31
Functional Principle of Conventional Gas Filled Proportional Detector Pros High sensitivity, low noise due to high intrinsic amplification caused by avalanche multiplication of charges (1 to 2 orders higher than solid state detector) Big active area for affordable costs possible Cons 2-D HI-STAR Limited maximum count rate due to long ion drift times (6 µsec) l (typically <10 3 counts/mm 2 /sec) Permanent detection gas flow required MBRaun PSD mounted on D8 ADVANCE With capillary sample stage 14-15/12/2011 Advanced XRD Workshop 32
Functional Principle of Conventional Gas Filled Proportional Detector X-Rays Voltage Source + - + + + - - - + - Anode + Electrical Current Measuring Device Detection Gas Cathode - 14-15/12/2011 Advanced XRD Workshop 33
MicroGap Detector Technology VÅNTEC-1 TM Detector Large active area of 50x16 mm Capture angle >12 2θ D8 ADVANCE 100 msec Snapshots Super speed continuous scan mode MikroGap technology Global count rate >10 6 cps Detector background <0.01 cps/mm 2 Dynamic Range 10 8 Very good energy resolution of <25% Wavelength range: from Cr- to Moradiation No operating gas purge required, maintenance free Radiation hard 14-15/12/2011 Advanced XRD Workshop 34
MicroGap Detector Technology How Does it Work MikroGap TM technology with resistive anode: shortens drift time of ions fast electrons induce charge on readout strips Adjusted surface resistance (10 5-10 7 Ω/ area): high enough to limit discharges low enough to support high count rates US Patent US 6,340,819 B1 14-15/12/2011 Advanced XRD Workshop 35
VÅNTEC-1 Scanning Diffraction Measurements Count rates: 0.85 kcps 1.7 kcps 3.9 kcps 6.6 kcps Conventional proportional counter Angular resolution 0.05-0.12 Strong function of count rate MikroGap TM, VÅNTEC-1 Angular resolution <0.05 Independent of count rate 14-15/12/2011 Advanced XRD Workshop 36
VÅNTEC-1 in SNAPSHOT Mode Kinetic Studies of Phase Transition Phase Transition of NH 4 NO 3, T = 3 K, 58 Snapshots melted Phase I (cubic) Phase II (tetragonal) Phase IV (orthorhombic) D8 ADVANCE with Bragg-Brentano geometry Power: 40kV, 50 ma Optics: 0.5 divergence slit 4 Soller slit Ni Cu-Kß-filter Step size: 0.023 Time per Snapshot: 1 sec High temperature chamber, permanent heating 14-15/12/2011 Advanced XRD Workshop 37
VÅNTEC-1 in Scanning Mode Hot Humidity Investigations by XRD Parallel beam Göbel Mirror Radial Soller slit Line focus X-ray tube VÅNTEC-1 detector Heated supply hose Hot Humidity Sample chamber 14-15/12/2011 Advanced XRD Workshop 38
VÅNTEC-1 in Scanning Mode Humidification Investigations on Creatine by Fast Continuous Scans 2500 2000 Scan speed 30 /minute 0.01 sec/step 0.0065 /step Lin (Counts) 1500 1000 50 C 0.5 % relative humidity 500 0 5 10 20 30 40 2Theta [deg] Type: 2Th/Th locked - Start: 5.000 - End: 40.005 - Step: 0.007 - Step time: 0. s - Anode: Cu 00-029-1649 (Q) - Creatine - C4H9N3O2 00-029-1650 (D) - Creatine hydrate - C4H9N3O2 H2O 14-15/12/2011 Advanced XRD Workshop 39
VÅNTEC-1 in Scanning Mode Humidification Investigations on Creatine by Fast Continuous Scans 110 100 Creatine hydrate 90 intensity [cps] 80 70 60 50 40 30 20 10 0 Creatine 5 10 20 30 40 2-Theta [deg] Measurement conditions: 5 40 2theta Scan speed 30 /min Step size 0.007 71 seconds/scan 50 C 80 % relative humidity 14-15/12/2011 Advanced XRD Workshop 40
BAXS Detectors for XPRD Dimension GF >150 GF >500 Gain factor 3 Capabilities 14-15/12/2011 Advanced XRD Workshop 41
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