Detector Technology, Tips, Tricks - S. N. Bose National ...xrdsnb11/Detector_technology.pdf ·...

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

Sen

sor

Pre

-am

plifi

catio

n

Photonsh⋅⋅⋅⋅νννν

Am

plifi

catio

n

Sig

nal

proc

essi

ng

Cou

ntin

g


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

Commonly Used X-Ray Detectors

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


(MWPC)



(IP)*

• Photographic film*

• Pixel detectors

• CMOS detectors* Integrating (analog) detectors, of little use for XRD










Point Detectors




detector

• Single wire



(IP)

• Linear CCD

• Photographic film


• CCD camera

• Multi wire


(MWPC)



(IP)


• Pixel detectors

• CMOS detectors


Scintillation Counter

Sodium-IodideCrystal

Photocathode

Optical Window

-Pulse

MeasuringDevice

Light Photon Photomultiplier Tube

Dynode Anode

X-Rays


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 >2x106 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)


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°


Solid State DetectorSOL-XE Detector

• Active area: 4 x 15 mm2

• Si(Li) solid state energy dispersive detector• Energy resolution < 350 eV(4.5%) at 50.000 cps

• Suppression of e.g. Fe-fluorescence and Cu-Kß radiation

• Linearity up to 75.000 cps integral events

• Wavelength range: 2 keV up to 30 keV (Cr-…Mo-radiation)


Solid State DetectorFunctional Principle

Lithium drifteddepletion region~ 0.5 – 3 mm

AmplifierSignal processing

counting

Au Cathode~ - 500 V~ 200 nm

Pre amplifierAu contact~ 20 nm

X-Rays

Be window

P-typeRegion~ 0.1µm

n-typeRegion~ 0.1µm

Bias voltage

h

e-


X-Ray Powder Diffraction with Energy Dispersive SOL-XE

D8 ADVANCE diffractometer

• Cu-radiation• 40 kV, 50 mA• 0.3 ° divergence and anti-scatter slit

• 2.5° axial Sollerslits

• 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°

SOL-XE: No Nickel filter, more than 2 times

more intensity


MuscoviteHematiteHematite/Muscovite, 2° Soller, 0,5° slits, 0,2 mm D S, Ni-Filter - Step: 0.020 ° - Step time: 1. s

Lin

(Cou

nts)

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

2-Theta - Scale

7 10 20 30 40 50

Ni-Filter

• Measurement on Hematite/Muscovite composite with Cu-Radiation and scintillation counter

Suppression of Fe-fluorescence


MuscoviteHematiteHematite/Muscovite, 2° Soller, 0,5° slits, 0,2 mm D S, Solid state Detektor - Step: 0.020 ° - Step time : 1. s

Lin

(Cou

nts)

0

100

200

300

400

500

600

700

800

900

1000

2-Theta - Scale

7 10 20 30 40 50

Sol-X Detector

• Measurement on Hematite/Muscovite composite with Cu-Radiation, SOL-XE detector

Suppression of Fe-fluorescence


X-Ray Powder Diffraction with SOL-XEMonochromatic Kβ-radiation

• 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 KeVfor Kβ

• Very easy and fast way to switch between Kαand Kβ radiation or between different radiation sources

Energy calibration window of SOL-XE detector


X-Ray Powder Diffraction with SOL-XEMonochromatic Kβ-radiation

• NIST1976 corundum plate

• Bragg-Brentano geometry• 0.5°divergence• 0.1 mm receiving slit

• Sol-XE detector

• Kβ peaks of corundum

• Kα peaks of corundum

00-046-1212 (*) - Corundum, syn - Al2O3 - WL: 1.392 2200-046-1212 (*) - Corundum, syn - Al2O3 - WL: 1.540 6File: NIST 1976_1sec kbeta.raw - Step: 0.010 ° - St ep time: 1. s

Lin

(Cps

)

0

100

200

300

400

500

600

700

2-Theta - Scale

46 50 60










Commonly Used X-Ray Detectors




detector

• Single wire



(IP)

• Linear CCD



• CCD camera

• Multi wire


(MWPC)



(IP)


• Pixel detectors

• CMOS detectors


Compound Si Strip DetectorLYNXEYE 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 >7x106

• Energy resolution: 25% (2 keV)• Wavelength range: from Cr- to Cu-radiation

• Maintenance free


Compound Si Strip DetectorHow Does it Work

h+

e-

Sketch taken from: from Kemmer et al., Phys. Bl., vol. 41, p117 (1985)

LYNXEYE: Compound Silicon Strip Detector


High Resolution XRPD in NIST 1976, LYNXEYE vs. Scintillation Counter

• 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

~ 150,000 counts



Inte

nsity

[cou

nts

]

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

100000

110000

120000

130000

140000

150000

2-Theta [deg]

25 30 40 50 60 70

Inte

nsity

[co

unts

]

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

100000

110000

120000

130000

140000

150000

2-Theta [deg]

34.71 34.8 34.9 35.0 35.1 35.2 35.3 35.4 35.5 35.6 35.7

Scinti:1100 counts

LYNXEYE:138,000 counts



SRM 660a

115.50 116.00 116.50 117.00 117.50

2θ deg

0.00

20.00

40.00

60.00

80.00

100.00

Irel

ScintiLynxEye

Normalised Intensity!


High-Resolution XRPD on NIST 660aResolution

SRM 660a

29.90 30.10 30.30 30.50 30.70 30.90

2θ deg

0

20000

40000

60000

80000

100000

Counts

LynxEye

FWHM = 0.0365° 2 θ

With standard slit settings,Using small slits and sollersresolution can be even improved!


High-Resolution XRPD on NIST 660a: LYNXEYE vs. Scintillation Counter

SRM 660a

0.00 40.00 80.00 120.00 160.00

2θ deg

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

FWHM

ScintiLynxEye


XRPD on NIST 660aResolution

SRM 660a

20.90 21.10 21.30 21.50 21.70 21.90

2θ deg

0

20

40

60

80

100

Irel

ScintiLynxEye


Bragg-Brentano Geometrie Flat Detector Error

• the 1-D Detector is tangential to goniometer circle, which causes shiftsand asymmetries of the reflections

A narrower detector capture angle reduces the drawbacks for the price of smaller intensities


XRPD at Low Angles with LYNXEYEAg-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 °


Compound Si Strip DetectorOptimized for Cu Radiation




Compound Si Strip DetectorOptimized for Cu Radiation

14-15/12/2011 28Advanced XRD Workshop

Wavelength

Linear absorptioncoefficient for Si

(cm-1)

Efficiency (300µµµµm sensor)

Cr 439.3 > 99%

Co 216.4 > 99%

Cu 139.4 > 98%

Mo 14.25 ~ 35%

Compound Si Strip DetectorFor Hard X-rays




500

µµ µµm

Compound Si Strip DetectorFor Hard X-rays


Wavelength

Linear absorptioncoefficient for Si

(cm-1)

Efficiency (500µµµµm sensor)

Cr 439.3 > 99%

Co 216.4 > 99%

Cu 139.4 > 99%

Mo 14.25 ~ 50%

Ag 7.09 ~ 30%


• Optimized discriminator settings• Improve peak-to-background ratio

Compound Si Strip DetectorFluorescence DiscriminationN

orm

aliz

edto

max

.Inte

nsity

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• Limited maximum count rate due to long ion drift times (6 µsec) l (typically <103 counts/mm2/sec)

• Permanent detection gas flowrequired

2-D HI-STAR

MBRaun PSD mounted on D8 ADVANCEWith capillary sample stage


Functional Principle of Conventional Gas Filled Proportional Detector

Detection Gas

ElectricalCurrent

Measuring Device

X-Rays

Cathode -

Anode +

+ -Voltage Source

+

-

+ + +

- - -


MicroGap Detector Technology VÅNTEC-1TM 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 >106 cps • Detector background <0.01 cps/mm2

• Dynamic Range 108

• Very good energy resolution of <25%• Wavelength range: from Cr- to Mo-radiation

• No operating gas purge required, maintenance free

• Radiation hard


• MikroGapTM technology with resistive anode: • shortens drift time of ions• fast electrons induce charge on readout strips

• Adjusted surface resistance (105 - 107 Ω/ area): • high enough to limit discharges

• low enough to support high count rates

MicroGap Detector TechnologyHow Does it Work

US Patent US 6,340,819 B1


VÅNTEC-1 – Scanning DiffractionMeasurements

• Conventional proportional counter

• Angular resolution 0.05° -0.12°

• Strong function of count rate

• MikroGapTM, VÅNTEC-1

• Angular resolution <0.05°

• Independent of count rate

Count rates:• 0.85 kcps• 1.7 kcps• 3.9 kcps• 6.6 kcps


VÅNTEC-1 in SNAPSHOT ModeKinetic Studies of Phase Transition

• 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

Phase Transition of NH 4NO3, ∆∆∆∆T = 3 K, 58 Snapshots

Phase IV (orthorhombic)

Phase II (tetragonal)

Phase I (cubic)

melted


VÅNTEC-1 in Scanning ModeHot Humidity Investigations by XRD

Parallel beamGöbel Mirror

Line focusX-ray tube

Hot HumiditySample chamber

VÅNTEC-1detector

Radial Sollerslit

Heated supplyhose


VÅNTEC-1 in Scanning Mode Humidification Investigations on Creatine by Fast Continuous Scans

00-029-1650 (D) - Creatine hydrate - C4H9N3O2·H2O

00-029-1649 (Q) - Creatine - C4H9N3O2

Type: 2Th/Th locked - Start: 5.000 ° - End: 40.005 ° - Step: 0.007 ° - Step time: 0. s - Anode: Cu

Lin

(Cou

nts)

0

500

1000

1500

2000

2500

2Theta [deg]

5 10 20 30 40

• Scan speed 30°/minute• 0.01 sec/step• 0.0065 °/step

• 50 °C

• 0.5 % relative humidity


VÅNTEC-1 in Scanning Mode Humidification Investigations on Creatine by Fast Continuous Scans

inte

nsity

[cps

]

0

10

20

30

40

50

60

70

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2-Theta [deg]

5 10 20 30 40

Measurement conditions:• 5° – 40° 2theta• Step size 0.007°

• Scan speed 30°/min

• 71 seconds/scan

Creatine

Creatinehydrate

• 50 °C

• 80 % relative humidity


BAXS Detectors for XPRDD

imen

sion

Capabilities

Gain factor 3

GF >150 GF >500


Detector Technology, Tips, Tricks - S. N. Bose National ...xrdsnb11/Detector_technology.pdf ·...

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