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 to CPS

Sen

sor

Pre

-am

plif

icat

ion Photons

h

Am

plif

icat

ion

Sig

nal

pro

cess

ing

Co

un

tin

g

14-15/12/2011 Advanced XRD Workshop 3

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

proportional counter

(MWPC)

MikroGap detector

Image plate detector

(IP)*

Photographic film*

Pixel detectors

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

14-15/12/2011 Advanced XRD Workshop 4

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

Point 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

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

Sodium-IodideCrystal

Photocathode

Optical Window

-Pulse

MeasuringDevice

Light Photon Photomultiplier Tube

Dynode Anode

X-Rays

14-15/12/2011 Advanced XRD Workshop 6

Scintillation Counter

Active Area: 30 mm 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)

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

2.5axial Soller slits 20m Ni Cu-K filter 0.05mm receiving slit Scintillation counter 0.006step 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 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-K 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 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~ 0.1m

n-typeRegion~ 0.1m

Bias voltage

h

e-

14-15/12/2011 Advanced XRD Workshop 10

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

2.5axial Sollerslits

No Ni Cu-K filter 0.05 receiving slit Sol-XE detector 0.006step 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

14-15/12/2011 Advanced XRD Workshop 11

MuscoviteHematiteHematite/Muscovite, 2 Soller, 0,5 slits, 0,2 mm DS, 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

14-15/12/2011 Advanced XRD Workshop 12

MuscoviteHematiteHematite/Muscovite, 2 Soller, 0,5 slits, 0,2 mm DS, 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

14-15/12/2011 Advanced XRD Workshop 13

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

Energy dispersive SOL-XE detector can be used with any radiation source, not only Cu.

Park the detector on K line of corundum, collect a peak and calibrate with 8.9 KeVfor K

Very easy and fast way to switch between Kand K radiation or between different radiation sources

Energy calibration window of SOL-XE detector

14-15/12/2011 Advanced XRD Workshop 14

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

NIST1976 corundum plate

Bragg-Brentano geometry 0.5divergence 0.1 mm receiving slit

Sol-XE detector

K peaks of corundum

K peaks of corundum

00-046-1212 (*) - Corundum, syn - Al2O3 - WL: 1.3922200-046-1212 (*) - Corundum, syn - Al2O3 - WL: 1.5406File: NIST 1976_1sec kbeta.raw - Step: 0.010 - Step time: 1. s

Lin

(Cps

)

0

100

200

300

400

500

600

700

2-Theta - Scale

46 50 60

14-15/12/2011 Advanced XRD Workshop 15

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

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 DetectorLYNXEYE Detector

Active Area: 14.4 x 16 mm Capture angle 3.72theta 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

14-15/12/2011 Advanced XRD Workshop 17

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

14-15/12/2011 Advanced XRD Workshop 18

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

D8 ADVANCE 35 kV, 50 mA 0.3divergence 2.5Soller 0.3anti-scatter 2.5Soller 0.5% Ni-filter 0.1 mm receiving slit 3opening 0.006step size 1 sec/step

~ 150,000 counts

14-15/12/2011 Advanced XRD Workshop 19

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

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

14-15/12/2011 Advanced XRD Workshop 20

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

SRM 660a

115.50 116.00 116.50 117.00 117.50

2 deg

0.00

20.00

40.00

60.00

80.00

100.00

Irel

ScintiLynxEye

Normalised Intensity!

14-15/12/2011 Advanced XRD Workshop 21

High-Resolution XRPD on NIST 660aResolution

SRM 660a

29.90 30.10 30.30 30.50 30.70 30.90

2 deg

0

20000

40000

60000

80000

100000

Counts

LynxEye

FWHM = 0.0365 2

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

14-15/12/2011 Advanced XRD Workshop 22

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

SRM 660a

0.00 40.00 80.00 120.00 160.00

2 deg

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

FWHM

ScintiLynxEye

14-15/12/2011 Advanced XRD Workshop 23

XRPD on NIST 660aResolution

SRM 660a

20.90 21.10 21.30 21.50 21.70 21.90

2 deg

0

20

40

60

80

100

Irel

ScintiLynxEye

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 shiftsand 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 LYNXEYEAg-Behenate

D8 ADVANCE 35 kV, 50 mA 500 mm 0.1 divergence slit 2.5Soller slits Anti-scatter screen Ni 0.5 % filter 30 rpm LYNXEYE 1opening Step size: 0.006 Step time: 0.1 sec/step

2Theta: 0.5

14-15/12/2011 Advanced XRD Workshop 26

Compound Si Strip DetectorOptimized 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 DetectorOptimized for Cu Radiation

14-15/12/2011 28Advanced XRD Workshop

Wavelength

Linear absorptioncoefficient for Si

(cm-1)

Efficiency (300m sensor)

Cr 439.3 > 99%

Co 216.4 > 99%

Cu 139.4 > 98%

Mo 14.25 ~ 35%

Compound Si Strip DetectorFor Hard X-rays

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 29

500

m

Compound Si Strip DetectorFor Hard X-rays

14-15/12/2011 30Advanced XRD Workshop

Wavelength

Linear absorptioncoefficient for Si

(cm-1)

Efficiency (500m 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 31Advanced XRD Workshop

Optimized discriminator settings Improve peak-to-background ratio

Compound Si Strip DetectorFluorescence DiscriminationN

orm

aliz

edto

max

.Inte

nsi

ty

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 sec) l (typically

Functional Principle of Conventional Gas Filled Proportional Detector

Detection Gas

ElectricalCurrent

Measuring Device

X-Rays

Cathode -

Anode +

+ -Voltage Source

+

-

+ + +

- - -

14-15/12/2011 Advanced XRD Workshop 33

MicroGap Detector Technology VNTEC-1TM Detector

Large active area of 50x16 mm Capture angle >122 D8 ADVANCE

100 msec Snapshots Super speed continuous scan mode

MikroGap technology Global count rate >106 cps Detector background

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

Adjusted surface resistance (105 - 107 / 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

14-15/12/2011 Advanced XRD Workshop 35

VNTEC-1 Scanning DiffractionMeasurements

Conventional proportional counter

Angular resolution 0.05 -0.12

Strong function of count rate

MikroGapTM, VNTEC-1

Angular resolution

VNTEC-1 in SNAPSHOT ModeKinetic Studies of Phase Transition

D8 ADVANCE with Bragg-Brentano geometry

Power: 40kV, 50 mA

Optics: 0.5divergence slit

4Soller slit Ni Cu-K-filter

Step size: 0.023 Time per Snapshot: 1 sec

High temperature chamber, permanent heating

Phase Transition of NH4NO3, T = 3 K, 58 Snapshots

Phase IV (orthorhombic)

Phase II (tetragonal)

Phase I (cubic)

melted

14-15/12/2011 Advanced XRD Workshop 37

VNTEC-1 in Scanning ModeHot Humidity Investigations by XRD

Parallel beamGbel Mirror

Line focusX-ray tube

Hot HumiditySample chamber

VNTEC-1detector

Radial Sollerslit

Heated supplyhose

14-15/12/2011 Advanced XRD Workshop 38

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

00-029-1650 (D) - Creatine hydrate - C4H9N3O2H2O

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

14-15/12/2011 Advanced XRD Workshop 39

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

inte

nsity

[cps

]

0

10

20

30

40

50

60

70

80

90

100

110

2-Theta [deg]

5 10 20 30 40

Measurement conditions: 5 402theta Step size 0.007

Scan speed 30/min

71 seconds/scan

Creatine

Creatinehydrate

50 C

80 % relative humidity

14-15/12/2011 Advanced XRD Workshop 40

BAXS Detectors for XPRDD

imen

sio

n

Capabilities

Gain factor 3

GF >150 GF >500

14-15/12/2011 Advanced XRD Workshop 41

Innovation with Integrity

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