High performances position- and energy- sensitive X-ray detectors have boosted the development of advanced instruments based on the Full Field X-Ray Fluorescence (FF-XRF) method providing a promising alternative to the conventional scanning approach for performing the two-dimensional elemental imaging.
FF-XRF works by using a broad X-ray beam for illuminating a large area (or even the full area) of a sample. The X-ray fluorescence induced by the primary radiation is detected on a position- and energy-sensitive detector, through a pinhole-collimator (or an Xray polycapillary) positioned between the sample and the detector. The selective detection of the characteristic X-rays hitting the detector allows to obtain the two-dimensional elemental distribution of the investigated samples.
The instrument available at NSIL uses different nozzles and collimators in front of the detector as to attain different values of magnification and spatial resolution:
|
x-ray tube
|
Two options
|
|
Anode material
|
Mo
|
|
Max. HV (kV)
|
50
|
|
Max current (uA)
|
40000
|
600
|
|
Detector
|
ANDOR CCD
|
|
Working temperature (oC):
|
- 85
|
|
Pixels
|
1024 x 1024
|
|
Pixel size (um)
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12 x 12
|
|
Energy resolution (eV):
|
145
|
|
Nozzle length (mm)
|
45
|
45
|
15
|
10
|
|
Collimator inner diameter (um)
|
15
|
25
|
25
|
100
|
|
Sample to nozzle distance (mm)
|
15
|
40
|
60
|
95
|
|
Spatial resolution (um):
|
20
|
40
|
60
|
350
|
|
Magnification (x):
|
5
|
2
|
0.8
|
0.4
|
