Application
The detecting unit is designed to register X-ray radiation with a wavelength of 0.7 to 2.5 Å with simultaneous determination of the coordinates of the place where X-ray quanta hit the input working window of the detector.
It is used in diffractometer systems for various purposes: analyzers of the phase composition of polycrystalline materials, X-ray stress analyzers, to accelerate the recording of weak small-angle diffractograms, diffractometers for general and special purposes. An indispensable tool for structural studies with a high temperature chamber and a low temperature chamber.
Composition
The registration unit consists of a polycapillary raster with an adjusting device, a linear or curved position-sensitive detector (PSD), an electronic power supply and recording unit, coordinated with this detector and the data acquisition program.
The principle of operation of a polycapillary raster
Spatial collimation makes it possible to minimize the instrumental width of the diffraction maximum. This achieves FWHM values using monochromatic X-ray radiation.
Advantages of a raster
The polycapillary raster system has the following advantages:
- provides filtration of scattered X-ray radiation
- improves the resolution of position-sensitive detectors by several times
- increases the peak / background ratio by 4 times
- increases the accuracy of determining the angular position of the diffraction peak
The combined use of a polycapillary raster system with an appropriate b-filter makes it possible to effectively use them in diffractometers for express analysis of polycrystalline materials with complex composition.
The polycapillary system is made in the form of a cellular structure
The collimating system is made in the form of a cellular structure containing a plurality of tubular channels for transporting diffracted X-ray radiation. The walls of adjacent tubular channels are fused.
The glass polycapillary collimating system has the shape of a spherical surface, and the tubular channels are oriented along the radii of this spherical surface. This maximizes the use of diffracted X-ray radiation. The bending radius of the raster system coincides with the radius of the used curved position-sensitive detector and is 114.7, 180 and 240 mm.
Spherical design of a polycapillary raster provides spatial collimation of diffracted X-ray radiation. At the same time, it filters spurious X-rays (such as fluorescence, Compton, elastic, etc.) that create a significant background.
Rigaku raster test results with DHS 900 high temperature chamber (Anton Paar)
Position-sensitive proportional detectors
The radiation-resistant resistive filamentary anode ensures high reliability of the detectors. The detectors are sealed-off gas-filled (Xe-based mixture).
Specifications
| Linear PSD | Curved PSD |
|---|
| Working window size, mm (LxH) | 50х10 | |
| Simultaneous registration range (2Θ), ˚ | | 55 (43) |
| Spatial resolution on the CuKα line, μm | 110 | 280 |
| Energy resolution on the CuKα line, % | 20 | 22 |
| Maximum count rate, c-1 | 5х10^4 | 5х10^4 |
| Working window thickness, μm (Be) | 200 | 200 |
| Overall dimensions, mm (LxWxH) | 118х82х50 | 164х120х42 |
| Weight, kg | 0,8 | 1,1 |
