Slit system
MiniFlex 600: Benchtop X-ray Diffractometer
83
Slit system
Regarding the slit conditions, MiniFlex 600 has two types of slit system for
measurement: the variable slit system and va fixed slit system.
The variable slit system enables performing a measurement with the constant
irradiation width of 20 mm at the range of 2θ=2
～
67°. X-ray is irradiated on a
measurement while changing the size of the scattering slit along with the sample
size 20 mm. The scattering angle of the incidence X-ray can be broadened up to
maximum approx. 4.2°. A measurement that exceeds 2θ=67°cannot be
performed due to the scattering angle exceeding the limit. Use the va
fixed slit system. For using the variable slit system, insert the IHS 10 mm
(length limiting slit 10 mm) into the DS.
For va fixed slit system, if only the fixed slit is used, the X-ray is
irradiated outside of the sample at low angle side. Combine a variable slit so the
X-ray irradiation width becomes the same with sample width 20 mm at low
angle side. Thus, the variable slit and fixed slit are used for low angle area and
high angle area within measurement range 2θ=2 to 145° respectively in a
measurement. By using slit correction, the intensity of the variable slit used at
the low angle side can be corrected to the intensity of fixed slit.
Slit Correction
The irradiation width of X rays extends outside of the width of the sample 20
mm in 2
θ
≒
20 or lower angle side when using only the fixed slit DS=1.25°. At
2
θ
≒
10, approximately half of the X rays are irradiated outside the sample, and
effective X rays that irradiate the sample become half the amount. Therefore, for
samples with many diffraction lines in low angles, the DS=0.625° is used for
measurement. However, even when using the DS=0.625°, the X–rays will
irradiate outside the sample and the effective width of DS will become narrow at
2
θ
≒
10 or lower. This system has a “Slit Correction” function, which calculates
the effective DS width of fixed slit by the va fixed slit system to correct
intensities of low angle data to the specified DS width. This correction is
performed upon General Measurement and Manual Control measurements and is
converted in real-time.
・
This correction is an
auxiliary
function for the data of pattern comparison and
qualitative analysis, etc. Perform sufficient verification when using for a
quantitative analysis and other precise analysis.
・
Use this correction in the area of 2
θ
≧
2°
1
Select Options –Slit correction (see Fig. 8.5).
