Rigaku 2080A211, Инструкция по эксплуатации

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Column
Tube voltage and tube current
The intensity of characteristic x-rays is proportional to the n -th power of the difference between tube voltage and
minimum excitation voltage (minimum voltage required for obtaining characteristic x-rays). It is also proportional
to tube current. When the tube voltage is low, the value of n approaches 2. As the tube voltage increases, the value
of n becomes smaller. On the other hand, the intensity of continuous x-rays that appear as a background in the K
β
filter method is proportional to the square of the tube voltage and is also proportional to the tube current. This
means that an optimum tube voltage value exists for measurements with each target. The following table gives the
optimum voltages for different target types. For measurements using the K
β filter method, it is a good way to set
the tube voltage so that the P/B ratio (peak-to-background ratio) will become the largest.
Optimum voltage
(equivalent load) (kV)
Target
Minimum
excitation
voltage
(kV)
Intensity at
maximum
P/B ratio at
maximum
Cu 8.86 40 ～ 55 25 ～ 35
Co 7.71 35
～
50 25
～
35
Fe 7.10 35
～
45 25
～
35
Cr 5.98 30 ～ 40 20 ～ 30