Abstract: An X-ray analyzing apparatus according to the invention includes an excitation ray generator for applying an excitation ray onto a sample, and an X-ray detector which is sealed in a vacuum container along with a cooling device; a first X-ray passing layer, where a first gas exists, is provided in a path through which the characteristic X-ray generated from the sample travels to the X-ray detector; X-ray transmission windows are provided on the first X-ray passing layer and on the vacuum container so as that the characteristic X-ray can reach to the X-ray detector through the windows; the first and second X-ray transmission windows are separated from each other so as to provide a second X-ray passing layer therebetween; and the second X-ray passing layer is arranged to be a vacuum or a second gas is circulated through the second X-ray passing layer.

Abstract: An apparatus for measuring the Sulfur component contained in oil includes an X-ray tube having a target made of Titanium or Scandium, a filter made of Titanium or Scandium for filtering said X-ray radiated from the X-ray tube, a measurement cell for introducing a sample to be measured therein, and a detector for detecting fluorescent X-rays radiated from the sample. According to the invention, the X-ray tube has a target made of Titanium or Scandium and the X-rays generated from the X-ray tube are filtered by the filter, which is made of Titanium or Scandium, so that the background of the X-rays for the measurement against the fluorescent X-rays of the Sulfur is reduced and therefore even a small amount of Sulfur contained in the sample can be correctly detected.

Abstract: There is disclosed a rectangular filter which has a simple configuration and is capable of producing an improved rectangular wave. An input step wave is differentiated by a differentiator circuit and amplified by a first amplifier. The output from the amplifier is inverted by an inverting amplifier having a gain of -1. The output from the first amplifier is integrated by an integrator circuit having a time constant equal to the time constant of the differentiator circuit. The output from the inverting amplifier and the output from the integrator circuit are summed up by an adding circuit. The input signal is faithfully reproduced at the output of the adding circuit. After a given time passes since the input signal has been applied, the capacitor of the integrator circuit is shorted out. In this way, a rectangular wave is obtained. There is also disclosed a filter amplifier comprising this rectangular filter and a gated integrator for integrating the output from the rectangular filter for a predetermined time.