Patent Number: 052992527
Section: summary

BACKGROUND OF THE INVENTION The present invention relates to a film thickness measuring apparatus utilizing fluorescent X-rays. In order to measure the thickness of a minute area using fluorescent X-rays, collimators have been used as means for illuminating a minute area of an object with primary X-rays for excitation. Among various kinds of collimators, a suitable one is selected according to the size of the object to be measured. Collimators are made generally in a circular or rectangular form. However since a collimator with a small aperture cannot pass an X-ray beam of sufficient intensity, a rectangular collimator has been used in order to obtain higher X-ray intensity for an elongated measuring portion. When a rectangular collimator is used for a measurement, a sample object is arranged so as to orient perfectly a long and narrow portion to be measured with the long dimension of the collimator aperture. A prior art rectangular collimator can obtain stronger X-ray strength. However there has been a disadvantage in that the workability is very bad in actual measurement. For example, a sample must be arranged in such a manner that a longer side of its measuring portion is matched perfectly with the long side of the collimator aperture, or if a sample has measuring portions oriented in different longer directions, a procedure must be repeated to match rotatably the longer side of a measuring portion with the long side of the collimator aperture. SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above conventionally inferior workability and to provide a fluorescent X-ray film thickness measuring apparatus which is capable of easily positioning a measuring portion with its longer direction having any orientation. In order to solve the above problem, a fluorescent X-ray film thickness measuring apparatus according to the present invention can freely rotate a rectangular type primary X-ray collimator through 180.degree. around the axis thereof and stop it at a desired angle, whereby its oriented direction can be confirmed by a sample observing device.