JPS6073447A - Light element fluorescent x-ray spectroscope - Google Patents

Abstract

PURPOSE:To remove secondary electrons and to improve S/N of a detection signal and the accuracy of analysis with a fluorescent X-ray spectroscope in which total reflection mirrors are used as a spectroscopic means and fluorescent X-rays of the wavelength having a specific value or above are totally reflected by impressing a magnetic field roughly perpendicularly to the fluorescent X-rays incident on the mirrors. CONSTITUTION:Secondary electrons in addition to fluorescent X-rays are generated from a sample excited by X-rays. Since the incident angle of the fluorescent X-rays to mirrors 4 is low, the angle at which the route of the fluorescent X-rays are bent in the midway is small and therefore the probability that the secondary electrons past slits 3 enter a detector 5 is extremely high. Magnetic poles 8, 9 are for shutting off these secondary electrons and generate the magnetic field crossing roughly perpendicularly with the route for the fluorescent X-rays by a U-shaped permanent magnet or electromagnet 10. The magnetic field bends the route for ahe secondary electrons withdout affecting the fluorescent X-rays thereby separating the secondary electrons from the fluorescent X- rays and preventing the secondary electrons from entering the detector 5.

Description

DETAILED DESCRIPTION OF THE INVENTION A) Field of Industrial Application The present invention relates to a fluorescence X-ray spectrometer for analyzing light elements such as carbon.

(b) Conventional technology Generally, when light elements are analyzed using fluorescent X-rays, since the wavelength of fluorescent X-rays is long, the fluorescent X-rays emitted from the sample are incident on a mirror at a low angle. , a method is used in which fluorescent X-rays of a predetermined wavelength or more are totally reflected, separated into spectra, and detected. However, with this method, the upper fluorescence X-rays are bent in a vacuum and the angle at which they are bent is small, making it easy for secondary electrons emitted from the sample to reach the X-ray detector, which is detected as background noise. However, this method has the disadvantage that the S/N ratio of the detection signal decreases.

(c) Purpose The present invention removes the above noise and improves the S/S of the detection signal.
The purpose is to improve the N ratio and the analytical accuracy of the light element fluorescence X-ray spectrometer.

(D) Structure The present invention provides a fluorescent X-ray spectrometer that uses a total reflection mirror as a spectroscopic means to totally reflect fluorescent X-rays having a wavelength of a certain value or more, in which the fluorescent X-rays incident on the mirror are The secondary electrons are removed by applying a magnetic field almost perpendicular to the .

(e) Embodiment The figure shows one embodiment of the present invention. In the figure, 1 is an X-ray source that generates excitation X-rays, and a sample 2 irradiated with X-rays generates fluorescent X-rays. Reference numeral 3 denotes a slit, which is arranged at a position such that fluorescent X-rays passing through the slit 3 are incident on a mirror 4 at a predetermined angle. For example, when analyzing carbon, the characteristic X-rays of elements heavier than carbon are absorbed by the mirror 3 without being reflected, and only the characteristic X-rays of carbon and elements lighter than carbon are totally reflected and incident on the detector 5. It has become. 6 is a slit provided in the front of the detector. Reference numeral 7 denotes a filter for blocking elements lighter than carbon, that is, fluorescent X-rays having a wavelength larger than a predetermined wavelength.

In addition to fluorescent X-rays, secondary electrons are also generated from the sample 2 excited by the X-rays. Since the angle of incidence of the fluorescent X-rays on the mirror 4 is low, the angle at which the path of the fluorescent X-rays is bent midway is small, so that the secondary electrons that have passed through the slit 3 reach the detector 5. There is a very high probability that it will be incident on the

The magnetic poles 8 and 9 are used to block these secondary electrons, and a U-shaped permanent magnet or electromagnet 10 generates a magnetic field that intersects approximately perpendicularly to the path of the fluorescent X-rays. This magnetic field bends the path of the secondary electrons without affecting the fluorescence X-rays, thereby separating the secondary electrons from the fluorescence X-rays and preventing the secondary electrons from entering the detector 5. It is.

(f) Effects As mentioned above, the light element fluorescence X-ray spectrometer according to the present invention has the following effects:
In the method of dispersing fluorescent X-rays using a total reflection mirror, a magnetic field is applied to the fluorescent X-rays incident on the mirror at a nearly right angle to the direction of incidence, so that the secondary radiation passing through the slit along with the fluorescent X-rays Electrons can be easily removed without affecting the path of fluorescence X-rays, and the background noise that was conventionally generated by secondary electrons that entered the detector along with fluorescence X-rays can be removed. This has the advantage that the S/N ratio of the detection signal can be improved.

[Brief explanation of the drawing]

The figure is a schematic perspective view showing an embodiment of the light element fluorescence spectrometer of the present invention. l...X-ray source, 2...sample, 3...slit, 4
...Mirror, 5...Detector, 6...Slit for detector, filter, 8,9...Magnetic pole, 10...
・Permanent magnet or electromagnet. Agent Patent Attorney ± 11 series Kosuke

Claims (1)

[Claims] An X-ray source that excites the sample, a slit that passes the fluorescent X-rays emitted from the sample, a mirror that totally reflects the fluorescent X-rays in a predetermined wavelength range among the fluorescent X-rays that have passed through the slit, and In a fluorescence X-ray spectrometer equipped with a detector for detecting reflected fluorescence/optical X-rays, a magnetic pole is provided to apply a magnetic field substantially perpendicular to the direction of incidence of the fluorescence X-rays incident on the mirror. A light element fluorescence X-ray spectrometer that removes secondary electrons emitted from a sample.