JPS6190042A - Analyzing method of uranium - Google Patents

Abstract

PURPOSE:To detect an extremely slight amt. of uranium elements with high accuracy by subjecting sodium fluoride contg. the uranium element to wavelength scanning at the specified wavelength difference provided between excitation light and detection light. CONSTITUTION:The light from a light source 1a is passed through a diffraction grating filter 1b and an optional wavelength is taken out in an excitation light emitting part 1. The light from a sample chamber 3 is subjected to wavelength selection by a diffraction grating filter 2a and is converted to an electric signal by a photodetector 2b in a fluorescent light detecting part 2. On the other hand, the sample chamber 3 is disposed on the optical path connecting the light emitting part 1 and the photodetecting part 2 and is so arranged that the wavelength scanning is executed while the specified wavelength difference is maintained between the filters 1b and 2a by a motor 4. The NaF-KCO3 flux eluted with uranium in the sample is imposed in the sample chamber 3 and while the wavelength of the excitation light is changed in one direction, the light from the sample S is detected at the specified wavelength difference provided with the excitation light.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Application of the Technology The present invention relates to a method of analyzing an extremely small amount of uranium element contained in a metal material or the like using a fluorescence method.

Mouth, conventional technology? With the remarkable progress of J4 integrated circuits, the influence of alpha rays from k, a uranium element contained in extremely small amounts of ψ in silicon oxide, which is the raw material, has become a problem.

By the way, in order to analyze the uranium base contained in metal materials such as NaF, the uranium contained in the sample is melted into sodium fluoride and then solidified to form a NaF-NaKCO3 flux, that is, the sample is prepared. It was analyzed using a fluorescence spectrometer.

However, while the excitation light scattered from sodium fluoride, which is the uranium carrier, is very large, the intensity of the fluorescence spectrum from the target component is extremely small, so the slope of the baseline level is large as shown in Figure 3. There was a problem that the analytical accuracy was low.

C. Objectives In view of the above problems, an object of the present invention is to provide an analysis method capable of detecting extremely small amounts of uranium element with high accuracy.

21. Structure of the Invention, that is, the feature of the present invention is that sodium fluoride containing uranium element is wavelength scanned with a certain wavelength difference between excitation light and detection light.

E. Embodiments The details of the present invention will now be described with reference to illustrated embodiments.

Fig. 1 shows an example of a device used in the invention, and reference numeral -1 in Fig. 1 is an excitation light emitting section, which converts light from a light source 1a such as a xenon lamp into an arbitrary shape using a diffraction grating filter b. It is configured to extract wavelengths. Reference numeral 2 denotes a fluorescent light receiving section, which is configured to selectively select light from a sample chamber 3, which will be described later, by a diffraction grating filter 2a and convert it into an electrical signal by a light receiving element 2b. Reference numeral 3 denotes the aforementioned sample chamber, which is disposed on the optical path connecting the excitation light emitting section and the fluorescence receiving section. 4 is a motor configured to perform wavelength scanning while maintaining a constant wavelength difference between the excitation light side filter lb and the light receiving side filter 2a. Note that the reference numeral 5 in the figure indicates a recording device that records the electrical value η from the fluorescent light receiving section 2.

In such an apparatus, a N a F K CO3 flux produced by eluting uranium from a sample is placed in the test tube 4 chamber 3, and while the wavelength of the excitation light is changed in one direction, a constant wavelength difference from the excitation light is set. When the light from the sample S was detected using the probe, the baseline of the detection output changed smoothly in response to the spectral intensity of the excitation light source. However, when the detection wavelength enters the ijf optical spectral region of uranium, the detection output exhibits a flat peak at the baseline, and after passing through this wavelength region, it shows a gentle base depending on the spectral intensity of the excitation light source. Showing line changes.

Connecting the baselines of the spectra obtained in this way, we
When we measured the size of the uranium, we found that it matched the concentration of uranium contained in the sample with extremely high accuracy. From this, it was found that the influence of diffused reflection of excitation light on the sample surface can be removed.

"Example" 5 g of silicon liquefied (Si02) as a sample and 10 cc of a Kasa n'+ JN mixture of hydrogen fluoride (HF) and nitric acid (HNO3) were placed in a platinum crucible, thermally decomposed, and dried. After adding 2 g of a mixed flux consisting of 11:1 of NaF, NaCO3, and 3Co3 at a ratio of 1:4:4 to this dry powder, the mixture was heated and melted.

It was solidified to adjust the NaF-NaKCO3 flux.

Thus obtained N a F - N a K C
The surface of the O3 flag was smoothed, a non-fluorescent quartz plate was placed on the entire surface, and the sample was placed in a sample chamber, and a wavelength of 266 nm was set between the excitation side wavelength and the light reception side wavelength.

When such preparations were completed, an analysis was performed by scanning the excitation wavelength from the low wavelength side to the long wavelength side, and a spectrum as shown in FIG. 2 could be obtained.

In other words, the spectral change of the excitation light source is used as the baseline, and the excitation wavelength is 556 nm (the fluorescence wavelength of uranium is 290 nm).
A spectrum was obtained in which the detected light had a peak at m). By connecting the baselines of this spectrum (dotted lines in Figure 2) and measuring the peak height P of the baseline, it was possible to detect uranium on the order of 0,0IPPb contained in the sample with an accuracy about 20% higher than with the conventional method. I was able to detect it.

1] In the above-mentioned embodiment, the wavelength difference between the excitation light side and the light receiving side is set to 266 nm, but it goes without saying that the wavelength difference is not limited to this.

1. Effects 2. As explained, in the uninvention, light from the NaF-NaKCO3 flux containing uranium is detected by performing wavelength scanning while keeping the wavelength difference between the excitation light side and the light reception side constant. This makes it possible to supplement the baseline of the spectrum while removing the influence of the excitation light reflected from the surface of sodium fluoride, making it possible to detect extremely small amounts of uranium with high precision.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an example of a device used in the invention;
Figure 2 is a waveform diagram showing the uninvented analysis results, Figure 3 is
It is a figure showing the analysis result by the conventional method.

Claims (1)

[Claims] NaF-NaKCO containing uranium is obtained by performing wavelength scanning while maintaining a constant wavelength difference between the excitation wavelength and the reception wavelength.
_3 A uranium analysis method that detects reflected light from flux.