JP2003215073A - Wavelength scattering fluorescent x-ray analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength scattering fluorescent X-ray analyzer that can be shortened in evacuating time required for starting measurement while the size of the analyzer is reduced. <P>SOLUTION: At the time of exchanging samples, a spectroscopic chamber 7 and an X-ray irradiating chamber 5 are set to measurement starting vacuums by switching stop valves 23 and 24 after a sample chamber 2 is set to a measurement starting vacuum by means of a single vacuum pump 18 in a state where the shutter 15 between the sample chamber 2 and X-ray irradiating chamber 5 is closed. Thereafter, the shutter 15 is opened. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to reduction of vacuum exhaust time in a wavelength dispersive X-ray fluorescence analyzer.

[0002]

2. Description of the Related Art Conventionally, a sample chamber in which a sample is exchangeably housed, an X-ray irradiation chamber in which a sample is irradiated with primary X-rays,
A sample chamber and an X-ray irradiating chamber, an X-ray irradiating chamber, and a spectroscope are provided, each of which includes a spectroscope that disperses a fluorescent X-ray generated from a sample and a spectroscopic chamber that stores a detector that detects the dispersed fluorescent X-ray. The chambers are arranged so as to communicate with each other, each chamber is evacuated by a vacuum pump through an opening / closing valve, and the sample is irradiated with X-rays in a vacuum atmosphere set to a vacuum degree at which measurement is started,
A wavelength-dispersive X-ray fluorescence analyzer that measures the intensity of X-ray fluorescence emitted from a sample and analyzes the sample is known.

In the conventional X-ray fluorescence analyzer described above,
For example, a vacuum shutter for sample exchange is provided between the sample chamber and the X-ray irradiation chamber. By exchanging the sample in the sample chamber with the vacuum shutter closed, the X-ray irradiation chamber and the spectroscopic chamber are held in vacuum, and after the sample exchange, if a single vacuum pump is used, the opening / closing valve Since only the sample chamber in the atmospheric state needs to be exhausted by the vacuum pump by switching, the vacuum exhaust time is shortened.

[0004]

However, when a gas flow type proportional counter tube or the like is used as the detector, the detector is kept inside the spectroscopic chamber while the sample chamber is evacuated by the vacuum pump and evacuated. The gas in the detector may leak from the thin film of the X-ray incidence window, and the degree of vacuum in the spectroscopic chamber and the X-ray irradiation chamber may be deteriorated. Therefore, the exhaust of the sample chamber is completed,
Even if the vacuum shutter between the sample chamber and the X-ray irradiation chamber is opened and an attempt is made to start the analysis, the degree of vacuum in all the chambers communicating with each other is lowered due to gas leakage in the spectroscopic chamber, so that it is necessary to evacuate again. In this case, the gas of the detector is diffused from the spectroscopic chamber and the X-ray irradiation chamber to the sample chamber, and the entire chamber must be exhausted by the vacuum pump in a state where the partial pressure is reduced. It takes time to evacuate. As a result of the longer vacuum evacuation time, there is a problem that the time required to analyze the sample becomes longer overall.
Particularly in the case of a gas having a high absorptivity for X-rays, it is necessary to lengthen the vacuum evacuation time in order to further increase the degree of vacuum. If the vacuum evacuation time is shortened, X
The line intensity will drift.

On the other hand, it is conceivable that the spectroscopic chamber is constantly evacuated to maintain the degree of vacuum at which measurement is started in response to gas leakage from the detector. In this case, a separate vacuum pump is provided for the spectroscopic chamber. It is necessary and the device becomes large.

An object of the present invention is to solve the above problems and to provide a wavelength dispersive X-ray fluorescence analyzer capable of shortening the vacuum exhaust time for starting the measurement while downsizing the apparatus. There is.

[0007]

In order to achieve the above-mentioned object, the invention of claim 1 provides a sample chamber in which a sample is exchangeably housed and an X-ray irradiation chamber in which the sample is irradiated with primary X-rays. And a spectroscope chamber for housing a spectroscope for separating fluorescent X-rays generated from the sample and a detector for detecting the separated fluorescent X-rays, and the sample chamber, the X-ray irradiation chamber, and the X-ray irradiation chamber. Spectroscopic chambers are arranged in communication with each other, a vacuum shutter for sample exchange is provided between the sample chamber and the X-ray irradiation chamber, and each chamber is evacuated to a vacuum by a single vacuum pump through an opening / closing valve. A wavelength dispersive X-ray fluorescence analyzer for analyzing a sample, which starts measurement in the sample chamber with the vacuum shutter between the sample chamber and the X-ray irradiation chamber closed during sample exchange. After setting the vacuum level to And the X-ray irradiation chamber set to vacuum to start a measurement, and then, to open the vacuum shutter.

According to the structure of claim 1, when the sample is replaced,
With the vacuum shutter between the sample chamber and X-ray irradiation chamber closed,
After setting the sample chamber to a vacuum degree at which measurement is started, the spectroscopic chamber and the X-ray irradiation chamber are set to a vacuum degree at which measurement is started by switching the open / close valve, and then the vacuum shutter is opened. Therefore, the detector gas is exhausted from the spectroscopic chamber and the X-ray irradiation chamber before it is diffused into the sample chamber, so that the gas can be efficiently exhausted without lowering the partial pressure of the gas. Vacuuming time can be shortened. Moreover, since these operations are performed by switching the opening / closing valve with a single vacuum pump, the apparatus does not become large because a separate vacuum pump is not provided for the spectroscopic chamber. As a result, the vacuum exhaust time for starting the measurement can be shortened while the device is downsized.

According to the second aspect of the present invention, a sample chamber in which the sample is replaceably housed, an X-ray irradiation chamber in which the sample is irradiated with primary X-rays, and a spectroscope for separating fluorescent X-rays generated from the sample And a spectroscopic chamber accommodating a detector for detecting the separated fluorescent X-rays, the sample chamber and the X-ray irradiation chamber, and the X-ray irradiation chamber and the spectroscopic chamber are respectively arranged in communication with each other, and the X-ray A vacuum shutter for sample exchange is provided between the irradiation chamber and the spectroscopic chamber, and each chamber is evacuated to a vacuum by a single vacuum pump through an opening / closing valve, and a wavelength dispersive X-ray fluorescence analysis is performed to analyze the sample. In the device, at the time of sample exchange, with the vacuum shutter between the sample chamber and the X-ray irradiation chamber closed, the X-ray irradiation chamber is set to a vacuum degree at which measurement is started, and then the switching valve is switched. After setting the vacuum chamber to a vacuum degree at which measurement is started, after that, And to open the serial vacuum shutter.

According to the structure of claim 2, when the sample is replaced,
After setting the X-ray irradiation chamber to the vacuum level at which measurement is started, with the vacuum shutter between the X-ray irradiation chamber and the spectroscopic chamber closed, set the vacuum level to start measurement at the spectroscopic chamber by switching the open / close valve. After that, the vacuum shutter is opened. Therefore, the gas of the detector is exhausted before it is diffused from the spectroscopic chamber to the X-ray irradiation chamber and the sample chamber, so that the gas can be efficiently exhausted without lowering the partial pressure of the gas. Vacuuming time can be shortened.
Moreover, since these operations are performed by switching the opening / closing valve with a single vacuum pump, the apparatus does not become large because a separate vacuum pump is not provided for the spectroscopic chamber. As a result, the vacuum exhaust time for starting the measurement can be shortened while the device is downsized.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a main part of a wavelength dispersive X-ray fluorescence analyzer according to the first embodiment of the present invention. In FIG. 1, the present apparatus has a sample chamber 2 in which a sample S is replaceably housed, and the sample chamber 2 has a main body case 12
A lid 14 is attached to the upper part of the so as to be openable / closable, and is formed by a space surrounded by the lid 14 and the upper wall 12a of the main body case 12. When setting or exchanging the sample S, the lid 14 of the sample chamber 2 is opened, and the lid 14 is opened during the analysis.
Is closed and a vacuum is created inside. Body case 1
A seal member 17 seals between the lid 2 and the lid 2 so as to maintain a vacuum.

The apparatus has an X-ray irradiation chamber 5 for irradiating the sample S with primary X-rays B1, and the X-ray irradiation chamber 5 is arranged below the upper wall 12a of the main body case 12. An X-ray generator 3 such as an X-ray tube has its head at the opening 16 of the upper wall 12.
It is provided close to the lower surface of the sample S via. In addition, the spectroscopic chamber 7 that houses the spectroscope 8 that disperses the fluorescent X-ray B2 generated from the sample S and the detector 9 that detects the disperse fluorescent X-ray B2 is below the upper wall 12 a of the main body case 12. It is arranged adjacent to the X-ray irradiation chamber 5, and the spectroscope 8 and the detector 9 are rotated by a goniometer (not shown) while maintaining a constant angular relationship. The detector 9 includes, for example,
A gas flow type proportional counter having an X-ray entrance window made of a thin film of polypropylene, polyester, or the like and used while flowing a gas for a detector is used. In this gas flow type proportional counter, gas leakage may occur from the thin film of the X-ray entrance window.

The sample chamber 2 and the X-ray irradiation chamber 5, and the X-ray irradiation chamber 5 and the spectroscopic chamber 7 are arranged so as to communicate with each other, and a vacuum for sample exchange is provided between the sample chamber 2 and the X-ray irradiation chamber 5. Shutter 1
5 are provided. The vacuum shutter 15 is rotated between the open position and the illustrated closed position by an opening / closing drive mechanism (not shown). A seal member 19 seals between the vacuum shutter 15 and the main body case 12 so as to maintain a vacuum.

This apparatus comprises a vacuum pump 18 such as an oil rotary vacuum pump for exhausting the sample chamber 2 and the spectroscopic chamber 7.
An on-off valve 2 for opening and closing a pipe line T1, T2 formed by a pipe between both chambers 2, 7 and a vacuum pump 18, respectively.
3 and 24, and leak valves 25 and 26 for breaking the vacuum in both chambers 2 and 7, respectively. The sample chamber 2 and the spectroscopic chamber 7 are evacuated to a vacuum by a single vacuum pump 18 via open / close valves 23 and 24, respectively. As the open / close valves 23 and 24 and the leak valves 25 and 26, for example, electromagnetic valves are used. The sample chamber 2 and the spectroscopic chamber 7 are provided with pressure sensors 21 and 22 such as Pirani gauges, respectively, and the degree of vacuum in the sample chamber 2 and the spectroscopic chamber 7 is detected.
The entire apparatus of this apparatus is controlled by a controller (control means) not shown, and the operation of the opening / closing drive mechanism of the vacuum shutter 15, the opening / closing valves 23 and 24, and the leak valve 2 are performed.
The switching of 5, 26, etc. is also controlled by the controller.

With each chamber 2, 5, 7 set to the degree of vacuum at which measurement is started, the X-ray generator 3 emits the primary X-ray B1 and irradiates the lower surface of the sample S. The primary X-ray B1 irradiated on the lower surface of the sample S excites the sample S to generate secondary X-rays (fluorescent X-rays) B2 specific to the element. This 2
The secondary X-ray B2 is incident on a spectroscope 8 such as a dispersive crystal to be dispersed, and the secondary X-ray B2 having a predetermined wavelength that satisfies the Bragg's equation.
Only 2 is diffracted at the same diffraction angle as the angle of incidence on the spectroscope 8. This diffracted secondary X-ray B2 is incident on the X-ray detector 9 and detected, and the elemental analysis of the sample S is performed based on the detected value.

The operation of the apparatus having the above configuration will be described. The vacuum state in the sample chamber 2 and the spectroscopic chamber 7 is shown in FIG. The horizontal axis represents the vacuum exhaust time (sec), and the vertical axis represents the degree of vacuum (Pa).
The degree of vacuum increases along the vertical axis. The operation of this apparatus is shown by a solid line (a vacuum state in the sample chamber 2 is α, the vacuum state in the spectroscopic chamber 7 is β), and the operation of the conventional apparatus is shown by a two-dot chain line.

First, when exchanging a sample, the sample chamber 2 and X in FIG.
With the vacuum shutter 15 between the radiation irradiation chambers 5 closed,
The lid 14 is opened, and the sample S is loaded into the sample chamber 2 from the outside. At this time, the opening / closing valve 23 of the pipeline T1 is closed and the leak valve 25 is opened. Next,
The lid 14 is closed, the leak valve 25 is closed,
The opening / closing valve 23 is opened, the inside of the sample chamber 2 is evacuated from the atmospheric state by the vacuum pump 18, and the degree of vacuum P1 at which the measurement is started is set (α in FIG. 2, time t1). The degree of vacuum in the sample chamber 2 is detected by the pressure sensor 21.
At this time, the open / close valve 24 and the leak valve 26 in the pipeline T2 are both closed. Since the vacuum shutter 15 is closed in the spectroscopic chamber 7 (and the X-ray irradiation chamber 5 in communication with it), the vacuum state is maintained. However, since there is gas leakage from the detector 9, a vacuum for starting measurement is obtained. Degree P1 to P2 (β in FIG. 2, time t1). The degree of vacuum in the spectroscopic chamber 7 is detected by the pressure sensor 22.

Next, the opening / closing valve 23 of the pipeline T1 is closed, the opening / closing valve 24 of the pipeline T2 is opened, the inside of the spectroscopic chamber 7 is evacuated by the vacuum pump 18, and the degree of vacuum is increased from the degree of vacuum P2. Degree of vacuum P1 that rises and starts measurement
Is set to. During this time, the sample chamber 2 maintains the degree of vacuum P1 at which the measurement is started. Then, the vacuum shutter 15 is opened, and the sample analysis is performed in a state where the inside of the sample chamber 2, the X-ray irradiation chamber 5, and the spectroscopic chamber 7 maintains the degree of vacuum P1 at which measurement is started (time t2 in FIG. 2). .

In FIG. 2, this apparatus (solid line) has a vacuum shutter 15 between the sample chamber 2 and the X-ray irradiation chamber 5 during sample exchange.
The degree of vacuum P1 for starting measurement in the sample chamber 2 with the closed
After the setting, the vacuum pump 18 switches the open / close valves 23 and 24 at time t1 to evacuate the gas in the detector 9 in the spectroscopic chamber 7 before the gas diffuses and measure the spectroscopic chamber 7 and the X-ray irradiation chamber 5. The vacuum degree P1 is set to start
The vacuum shutter 15 is opened at 2 and the measurement is started at the vacuum degree P1. On the other hand, in the conventional apparatus (two-dot chain line), after the sample chamber is evacuated with the vacuum shutter closed, the vacuum shutter is opened at time t1 and the gas of the detector diffuses, and then the entire chamber is opened. The gas is evacuated and the measurement is started at the vacuum degree P1 at time t3. In the conventional apparatus, since the vacuum shutter is opened at time t1, the sample chamber communicates with the spectroscopic chamber and the X-ray irradiation chamber at this point, so the degree of vacuum is slightly improved as compared with the present apparatus (γ in FIG. 2). ). Unlike the conventional device, this device exhausts the gas of the detector 9 from the spectroscopic chamber 7 and the X-ray irradiation chamber 5 before diffusing it into the sample chamber 2, so that the partial pressure of the gas is not lowered and the gas is efficiently extracted. Since the gas can be evacuated, when the vacuum pump 18 is operated under the same conditions, the vacuum evacuation time for starting the measurement can be shortened (time t2 <t3), as compared with the conventional device that evacuates after diffusion. In addition, these operations are performed by switching the open / close valve to a single vacuum pump 1
Since it is performed in step 8, the vacuum chamber is not separately provided for the spectroscopic chamber 7, so that the apparatus does not become large. As a result, the vacuum exhaust time for starting the measurement can be shortened while the device is downsized.

Next, a second embodiment will be described.
FIG. 3 is a vertical cross-sectional view of the main part of the wavelength dispersive X-ray fluorescence analyzer according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in that the vacuum shutter 15 is provided between the sample chamber 2 and the X-ray irradiation chamber 5 to evacuate the sample chamber 2, and unlike the X-ray irradiation chamber 5 and the spectroscopic chamber. Vacuum shutter 3 between 7
5 is provided and the X-ray irradiation chamber 5 is evacuated. Other configurations are similar to those of the first embodiment.

In FIG. 3, when the sample is replaced, with the vacuum shutter 35 between the X-ray irradiation chamber 5 and the spectroscopic chamber 7 closed,
After the X-ray irradiation chamber 5 is set to the degree of vacuum at which measurement is started, the spectroscopic chamber 7 is set to the degree of vacuum at which measurement is started by switching the open / close valves 23 and 24, and then the vacuum shutter 35 is set.
I'm trying to open. Therefore, similarly to the above, the detector gas in the spectroscopic chamber 7 is exhausted before being diffused from the spectroscopic chamber 7 to the X-ray irradiation chamber 5 and the sample chamber 2, so that the gas partial pressure is not lowered and the efficiency is improved. Since the gas can be evacuated well, the vacuum evacuation time can be shortened as compared with the case of evacuating after diffusion. Further, since these operations are performed by the single vacuum pump 18 by switching the open / close valves 23 and 24,
Since no separate vacuum pump is provided for the spectroscopic chamber 7, the device does not become large. As a result, the vacuum exhaust time can be shortened while the device is downsized.

[0022]

As described above, according to the present invention, the gas leaked from the detector in the spectroscopic chamber is exhausted before it is diffused to the sample chamber, so that the gas partial pressure can be efficiently reduced without lowering the partial pressure of the gas. Since it can be evacuated, the vacuum evacuation time can be shortened compared to evacuation after diffusion, and since these operations are performed by switching the open / close valve with a single vacuum pump, measurement can be started while downsizing the device. The vacuum evacuation time for this can be shortened.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a main part of a wavelength dispersive X-ray fluorescence analyzer according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an operation of the device.

FIG. 3 is a vertical cross-sectional view showing the main parts of a wavelength dispersive X-ray fluorescence analyzer according to a second embodiment of the present invention.

[Explanation of symbols]

2 ... Sample chamber, 5 ... X-ray irradiation chamber, 7 ... Spectroscopic chamber, 15 ... Vacuum shutter, 18 ... Vacuum pump, 23, 24 ... Open / close valve, S ... Sample.

Claims (2)

[Claims] 1. A sample chamber in which a sample is exchangeably housed,
An X-ray irradiation chamber for irradiating the sample with primary X-rays, and a spectroscopic chamber for accommodating a spectroscope for separating fluorescent X-rays generated from the sample and a detector for detecting the spectroscopic X-rays, The sample chamber and the X-ray irradiation chamber, and the X-ray irradiation chamber and the spectroscopic chamber are arranged to communicate with each other, a vacuum shutter for sample exchange is provided between the sample chamber and the X-ray irradiation chamber, and each chamber is an opening / closing valve. A wavelength dispersive X-ray fluorescence analyzer for analyzing a sample, which is evacuated to a vacuum by a single vacuum pump via a vacuum pump, wherein a vacuum shutter is provided between the sample chamber and the X-ray irradiation chamber during sample exchange. In the closed state, the sample chamber is set to a vacuum degree at which measurement is started, and then the spectroscopic chamber and the X-ray irradiation chamber are set to a vacuum degree at which measurement is started by switching the opening / closing valve, and then the vacuum is set. Wavelength dispersive X-ray fluorescence analyzer with open shutter . 2. A sample chamber in which samples are exchangeably housed,
An X-ray irradiation chamber for irradiating the sample with primary X-rays, and a spectroscopic chamber for accommodating a spectroscope for separating fluorescent X-rays generated from the sample and a detector for detecting the spectroscopic X-rays, The sample chamber and the X-ray irradiation chamber, and the X-ray irradiation chamber and the spectroscopic chamber are arranged to communicate with each other, a vacuum shutter for sample exchange is provided between the X-ray irradiation chamber and the spectroscopic chamber, and each chamber is an opening / closing valve. A wavelength dispersive X-ray fluorescence analyzer for analyzing a sample, which is evacuated to a vacuum by a single vacuum pump via a vacuum pump, wherein a vacuum shutter between the X-ray irradiation chamber and the spectroscopic chamber is used during sample replacement. In the closed state, the X-ray irradiation chamber is set to a vacuum degree at which measurement is started, and then the spectroscopic chamber is set to a vacuum degree at which measurement is started by switching the opening / closing valve.
A wavelength dispersive X-ray fluorescence analyzer which opens the vacuum shutter.