JP2015215209A - Sample cell for x-ray absorption fine structure transmission measurement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sample cell for X-ray absorption fine structure transmission measurement in which the length in the X-ray irradiation direction of a storage region of a sample is made shorter than that of the prior art.SOLUTION: A storage recess is formed with cutting work on a center part of a polyimide sample storage member 20. A sample being a measurement object is stored in the storage recess, and sealed with an X-ray transmission window 10. The sample storage member 20 is held by a holding surface provided on a base part 110. The holding surface is a tapered surface projecting frontward, and the sample storage member 20 is curved with the holding surface. Consequently, tension acts on the sample storage member 20, and thereby the occurrence of wrinkles in the sample storage member 20 is suppressed.

Description

  The present invention relates to a sample cell for X-ray absorption fine structure transmission measurement.

  For measurement of transmitted X-ray intensity of an X-ray absorption fine structure (XAFS), a sample cell containing a sample to be measured is used. For example, Patent Document 1 discloses a sample cell for in-situ XAFS measurement. In the sample cell described in Patent Document 1, a fixed catalyst that holds a gas phase or liquid phase sample is disposed between two X-ray transmission windows. The length of the sample accommodation region in the X-ray irradiation direction, that is, the distance between the two X-ray transmission windows is set to 2 mm. As described above, in the conventional sample cell for XAFS measurement, the length of the sample accommodation region in the X-ray irradiation direction is generally about several mm.

JP 2006-162506 A

  If the length of the sample storage region and the transmission window region in the X-ray irradiation direction is too large, the measurement accuracy of the transmission X-ray intensity may be reduced due to the X-ray absorption of the sample and the transmission window. Further, the transmissive window has a small amount of X-ray absorption, and it is necessary to use a member having a uniform thickness. The irradiated X-ray has a size of several hundreds μm in length and width, and in the transmission measurement, it is necessary that the sample exists with a uniform thickness in the size of the X-ray. In particular, in the case of X-rays with a low energy of 5 keV or less, the influence of absorption by the transmission window is remarkable. Moreover, if the length of the sample storage region is large, the irradiated X-rays are not transmitted and are all absorbed by the sample, and the transmitted X-ray intensity cannot be measured. Therefore, it is desired to reduce the length of the sample accommodation region and the transmission window region in the X-ray irradiation direction as much as possible.

  This invention is made | formed in view of this situation, The main objective is to provide the sample cell for X-ray absorption fine structure transmission measurement which can solve the said subject.

  In order to solve the above-described problem, a sample cell according to one aspect of the present invention is a sample cell that stores a sample to be measured, and an X-ray transmission window that transmits X-rays emitted from a light source; A storage recess for storing the sample is formed, and the X-ray transmission window is attached so as to close the storage recess, whereby a sample storage region is formed by the X-ray transmission window and the storage recess. A sample storage member, a base for holding the sample storage member and the X-ray transmission window, a fixing member attached to the base and fixing the sample storage member and the X-ray transmission window to the base, The sample storage member is made of super engineering plastic, and the storage recess is formed by cutting.

  In the above aspect, the X-ray transmission window may be made of super engineering plastic.

  In the above aspect, the accommodating recess may have a depth of 10 μm to 100 μm.

  In the above aspect, the sample housing member may have a thickness of 15 μm to 110 μm.

  The said aspect WHEREIN: The said fixing member may be comprised so that the said sample storage member may be fixed with respect to the said base so that tension | tensile_strength may arise in the said sample storage member.

  In the above aspect, the sample storage member may be configured such that tension is generated in a direction along the main surface.

  In the above aspect, the sample storage member may be configured so that tension is evenly generated radially.

  In the above aspect, the base is provided with a through hole extending in the X-ray irradiation direction, and the through hole is formed so as to hold the sample storage member in a state where the storage recess is positioned in the through hole. A holding surface of the sample storage member is formed at the periphery, and the holding surface is inclined so that the position changes to the same side in the X-ray irradiation direction toward the outside, and the fixing member is The sample storage member held by the holding surface may be configured to generate tension by pressing the sample storage member in the X-ray irradiation direction.

  In the above aspect, the holding surface may have a truncated cone shape, and the fixing member may have an annular shape corresponding to the holding surface.

  In the above aspect, the sample housing member may be made of polyimide.

  According to the present invention, it is possible to make the length in the X-ray irradiation direction of the sample accommodation region and the transmission window region smaller than the conventional one.

The front view which shows the structure of the sample cell which concerns on embodiment. FIG. 3 is a plan cross-sectional view illustrating a configuration of a sample cell according to the embodiment. Side surface sectional drawing which shows the structure of the sample cell which concerns on embodiment. The front view which shows the structure of a base. The plane sectional view showing the composition of a base. The front view which shows the structure of a sample storage member. The fragmentary plane sectional view which shows the structure of a sample storage member. The partial expanded plane sectional view of the sample cell for demonstrating the mode of attachment in the holding surface of a lock ring, an X-ray transmissive window, and a sample storage member. The schematic diagram for demonstrating the tension | tensile_strength which acts on a sample storage member. The graph which shows the result of evaluation experiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  Each of FIG. 1 to FIG. 3 is a front view, a plan sectional view, and a side sectional view showing the configuration of the sample cell according to the present embodiment. Hereinafter, the vertical direction in FIG. 1 is referred to as “vertical direction”, the horizontal direction is referred to as “horizontal direction”, the front side of the paper is referred to as “front (front side)”, and the back side of the paper is referred to as “rear (back side)”. In FIG. 2, the upper side is “rear”, the lower side is “front”, the left-right direction is “left-right direction”, the front side of the page is “upper”, and the rear side of the page is “lower”. In FIG. 3, the vertical direction is “vertical direction”, the left is “front”, the right is “rear”, the front side of the paper is “right”, and the back side of the paper is “left”.

  The sample cell 100 according to the present embodiment is disposed so as to face the X-ray irradiation apparatus when used for measuring a sample. At this time, it arrange | positions with respect to an X-ray irradiation apparatus so that an X-ray irradiation direction may become back (refer FIG.2 and FIG.3).

  The sample cell 100 according to the present embodiment is used for X-ray absorption fine structure transmission measurement. The sample cell 100 includes a base 110 that holds an X-ray transmission window 10 formed of an X-ray filter that transmits X-rays and a sample storage member 20 that stores a sample to be measured.

  4 and 5 are a front view and a plan sectional view showing the configuration of the base 110. The base 110 is made of stainless steel and has a substantially rectangular parallelepiped shape. The base portion 110 is provided with a through hole 111 having a circular shape when viewed from the front and passing through in the front center direction. In addition, a concave attachment portion 113 that is recessed rearward at the periphery of the through hole 111 is formed on the front side of the base portion 110, and the bottom surface of the attachment portion 113 serves as the holding surface 112 of the sample storage member 20. Yes.

  The holding surface 112 has an annular shape when viewed from the front, and is inclined so as to recede backward from the inside toward the outside. That is, the holding surface 112 is a truncated cone-shaped tapered surface that protrudes forward as it approaches the front-side opening of the through-hole 111.

  6 and 7 are a front view and a partial plan sectional view showing the configuration of the sample storage member 20. The sample storage member 20 is made of polyimide and has a circular film shape when viewed from the front. The sample storage member 20 is provided with a circular storage recess 21 at the front center. A sample to be measured is accommodated in the accommodating recess 21. The housing recess 21 is formed by cutting a polyimide film having a uniform thickness. The thickness of the sample storage member 20 is 60 μm, and the depth of the storage recess 21 is 50 μm or more and 55 μm or less.

  In the present embodiment, the material of the sample storage member 20 is polyimide, but the material is not limited to this. It is also possible to configure the sample storage member 20 with another super engineering plastic. Here, “super engineering plastic” means a synthetic resin having a heat resistant temperature of 150 ° C. or higher, a strength of 49 MPa or higher, and a flexural modulus of 2.4 GPa or higher. Examples include sulfide, polyether ether ketone, polyimide, polyether imide, fluororesin, and liquid crystal polymer. Since such super engineering plastic has good machinability, it can be machined with high precision by cutting. Super engineering plastics are suitable because high processing accuracy is required to form the fine accommodating recesses as described above. Further, in the measurement, the sample temperature may be changed, and the super engineering plastic is also suitable in that the liquid sample can be held under various temperature environments.

  The X-ray transmission window 10 is disposed on the front surface of the sample storage member 20 so as to close the storage recess 21. The X-ray transmission window 10 is made of polyimide and has a circular film shape with a thickness of 5 μm when viewed from the front. The X-ray transmission window 10 is preferably made of a material having X-ray permeability and a small X-ray absorption amount. As in the case of the sample storage member 20, the X-ray transmission window 10 may be made of super engineering plastic other than polyimide.

  A sample (gas phase or liquid phase) is accommodated in the accommodating recess 21 of the sample accommodating member 20 as described above, and the X-ray transmission window 10 is attached to the front surface of the sample accommodating member 20. The sample storage member 20 and the X-ray transmission window 10 that are brought into close contact with each other in this manner are attached to the holding surface 112 so that the sample storage member 20 is positioned on the rear side and the X-ray transmission window 10 is positioned on the front side. At this time, the sample storage member 20 is disposed so that the storage recess 21 is positioned on the through hole 111.

  Further, on the front side of the X-ray transmission window 10, lock rings 31 and 32, which are pressing members, are arranged (see FIGS. 2 and 3). Each of the lock rings 31 and 32 is an annular member in a front view, and the lock ring 31 is made of oxygen-free copper and the lock ring 32 is made of brass. The outer diameter of the lock ring 31 is slightly larger than the inner diameter of 32, and the lock ring 32 is fitted inside the lock ring 31.

  A lock screw 41 that fixes the lock ring 31 is disposed on the front side of the lock ring 31. The lock screw 41 is a brass member that has an annular shape when viewed from the front. A male screw is formed on the outer peripheral surface of the lock screw 41. A female screw is formed on the inner peripheral surface of the attachment portion 113 on the front side of the base 110 (see FIG. 5), and the lock screw 41 is screwed into the attachment portion 113.

  A lock screw 42 for fixing the lock ring 32 is disposed on the front side of the lock ring 32. The lock screw 42 is a cylindrical member made of stainless steel. The outer diameter of the lock screw 42 is substantially the same as the inner diameter of the lock screw 41, and is arranged coaxially inside the lock screw 42. A male screw is formed on the outer peripheral surface of the rear portion of the lock screw 42. A female screw is formed on the inner peripheral surface of the lock screw 41, and the lock screw 42 is screwed to the lock screw 41.

  FIG. 8 is a partially enlarged view of FIG. FIG. 8 shows a state in which the lock rings 31 and 32, the X-ray transmission window 10 and the sample storage member 20 are attached to the holding surface 112. When the lock screw 41 is fastened to the mounting portion 113 (see FIGS. 2 and 3), the lock ring 31 presses the X-ray transmission window 10 and the sample storage member 20 backward as shown in FIG. When the lock screw 42 is tightened to the lock screw 41 (see FIGS. 2 and 3), the lock ring 32 presses the X-ray transmission window 10 and the sample storage member 20 backward as shown in FIG. At this time, since the holding surface 112 is a tapered surface, the X-ray transmission window 10 and the sample storage member 20 pressed against the lock rings 31 and 32 try to slide on the holding surface 112 from the center toward the outside. . Further, since the X-ray transmission window 10 and the sample storage member 20 are along the holding surface 112, they are curved so that the center protrudes forward. Thereby, tension is generated in the X-ray transmission window 10 and the sample storage member 20 in the radial direction from the center toward the outside along the main surfaces.

  FIG. 9 is a schematic diagram for explaining the tension acting on the sample storage member 20. As shown in FIG. 9, uniform tension is generated in the sample housing member 20 in the circumferential direction. The same applies to the X-ray transmission window 10.

  The portion of the X-ray transmission window 10 and the sample storage member 20 where the storage recess 21 is provided has a very small thickness of about 5 μm and easily wrinkles, and the depth of the storage recess 21 (that is, the storage recess 21 is stored). The thickness of the sample is not uniform. Since these are portions where X-rays are irradiated and measurement is performed, if the wrinkles occur or the depth of the housing recess 21 is not uniform, the measurement results are adversely affected. By applying the tension from the center to the outside on the X-ray transmission window 10 and the sample storage member 20 as described above, the generation of wrinkles can be suppressed and the depth of the storage recess 21 can be made uniform.

  Further, an insertion hole 5 extending rightward is provided from the left side surface of the base 110. The insertion hole 5 extends to the vicinity of the through-hole 111, and a thermocouple probe as a temperature sensor is inserted therein. The temperature of the sample is measured by this temperature sensor.

  When the sample is stored in the sample cell 100 as described above, the sample cell 100 is placed in the vacuum chamber. The sample cell 100 disposed in the vacuum chamber is irradiated with X-rays, and the sample is measured by X-ray absorption fine structure analysis.

(Evaluation experiment)
The inventors manufactured the sample cell 100 according to the above-described embodiment, and performed an evaluation experiment on its performance. FIG. 10 is a graph showing experimental results. In the graph of FIG. 10, the horizontal axis indicates X-ray energy, and the vertical axis indicates the amount of X-ray absorption. In this experiment, a sample containing cesium was used as a measurement target, and the depth of the housing recess 21 was 50 μm.

  As shown in FIG. 10, the absorption edge appears when the X-ray energy is 5.0 keV. A clear peak is observed at the absorption edge, and a fine structure is clearly recognized in the energy region continuing from the absorption edge. As described above, if the thickness of the sample is made minute, the measurement accuracy is improved and the X-ray absorption fine structure can be clearly observed. According to the sample cell according to the present embodiment, it is possible to form the accommodating recess 21 with a very small depth, and thus it is possible to configure a sample cell with high measurement accuracy.

(Other embodiments)
In the above-described embodiment, the depth of the accommodating recess 21 is 50 μm or more and 55 μm or less, but is not limited to this. The depth of the housing recess 21 can be arbitrarily set. However, since the measurement accuracy is improved as the thickness of the sample is smaller as described above, the depth of the accommodating recess 21 is preferably 100 μm or less. Moreover, it is preferable that the depth of the accommodation recessed part 21 is 10 micrometers or more from a viewpoint of processing accuracy.

  In the above-described embodiment, the thickness of the sample storage member 20 is 60 μm, but the present invention is not limited to this. The thickness of the sample accommodation member 20 should just be larger than the depth of an accommodation recessed part. However, the thickness of the bottom of the housing recess 21 is preferably small from the viewpoint of measurement accuracy, and is particularly preferably 10 μm or less. Further, from the viewpoint of the strength and processing accuracy of the sample storage member 20, it is preferable that the thickness of the bottom of the storage recess 21 is 5 μm or more. From these viewpoints, when the depth of the housing recess 21 is 10 μm or more and 100 μm or less, the thickness of the sample housing member 20 is preferably 15 μm or more and 110 μm or less.

  In the above-described embodiment, the holding surface 112 is a tapered surface, and the sample accommodating member 20 is bent along the holding surface 112 so that tension is applied to the sample accommodating member 20. It is not limited to. The tension can be generated in the sample storage member 20 by another configuration. For example, the sample storage member 20 (and the X-ray transmission window 10) attached to the base 110 is pulled from the surroundings by a spring or the like to generate tension in the sample storage member 20 (and the X-ray transmission window 10). It is also possible.

  In the above-described embodiment, the holding surface 112 is a tapered surface having a truncated cone shape, and the X-ray transmission window 10 and the sample storage member 20 are pressed against the holding surface 112 by the annular lock rings 31 and 32. The configuration was described. With this configuration, the X-ray transmission window 10 and the sample storage member 20 are uniformly tensioned radially. For this reason, there is no bias in tension, and it is possible to prevent wrinkles and variations in the depth of the accommodating recess 21 from occurring. However, it is not limited to the said structure. For example, the holding surface 112 may be a truncated pyramid tapered surface having a plurality of inclined surfaces, and the X-ray transmission window 10 and the sample storage member 20 may be pressed against each inclined surface. Also by doing in this way, the effect of suppressing the generation of wrinkles or making the depth of the accommodating recess 21 uniform can be obtained.

  In the above-described embodiment, each of the X-ray transmission window 10 and the sample storage member 20 is formed in a circular film shape, but is not limited thereto. The X-ray transmission window 10 and the sample storage member 20 can be formed into a film shape other than a circle in front view.

  The sample cell of the present invention is useful, for example, as a sample cell for X-ray absorption fine structure transmission measurement with low energy and variable temperature.

DESCRIPTION OF SYMBOLS 10 X-ray transmissive window 20 Sample storage member 21 Storage recessed part 31, 32 Lock ring 41, 42 Lock screw 100 Sample cell 110 Base 111 Through-hole 112 Holding surface

Claims (10)

A sample cell for storing a sample to be measured,
An X-ray transmission window that transmits X-rays emitted from the light source;
A storage recess for storing the sample is formed, and the X-ray transmission window is attached so as to close the storage recess, whereby a sample storage region is formed by the X-ray transmission window and the storage recess. A sample storage member,
A base for holding the sample storage member and the X-ray transmission window;
A fixing member attached to the base, and fixing the sample storage member and the X-ray transmission window to the base;
With
The sample storage member is made of super engineering plastic, and the storage recess is formed by cutting,
Sample cell for X-ray absorption fine structure transmission measurement. The X-ray transmission window is made of super engineering plastic.
A sample cell for X-ray absorption fine structure transmission measurement according to claim 1. The accommodation recess has a depth of 10 μm or more and 100 μm or less,
A sample cell for X-ray absorption fine structure transmission measurement according to claim 1 or 2. The sample housing member has a thickness of 15 μm or more and 110 μm or less.
A sample cell for X-ray absorption fine structure transmission measurement according to claim 3. The fixing member is configured to fix the sample storage member to the base so that tension is generated in the sample storage member.
The sample cell for X-ray absorption fine structure permeation | transmission measurement in any one of Claims 1 thru | or 4. The sample storage member is configured to generate tension in a direction along the main surface thereof.
The sample cell for X-ray absorption fine structure permeation | transmission measurement of Claim 5. The sample storage member is configured so that tension is evenly generated radially,
The sample cell for X-ray absorption fine structure permeation | transmission measurement of Claim 6. The base is provided with a through-hole extending in the X-ray irradiation direction, and the sample is disposed at the periphery of the through-hole so as to hold the sample-accommodating member in a state where the accommodating recess is positioned in the through-hole. A holding surface of the housing member is formed,
The holding surface is inclined so that its position changes to the same side in the X-ray irradiation direction as it goes outward.
The fixing member is configured to generate tension on the sample storage member by pressing the sample storage member held on the holding surface in the X-ray irradiation direction.
The sample cell for X-ray absorption fine structure permeation | transmission measurement in any one of Claim 5 thru | or 7. The holding surface has a truncated cone shape,
The fixing member has an annular shape corresponding to the holding surface;
The sample cell for X-ray absorption fine structure permeation | transmission measurement of Claim 8. The sample storage member is made of polyimide.
A sample cell for X-ray absorption fine structure transmission measurement according to any one of claims 1 to 9.

Images