CN117129500A - Method for calibrating absolute strength of sample in SAXS at different positions - Google Patents
Method for calibrating absolute strength of sample in SAXS at different positions Download PDFInfo
- Publication number
- CN117129500A CN117129500A CN202310985011.9A CN202310985011A CN117129500A CN 117129500 A CN117129500 A CN 117129500A CN 202310985011 A CN202310985011 A CN 202310985011A CN 117129500 A CN117129500 A CN 117129500A
- Authority
- CN
- China
- Prior art keywords
- sample
- intensity
- preset position
- distance
- relative
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000000235 small-angle X-ray scattering Methods 0.000 title claims abstract description 30
- 238000006243 chemical reaction Methods 0.000 claims abstract description 31
- 239000007787 solid Substances 0.000 claims description 4
- 238000002834 transmittance Methods 0.000 claims description 3
- 238000009795 derivation Methods 0.000 claims description 2
- 230000009466 transformation Effects 0.000 claims 2
- 238000012360 testing method Methods 0.000 abstract description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 13
- 229910052799 carbon Inorganic materials 0.000 description 10
- 239000011521 glass Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 7
- 229910021397 glassy carbon Inorganic materials 0.000 description 7
- 239000003245 coal Substances 0.000 description 4
- 230000005469 synchrotron radiation Effects 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000003763 carbonization Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000012613 in situ experiment Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 239000007783 nanoporous material Substances 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000012607 small angle X-ray scattering experiment Methods 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910001868 water Inorganic materials 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/201—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials by measuring small-angle scattering
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/20008—Constructional details of analysers, e.g. characterised by X-ray source, detector or optical system; Accessories therefor; Preparing specimens therefor
Abstract
The invention provides a method for calibrating absolute intensity of a sample at different positions in SAXS, which comprises the following steps: respectively placing a sample and a standard sample at a first preset position and a second preset position and measuring the relative strength of the sample and the relative strength of the standard sample; based on a conversion formula, converting the relative intensity of the standard sample into the relative intensity of the standard sample corresponding to the first preset position according to a first distance and a second distance; the first distance is the distance from the first preset position to the detector, and the second distance is the distance from the second preset position to the detector; calculating an absolute intensity calibration factor by using the scattering curve of the standard sample and the theoretical curve of the standard sample; and calculating the absolute intensity of the sample by using the absolute intensity scaling factor and the relative intensity of the sample. The method solves the problem that the absolute strength of the sample cannot be calibrated by testing the sample and the standard sample at different positions in the prior art.
Description
Technical Field
The invention relates to the technical field of scattering intensity calibration, in particular to a method for calibrating absolute intensities of samples at different positions in SAXS.
Background
The small angle X-ray scattering (SAXS) is a physical technology and means for researching the sub-microstructure and morphological characteristics of substances, is applicable to solid or liquid samples, requires a small amount of samples, is an accurate and nondestructive analysis method, and is widely applied to researches in the fields of polymers, biological macromolecules, nano materials, porous materials and the like.
The SAXS experimental geometry is shown in FIG. 2, and the typical scattering angle 2 theta is less than or equal to 5 deg.. The detectors may be symmetrically arranged with respect to the through light; samples with isotropic scattering signals can also be biased, i.e. only half of the scattering signals are taken, which has the advantage that the measured scattering angle can be increased, which is particularly suitable for small-sized detectors.
The SAXS detector measures the relative scattering intensity of the sample (referred to simply as the relative intensity) in the experiment, which is related not only to the structure of the sample, but also to the instrument parameters and test conditions. The differential scattering cross section of a sample is called absolute scattering intensity (simply absolute intensity) and depends on the ratio of scattering intensity to incident intensity, i.e. on the sample structure only, independent of instrument parameters and test conditions. From the relative intensities, geometric parameters of the scatterers (e.g., particles, pores, etc.) inside the sample can be derived, such as the fractal dimension of the scatterers, shape, size, distribution thereof, etc. To obtain parameters related to the mass density of the sample, such as molecular weight, volume fraction (e.g. porosity of the porous material), etc., absolute strength must be used. Absolute intensity calibration is of no doubt significant importance.
Since absolute intensity depends on the ratio of scattered intensity to incident intensity, directly calculating the ratio requires accurate measurement of the incident light intensity. However, since the incident light is too strong, typical detectors are difficult to measure due to dynamic range limitations. Attempts have been made to measure the intensity of incident light using the decay method and thus calculate the absolute intensity. The attenuation method is to mechanically attenuate the incident light intensity by using absorbing sheets or foils (such as Ni sheets, si sheets, etc.) or rotating discs with different thicknesses to reach the accurately measurable range, and then extrapolate the incident light intensity. The attenuation method has the advantages of troublesome operation, relatively complex calculation, poor result repeatability and less application in practice.
Another common method of measuring the absolute intensity of a sample is known as the standard sample method (standard sample method for short). The method uses samples with known absolute strength, such as glass carbon, water, silicon dioxide suspension, gold sol, polyethylene balls and the like as standard samples, tests the scattering strength of the standard samples (including a test instrument, test parameters and the distance from the sample to a detector) under the same conditions as the test samples (also called samples), and obtains a calibration factor, namely the method can be applied to converting the relative strength of the samples into the absolute strength. Compared with the attenuation method, the standard sample method has the advantages of convenient operation, simple calculation, stable result and wide application.
In 2016, the National Institute of Standards and Technology (NIST) introduced a new standard sample, glassy carbon SRM3600, as shown in fig. 3, in the form of black square flakes with a side length of 10mm and a thickness of 1.055mm, which has been widely used for SAXS absolute strength calibration of samples measured at the same location. Theoretical absolute intensity curve of the glassy carbonAs shown in FIG. 4, wherein I a Q is the scattering vector, q=4pi sin θ/λ,2θ is the scattering angle, and λ is the X-ray wavelength.
The main principle of calibrating absolute intensity by using glass carbon is to measure SAXS signals of the glass carbon and a sample at the same position under the same condition, compare an actual measurement scattering curve of the glass carbon with a theoretical scattering curve of the glass carbon, calculate an absolute intensity calibration factor CF, multiply the relative intensity of the sample by the calibration factor, and divide the product of the transmitted light intensity (usually the relative intensity recorded by a photodiode integrated into a through beam blocker) and the thickness of the sample when the sample is tested to convert the product into absolute intensity.
In the application of the above standard method, particular emphasis is placed on the fact that the standard and the sample are tested under identical conditions. The same conditions mainly refer to: the same test instrument was used, the same experimental parameters were maintained, and samples were replaced at the same locations. In general, these conditions are easily met. In a few cases, the requirement to test the standard and specimen at the same location may be difficult to meet. For example, the sample is tested in a chamber of a type that is limited by volume or environment so that a standard sample (e.g., glass carbon) is not placed in the sample chamber. Fig. 5 is a photograph of an in situ experiment of coal carbonization performed at a 1W2A beam line SAXS laboratory station of a beijing synchrotron radiation device (BSRF), with the size of the sample holder in the furnace chamber being limited by the high temperature heating, standard sample vitreous carbon is not placed in the furnace. The existing method is to remove the furnace from the light path, install another sample support capable of placing glass carbon on the light path, make the distance from the standard sample to the detector the same as the distance from the sample to the detector, and then test the standard sample. The operation is troublesome, the efficiency is low, the repeatability is poor, and the error is large. Is it possible to test directly a glass carbon on the light exit of a straight-through X-ray of a furnace without removing the furnace? This protocol is simple to test, but requires conversion of the relative intensity of the standard sample tested at the furnace port to a relative intensity corresponding to that at the sample site.
In summary, the prior art has the problem that the absolute strength of the sample cannot be calibrated by testing the sample and the standard sample at different positions.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a method for calibrating absolute strength of a sample at different positions in SAXS, and solves the problem that the absolute strength of the sample cannot be calibrated by testing the sample and the standard sample at different positions in the prior art.
In order to achieve the above object, the present invention provides the following solutions:
a method for absolute intensity calibration of a sample at different locations in SAXS, comprising:
respectively placing a sample and a standard sample at a first preset position and a second preset position and measuring the relative strength of the sample and the relative strength of the standard sample;
based on a conversion formula, converting the relative intensity of the standard sample into the relative intensity of the standard sample corresponding to the first preset position according to a first distance and a second distance; the first distance is the distance from the first preset position to the detector, and the second distance is the distance from the second preset position to the detector;
calculating an absolute intensity calibration factor by using the scattering curve of the standard sample and the theoretical curve of the standard sample;
and calculating the absolute intensity of the sample by using the absolute intensity scaling factor and the relative intensity of the sample.
Preferably, the conversion formula is specifically:
wherein,for the relative intensity of the standard corresponding to the first preset position, I st,B (q) the relative strength of the standard sample corresponding to the second preset position, L A At a first distance, L B Is the second distance.
Preferably, the derivation process of the conversion formula is as follows:
obtaining a second sample strength relational expression according to the first sample strength relational expression and the space angle relational expression;
obtaining a relative intensity relation of the first preset position and a relative intensity relation of the second preset position according to the second sample intensity relation;
obtaining a pre-conversion formula according to the relative intensity relation of the first preset position and the relative intensity relation of the second preset position;
and obtaining the conversion formula according to the pre-conversion formula.
Preferably, the first sample relative intensity relationship is:
wherein, I (q) is the relative scattering intensity of the sample measured by the detector after the back scattering is subtracted, and the relative intensity is short for short; i 0 For the relative intensity of incident light (phs/mm 2 /s)；S is the irradiated area (cm) of the sample 2 ) The method comprises the steps of carrying out a first treatment on the surface of the ΔΩ is the solid angle (sr) corresponding to a single pixel of the detector; η is detector efficiency (%); t is the transmittance (%) of the sample to X-rays; d is the sample thickness (mm);absolute scattering intensity, absolute intensity for short.
Preferably, the spatial angle relation is:
where L is the distance of the sample from the detector, pixel is the detector pixel size, 2 θ is the scatter angle, and R is the distance of the sample from above a single pixel on the detector.
Preferably, the second sample relative intensity relationship is:
preferably, the relative intensity relation of the first preset position is:
wherein I is 0,A For the relative intensity of the first preset position, L A For the distance from the first preset position to the detector, I 0,B For the relative intensity of the second preset position, L B Is the distance from the second preset position to the detector.
Preferably, the relative intensity relation of the second preset position is:
preferably, the pre-conversion formula is:
according to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention provides a method for calibrating absolute intensities of samples at different positions in SAXS (software defined extensible sample).
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for calibrating absolute intensity of a sample at different positions in SAXS according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of SAXS experimental geometry according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a new standard sample glass carbon SRM3600 provided in an embodiment of the present invention;
FIG. 4 is a schematic diagram of a theoretical absolute intensity curve of a novel standard sample glass carbon SRM3600 provided in an embodiment of the present invention;
fig. 5 is a diagram showing an in-situ experimental demonstration of coal carbonization performed at a 1W2A harness SAXS experimental station of a beijing synchrotron radiation device (BSRF) according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a method for calibrating absolute intensity of a sample at different locations in SAXS according to an embodiment of the present invention;
FIG. 7 is a graph showing the relative scattering intensity test of a sample and a glassy carbon according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of experimental measurement of a standard sample and a sample provided by an embodiment of the present invention;
FIG. 9 is a graph showing the relative intensities of the various positional standards and samples provided in accordance with an embodiment of the present invention;
FIG. 10 is a schematic diagram showing a comparison of the calculated A position data and the measured data of the standard sample according to the embodiment of the present invention;
FIG. 11 is a graph of absolute intensity of a sample provided by an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a method for calibrating absolute strength of a sample at different positions in SAXS, which solves the problem that the absolute strength of the sample cannot be calibrated by testing the sample and a standard sample at different positions in the prior art.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
As shown in FIG. 1, the invention provides a method for calibrating absolute intensity of a sample at different positions in SAXS, comprising the following steps:
step 100: respectively placing a sample and a standard sample at a first preset position and a second preset position and measuring the relative strength of the sample and the relative strength of the standard sample;
step 200: based on a conversion formula, converting the relative intensity of the standard sample into the relative intensity of the standard sample corresponding to the first preset position according to a first distance and a second distance; the first distance is the distance from the first preset position to the detector, and the second distance is the distance from the second preset position to the detector;
step 300: calculating an absolute intensity calibration factor by using the scattering curve of the standard sample and the theoretical curve of the standard sample;
step 400: and calculating the absolute intensity of the sample by using the absolute intensity scaling factor and the relative intensity of the sample.
Further, the conversion formula specifically includes:
wherein I is st,A (q) the relative intensity of the standard sample corresponding to the first preset position, I st,B (q) the relative strength of the standard sample corresponding to the second preset position, L A At a first distance, L B Is the second distance.
As shown in fig. 6, the specific flow of the method for calibrating absolute intensity of a sample at different positions in SAXS is as follows:
the relative intensities of the sample and standard were measured at different locations: samples, standards (e.g., vitreous carbon) and their backs were measured separately at different locations along the optical path using the same SAXS instrument. As shown in fig. 7, the sample and its back were measured at the a position and the standard sample and its back were measured at the B position. The relative strength of the sample and the standard sample is obtained by subtracting the back bottom and is marked as I s,A (q) and I st,B (q). The vacuum line in fig. 7 is used to protect the incident and scattered light, the slit upstream of the sample is used for parasitic scattering, the ionization chamber is used to record the relative incident light intensity, the photodiode integrated in the through beam blocker (also called beam flow blocker) is used to record the relative transmitted light intensity, and the SAXS detector records the relative scattered signal;
calculating the relative intensity of the standard sample corresponding to the sample position: that is, the relative intensity I of the standard sample measured at the position B in FIG. 7 st,B (q) conversion to relative intensity I corresponding to position A st,A (q)；
Calculating the absolute intensity calibration factor of the sample position: scattering curve I of comparative standard st,A (q) and theoretical curve thereof(FIG. 4), an absolute intensity scaling factor (CF) was determined.
Calculating the absolute intensity of the sample: based on the absolute intensity calibration factor, the relative intensity I of the sample measured at the A position is calculated s,A (q) conversion to absolute intensity
Further, the deduction process of the conversion formula is as follows:
obtaining a second sample strength relational expression according to the first sample strength relational expression and the space angle relational expression;
obtaining a relative intensity relation of a first preset position and a relative intensity relation of a second preset position according to the second sample intensity relation;
obtaining a pre-conversion formula according to the relative intensity relation of the first preset position and the relative intensity relation of the second preset position;
and obtaining the conversion formula according to the pre-conversion formula.
Preferably, the first sample relative intensity relationship is:
wherein, I (q) is the relative scattering intensity of the sample measured by the detector after the back scattering is subtracted, and the relative intensity is short for short; i 0 For the relative intensity of incident light (phs/mm 2 S); s is the irradiated area (cm) of the sample 2 ) The method comprises the steps of carrying out a first treatment on the surface of the ΔΩ is the solid angle (sr) corresponding to a single pixel of the detector; η is detector efficiency (%); t is the transmittance (%) of the sample to X-rays; d is the sample thickness (mm);absolute scattering intensity, absolute intensity for short.
Further, the spatial angle relation is:
where L is the distance of the sample from the detector, pixel is the detector pixel size, 2 θ is the scatter angle, and R is the distance of the sample from above a single pixel on the detector.
Further, the second sample relative intensity relationship is:
the same sample is respectively placed at different positions, such as position A and position B, on the optical path of the same SAXS instrument, and the scattering intensity, eta, T, d, pixel and eta in the spatial angle relation are respectively measuredRemain unchanged. For parallel beams, S also remains unchanged; for focused and divergent beams, theoretically, S at different positions is different, but the X-ray divergence of the modern instrument is small, the collimation is good, and the distance between the A position and the B position is not far<0.1 m), S is approximately equal, so the relative intensity relation of the first preset position is further obtained as:
wherein I is 0,A For the relative intensity of the first preset position, L A For the distance from the first preset position to the detector, I 0,B For the relative intensity of the second preset position, L B Is the distance from the second preset position to the detector.
The relative intensity relation of the second preset position is as follows:
further, the relative intensity relation of the second preset position is divided by the relative intensity relation of the first preset position to obtain a pre-conversion formula, wherein the pre-conversion formula is as follows:
for laboratory SAXS instrument of common light source and synchronous radiation SAXS instrument of constant-current Top-up injection mode of constant light intensity, I 0,A And I 0,B Equal; for a synchrotron radiation SAXS instrument that gradually attenuates the periodic injection mode, the two are not equal. When the incident light intensity is the same, the pre-conversion formula is simplified to a conversion formula.
The invention also provides the following specific embodiments:
standard sample: glass fiber reinforced plastic SRM3600 in square sheet shape with side length of 10mm and thickness of 1.055mm
Sample: lean coal produced from Shanxi province and Changzhiyang coal mine is in a round sheet shape, and has the diameter of 10mm and the thickness of 1mm
SAXS experiments were performed on a sea-going synchrotron radiation BL16B1 small angle scattered beam line station with an incident light energy of 10keV, a wavelength of 0.124nm and a detector specification of Pictures 2M. Rectangular integration using Fit2d software (j.appl. Crystal. 2016,49,646-652.) converts the two-dimensional scatter images into one-dimensional scatter curves. Data were subjected to relevant parameter calculations using s.exe software (chinese Phys. C,2013,37,110-115.).
The specific calibration verification steps are as follows:
1. the scattering intensity of the sample and its back was measured at position a (fig. 8), and the relative intensity of the standard (vitreous carbon SRM 3600) and its back was measured at position A, B, respectively. The scattering curves of the standard sample and the sample minus the back substrate are respectively marked as I st,A ′(q)，I st,B ′(q)，I s,A (q) (see FIG. 9). Measuring the distance from A, B to the detector, L a ＝2020mm，L b =1910 mm. Will I st,B ' conversion of (q) to relative intensity I at the A position st,A (q)：
Curve I after conversion st,A (q) I measured with A position st,A ' and (q) are plotted in a graph for comparison, and as can be seen from fig. 10, the data calculated by the conversion formula at the B position is better matched with the data actually measured at the a position, thereby proving the feasibility of the conversion formula.
Calculating the calibration factors converted from the B position to the A position respectively, and comparing the calibration factors calculated by the measured data of the A position with the calibration factors calculated by the measured data of the A position:
wherein CF is a scale factor, A, B corresponds to the position, k, respectively, in FIG. 8 st+stb Count d for diode with backscatter standard st The thickness of the standard sample is expressed in mm,absolute strength of glassy carbon.
CF B And CF (compact flash) A The relative error of (2) is 0.286%, proving the feasibility of the conversion formula.
Calculating the absolute intensity of the sample according to the following formulaThe results are shown in FIG. 11.
K in s+sb Count the number of diodes on the sample and its back, d s Is the thickness of the sample.
The beneficial effects of the invention are as follows:
the absolute scattering intensity for a certain distance in the present invention is no longer limited to measuring standard and sample at the same location; under the same test conditions, the relative intensities of the samples measured at a certain distance can be converted into the relative intensities at other distances. The calibration method is suitable for any standard sample position, and only the distance from the standard sample to the sample needs to be accurately known. The method has the advantages of simple operation, high efficiency, good repeatability and small error.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (9)
1. A method for absolute intensity calibration of a sample at different locations in SAXS, comprising:
respectively placing a sample and a standard sample at a first preset position and a second preset position and measuring the relative strength of the sample and the relative strength of the standard sample;
based on a conversion formula, converting the relative intensity of the standard sample into the relative intensity of the standard sample corresponding to the first preset position according to a first distance and a second distance; the first distance is the distance from the first preset position to the detector, and the second distance is the distance from the second preset position to the detector;
calculating an absolute intensity calibration factor by using the scattering curve of the standard sample and the theoretical curve of the standard sample;
and calculating the absolute intensity of the sample by using the absolute intensity scaling factor and the relative intensity of the sample.
2. The method for calibrating absolute intensity of a sample at different positions in SAXS according to claim 1, wherein the transformation formula is specifically:
wherein I is st，A (q) the relative intensity of the standard sample corresponding to the first preset position, I st,B (q) the relative strength of the standard sample corresponding to the second preset position, L A At a first distance, L B Is the second distance.
3. The method of claim 2, wherein the derivation of the transformation formula is:
obtaining a second sample strength relational expression according to the first sample strength relational expression and the space angle relational expression;
obtaining a relative intensity relation of the first preset position and a relative intensity relation of the second preset position according to the second sample intensity relation;
obtaining a pre-conversion formula according to the relative intensity relation of the first preset position and the relative intensity relation of the second preset position;
and obtaining the conversion formula according to the pre-conversion formula.
4. A method of calibrating absolute intensities of samples at different positions in SAXS according to claim 3, wherein the first sample relative intensity relationship is:
wherein, I (q) is the relative scattering intensity of the sample measured by the detector after the back scattering is subtracted, and the relative intensity is short for short; i 0 For the relative intensity of incident light (phs/mm 2 S); s is the irradiated area (cm) of the sample 2 )；ΔΩA solid angle (sr) corresponding to a single pixel of the detector; η is detector efficiency (%); t is the transmittance (%) of the sample to X-rays; d is the sample thickness (mm);and (q) is absolute scattering intensity, which is simply called absolute intensity.
5. The method of claim 4, wherein the spatial angular relationship is:
where L is the distance of the sample from the detector, pixel is the detector pixel size, 2 θ is the scatter angle, and R is the distance of the sample from above a single pixel on the detector.
6. The method of claim 5, wherein the absolute intensity of the sample at the different locations is calibrated by a second sample relative intensity relationship:
7. the method of claim 6, wherein the relative intensity relationship at the first predetermined location is:
wherein I is 0,A For the relative intensity of the first preset position, L A For the distance from the first preset position to the detector, I 0,B For the relative intensity of the second preset position, L B Is the distance from the second preset position to the detector.
8. The method of claim 7, wherein the relative intensity relationship at the second predetermined location is:
9. the method of claim 8, wherein the pre-conversion formula is:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310985011.9A CN117129500A (en) | 2023-08-07 | 2023-08-07 | Method for calibrating absolute strength of sample in SAXS at different positions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310985011.9A CN117129500A (en) | 2023-08-07 | 2023-08-07 | Method for calibrating absolute strength of sample in SAXS at different positions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117129500A true CN117129500A (en) | 2023-11-28 |
Family
ID=88861973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310985011.9A Pending CN117129500A (en) | 2023-08-07 | 2023-08-07 | Method for calibrating absolute strength of sample in SAXS at different positions |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117129500A (en) |
-
2023
- 2023-08-07 CN CN202310985011.9A patent/CN117129500A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhang et al. | Glassy carbon as an absolute intensity calibration standard for small-angle scattering | |
| Kono et al. | Toward comprehensive studies of liquids at high pressures and high temperatures: Combined structure, elastic wave velocity, and viscosity measurements in the Paris–Edinburgh cell | |
| Naftaly | Metrology issues and solutions in THz time-domain spectroscopy: Noise, errors, calibration | |
| AU2009211833B2 (en) | Apparatus and method for X-ray fluorescence analysis of a mineral sample | |
| US8923480B2 (en) | X-ray diffraction instrument | |
| CN102213682B (en) | Method for measuring transmission of interference-insensitive terahertz wave | |
| US20040109531A1 (en) | Beam centering and angle calibration for X-ray reflectometry | |
| CN105928906B (en) | A kind of material reflectance dynamic measurement system varied with temperature and measurement method | |
| CN109374659A (en) | A kind of localization method of short wave length X-ray diffraction test sample | |
| Welzel et al. | Use of polycapillary X-ray lenses in the X-ray diffraction measurement of texture | |
| CN105572076A (en) | Terahertz spectrum measuring device based on scattering effect and measuring method thereof | |
| CN111964596B (en) | Caliper type thickness measuring device and method based on terahertz pulse | |
| CN111537399B (en) | Liquid surface tension measuring device and method based on light reflection | |
| CN113740269B (en) | High-pressure spectrum ellipsometry measuring device and measuring method | |
| CN117129500A (en) | Method for calibrating absolute strength of sample in SAXS at different positions | |
| KR20080089404A (en) | Characterization of three-dimensional distribution of defects by x-ray topography | |
| Komander et al. | Hydrogen site location in ultrathin vanadium layers by N-15 nuclear reaction analysis | |
| JP2008170236A (en) | Measuring method for reflectivity curve of x ray and of neutron radiation and measuring instrument | |
| CN103454290B (en) | A kind of bimirror formula detection analysis method of X-ray detection and imaging system | |
| CN113916864A (en) | ICF target internal D2Method for Raman spectrum quantitative analysis of fuel gas | |
| CN205679527U (en) | A kind of material reflectance dynamic measurement system varied with temperature | |
| Kupsch et al. | Direct X-ray refraction of micro structures | |
| Li et al. | Energy-dispersive small-angle X-ray scattering with cone collimation using X-ray capillary optics | |
| Karl et al. | Investigation of failure mechanisms in polymer composites by simultaneous measurement of ultra-small-angle scattering and acoustic emission during the deformation. I. Method | |
| Escudero et al. | Breast cancer analysis by confocal energy dispersive micro-XRD |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |