Method for correcting bias voltage of detector of wavelength dispersion X-ray fluorescence spectrophotometer

Abstract

The invention relates to the technical field of photoelectric detection, and discloses a wavelength dispersion X-ray fluorescence spectrometer detector bias correction method, which comprises the following steps: preparing a bias correction sample containing various elements; loading the bias correction sample into a wavelength dispersion X-ray fluorescence spectrophotometer, adjusting excitation conditions of each element to obtain preset signal intensity, adjusting detector bias to enable spectral peaks of each element to be located at a specific channel position, recording detector bias corresponding to characteristic line wavelengths of each element, and determining the spectral peaks of each element according to the detector bias. Establishing a numerical relationship between the detector bias voltage and the element characteristic line wavelength; and automatically matching and setting a corresponding detector bias voltage according to the characteristic line wavelength of the to-be-detected element in the to-be-detected sample and the established numerical relationship. The method is simple and easy to operate, the detector bias value corresponding to the wavelength of the to-be-detected element can be rapidly and accurately determined through self-made powder tabletting, the operation process is simplified, the element coverage range is expanded, and the calibration precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic detection, and particularly to a method for correcting the detector bias voltage of a wavelength dispersive X-ray fluorescence spectrometer. Background Art

[0002] As an important element analysis tool, the performance of a wavelength dispersive X-ray fluorescence (WDXRF) instrument depends on the accurate capture and analysis of characteristic X-rays by the detector. In a wavelength dispersive X-ray fluorescence spectrometer, the detector bias voltage affects the peak position and intensity of the spectrum, thereby affecting the accuracy and sensitivity of the instrument. Therefore, the correction of the detector bias voltage is an important part of instrument calibration and needs to be performed regularly.

[0003] In the prior art, for two types of detectors, namely the gas-flow proportional counter (PC) and the scintillation counter (SC), a step-by-step manual calibration method is usually adopted. Specifically, for the PC detector, the operator needs to sequentially scan samples of titanium alloy, pure aluminum, and magnesium sulfate tablets to obtain the bias voltage values of elements such as titanium (Ti), aluminum (Al), sulfur (S), and magnesium (Mg), and then manually modify and use them; for the SC detector, samples of stainless steel and pure copper need to be scanned to obtain the bias voltage values of elements such as iron (Fe), nickel (Ni), and copper (Cu), which also rely on manual modification. The above methods have significant defects: First, the frequent switching of different samples results in a long calibration process and low operation efficiency; second, the calibration covers only a limited number of elements, only for the major elements in a few typical samples, and it is difficult to meet the requirements of multi-element analysis; third, manual intervention is likely to introduce operation errors, and affected by factors such as sample uniformity and surface state, the repeatability and accuracy of the calibration results are insufficient. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for correcting the detector bias voltage of a wavelength dispersive X-ray fluorescence spectrometer, which can quickly and accurately determine the detector bias voltage value corresponding to the wavelength of the element to be measured by using a self-made powder tablet, simplify the operation process, expand the element coverage range, and improve the calibration accuracy.

[0005] To achieve the above purpose, the present invention provides the following solution: A method for correcting the detector bias voltage of a wavelength dispersive X-ray fluorescence spectrometer, the method comprising the following steps: S1, preparing a bias voltage correction sample containing multiple elements; S2. Load the bias correction sample into a wavelength dispersive X-ray fluorescence spectrometer, adjust the excitation conditions of each element to obtain a preset signal intensity, adjust the detector bias so that the spectral peaks of each element are located at specific channel positions, record the detector bias corresponding to the wavelengths of the characteristic lines of each element, and establish a numerical relationship between the detector bias and the wavelengths of the characteristic lines of the elements. S3. For the elements to be measured in the sample to be measured, automatically match and set the corresponding detector bias according to the wavelengths of the characteristic lines of the elements to be measured and the numerical relationship established in S2.

[0006] Further, in S1, preparing a bias correction sample containing multiple elements specifically includes: Select compounds or pure substance powders containing multiple elements, mix them in a certain proportion, and then press them into stable powder tablets using a press as the bias correction sample.

[0007] Further, in S1, the multiple elements include: Mg, Si, S, Ca, Ti, Fe, Cu, Zn, Pb, Mo, Sn.

[0008] Further, in S2, adjusting the excitation conditions of each element includes: Select the target type, X-ray tube voltage, X-ray tube current, collimator, diaphragm, etc. to ensure that the signal intensities of the characteristic lines of each element are within the preset dynamic range.

[0009] Further, in S2, the numerical relationship between the detector bias and the wavelengths of the characteristic lines of the elements is specifically a linear relationship between the detector bias and the natural logarithm value of the wavelengths of the characteristic lines of the elements, expressed as: V = k ×ln( L ) + b Where L is the wavelength of the characteristic line of the element, V is the detector bias corresponding to the element to be measured, k , b are fitting coefficients.

[0010] Further, the method is applicable to the bias correction of two types of detectors, namely the gas-flow proportional counter PC and the scintillation counter SC.

[0011] The present invention also provides a wavelength dispersive X-ray fluorescence spectrometer, which realizes the automatic bias correction function by using the above detector bias correction method.

[0012] According to the specific embodiments provided by the present invention, the following technical effects are disclosed: For the method for correcting the detector bias voltage of a wavelength dispersive X-ray fluorescence spectrometer provided by the present invention, first, a bias voltage correction sample containing multiple elements is prepared. The elements contained in the bias voltage correction sample cover the high-sensitivity range of the wavelength dispersive X-ray fluorescence spectrometer, have strong representativeness, and are easy to prepare, store, and circulate in this way; then, the bias voltage correction sample is loaded into the wavelength dispersive X-ray fluorescence spectrometer, the excitation conditions of each element are adjusted to obtain a preset signal intensity, the detector bias voltage is adjusted so that the spectral peaks of each element are located at specific channel positions, the detector bias voltage corresponding to the wavelength of the characteristic line of each element is recorded, and a numerical relationship between the detector bias voltage and the wavelength of the element characteristic line is established. This numerical relationship provides a technical basis for the rapid determination of the corresponding bias voltage values of various elements to be measured in the future; finally, for the elements to be measured in the sample to be measured, according to the wavelength of the characteristic line of the element to be measured and the established numerical relationship, the corresponding detector bias voltage is automatically matched and set. The present invention can simultaneously obtain the bias voltage values of elements such as titanium, calcium, silicon, magnesium, sulfur, copper, tin, molybdenum, lead, zinc, and iron under specific channels, establish a numerical relationship with the characteristic wavelength of the element through numerical fitting, simplify the scanning process and save time, thereby improving the speed of adjusting the detector bias voltage of the X-ray fluorescence spectrometer, and accurately determining the detector bias voltage value corresponding to the wavelength of the element to be measured, providing technical guarantee for the reliability and analysis ability of the WDXRF instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0014] Figure 1 It is a flowchart of the method for correcting the detector bias voltage of a wavelength dispersive X-ray fluorescence spectrometer according to an embodiment of the present invention; Figure 2 It is a schematic diagram of a bias voltage correction sample according to an embodiment of the present invention; Figure 3 It is an adjustment interface for correcting the detector bias voltage of a wavelength dispersive X-ray fluorescence spectrometer according to an embodiment of the present invention; Figure 4 It is a relationship curve diagram of the element signal intensity and the peak position value according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] Embodiments of the present invention will be described in detail below. These embodiments are intended to explain the present invention and should not be construed as limiting the present invention. For those specific technologies or conditions not specified in the embodiments, they shall be in accordance with the technologies or conditions described in the literature in this field or in accordance with the product specifications. For reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchases.

[0016] The method for correcting the detector bias of a wavelength-dispersive X-ray fluorescence spectrometer provided by the present invention can quickly and accurately determine the detector bias value corresponding to the wavelength of the element to be measured by using a self-made powder tablet.

[0017] As Figure 1 shown, the method for correcting the detector bias of a wavelength-dispersive X-ray fluorescence spectrometer provided by the present invention includes the following steps: S1. Prepare a bias correction sample containing multiple elements: Select powders of compounds or pure substances containing multiple elements such as Mg (magnesium), Si (silicon), S (sulfur), Ca (calcium), Ti (titanium), Fe (iron), Cu (copper), Zn (zinc), Pb (lead), Mo (molybdenum), Sn (tin), etc., mix them in a certain proportion, and then press them into a stable powder tablet using a tablet press as the bias correction sample for adjusting the detector bias of the wavelength-dispersive X-ray fluorescence spectrometer; the elements contained in this powder tablet cover the high-sensitivity range of the wavelength-dispersive X-ray fluorescence spectrometer, have strong representativeness, and are easy to prepare, store, and circulate in this way.

[0018] S2. Establish a numerical relationship between each detector bias and the wavelength of the element characteristic line: Load the bias correction sample into the wavelength-dispersive X-ray fluorescence spectrometer, adjust the excitation conditions of each element to obtain a preset signal intensity (for example, 20 ± 0.5 kcps), and adjust the detector bias to make the spectral peaks of each element located at specific channel positions (for example, 175 ± 2 channels, full scale 512 channels), record the detector bias corresponding to the wavelength of each element characteristic line, repeat the test for multiple elements, and obtain multiple sets of data, then the numerical relationship between the detector bias and the wavelength of the element characteristic line can be established; among them, adjusting the excitation conditions of each element includes: Select the target material type, X-ray tube voltage, X-ray tube current, collimator, diaphragm, etc. to ensure that the signal intensity of each element characteristic line is within the preset dynamic range; Specifically, through numerical fitting, it is obtained that the detector bias has a linear relationship with the natural logarithm value of the wavelength of the element characteristic line, that is: V = k ×ln( L )+ b where L is the wavelength of the element characteristic line,V is the detector bias voltage value (i.e., high voltage) corresponding to the element, k is the slope, b is the intercept. The values of k and b in the expression are obtained by logarithmic fitting using multiple sets of measured data.

[0019] S3. For the element to be measured in the sample to be tested, according to the numerical relationship established between the characteristic line wavelength of the element to be measured and S2, the corresponding detector bias voltage is automatically matched and set. Using this detector bias voltage can ensure that the peak of the spectrum is at an appropriate position in the multi-channel pulse analyzer MCA.

[0020] In actual use, if a certain element needs to be measured, substituting the characteristic line wavelength of the element to be measured into the above linear expression can calculate the required detector bias voltage value. Using this value can ensure that the peak of the spectrum is always at an appropriate position in the multi-channel pulse analyzer MCA. Even if the element to be measured is not included in the bias correction sample, a suitable bias voltage value and spectrum can still be obtained.

[0021] The above correction method is applicable to the bias correction of two types of detectors: the gas-flow proportional counter PC and the scintillation counter SC.

[0022] The detector high-voltage correction method for wavelength-dispersive X-ray fluorescence spectrometers provided by the embodiments of the present invention uses compounds or pure substance powders containing elements such as Mg (magnesium), Si (silicon), S (sulfur), Ca (calcium), Ti (titanium), Fe (iron), Cu (copper), Zn (zinc), Pb (lead), Mo (molybdenum), Sn (tin), etc., which are mixed in a certain proportion and pressed into a stable detector bias correction sample. Using this sample to adjust the bias voltage of the detector of the wavelength-dispersive X-ray fluorescence spectrometer, compared with the prior art, the correction sample obtained by this solution can obtain the bias voltage values of elements such as titanium, calcium, silicon, magnesium, sulfur, copper, tin, molybdenum, lead, zinc, and iron at specific channels for both the scintillation counter SC and the gas-flow proportional counter PC, establish a numerical relationship with the characteristic wavelength of the measured element, simplify the scanning process and save time, thereby improving the speed of adjusting the detector bias voltage of the X-ray fluorescence spectrometer and accurately determining the detector bias voltage value corresponding to the wavelength of the measured element.

[0023] In a specific embodiment, the detector high-voltage correction method for wavelength-dispersive X-ray fluorescence spectrometers provided by the present invention includes the following steps: (1). Prepare a bias correction sample First, prepare compounds or pure substance powders containing elements such as Mg, Si, S, Ca, Ti, Fe, Cu, Zn, Pb, Mo, Sn, etc. Put a certain amount of the sample into a sample bag, place it in an oven, dry it at 110°C for 2 hours, and place the dried sample in a desiccator; Then, weigh a certain proportion of the sample, mix it well, spread the well-mixed sample evenly in the aluminum ring, place it in the sample slot of the press, keep it static under a pressure of 35 T for 30 s to form a tablet, and then spray the words "Bias Check" on the aluminum ring surface. The bias correction sample is as Figure 2 shown.

[0024] (2) Detector bias adjustment On the wavelength dispersive X-ray fluorescence spectrometer, open the detector bias adjustment interface (as Figure 3 shown), load the detector bias correction sample, click the test button on the PC interface of the gas-flow proportional counter, set the tube voltage of the X-ray tube for the test element, adjust the tube current of the X-ray tube to obtain an appropriate signal intensity (about 20 ± 0.5 kcps), automatically adjust the detector bias to ensure that the spectral peak is at a specific appropriate position (about 175 ± 2 channels), record the set bias value, and obtain the bias values of Mg, Si, S, Ca, Ti, Fe, and Cu as 1805, 1778, 1755, 1715, 1696, 1663, and 1642 V respectively. Establish the numerical relationship between the bias value of the measured element and the wavelength of the characteristic line of the measured element, V = 88.17×ln( L ) + 1808.71, the coefficient of determination R 2 = 0.9996.

[0025] Similarly, click the test button on the SC interface of the scintillation counter, set the tube voltage of the X-ray tube for the test element, adjust the tube current of the X-ray tube to obtain an appropriate signal intensity (about 20 ± 0.5 kcps), automatically adjust the detector bias to ensure that the spectral peak is at a specific appropriate position (about 175 ± 2 channels), record the set bias value, and obtain the bias values of Fe, Cu, Zn, Pb, Mo, and Sn as 939, 910, 901, 877, 827, and 790 V respectively. Establish the numerical relationship between the bias value of the measured element and the wavelength of the characteristic line of the measured element, V = 107.46×ln( L ) + 1114.11, the coefficient of determination R 2 = 0.9972.

[0026] According to the numerical relationship obtained above, based on the wavelength of the characteristic line of the element to be measured, the bias value of the element to be measured under the conditions of this detector can be obtained. The detector bias adjustment interface is shown in Figure 3 .

[0027] (3) Practical application The Al element in the cement raw meal is detected by a wavelength dispersive X-ray fluorescence spectrometer. According to the numerical relationship obtained in step (2), the bias voltage value of the Al element under the PC condition of the detector is 1792 V based on the logarithm of the Al element wavelength (0.8339 nm). Set the test conditions: collimator S450, crystal PET, detector PC, X-ray tube voltage 20 kV. Adjust the X-ray tube current. When the X-ray tube current is 105 mA, the intensity value of the Al element is 20,240 cps, and the corresponding peak position value (i.e., the channel) is 175.0 Channel, as shown in Figure 4 , Figure 4 The curve in represents a spectral peak, and its signal intensity is the sum of the intensities at each channel. Among them, L represents the left boundary of the spectral peak, V represents the highest point of the spectral peak intensity, i.e., the peak position, and U represents the right boundary of the spectral peak.

[0028] The present invention also provides a wavelength dispersive X-ray fluorescence spectrometer, which realizes the automatic bias correction function by using the above-mentioned detector bias correction method.

[0029] Matters not described in the present invention are well-known technologies.

[0030] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technologies in the market, or to enable other ordinary technical personnel in the technical field to understand the embodiments disclosed herein.

Claims

1. A method for correcting the detector bias of a wavelength dispersive X-ray fluorescence spectrometer, characterized in that, It includes the following steps: S1. Prepare a bias correction sample containing multiple elements; S2. Load the bias correction sample into a wavelength dispersive X-ray fluorescence spectrometer, adjust the excitation conditions of each element to obtain a preset signal intensity, adjust the detector bias so that the spectral peaks of each element are located at specific channel positions, record the detector bias corresponding to the wavelength of the characteristic line of each element, and establish a numerical relationship between the detector bias and the wavelength of the element characteristic line; S3. For the element to be measured in the sample to be measured, automatically match and set the corresponding detector bias according to the wavelength of the characteristic line of the element to be measured and the numerical relationship established in S2.

2. The wavelength dispersion X-ray fluorescence spectrometer detector bias correction method according to claim 1, wherein In S1, to prepare a bias correction sample containing multiple elements, specifically including: Select a compound or pure substance powder containing multiple elements, mix them in a certain proportion, and then use a press to press them into a stable powder tablet as the bias correction sample.

3. The wavelength-dispersive X-ray fluorescence spectrometer detector bias correction method according to claim 1, wherein, In S1, the multiple elements include: Mg, Si, S, Ca, Ti, Fe, Cu, Zn, Pb, Mo, Sn.

4. The wavelength dispersion X-ray fluorescence spectrometer detector bias correction method according to claim 1, characterized in that In S2, to adjust the excitation conditions of each element, including: Select the target type, X-ray tube voltage, X-ray tube current, collimator and aperture to ensure that the signal intensity of the characteristic line of each element is within the preset dynamic range.

5. The wavelength dispersion X-ray fluorescence spectrometer detector bias correction method according to claim 1, characterized in that, In S2, the numerical relationship between the detector bias and the wavelength of the element characteristic line is specifically a linear relationship between the detector bias and the natural logarithm value of the wavelength of the element characteristic line, expressed as: V = k ×ln( L )+ b Wherein, L is the wavelength of the element characteristic line, V is the detector bias voltage corresponding to the measured element, k , b are fitting coefficients.

6. The wavelength-dispersive X-ray fluorescence spectrometer detector bias correction method according to claim 1, characterized in that This method is applicable to the bias correction of two types of detectors, namely the gas-flow proportional counter PC and the scintillation counter SC.

7. A wavelength dispersive X-ray fluorescence spectrometer, characterized in that, Implement the automatic bias correction function by using the detector bias correction method described in any one of claims 1-6.

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