WO2022162976A1 - X線分析用信号処理装置 - Google Patents
X線分析用信号処理装置 Download PDFInfo
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- 238000002441 X-ray diffraction Methods 0.000 title claims abstract description 18
- 238000012545 processing Methods 0.000 title claims abstract description 18
- 238000001514 detection method Methods 0.000 claims abstract description 39
- 230000000630 rising effect Effects 0.000 claims abstract description 37
- 230000000694 effects Effects 0.000 abstract description 4
- 230000004069 differentiation Effects 0.000 abstract description 3
- 238000001228 spectrum Methods 0.000 description 29
- 238000006243 chemical reaction Methods 0.000 description 13
- 238000010586 diagram Methods 0.000 description 11
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 11
- 230000008859 change Effects 0.000 description 10
- 230000007423 decrease Effects 0.000 description 9
- 238000005259 measurement Methods 0.000 description 6
- 238000005452 bending Methods 0.000 description 4
- 229910001369 Brass Inorganic materials 0.000 description 3
- 239000010951 brass Substances 0.000 description 3
- 238000002083 X-ray spectrum Methods 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000004451 qualitative analysis Methods 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000004876 x-ray fluorescence Methods 0.000 description 1
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- 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
- G01N23/22—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 measuring secondary emission from the material
- G01N23/223—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 measuring secondary emission from the material by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/17—Circuit arrangements not adapted to a particular type of detector
Definitions
- the present invention relates to an X-ray analysis signal processing apparatus, and more particularly to an X-ray analysis signal processing apparatus equipped with a waveform conversion digital filter that converts the waveform of a differential wave.
- a fluorescent X-ray analyzer irradiates a solid sample, powder sample, or liquid sample with excitation X-rays (primary X-rays), and detects fluorescent X-rays that are emitted by being excited by the irradiated primary X-rays with a spectrometer. Qualitative and quantitative analysis of the elements contained in the sample is then performed.
- a fluorescent X-ray spectrometer there are a wavelength dispersive X-ray fluorescent spectrometer and an energy dispersive X-ray fluorescent spectrometer.
- a wavelength-dispersive X-ray fluorescence spectrometer has a configuration in which an X-ray spectrometer that combines an analyzing crystal and a slit selects fluorescent X-rays of a specific wavelength and then detects them with a detector.
- the energy dispersive X-ray fluorescence spectrometer directly detects fluorescent X-rays with a semiconductor detector or the like without performing such wavelength selection, and then separates the output signal by wavelength ⁇ (that is, X-ray energy E). It has a configuration for performing processing (see Patent Documents 1 and 2, for example).
- FIG. 3 is a schematic configuration diagram showing the configuration of a conventional general energy dispersive X-ray fluorescence spectrometer.
- An energy dispersive X-ray fluorescence spectrometer 101 includes an X-ray tube 10 that emits primary X-rays to a sample S, an energy dispersive spectrometer 30 (also called a detector) that detects the intensity of fluorescent X-rays I, and a preamplifier. 41, a differentiating circuit 42 consisting of a capacitor C and a resistor R, an A/D converter 43, an FPGA (Field-programmable gate array) 160 consisting of a waveform conversion digital filter 61, a peak detector 62, and a histogram memory 63.
- the X-ray tube 10 applies a high voltage to the target and a low voltage to the filament to cause thermoelectrons emitted from the filament to collide with the end face of the target, thereby generating primary electrons at the end face of the target. It is designed to emit X-rays.
- the energy dispersive spectroscope 30 has, for example, a detection element (lithium drift type Si semiconductor detector) that detects the fluorescent X-ray intensity I inside the housing.
- An output signal from the energy dispersive spectroscope 30 is amplified by the preamplifier 41 .
- This output signal has a stepped wave shape, and each step of the stepped wave indicates that fluorescent X-rays are detected, and the height (wave height) of each step represents the wavelength ⁇ , that is, the X-ray energy E.
- the output signal amplified by the preamplifier 41 is sent to the differentiating circuit 42, and the differentiating circuit 42 converts the staircase wave into a differentiated wave represented by the following equation (1).
- T is the sampling period
- n is the number of samples
- a is the time constant (exp(-T/ ⁇ )).
- the A/D converter 43 converts the differential wave input as an analog signal into a differential wave digital signal, and inputs the digital signal to the waveform conversion digital filter 61 of the FPGA 160 .
- the waveform conversion digital filter 61 converts the input differential wave digital signal into a trapezoidal wave digital signal using the transfer function represented by the following equation (2), as shown in FIG. By converting the differentiated wave digital signal into the trapezoidal wave digital signal in this manner, the crest value of the peak (peak top value) can be accurately calculated.
- M is the top time of the trapezoidal wave (the time of the upper part), and N is the rise/fall time of the trapezoidal wave.
- FIG. 5 is a waveform diagram schematically showing a differentiated wave digital signal input to the waveform conversion digital filter 61 and a trapezoidal wave digital signal output after waveform conversion by the waveform conversion digital filter 61.
- detector 30 detects staircase wave signals of various sizes at irregular time intervals, differential wave digital signals of various sizes pass through differentiating circuit 42 and A/D converter 43 to waveform conversion digital filter 61.
- a trapezoidal wave digital signal is generated which is input one after another at regular time intervals and has a corresponding crest value.
- the peak detection unit 62 detects the peaks of the trapezoidal wave digital signal to obtain the peak values (peak top values), and measures the X-ray energy E according to the peak top values each time one peak is detected. The numerical value is incremented and stored in the histogram memory 63 .
- the CPU 150 creates a pulse height distribution map (energy spectrum histogram ) is created.
- JP 2015-21957 A Japanese Patent Application Laid-Open No. 2020-51900
- the peak detection unit 62 detects the upper side (upper base) of the trapezoidal wave digital signal, and one point included in the upper side (for example, from the oblique side on the rising side to the upper side) The starting point of the upper side which is a bending point) or the average value of a plurality of points included in the upper side is obtained, and this is extracted as the peak top value (crest value).
- the peak top value crest value
- the applicants set a threshold value T for peak detection in the peak detection unit 62, and the fluctuation width (increase width) of the rising side oblique side portion of the trapezoidal wave digital signal, the falling edge
- T the threshold value
- the wave height fluctuation width (decrease width) at the hypotenuse portion has fluctuated by a magnitude greater than the threshold value T
- it is recognized as one trapezoidal wave digital signal to be counted, and the peak is detected from the upper side portion.
- the top value is extracted, the count value of the X-ray energy E is incremented according to the peak top value, and stored in the histogram memory 63 .
- a trapezoidal wave digital signal (see, for example, FIG. 5) input to the peak detector 62
- the first count to be performed The signal is recognized as a trapezoidal wave digital signal, and the flat top portion of the subsequent signal change is detected as a peak to extract the peak top value. Further, a signal change on the falling oblique side where the signal decreases from the upper side (peak top value) is detected.
- the process of detecting a signal change on the rising side of the second trapezoidal wave signal is started.
- the detection of the subsequent trapezoidal wave digital signal is started assuming that the dead time of the first trapezoidal wave digital signal has ended when the width of decrease in the falling signal change exceeds the threshold value T.
- the "dead time” is the time required for recovery from when the detector 30 receives the first signal until it can receive the second signal.
- the point in time when the dead time of the device 30 ends corresponds to the point in time when the width of the decrease in the signal on the falling-side oblique side exceeds the threshold value T.
- FIG. If the threshold value T set by the peak detector 62 is set large, the end point of the dead time of the first signal will be delayed, and the time during which subsequent signals cannot be measured (dead time) will increase.
- FIG. 6 shows a pulse height distribution map when actually measuring a brass sample.
- Each spectrum A to D in the drawing is a spectrum distribution when the value of the threshold value T is changed as shown below (spectrum E will be described later).
- Spectrum A has a large background around 10 KeV to 14 KeV
- spectrum B has a medium background around 10 KeV to 12 KeV
- spectrum C has a small background around 10 KeV to 11 KeV.
- almost no background occurs in spectrum D.
- FIG. 7 is a schematic diagram for explaining a piled-up trapezoidal wave digital signal.
- the horizontal axis is the time axis, and the vertical axis is the peak value of the trapezoidal wave digital signal output from the waveform conversion digital filter 61, that is, the value corresponding to the X-ray energy E.
- FIG. 7 is a schematic diagram for explaining a piled-up trapezoidal wave digital signal.
- the horizontal axis is the time axis
- the vertical axis is the peak value of the trapezoidal wave digital signal output from the waveform conversion digital filter 61, that is, the value corresponding to the X-ray energy E.
- the following trapezoidal wave digital signal U2 When the incident interval between the preceding trapezoidal wave digital signal U1 (amplitude S1) and the subsequent trapezoidal wave digital signal U2 (amplitude S2) is short and the waveforms overlap (pile up), the following trapezoidal wave digital signal U2 has A trapezoidal wave digital signal may be read as a trapezoidal wave digital signal with a slightly larger amplitude (wave height) S2' instead of the original amplitude (wave height) S2 due to the influence of the falling side oblique side of the trapezoidal wave digital signal U1. It is counted as a peak value (X-ray energy) that is greater than the peak value of the trapezoidal wave digital signal U2.
- the piled-up trapezoidal wave digital signal U2 can be divided into the X-ray energy range in which there is originally no signal in the energy spectrum. It is considered that U2 is counted and appears as a background signal.
- the peak detection threshold T in the peak detection unit 62 should be set to a value large enough to prevent the background from occurring.
- the influence of the piled-up trapezoidal wave digital signal U2 can be suppressed. That is, the background can be suppressed by setting the peak detection threshold value T so that the trapezoidal wave having the wave height width indicated by "a" in FIG. 7 is not counted due to the pile-up.
- the peak detection threshold T is set to be large, as described above, the end point of the dead time will be delayed, resulting in an increase in the dead time during which the subsequent trapezoidal wave digital signal cannot be measured. It becomes difficult to measure lines.
- a signal processing apparatus for X-ray analysis comprises a differentiating circuit for converting a plurality of staircase wave signals detected by an X-ray detector into differential wave signals;
- a signal processing device for X-ray analysis comprising: a digital filter for converting into a trapezoidal wave signal or a triangular wave signal;
- the peak detection unit sets a rising threshold Tu to be compared with the signal on the rising side of the trapezoidal wave signal or the triangular wave signal, and a falling threshold Td to be compared with the signal on the falling side of the trapezoidal wave signal or the triangular wave signal so that Tu>Td.
- the peak detection unit selects a trapezoidal wave signal or triangular wave signal to be counted from the converted trapezoidal wave signal or triangular wave signal based on the rising threshold Tu, and the falling threshold Td is set to Based on this, the detection of the peak portion of the trapezoidal wave signal or triangular wave signal is terminated.
- the ratio between the rising threshold value Tu and the falling threshold value Td is in the range of 2:1 to 4:1.
- a rising threshold value to be compared with the variation width (increase width) of the signal on the rising side oblique side portion Tu and a falling threshold value Td to be compared with the variation width (decrease width) of the signal at the falling side oblique side portion are provided separately, and the rising threshold value Tu is set to be larger than the falling threshold value Td.
- the peak detection unit compares the increase width of the signal (wave height) with the rising threshold Tu, which is the larger threshold value, in the rising side oblique side portion, thereby determining whether the trapezoidal wave should be counted as a signal.
- the peak portion thereof is detected, and the wave height value extracted from the peak portion is discriminated and counted.
- the trapezoidal wave whose peak is detected is compared with the falling threshold Td, which is the smaller threshold with respect to the reduction width of the signal (wave height) in the falling side oblique side after the peak. , it is recognized that the peak of the trapezoidal wave has passed when the decrease width of the signal has decreased by the falling threshold value Td or more, and the peak detection for the trapezoidal wave is finished.
- the falling threshold value Td is set smaller than the rising threshold value Tu, it is possible to detect the peak exceeding earlier than when the rising threshold value Tu and the falling threshold value Td are set to the same threshold value T, so that the dead time is shortened. can be used to expedite the detection of subsequent X-rays.
- the rise threshold Tu can be set to be large enough to eliminate the background (see spectrum D in FIG. 6). Therefore, according to the present invention, the rise threshold Tu can be set so as not to count the piled-up trapezoidal wave digital signal to eliminate the background, and the fall threshold Td can be set small to shorten the dead time. It becomes possible to measure more X-ray measurements.
- the ratio of the rising threshold value Tu to the falling threshold value Td is preferably in the range of 2:1 to 4:1.
- FIG. 4 is a schematic diagram illustrating the relationship between a trapezoidal wave, a rising threshold Tu, and a falling threshold Td; 1 is a schematic configuration diagram showing a conventional energy dispersive X-ray fluorescence spectrometer; FIG. It is a figure explaining the relationship between a differential wave and a trapezoidal wave.
- FIG. 4 is a waveform diagram schematically showing a differentiated wave digital signal input to a digital filter and a trapezoidal wave digital signal output after waveform conversion; It is a wave height distribution map (energy spectrum histogram) when actually measuring a brass sample. It is a schematic diagram explaining the trapezoidal wave digital signal piled up.
- FIG. 1 is a diagram showing a schematic configuration of an energy dispersive X-ray fluorescence spectrometer using an X-ray analysis signal processing apparatus according to an embodiment of the present invention.
- the energy dispersive X-ray fluorescence analyzer 1 includes an X-ray tube 10, an energy dispersive spectrometer (detector) 30, a preamplifier 41, a differentiation circuit 42, an A/D converter 43, and a waveform conversion digital It has an FPGA 60 (X-ray analysis signal processing device) consisting of a filter 61, a peak detector 72 and a histogram memory 63, and a CPU 150 for controlling the X-ray tube 10, the energy dispersive spectrometer 30, the FPGA 60 and the like.
- FPGA 60 X-ray analysis signal processing device
- the peak detector 72 of the energy dispersive X-ray fluorescence spectrometer 1 according to the present invention, two thresholds, a rising threshold Tu and a falling threshold Td, are provided. This is different from the peak detection section 62 of .
- the peak detector 72 Based on the rising threshold Tu and the falling threshold Td, the peak detector 72 removes background caused by the piled-up trapezoidal wave and shortens the dead time, in addition to removing noise. do.
- FIG. 2 is a schematic diagram illustrating the relationship between the trapezoidal wave digital signal H input from the waveform conversion digital filter 61 to the peak detection unit 72, the rising threshold Tu, and the falling threshold Td.
- the input trapezoidal wave digital signal H is composed of a rising-side oblique side Hu, an upper side Hf (peak portion), and a falling-side oblique side Hd.
- the difference from (lower side) Hb is the amplitude (peak value) of the trapezoidal wave digital signal.
- the rising threshold Tu is a threshold to be compared at the portion of the rising side oblique side Hu of the trapezoidal wave H (the portion where the wave height increases).
- the peak detection unit 72 detects that the variation width (increase width) of the rising side oblique side Hu from the baseline Hb is greater than or equal to the rising threshold Tu. Recognize the peaks of the trapezoidal wave to be counted, not the peaks of the signal to be removed as noise.
- the upper side starting point H1 which is a bending point from the rising-side oblique side Hu to the upper side Hf
- the upper side Hf which is the maximum height
- the peak value to be extracted may be the peak value at the upper side starting point H1, the peak value at another point on the upper side, or the average value of the peak values at a plurality of points on the upper side.
- the peak detection unit 72 detects the upper side end point H2, which is the inflection point from the upper side Hf to the falling oblique side Hd, and further based on the change in wave height, detects the falling edge of the trapezoidal wave H. Each point on the oblique side Hd is detected.
- the falling threshold Td is a threshold that is compared at the falling oblique side Hd of the trapezoidal wave H (the portion where the wave height decreases).
- the peak detection unit 72 detects that the fluctuation width (decrease width) of the falling oblique side Hd from the upper side Hu becomes equal to or greater than the falling threshold value Td, it recognizes that the peak of the trapezoidal wave H has passed at that time. , the peak detection for this trapezoidal wave H ends. That is, the dead time DT of the first trapezoidal wave starting from the start time DTs of the trapezoidal wave H is ended at DTe.
- the peak detection unit 72 detects the occurrence state of an inflection point from the falling-side oblique side Hd to the rising-side oblique side Hu where the wave height increases (even before reaching the baseline Hb) based on the change in wave height. To detect. Then, based on the change in wave height, a bending point to the rising side oblique side Hu is detected, and when it is detected that it has changed to the rising side oblique side, the first trapezoidal wave is generated with the wave height of the bending point as the height of the base.
- the rise threshold Tu Similar to the input, by comparing the rise threshold Tu and the variation width (increase width), it is recognized whether the signal to be removed as noise or the beginning of the peak of the trapezoidal wave to be counted. As described above, by selecting a value that can remove the piled-up trapezoidal wave (of the wave height indicated by "a" in FIG. 7) and setting it as the rising threshold Tu (for example, in FIG. 6 (threshold in spectrum D) background can be suppressed.
- the end point DTe of the dead time can be advanced by setting the falling threshold Td small.
- the rising threshold Tu to a value such that the piled-up trapezoidal wave is not counted
- the falling threshold Td smaller than Tu
- the following values were set so that Tu>Td.
- the rise threshold Tu was set to 480 eV
- Td was set to 180 eV so that the ratio of Tu:Td was 3:1, referring to spectrum D, which could reduce the background most.
- the material to be measured in FIG. 6 is brass, and the energy spectrum was measured in the range of 10 to 20 eV.
- the present invention can be used for X-ray analysis signal processing devices such as fluorescent X-ray analysis devices.
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Abstract
Description
y=exp(-nT/τ)=an ・・・(1)
ただし、τはRC時定数、Tはサンプリング周期、nはサンプル数、aは時定数(exp(-T/τ))である。
波形変換デジタルフィルタ61は、入力された微分波デジタル信号を、図4に示すように、下記式(2)で示す伝達関数を用いて台形波デジタル信号に変換する。このように微分波デジタル信号を台形波デジタル信号に変換することで、ピークの波高値(ピークトップ値)を正確に算出できるようになる。
しかしながら、小さなノイズ変動までを台形波デジタル信号のピークと認識して誤ってカウントしてしまうと、正確なエネルギースペクトルの取得が困難になる。
なお「不感時間」は、検出器30が1つ目の信号を受け取ってから2つ目の信号を受け取れるようになるまで回復に要する時間であるが、台形波デジタル信号で見たときは、検出器30の不感時間の終了時点が、立ち下がり側斜辺での信号の減少幅が閾値Tを超えた時点に対応することになる。
そしてピーク検出部62で設定する閾値Tを大きく設定すると1つ目の信号の不感時間の終了時点が遅れることになり、後続の信号が計測できない時間(不感時間)が増加することになる。
スペクトルA: ピーク検出用閾値T≒160eV
スペクトルB: ピーク検出用閾値T≒320eV
スペクトルC: ピーク検出用閾値T≒400eV
スペクトルD: ピーク検出用閾値T≒480eV
一方、スペクトルDではバックグランドがほとんど生じていない。
このピーク検出閾値Tが小さい設定でバックグランドが高くなる理由について分析したところ、先の台形波デジタル信号に、後の台形波デジタル信号が重なってパイルアップした台形波デジタル信号を、X線エネルギーEの信号としてカウントしたことが影響していることが判明した。
先の台形波デジタル信号U1(振幅S1)と、後の台形波デジタル信号U2(振幅S2)との入射間隔が短くて波形が重なると(パイルアップすると)、後の台形波デジタル信号U2には先の台形波デジタル信号U1の立ち下がり側斜辺部分の影響を受けて本来の振幅(波高)S2ではなく、少し大きい振幅(波高)S2’の台形波デジタル信号として読み取られることがあり、本来の台形波デジタル信号U2の波高値よりも大きい波高値(X線エネルギー)としてカウントされることになる。
前記ピーク検出部は前記台形波信号又は三角波信号における立ち上がり側斜辺の信号と比較する立ち上がり閾値Tu、および、立ち下がり側斜辺の信号と比較する立ち下がり閾値TdがTu>Tdの関係となるようにして設定され、前記ピーク検出部は、前記立ち上がり閾値Tuに基づいて、前記変換された台形波信号又は三角波信号のなかから計数する台形波信号又は三角波信号を選別するとともに、前記立ち下がり閾値Tdに基づいて、当該台形波信号又は三角波信号のピーク部分の検出を終了するようにしている。
ここで、前記前記立ち上がり閾値Tuと前記立ち下がり閾値Tdとの比は2:1~4:1の範囲とするのが好ましい。
これにより、ピーク検出部は立ち上がり側斜辺部分では信号(波高)の増加幅に対し、大きい方の閾値である立ち上がり閾値Tuと比較することで信号としてカウントされるべき台形波であるかが判断され、立ち上がり閾値Tu以上の信号(波高)を有する台形波の場合はそのピーク部分を検出して、ピーク部分から抽出した波高値を弁別して計数する。
ピーク部分が検出された台形波(計数された台形波)は、ピーク後の立ち下がり側斜辺部分では信号(波高)の減少幅に対し、小さい方の閾値である立ち下がり閾値Tdと比較することで、信号の減少幅が立ち下がり閾値Td以上減少したときにその台形波のピークが過ぎたと認識し、当該台形波に対するピーク検出を終える。
立ち上がり閾値Tuについては、バックグランドが消える程度に(図6のスペクトルD参照)大きめに設定することができる。
よって、本発明によればパイルアップした台形波デジタル信号をカウントしないように立ち上がり閾値Tuを設定してバックグランドを消すことができるとともに、立ち下がり閾値Tdを小さく設定して不感時間を短くし、より多くのX線計測を計測することができるようになる。
台形波デジタル信号の振幅(波高)が大きいほど立ち上がり時間、立ち下がりが長くなるので、測定対象のX線エネルギー範囲に応じて、波高が大きい範囲は比率を大きく、波高が小さい範囲は比率を小さく設定することで測定範囲に応じたバランスのよい調整が可能になる。
エネルギー分散型蛍光X線分析装置1は、X線管球10と、エネルギー分散型分光器(検出器)30と、プリアンプ41と、微分回路42と、A/D変換器43と、波形変換デジタルフィルタ61、ピーク検出部72、ヒストグラムメモリ63からなるFPGA60(X線分析用信号処理装置)と、X線管球10やエネルギー分散型分光器30やFPGA60等を制御するCPU150とを備える。
なお、既述のように、(図7において「a」で示した波高の)パイルアップした台形波が除去可能な値を選択して、立ち上がり閾値Tuとして設定しておくことで(例えば図6のスペクトルDでの閾値)バックグランドを抑えることができる。
これに対し、スペクトルEではTu>Tdとなるように、以下の値で設定した。
スペクトルE: 立ち上がり閾値Tu≒480eV
立ち下がり閾値Td≒160eV
しかも、スペクトルEの不感時間についても別途測定した結果、スペクトルDの不感時間と比べて8~16ナノ秒減少したことが確認できた。
30 エネルギー分散型分光器(検出器)
42 微分回路
43 A/D変換器
60 FPGA(X線分析用信号処理装置)
61 波形変換デジタルフィルタ
62 ピーク検出部
63 ヒストグラムメモリ
Tu 立ち上がり閾値
Td 立ち下がり閾値
H 台形波
Hu 立ち上がり側斜辺
Hf 上辺(ピーク部分)
Hd 立ち下がり側斜辺
DT 不感時間
DTe 不感時間終了時点
Claims (2)
- X線検出器で検出された複数の階段波信号を微分波信号に変換する微分回路と、
前記微分波信号を台形波信号又は三角波信号に変換するデジタルフィルタと、
前記台形波信号又は三角波信号におけるピーク部分から抽出した波高値を弁別して計数するピーク検出部とを備えるX線分析用信号処理装置であって、
前記ピーク検出部は前記台形波信号又は三角波信号における立ち上がり側斜辺の信号と比較する立ち上がり閾値Tu、および、立ち下がり側斜辺の信号と比較する立ち下がり閾値TdがTu>Tdの関係となるようにして設定され、
前記ピーク検出部は、前記立ち上がり閾値Tuに基づいて、前記変換された台形波信号又は三角波信号のなかから計数する台形波信号又は三角波信号を選別するとともに、
前記立ち下がり閾値Tdに基づいて、当該台形波信号又は三角波信号のピーク部分の検出を終了することを特徴とするX線分析用信号処理装置。 - 前記前記立ち上がり閾値Tuと前記立ち下がり閾値Tdとの比が2:1~4:1の範囲である請求項1に記載のX線分析用信号処理装置。
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US4658216A (en) * | 1983-07-14 | 1987-04-14 | The United States Of America As Represented By The Department Of Energy | High resolution, high rate X-ray spectrometer |
JPH10221455A (ja) * | 1997-02-05 | 1998-08-21 | Jeol Ltd | X線発生検出装置 |
JP2000227479A (ja) * | 1999-02-08 | 2000-08-15 | Jeol Ltd | パルスプロセッサ |
JP2005121392A (ja) * | 2003-10-14 | 2005-05-12 | Seiko Eg & G Co Ltd | 信号処理装置およびその調整方法 |
JP2015021957A (ja) | 2013-07-24 | 2015-02-02 | 株式会社島津製作所 | X線分析用信号処理装置 |
JP2019066243A (ja) * | 2017-09-29 | 2019-04-25 | 株式会社リガク | X線分析用信号処理装置及びx線分析用信号処理装置の調整方法 |
JP2020051900A (ja) | 2018-09-27 | 2020-04-02 | 株式会社島津製作所 | X線分析用信号処理装置 |
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Publication number | Priority date | Publication date | Assignee | Title |
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US4658216A (en) * | 1983-07-14 | 1987-04-14 | The United States Of America As Represented By The Department Of Energy | High resolution, high rate X-ray spectrometer |
JPH10221455A (ja) * | 1997-02-05 | 1998-08-21 | Jeol Ltd | X線発生検出装置 |
JP2000227479A (ja) * | 1999-02-08 | 2000-08-15 | Jeol Ltd | パルスプロセッサ |
JP2005121392A (ja) * | 2003-10-14 | 2005-05-12 | Seiko Eg & G Co Ltd | 信号処理装置およびその調整方法 |
JP2015021957A (ja) | 2013-07-24 | 2015-02-02 | 株式会社島津製作所 | X線分析用信号処理装置 |
JP2019066243A (ja) * | 2017-09-29 | 2019-04-25 | 株式会社リガク | X線分析用信号処理装置及びx線分析用信号処理装置の調整方法 |
JP2020051900A (ja) | 2018-09-27 | 2020-04-02 | 株式会社島津製作所 | X線分析用信号処理装置 |
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