Signal detecting device, measuring device, and mass spectrometer

Abstract

This disclosure proposes a signal detection device to reduce the impact of interference propagation noise inside and outside the signal detection device and improve signal detection accuracy. The device includes: a detector comprising a photoelectric conversion element that converts photons (the object to be detected) into a current signal and a current / voltage converter that converts the current signal into a voltage signal; a transmission unit that transmits the voltage signal; and a data collection unit that detects and collects the transmitted voltage signal. Here, the detector is disposed inside a first shielded housing connected to the rack ground. The current / voltage converter includes a differential amplifier having first and second input terminals. The first input terminal is connected to the first output terminal of the photoelectric conversion element via a first input resistor, and the second input terminal is connected to the second output terminal of the photoelectric conversion element and the ground via a second input resistor having a resistance value larger than the first input resistor. Furthermore, the first and second output terminals of the current / voltage converter are connected to the data collection unit via a cable transmission unit. The cable transmission unit, along with the current / voltage converter and the data collection unit, is connected to the ground (see Figure 1).

Description

Technical Field

[0001] This disclosure relates to signal detection devices, measuring devices, and quality analysis devices. Background Technology

[0002] For example, a signal detection device is used in a beta ray measuring apparatus, which includes a scintillator that emits scintillation light when beta rays are incident, a wavelength conversion fiber that absorbs the scintillation light and converts it into scintillation light of different wavelengths, and a photomultiplier tube that captures the light propagated by the wavelength conversion fiber.

[0003] In addition, for example, a signal detection device is used in a mass analysis apparatus whereby, after the sample to be analyzed is vaporized, it is ionized by applying a high electric field, and the ionized sample collides with a conversion multiplier electrode to generate secondary electrons. These secondary electrons are then incident on a scintillator to generate scintillation light, which is then captured by a photomultiplier tube.

[0004] Regarding such signal detection devices, for example, Patent Document 1 discloses a signal detection device comprising: a generally flat first β-ray detector 2 having a scintillator and a wavelength conversion fiber; a generally flat second β-ray detector 3 overlapping the first β-ray detector 2 in the thickness direction, having a scintillator and a wavelength conversion fiber; and a β-ray shielding plate 4 disposed between the first β-ray detector 2 and the second β-ray detector 3 to shield β-rays. In this signal detection device, the scintillator of the first β-ray detector 2 and the scintillator of the second β-ray detector 3 are made to have the same shape, and the wavelength conversion fiber of the first β-ray detector 2 and the wavelength conversion fiber of the second β-ray detector 3 are made to have the same structure, thereby distinguishing the β-rays of the detection target from the γ-rays which are noise, and ensuring the signal-to-noise ratio (S / N) and reducing noise at ambient temperature.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-145213 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, the noise that degrades the signal-to-noise ratio (S / N) of a signal detection device, which includes photoelectric conversion elements, signal detectors, and data collection units, includes not only the detection signal other than the object being detected in sensors such as scintillators and thermal noise at ambient temperature, but also electromagnetic noise generated by other electrical equipment inside the measuring device when the signal detection device is mounted on the measuring device (hereinafter referred to as "interference propagation noise"), and interference propagation noise incident from outside the measuring device. Electrical equipment inside the measuring device that generates interference propagation noise includes, for example, switching power supplies or digital circuits. Interference propagation noise incident from outside the measuring device includes, for example, other measuring devices located near the measuring device, communication radio waves, and broadcast radio waves. Generally, in measuring devices with high detection accuracy, weaker signals are detected by increasing the sensitivity of photoelectric conversion elements such as photomultiplier tubes used in the mounted signal detection device.

[0010] However, increasing the sensitivity of the photoelectric conversion element will also result in the high-sensitivity detection of interference propagation noise generated inside and outside the signal detection device, making normal measurement impossible. In view of this situation, this disclosure proposes a technique to reduce the influence of interference propagation noise inside and outside the signal detection device and improve signal detection accuracy.

[0011] Methods for solving problems

[0012] To address the aforementioned problem, this disclosure provides a signal detection apparatus comprising: a detector including a photoelectric conversion element that converts photons, the object of detection, into a current signal and a current / voltage converter that converts the current signal into a voltage signal; a transmission unit that transmits a voltage signal; and a data collection unit that detects and collects the transmitted voltage signal. The detector is disposed inside a first shielded housing connected to a rack ground wire. The current / voltage converter includes a differential amplifier having a first input terminal and a second input terminal. The first input terminal is connected to a first output terminal of the photoelectric conversion element via a first input resistor. The second input terminal is connected to a second output terminal of the photoelectric conversion element and a ground wire via a second input resistor having a resistance value larger than the first input resistor. The first and second output terminals of the current / voltage converter are connected to the data collection unit via a cable transmission unit. The cable transmission unit, the current / voltage converter, and the data collection unit are connected to a ground wire together.

[0013] Further features associated with this disclosure will become clear from the description and accompanying drawings in this specification. Furthermore, this disclosure is implemented through elements and combinations of elements, as well as detailed descriptions and additional claims of protection. Moreover, the descriptions in this specification are merely typical examples and do not in any way limit the scope of claims or application of this disclosure.

[0014] Invention Effects

[0015] According to the technology disclosed herein, when interference propagation noise is incident on the signal detection device, the impact of interference propagation noise on signal detection can be reduced, thereby improving detection accuracy. Attached Figure Description

[0016] Figure 1 This is a diagram illustrating a structural example of the signal detection device 100 according to the first embodiment.

[0017] Figure 2 This is a diagram illustrating an example of the circuit structure of a signal detection device in the prior art.

[0018] Figure 3 This is a diagram illustrating an example of the circuit structure of the signal detection device 100 according to the first embodiment.

[0019] Figure 4 This is a diagram illustrating a structural example of the signal detection device 400 according to the second embodiment.

[0020] Figure 5 This is a diagram illustrating a structural example of the signal detection device 500 according to the third embodiment.

[0021] Figure 6 This is a diagram showing the arrangement (example) of the signal detection devices 100, 400 or 500 in the measuring apparatus 600 of the fourth embodiment.

[0022] Figure 7 This is a diagram showing a structural example of the quality analysis apparatus 700 according to the fifth embodiment (vertical sectional view of the side of the apparatus).

[0023] Figure 8 This is a horizontal cross-sectional view of the quality analysis device 700 from above, showing the location where the signal detection device is installed.

[0024] Figure 9 The graph shows an example of the measurement results and an example of the improvement effect of S / N when interference propagation noise is irradiated during the measurement of the quality analysis apparatus 700 in the fifth embodiment. Detailed Implementation

[0025] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the drawings, functionally identical elements are sometimes shown with the same numbers. Furthermore, the drawings illustrate specific embodiments and installation examples consistent with the principles of the present disclosure, but these are for understanding the present disclosure and are in no way intended to limit its interpretation. In addition, in this embodiment, the same or identical parts are generally not repeated except where specifically necessary.

[0026] In this embodiment, a thorough and detailed description has been provided to enable those skilled in the art to implement this disclosure. However, it is also understood that other installations and methods are possible, and structural and constructional changes and substitutions of various elements can be made without departing from the scope and spirit of the technical concept of this disclosure. Therefore, the following description should not be interpreted as limited to this.

[0027] (1) First implementation method

[0028] The following describes a technique for reducing interference propagation noise that overlaps with the signal output of the photoelectric conversion element in a signal detection device comprising a detector, a cable transmission section, and a data collection section, which consists of a photoelectric conversion element, a current / voltage converter, and a shielding housing.

[0029] <Example of the structure of a signal detection device>

[0030] Figure 1 This is a diagram illustrating a structural example of the signal detection device 100 according to the first embodiment. The signal detection device 100 includes: a photoelectric conversion element 120 that converts photons, which are to be detected, into current signals; a current / voltage converter 121 that converts the current signals output from the photoelectric conversion element 120 into voltage signals; a cable transmission section 103 that transmits the voltage signals output from the current / voltage converter 121; a data collection section 104 that detects and collects the transmitted voltage signals; a control device (computer) 105; a shielding housing 102 that houses the photoelectric conversion element and the current / voltage converter; and an insulated power supply 106 that supplies power to the photoelectric conversion element, the current / voltage converter, and the data collection section.

[0031] Photons that are detected include, for example, the scintillation light output by a scintillator, or the reflected light from an optical measuring device using a laser or the like.

[0032] The photoelectric conversion element 120 is a sensor that outputs a current quantity corresponding to the amount of incident photons; for example, a photomultiplier tube or a photodiode can be used.

[0033] The current / voltage converter 121 is a transimpedance circuit that outputs a voltage corresponding to the input current, and has first and second differential input terminals and first and second differential output terminals.

[0034] The cable transmission unit 103 is a transmission path that propagates the differential voltage signal output from the current / voltage converter 121 as an analog signal to the data collection unit 104. For example, a coaxial cable with shielding effect by covering the signal line with an insulating layer and a conductive layer can be used. Alternatively, the cable transmission unit 103 can be a differential coaxial cable that transmits the differential voltage signal of the current / voltage converter 121 in pairs, or the first and second output terminals can be independently connected to the data collection unit 104 with two coaxial cables.

[0035] The data collection unit 104 includes a signal detector 107 that detects the differential voltage signal transmitted from the cable transmission unit 103. To improve the detection accuracy of the signal detector 107, an amplifier and a filter for selecting the detection frequency band can be installed before it. The signal detector 107 has the function of detecting and collecting the differential voltage signal and transmitting it to the control device 105. Furthermore, the signal detector 107 may include, for example, an analog-to-digital converter, a memory, and a data forwarding unit. The analog-to-digital converter samples and discretizes the differential voltage signal to generate digital data, which is then temporarily stored in the memory. If a fixed amount of data is stored in the memory, the data forwarding unit forwards the digital data to the control device 105. Additionally, the signal detector 107 may also include, for example, a comparator, a threshold voltage generator, and a data forwarding unit. The comparator compares the voltage signal with a threshold voltage; if the voltage signal exceeds the threshold voltage, it forwards a digital value "1" to the control device 105; if the voltage signal does not exceed the threshold voltage, it forwards a "0" to the control device 105.

[0036] The insulated power supply 106 is a power supply that insulates the photoelectric conversion element 120, the current / voltage converter 121, and the data collection unit 104 from the ground wire 110 of the measuring device frame, and supplies the required power to the photoelectric conversion element 120, the current / voltage converter 121, and the data collection unit 104. For example, it is an insulated power supply that can electrically insulate the primary side from the secondary side.

[0037] The control device 105 processes the detected and collected data and controls the operation of the data collection unit 104. Additionally, the control device 105 is also responsible for controlling the measuring device. For example, in the case of a mass analysis device, the control device 105 controls the ion source 701, convergence unit 702, separation unit 703, and fluorescence unit 704 (described later) of the mass analysis device. Figure 8 The applied voltage value.

[0038] <Inflow path of interference propagation noise>

[0039] Figure 2 This is a diagram illustrating an example of the circuit structure of a prior art signal detection device 200.

[0040] First, the detection principle of the existing signal detection device 200 will be explained. A current / voltage converter 122 with one output terminal converts the current signal output from the photoelectric conversion element 120 into a voltage signal. The typical current / voltage conversion factor is the feedback resistor Rf (voltage signal = current signal × Rf). The voltage signal is transmitted to the signal detector 107 via a signal transmission path such as a cable.

[0041] Next, the noise path in the case where interference propagation noise is incident on the signal detection device 200 in the prior art will be explained. Typically, in the prior art, the entire signal detection device is shielded to prevent interference propagation noise from directly incident on the wiring of the transmitted signal. However, interference propagation noise flows into the input terminal of the current / voltage converter 122 via the conductor used for this shielding. As a result, the current / voltage converter 122 sends the interference propagation noise as a voltage signal to the signal detector 107. Furthermore, interference propagation noise also flows into the signal detector 107 via the conductor used for shielding the transmission line, such as a cable. This results in a deterioration of the signal-to-noise ratio (S / N) of the signal detection.

[0042] <Example of a structure used to reduce noise propagation interference>

[0043] Figure 3 This is a diagram illustrating an example of the circuit structure of the signal detection device 100 according to the first embodiment. (and the...) Figure 2 Similarly, in the case where interference propagation noise overlaps on the conductor where the signal wiring is shielded, in the first embodiment, the interference propagation noise flows into the input terminal of the current / voltage converter 121 via a virtual resistor (also called a replicated resistor: resistance value Rd) 300. Therefore, it is believed that if the interference propagation noise is attenuated through the virtual resistor 300, the voltage signal output by the current / voltage converter 121 originating from the interference propagation noise can be reduced. In addition, by setting the output of the current / voltage converter 121 to differential, the path of the interference propagation noise flowing to the signal detector 107 can be cut off. As a result, the signal / noise ratio of signal detection can be maintained.

[0044] Here, taking the case where a photomultiplier tube is used as the photoelectric conversion element 120 as an example, the attenuation of interference propagation noise is explained. The general circuit equivalent model of a photomultiplier tube is a parallel connection of an ideal current source and a resistor, with a resistance value of approximately several MΩ to tens of MΩ. If this resistor is set as Rp( Figure 2 and Figure 3 (as shown), then Figure 2In existing signal detection devices, the amplification of interference propagation noise is 1 + Rf / Rp. Typically, Rf is used in the range of hundreds of Ω to several kΩ, so Rf / Rp can be approximated as zero. Therefore, the amplification of interference propagation noise in existing devices is 1 + Rf / Rp ≈ 1, outputting noise at its original strength.

[0045] on the other hand, Figure 3 The amplification rate of the interference propagation noise in the signal detection device 100 of the first embodiment shown is Rf / (Rin+Rd). The value of Rf is used from several hundred Ω to several kΩ, and the value of Rin is used from tens of Ω to several hundred Ω. Here, the value of Rd of the virtual resistor 300 can be used from several kΩ to tens of kΩ. That is, the amplification rate of the interference propagation noise is Rf / (Rin+Rd)≈Rf / Rd<1, and can be set to less than 1. This attenuates the interference propagation noise and outputs it.

[0046] As described above, while increasing the value of the virtual resistance Rd can further attenuate interference propagation noise, it also leads to an increase in the thermal noise of the virtual resistance Rd itself and a decrease in the bandwidth of the current / voltage converter. Therefore, the value of the virtual resistance Rd can be determined by achieving a balance between the circuit characteristics (electrical characteristics) of the signal detection device 100 and the attenuation of interference propagation noise. In the circuit characteristics, the bandwidth of the frequency that can be detected by the signal detection device 100 is proportional to the value (Rd) of the virtual resistance 300. If the resistance value Rd is too large, only low-frequency signals can be detected. If the photomultiplier tube outputs a signal slowly, the value of Rd can be made extremely large, but this is only effective for signal detection devices with slow signal output speeds. Therefore, when the signal output frequency of the photomultiplier tube is high, Rd is not excessively increased and is set to an upper limit of around tens of kΩ.

[0047] Furthermore, while Rin and Rd are labeled as different resistive elements, they can also be used as a single resistive element Rind, which has the sum of the resistance values ​​of Rin and Rd. In this case, the resistance values ​​of the first and second input terminals of the current / voltage converter are in the relationship Rin < Rind.

[0048] <Regarding impedance mismatch caused by the insertion of virtual resistors>

[0049] Reference Figure 1The impedance mismatch and its countermeasures when the signal detection device 100 of the first embodiment is mounted on the measuring device will be explained. In the signal detection device 100, as described above, a virtual resistor is used to attenuate interference propagation noise, but the input impedance of the current / voltage converter increases due to the virtual resistor. This results in an impedance mismatch between the wiring that transmits the output signal of the photoelectric conversion element 120 and the input impedance of the current / voltage converter 121. Therefore, in order to accurately transmit the output signal of the photoelectric conversion element 120 to the current / voltage converter 121, it is necessary to arrange the photoelectric conversion element 120 and the current / voltage converter 121 close together and shorten the wiring length. For example, the photoelectric conversion element 120 and the current / voltage converter 121 can be arranged close together within 1 / 10 of the wavelength of the output signal of the photoelectric conversion element 120.

[0050] Furthermore, photoelectric conversion elements 120, such as photomultiplier tubes, mostly have high output impedance, and current / voltage converters 121 also have high input impedance. That is, the wiring transmitting the output signal of the photoelectric conversion element 120 has high impedance, leading to significant noise overlap when interference propagation noise directly strikes this wiring. Therefore, to suppress the direct incidence of interference propagation noise, the photoelectric conversion element 120 and the current / voltage converter 121 need to be housed inside the shielding housing 102. In other words, the shielding housing 102 separately shields the photoelectric conversion element 120 and the current / voltage converter 121 from the housing that shields the entire device. The shielding housing 102 can be made of a metal with low resistivity, such as stainless steel or aluminum.

[0051] <Regarding grounding wiring and insulation>

[0052] Reference Figure 1 The wiring and insulation of the ground wire when the signal detection device 100 of the first embodiment is mounted on the measuring device will be described. In order to accurately transmit the signal output by the photoelectric conversion element 120 to the data collection unit 104, the ground wires of the photoelectric conversion element 120, the current / voltage converter 121, the cable transmission unit 103, and the data collection unit 104 may also be connected to the signal ground wire 111.

[0053] The shielding housing 102 is connected to the rack ground 110 to suppress incident interference propagation noise from flowing into the photoelectric conversion element 120, current / voltage converter 121, cable transmission section 103, and data collection section 104. Alternatively, the rack ground 110 and signal ground 111 can also be connected via a noise canceller (not shown) such as a low-pass filter.

[0054] In addition, as described above, in order to separate the rack ground wire 110 from the signal ground wire 111, the power supply for supplying the photoelectric conversion element 120, the current / voltage converter 121, the cable transmission unit 103, and the data collection unit 104 can use an insulated power supply 106 that can isolate the primary side from the secondary side.

[0055] In addition, the location of the noise canceller (not shown) connecting the rack ground wire 110 and the signal ground wire 111 can be matched with the shape of the measuring device and the noise path, and can be a signal detector 107, or it can be connected to the primary side and the secondary side of the insulated power supply 106.

[0056] <Technical Effects of the First Embodiment>

[0057] As described above, even if interference propagation noise is incident on the signal detection device 100 and / or the measuring device (e.g., a quality analysis device), the interference propagation noise can be attenuated, thereby reducing the impact on the measurement and improving the signal detection accuracy.

[0058] (2) Second implementation method

[0059] In the first embodiment, a coaxial cable is used in the cable transmission section 103 to transmit the signal from the photoelectric conversion element 120 to the data collection section 104 in the form of an analog signal. In the second embodiment, the signal detection device 100 described in the first embodiment is described in which digital signals and optical signals are used in the cable transmission section 103.

[0060] <Example of the structure of a signal detection device>

[0061] Figure 4 This is a diagram illustrating a structural example of the signal detection device 400 according to the second embodiment. (Refer to...) Figure 4 The operating principle of a signal detection device that uses digital signals is explained.

[0062] In the signal detection device 400, the cable transmission unit 103 includes: an analog-to-digital converter 402, which samples and discretizes the analog signal, i.e., the voltage signal, output by the current-to-voltage converter 121 to convert it into a digital value; a digital transmitter 403, which transmits the voltage signal converted into a digital value; and a digital transmission path 404, which transmits the digital signal.

[0063] The analog-to-digital converter 402 can be, for example, a general A / D converter. Alternatively, the analog-to-digital converter 402 can be configured with a threshold voltage generator and a comparator. The comparator compares the voltage signal output from the current / voltage converter 121 with the threshold voltage output from the threshold voltage generator. If the voltage signal exceeds the threshold voltage, it is converted to a digital value "1", and if it does not exceed the threshold voltage, it is converted to a digital value "0" and output.

[0064] The digital transmitter 403 performs digital data transmission processing such as encoding, synchronization, and modulation on the voltage signal converted into a digital value as needed. For example, a common standard transmission method such as Ethernet can also be used. When digital data transmission processing is not required, the digital transmitter 403 can also directly output the digital signal output from the analog-to-digital converter 402 to the digital transmission path 404.

[0065] As described above, when digital circuits such as the analog-to-digital converter 402 and the digital transmitter 403 are connected to the stage following the current-to-voltage converter 121, noise generated from the digital circuits flows into the current-to-voltage converter 121, degrading the signal-to-noise ratio (S / N). The noise generated from the digital circuits includes propagated noise 406 radiated through digital operation and conducted noise (grounding noise) 405 conducted from the ground wire of the digital circuits.

[0066] To suppress propagated noise 406 emitted through digital operation, the analog-to-digital converter 402 and the digital transmitter 403 are disposed outside the shielding housing 102. Furthermore, conducted noise (ground noise) 405 from the ground wire can be attenuated by the resistive element Rind, as described in the first embodiment, which has a virtual resistance Rd or the sum of the virtual resistance Rd and the input resistance Rin. Additionally, conducted noise (ground noise) 405 generated by interference propagation noise incident on the analog-to-digital converter 402, the digital transmitter 403, and the digital transmission path 404 can also be attenuated by the aforementioned resistive element Rind.

[0067] In addition, in order to suppress interference propagation noise incident on the analog-to-digital converter 402 and the digital transmitter 403, the shielding housing (shielding housing for digital transmitter) 401 can be configured separately from the shielding housing 102.

[0068] <Effects of the Second Implementation>

[0069] According to the second embodiment, in the signal detection device 400 using digital signals, when interference propagation noise is incident, the interference propagation noise can be attenuated, thereby reducing the impact on the measurement and improving accuracy.

[0070] (3) Third implementation method

[0071] <Example of the structure of a signal detection device>

[0072] Figure 5This diagram illustrates a structural example of the signal detection device 500 according to the third embodiment. The third embodiment relates to signal detection using optical signals. The signal detection device 500 differs only in the structure of the cable transmission section 103; the other structures are the same as those of the signal detection device 400 according to the second embodiment.

[0073] The cable transmission section 103 of the signal detection device 500 includes an electro-optical converter 502, an optical transmitter 503, and an optical transmission path 504.

[0074] The electro-optical converter 502 converts the voltage signal output from the current-to-voltage converter 121 into an optical signal. The optical transmitter 503 outputs the optical signal converted by the electro-optical converter 502 to the optical transmission path 504. The electro-optical converter 502, the optical transmitter 503, and the optical transmission path 504 can, for example, use digital optical communication using general optical fibers. Alternatively, if the transmission distance of the cable transmission section 103 is shortened by arranging the detector 101 and the data collection unit 104 close together, analog optical communication using an optocoupler or the like in the optical transmitter can also be used.

[0075] Similar to the signal detection device 400 using digital signals (second embodiment), the electro-optical converter 502 and the optical transmitter 503 are disposed outside the shielding housing 102 to suppress propagation noise 406 generated from the electro-optical converter 502 and the optical transmitter 503. Furthermore, conducted noise (grounding noise) 505 from the ground wire can be attenuated by the resistive element Rind, which has a virtual resistance Rd or the sum of the virtual resistance Rd and the input resistance Rin, as described in the first embodiment. Furthermore, conducted noise 505 generated by interference propagation noise incident on the electro-optical converter 502 and the optical transmitter 503 can also be attenuated by the aforementioned resistive element Rind.

[0076] In addition, in order to suppress the interference propagation noise incident on the electro-optical converter 502 and the optical transmitter 503, the electro-optical converter 502 and the optical transmitter 503 may be equipped with a shielding housing (shielding housing for optical transmission section) 501 that is different from the shielding housing 102.

[0077] <Effects of this implementation method>

[0078] According to the third embodiment, in the signal detection device 500 that uses optical signals, when interference propagation noise is incident, the interference propagation noise can be attenuated, thereby reducing the impact on the measurement and improving the accuracy.

[0079] (4) Fourth Implementation

[0080] The fourth embodiment describes a measurement device equipped with the signal detection devices 100, 400, or 500 of the first to third embodiments, in which the configuration of the signal detection device improves the S / N ratio of the signal detection by reducing the intensity of the interference propagation noise incident on the signal detection device itself.

[0081] <Configuration of the signal detection device in the measuring apparatus>

[0082] Figure 6 This diagram shows an example of the arrangement of the signal detection devices 100, 400, or 500 in the measuring apparatus 600 according to the fourth embodiment. The measuring apparatus 600 includes a component 602 and a signal detection device comprising a detector 101, a cable transmission unit 103, and a data collection unit 104 inside the measuring apparatus housing 601. The component 602 of the measuring apparatus 600 includes, for example, equipment for performing processing for detecting the object to be measured, and a power supply for the measuring apparatus.

[0083] The measuring device frame 601 serves as the rack ground 110. Alternatively, the rack ground 110 can also be grounded (connected to the earth).

[0084] Alternatively, an insulator may be provided between the signal detection device 100, 400 or 500 and the component 602 of the measuring device, with them arranged nearby to each other.

[0085] <Configuration of the cable transmission section>

[0086] Next, the configuration of the cable transmission section 103 will be described. The intensity of the interference propagation noise incident on the measuring device 600 is attenuated by the measuring device frame 601, but it generally penetrates into the interior of the measuring device 600. Therefore, the interference propagation noise that penetrates into the interior of the measuring device 600 is incident on the cable transmission section 103, causing the signal / noise ratio (S / N) of the signal detection to deteriorate. Therefore, the cable transmission section 103 is positioned at a distance from the measuring device frame 601, so that the intensity of the interference propagation noise that penetrates into the measuring device 600 is further attenuated before it is incident. In particular, the cable transmission section 103 constituting the signal detection device is positioned in the center of the measuring device 600, so that the intensity of the interference propagation noise can be further attenuated by the measuring device component 602. This can be achieved by, for example, placing an insulator on the component 602 at the center of the bottom surface of the measuring device 600, and mounting the signal detection device 100, 400, or 500 on the insulator.

[0087] <Effects of the Fourth Implementation Method>

[0088] According to the fourth embodiment, the intensity of the interference propagation noise incident on the signal detection devices 100, 400 or 500 can be reduced, thereby reducing the impact on the measurement of the measuring device 600 and improving the measurement accuracy.

[0089] (5) Fifth Implementation

[0090] The fifth embodiment describes a quality analysis device 700 that performs high-precision quality analysis by reducing interference propagation noise, and includes the signal detection devices 100, 400, or 500 of the first to third embodiments.

[0091] <Example of the structure of a mass analysis device>

[0092] Figure 7 This is a diagram showing a structural example of the mass analysis apparatus 700 according to the fifth embodiment (a vertical sectional view of the side of the apparatus). Additionally, Figure 8 This is a horizontal cross-sectional view of the quality analysis device 700 from above, showing the location where the signal detection device is installed.

[0093] The mass analysis apparatus 700 includes: an ion source 701 that ionizes the sample of the analyte fed from the pretreatment unit; a convergence unit 702 that converges the ionized sample 710; a separation unit 703 that filters the converged ionized sample according to the mass-charge ratio, thereby allowing only the ionized sample of the analyte to pass through; a fluorescence unit 704 that causes the ionized sample passing through the separation unit to collide with a conversion multiplier 709, converting it into electrons corresponding to the amount of the ionized sample, and then directing these electrons to a scintillator 705, thereby outputting photons corresponding to the amount of electrons; a detector 101 that outputs an electrical signal corresponding to the photons; a cable transmission unit 103 that transmits the electrical signal output from the detector; a data collection unit 104 that detects and collects the electrical signal; a control unit 706 that controls the mass analysis; a power supply unit 707 that supplies power to each part; and a frame 708 for the mass analysis apparatus.

[0094] The detector 101, cable transmission unit 103, and data collection unit 104 are components included in the signal detection device 100, 400, or 500. Additionally, the power supply unit 707 also includes the isolated power supply 106. Furthermore, the control unit 706 includes the control device 105. Moreover, the location of the signal detection device 100, 400, or 500 (especially the cable transmission unit 103) in the quality analysis device 700, as described in the fourth embodiment, can be set in the central part of the quality analysis device 700 (see reference). Figure 7 as well as Figure 8 ).from Figure 7 as well as Figure 8It is also understood that the signal detection devices 100, 400, or 500 are surrounded by a resin block and disposed in the central part of the quality analysis device 700. The signal detection devices 100, 400, or 500 are mounted on other components of the quality analysis device 700, arranged to reach the central part in the vertical direction. Furthermore, as described above, by housing the signal detection devices 100, 400, or 500 within a frame (shielding housing 102, 401, 501) different from the frame 708 of the quality analysis device 700, interference propagation noise is reduced.

[0095] <Example of measurement results>

[0096] Figure 9 The graph shows an example of the measurement results and an example of the improvement effect of S / N when interference propagation noise is irradiated during the measurement of the quality analysis apparatus 700 in the fifth embodiment.

[0097] Measurement result 801 indicates a situation where interference propagation noise overlaps with the detection signal, resulting in a measurement value variation 803. Measurement result 802 indicates a situation where interference propagation noise is attenuated, thus improving the S / N ratio. By suppressing the generation of measurement value variation 803, quality can be accurately analyzed.

[0098] <Effects of the Fifth Implementation Method>

[0099] According to the fifth embodiment, quality analysis can be performed with high precision by reducing interference propagation noise.

[0100] (6) Other

[0101] The present disclosure has been described in detail above based on multiple embodiments, but the technology disclosed is not limited to these embodiments, and various modifications can be made without departing from its spirit. For example, the structures of the first to fifth embodiments can be combined in multiple ways.

[0102] Explanation of reference numerals in the attached figures

[0103] 100, 400, 500 signal detection devices;

[0104] 101 detector;

[0105] 102 Shielding Housing;

[0106] 103 Cable Transmission Department;

[0107] 104 Data Collection Department;

[0108] 105 control device;

[0109] 106 Insulated Power Supply;

[0110] 107 signal detector;

[0111] 110 rack ground wire;

[0112] 111 signal ground wire;

[0113] 112 photoelectric conversion element power supply;

[0114] 113 Current / Voltage Converter Power Supply;

[0115] 114 Data Collection Unit Power Supply;

[0116] 120 photoelectric conversion element;

[0117] 121 Current / Voltage Converter;

[0118] 300 virtual resistor;

[0119] Shielding housing for 401 digital transmitter;

[0120] 402 Analog / Digital Converter;

[0121] 403 Digital Transmitter;

[0122] 404 Digital Transmission Path;

[0123] 405 and 505 conducted noise;

[0124] 406 and 506 propagate noise;

[0125] Shielding housing for 501 optical transmitter;

[0126] 502 electro-optical converter;

[0127] 503 optical transmitter;

[0128] 504 Optical Transmission Path;

[0129] 600 measuring device;

[0130] 601 Measuring Device Frame;

[0131] 700 quality analysis device;

[0132] 701 ion source;

[0133] 702 Convergence;

[0134] 703 Separation Section;

[0135] 704 fluorescent part;

[0136] 705 flasher;

[0137] 706 Control Department;

[0138] 707 Power Supply Section;

[0139] 709 conversion multiplier.

Claims

1. A signal detection device, characterized in that, The signal detection device has the following features: The detector includes a photoelectric conversion element that converts photons, which are the objects to be detected, into an electric current signal, and a current-to-voltage converter that converts the electric current signal into a voltage signal; The transmission unit transmits the voltage signal; as well as The data collection unit detects and collects the transmitted voltage signal. The detector is disposed inside a first shielded housing connected to the rack ground, and the current / voltage converter includes a differential amplifier having a first input terminal and a second input terminal. The first input terminal is connected to the first output terminal of the photoelectric conversion element via a first input resistor. The second input terminal is connected to the second output terminal of the photoelectric conversion element and the ground line via a second input resistor having a resistance value larger than that of the first input resistor. The first and second output terminals of the current / voltage converter are connected to the data collection unit via the transmission unit. The transmission unit, together with the current / voltage converter and the data collection unit, is connected to the ground wire.

2. The signal detection device according to claim 1, characterized in that, The photoelectric conversion element, the current / voltage converter, and the data collection unit are insulated from the rack ground wire.

3. The signal detection device according to claim 1, characterized in that, The photoelectric conversion element is a photomultiplier tube.

4. The signal detection device according to claim 1, characterized in that, The second input resistor includes: A resistor, having the same resistance value as the first input resistor, and connected to the second input terminal; and A virtual resistor, whose resistance value is greater than the first input resistor, is connected to the photoelectric conversion element and the ground wire.

5. The signal detection device according to claim 1, characterized in that, The photoelectric conversion element, the current / voltage converter, and the data collection unit are insulated from the rack ground by being powered from an insulated power source.

6. The signal detection device according to claim 1, characterized in that, The rack ground wire is grounded.

7. The signal detection device according to claim 1, characterized in that, The transmission unit transmits the voltage signal from the current / voltage converter to the data collection unit in the form of an analog signal.

8. The signal detection device according to claim 1, characterized in that, The transmission unit converts the voltage signal from the current / voltage converter into a digital signal and transmits it to the data collection unit.

9. The signal detection device according to claim 8, characterized in that, The transmission unit is housed in a second shielding housing, which is different from the first shielding housing.

10. The signal detection device according to claim 1, characterized in that, The transmission unit converts the voltage signal from the current / voltage converter into an optical signal and transmits it to the data collection unit.

11. The signal detection device according to claim 10, characterized in that, The transmission unit is housed in a second shielding housing, which is different from the first shielding housing.

12. A measuring device, characterized in that, The measuring device frame includes the signal detection device as described in claim 1. At least the transmission unit included in the signal detection device is disposed in the central part of the measuring device frame.

13. A quality analysis device, characterized in that, The frame contains: An ion source, which ionizes the sample containing the analyte; A separation section that allows only ions with the desired mass-to-charge ratio to pass through in the ionized sample; The conversion multiplier electrode emits secondary electrons through ion collisions; A scintillator that receives the secondary electrons and emits scintillating light; as well as The signal detection device of claim 1 detects light emitted from the scintillator and collects data.

14. The quality analysis apparatus according to claim 13, characterized in that, The signal detection device is located in the center of the frame.

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