Radiation detector

Abstract

Radiation detector comprising: a radiation indicator element (1) for detecting radiation and outputting a signal; an amplifier (2) into which the signal from the radiation indicator element (1) can be input; and a plurality of connecting wires (11, 12, 22, 23) which are each connected to the radiation indicator element (1) or the amplifier (2) and which are each to be connected to an external power supply or ground, characterized by a circuit element (5) which is connected between at least one of the plurality of connecting wires (11, 12, 22, 23) and another connecting wire (11, 12, 22, 23) and has a capacitance; and a signal wire (3) through which a signal is transmitted from the radiation indicator element (1) to the amplifier (2), wherein the signal wire (3) is connected only to the radiation indicator element (1) and the amplifier (2), and the circuit element (5) is not connected to the signal wire (3).

Description

BACKGROUND 1. Technical field

[0001] The present invention relates to a radiation detector which is provided with a radiation indicator element and an amplifier which can be used as a whole or as part of a preamplifier. 2. Description of the state of the art

[0002] A radiation detector for detecting radiation, such as X-rays, is provided with a radiation indicator element, such as a silicon drift detector (SDD). A radiation indicator element outputs a charge signal corresponding to detected radiation. This charge signal is converted into a voltage signal by a preamplifier, and signal processing, such as spectrum generation, is performed based on the voltage signal. Some conventional radiation detectors, together with a radiation indicator element and a preamplifier, form a single unit. An example of a radiation detector formed as a single unit is disclosed in Japanese patent JP 3 127 930 B2.

[0003] A radiation detector formed as a single unit comprises, in addition to a radiation indicator element and a preamplifier, connecting wires or cables (the terms "wire" and "cable" will be used synonymously hereafter) that are connected to the radiation indicator element and the preamplifier, respectively, to supply them with electrical power. Each connecting wire is connected to an external power supply or ground via a connection terminal. Some other radiation detectors formed as a single unit do not include the entire circuit of a preamplifier, but only a portion of it. For example, in some radiation detectors, a FET (field-effect transistor), which is part of a preamplifier, is connected to a radiation indicator element. In such a radiation detector, the FET is connected to the other part of the preamplifier, which is located externally, via a connection terminal.

[0004] Furthermore, JP H04 - 274 794 A describes the practice of providing vibration detection in the vicinity of radiation detection in order to eliminate the possibility of faulty actuation caused by vibrations by temporarily stopping the operation of a position detection device while the output of the vibration detection exceeds a reference value.

[0005] JP 2012 - 13 515 A discloses an attenuation circuit for attenuating detection signals resulting from X-ray analysis, comprising a plurality of first capacitors, one for each channel, located between a multi-channel semiconductor detector that detects incident X-rays and an application integrated circuit (ASIC) that amplifies the detection signal for the incident X-rays. SUMMARY OF THE INVENTION

[0006] With regard to a radiation detector, since the input capacitance from a radiation indicator to a preamplifier is increased, the noise contained in the output signal is amplified, and because the noise is increased, the energy resolution of the radiation detection deteriorates. To increase or improve the energy resolution of the radiation detection, it is preferred to decrease the input capacitance of a preamplifier. If a circuit element, such as a capacitor, is provided on a signal wire for inputting a signal from a radiation indicator to a preamplifier as a countermeasure against static electricity, the input capacitance of the preamplifier is also increased. Currently, only an insufficient countermeasure against static electricity on a signal wire is implemented to suppress the input capacitance.Accordingly, the handling of a conventional radiation detector presents a problem in that static electricity can damage a signal wire or a preamplifier by connecting a wire to a terminal, which can lead to a failure of the radiation detector.

[0007] The present invention was made in the background of these problems, the objective being to provide a radiation detector which is improved by a suitable countermeasure against static electricity, while keeping the input capacitance of a preamplifier low.

[0008] A radiation detector according to the present invention is a radiation detector comprising the following features: a radiation indicator element for detecting radiation and outputting a signal; an amplifier into which the signal from the radiation indicator element is input; and a plurality of connecting wires or cables, each of which is to be connected to the radiation indicator element or the amplifier and each to an external power source or ground; and is characterized by a circuit element which is connected between at least one of the plurality of connecting wires and a further connecting wire and has a capacitance, and a signal wire through which a signal is transmitted from the radiation detector element to the amplifier, wherein the signal wire is connected only to the radiation detector element and the amplifier, and the circuit element is not connected to the signal wire.

[0009] The radiation detector according to the present invention is characterized by the circuit element which is connected between a connecting wire which is connected to the amplifier and another connecting wire which is connected to the radiation detector element.

[0010] The radiation detector according to the present invention is characterized in that the circuit element between the connecting wire, which has the lowest electrical resistance to the signal wire under one or more connecting wires connected to the radiation detector element, and the other connecting wire, which is connected to the radiation detector element or the amplifier, is switchable.

[0011] The radiation detector according to the present invention is further characterized in that it has a plurality of substrates, wherein the radiation indicator element and the amplifier are attached to one of the plurality of substrates and the circuit element is attached to another substrate.

[0012] The radiation detector according to the present invention is characterized in that the circuit element has a property of not conducting electric current in a predetermined direction at a DC voltage below a predetermined voltage value and of conducting electric current at a pulsed voltage at a voltage value which is lower than the predetermined voltage value.

[0013] The radiation detector according to the present invention is characterized in that the circuit element is a capacitor which is formed using a parasitic capacitance between a connecting wire and another connecting wire.

[0014] The radiation detector according to the present invention is characterized in that it further comprises a sealed housing which has a reduced negative internal pressure or contains a noble gas enclosed therein, wherein the sealed housing contains the radiation indicator element, the amplifier and the circuit element therein.

[0015] In the present invention, with respect to a radiation detector equipped with a radiation indicator element and an amplifier, a capacitive circuit element is connected between a plurality of connecting wires, each of which is connected to the radiation indicator element and the amplifier and is also connected to the outside. For example, a capacitive circuit element, such as a capacitor, a diode, or a varistor, is connected between connecting wires. In another example, a circuit element is provided using a parasitic capacitance between connecting wires. This circuit element suppresses damage caused by static electricity via the connecting wires.

[0016] Furthermore, in the present invention, a circuit element with a capacitor is connected between a connecting wire which is connected to the radiation indicator element and a connecting wire which is connected to the amplifier and must be connected to an external ground. An electric current generated by static electricity flows through the circuit element to ground.

[0017] Furthermore, in the present invention, a circuit element having a capacitance is attached to a substrate which is different from the substrate on which a radiation indicator element is attached, in a position which does not negatively affect radiation detection.

[0018] Furthermore, in the present invention, a circuit element with a capacitor has the property of not conducting electric current in a predetermined direction when a DC voltage below a predetermined voltage value is applied, and of conducting electric current when a pulsed voltage is applied at a voltage value lower than the predetermined voltage value. Therefore, such a circuit element does not function in a state where a DC voltage is applied to operate a radiation detector, whereas the element functions even at a low voltage when static electricity is generated, thus protecting the circuit.

[0019] Furthermore, in the present invention a radiation detector is constructed in such a way that the radiation indicator element, the amplifier and the circuit element are housed in a sealed enclosure.

[0020] The present invention protects a radiation indicator element from static electricity while keeping the input capacitance of an amplifier, which is to be used at least as part of a preamplifier, low. Accordingly, the present invention produces advantageous effects, such as the improvement of a radiation detector through sufficient countermeasures against static electricity, while keeping the input capacitance of a preamplifier low. BRIEF DESCRIPTION OF SOME DRAWING VIEWS Fig. Figure 1 is a schematic circuit diagram of a radiation detector of the present invention; Fig. Figure 2 is a schematic section view illustrating an example of the structure of a radiation detector; Fig. Figure 3 is a schematic circuit diagram illustrating an example of a radiation detector, where the number of capacitors has been reduced; Fig. Figure 4 is a schematic circuit diagram illustrating an example of a radiation detector, where the number of capacitors has been reduced; Fig. Figure 5 is a schematic circuit diagram illustrating an example of a radiation detector, where a substrate is provided; Fig. Figure 6 is a schematic circuit diagram illustrating an example of a radiation detector including part of a preamplifier; and Fig. Figure 7 is a schematic perspective view illustrating an example of a radiation detector improved by a countermeasure against static electricity using parasitic capacitance. DETAILED DESCRIPTION

[0021] The following description will explain the present invention using specific terms with reference to the drawings, which represent one embodiment thereof.

[0022] Fig. Figure 1 is a schematic circuit diagram of a radiation detector according to the present invention. A radiation detector is equipped with a radiation indicator element 1 for detecting or receiving radiation, such as X-rays. The radiation indicator element 1 is a semiconductor receiving element, such as an SDD. When radiation strikes the radiation indicator element 1, the radiation indicator element 1 generates a charge signal proportional to the energy of the radiation. An output terminal of the radiation indicator element 1 is connected to a signal wire or cable 3. The radiation indicator element 1 outputs a charge signal, which is transmitted via the signal cable 3. The radiation detector is further equipped with a preamplifier 2, an input terminal of which is connected to the signal cable 3.The preamplifier 2 is an amplifier according to the present invention and consists, for example, of integrated circuits. A charge signal output by the radiation indicator 1 passes through the signal cable 3 and is input to the preamplifier 2. The preamplifier 2 converts the input charge signal into a voltage signal proportional to the energy of the radiation. An output terminal of the preamplifier 2 is connected to an output line 21, which is connected to a connection terminal 6 to the external circuit. The preamplifier 2 outputs a voltage signal to the external circuit via the output line 21 and the connection terminal 6. The radiation indicator 1 and the preamplifier 2 are mounted on a substrate 41.

[0023] The radiation indicator element 1 is connected to connecting cables 11 and 12, in addition to the signal cable 3. Each of the connecting cables 11 and 12 is connected to a connection terminal 6. Each of the connecting cables 11 and 12 is connected to an external power supply and ground, respectively, via a connection terminal 6. A voltage used to operate the radiation indicator element 1 is applied externally to the radiation indicator element 1 via connecting cables 11 and 12. The electrical resistance between connecting cable 11 and signal cable 3 is lower than the electrical resistance between any other connecting cable connected to the radiation indicator element 1 and signal cable 3.The electrical resistance in the radiation indicator element 1, which is located along a path between the output terminal of the radiation indicator element 1, which is connected to the signal cable 3, and a connection terminal, which is connected to the connection cable 11, is lower than that of any other path. Although... Fig. 1 represents an arrangement in which two connecting cables are connected to the radiation indicator element 1, a radiation detector can have a configuration in which a single connecting cable is connected to the radiation indicator element 1, or a configuration in which three or more connecting cables are connected.

[0024] The preamplifier 2 is connected by connecting cables 22 and 23, in addition to the signal cable 3 and the output line 21. Each of the connecting cables 22 and 23 is connected to a connection terminal 6. Connecting cable 22 is a ground cable, which must be connected to an external ground via a connection terminal 6. Connecting cable 23 is connected to an external power supply via a connection terminal 6. Although Fig. While Figure 1 represents a configuration where two connecting cables are connected to the preamplifier 2, a radiation detector can have a configuration where a single connecting cable is connected to the preamplifier 2, or a configuration where three or more connecting cables are connected. When three or more connecting cables are connected, each of the connecting cables is connected to an external power supply or ground.

[0025] Fig. Figure 2 is a schematic section view illustrating an example of the structure of a radiation detector. The substrate 41, the radiation indicator element 1, and the preamplifier 2 are housed in a sealed enclosure 73. A tip of each of the connection terminals 6 protrudes from the outside of the sealed enclosure 73. The sealed enclosure 73 has a reduced internal pressure or contains a noble gas enclosed within it. The sealed enclosure 73 is sealed by a method such as gluing, soldering, or brazing to create a structure that cannot be easily opened. The sealed enclosure 73 is provided with a window element 74. The window element 74 consists of a material that transmits radiation to be detected by the radiation detector, such as a carbon film (e.g., diamond), a SiN film, a beryllium film, or a polymer film.Window element 74 can be treated accordingly so that it is transparent to visible light.

[0026] The radiation indicator element 1 is arranged on one surface of the substrate 41 so that it is positioned in front of the window element 74. Radiation passes through the window element 74, strikes the radiation indicator element 1, and is detected or received there. The preamplifier 2 is arranged on the other surface of the substrate 41 so that it is located behind the substrate 41 with respect to the radiation indicator element 1. The signal cable 3 extends through a through-hole in the substrate 41 and is connected to the radiation indicator element 1 and the preamplifier 2. Each of the connecting cables 11, 12, 22, and 23, and the output line 21, comprises: wiring formed on or within the surface of the substrate 41; a connection point; and a wire or cable.

[0027] The sealed housing also contains a cooling unit 71 for cooling the radiation indicator element 1. The cooling unit 71 is, for example, a Peltier element. The radiation detector is further equipped with: a connection unit, not shown in the figures, for connecting to an external power source to supply the cooling unit 71 with electrical current from the outside; and a thermal radiation unit, not shown in the figures. The cooling unit 71 is coupled to a heat transfer unit 72, which is in contact with the radiation indicator element 1 and the substrate 41. The radiation indicator element 1 and the preamplifier 2 are cooled by the cooling unit 71 via the heat transfer unit 72 and the substrate 41. It should be noted that the heat transfer unit 72 can be part of the substrate 41.Cooling the radiation indicator element 1 and the preamplifier 2 leads to a reduction in noise.

[0028] For example, the radiation detector is provided in an X-ray detection apparatus. During operation, output line 21 is connected to a signal processor in the X-ray detection apparatus via a connection port 6. Furthermore, connecting cables 11 and 12 are connected to a power supply in the X-ray detection apparatus, connecting cable 22 is connected to ground in the X-ray detection apparatus, and connecting cable 23 is connected to a power supply. The radiation indicator element 1 and the preamplifier 2 are supplied with electrical current, enabling their operation. The radiation detector outputs a voltage signal via output line 21, which is processed by the signal processor in the X-ray detection apparatus.The signal processor, for example, performs a processing action by counting voltage signals of different values ​​and thus obtaining a spectrum of the detected X-rays. In another example, the radiation detector is provided in an X-ray fluorescence analyzer. In the X-ray fluorescence analyzer, the radiation detector detects fluorescence X-rays from a sample and analyzes the sample for X-ray fluorescence. Furthermore, the radiation detector can, for example, be a photodetector.

[0029] As in Fig. 1 and Fig. As shown in Figure 2, the radiation detector is provided with a substrate 42 in addition to the substrate 41. The substrate 42 is arranged in the sealed housing 73 and, in the Fig. In the example shown in Figure 2, the components are arranged parallel to the substrate 41, in a position surrounding the cooling unit 71. A capacitor 5 is connected between the connecting cable 22, which serves as the ground cable, and each of the other connecting cables, with the majority of the capacitors 5 being mounted on the substrate 42. That is, one capacitor 5 is connected between connecting cable 22 and connecting cable 11, another capacitor 5 is connected between connecting cable 22 and connecting cable 12, and yet another capacitor 5 is connected between connecting cable 22 and connecting cable 23. Each of the connecting cables 11, 12, 22, and 23, and the output line 21, comprise: wiring formed on or within the surface of the substrate 42; and a connection point.Furthermore, part of a connecting cable for connecting a capacitor 5 between the connecting cable 22 and another connecting cable consists of wiring which is in . Fig. 2 is shown with dashed lines and is formed within the substrate 42. Since a capacitor 5 is connected between each connecting cable and the connecting cable 22, electric current generated by static electricity, which can be generated at any connecting terminal 6, flows through a capacitor 5 to ground and does not flow through a connecting cable to the signal cable 3. Therefore, neither the signal cable 3 nor the preamplifier 2 is damaged by static electricity, and the radiation detector is protected from static electricity. Preferably, each capacitor 5 has sufficient capacitance to prevent electric current generated by static electricity from flowing through a connecting cable to the signal cable 3. For example, the capacitance of a capacitor 5 is preferably equal to or greater than 100 pF.If the capacitance of a capacitor is 5100 pF, it is possible to protect the radiation detector from static electricity with a voltage of 50 V.

[0030] With regard to the radiation detector, the signal cable 3 or the preamplifier 2 experiences maximum damage when an electric current generated by static electricity flows to the signal cable 3 via the connecting cable 11, which, with respect to the signal cable 3, has the lowest electrical resistance of all the connecting cables connected to the radiation indicator element 1. For this reason, the radiation detector is extremely sensitive to static electricity via the connecting cable 11. In the present invention, where a capacitor 5 is connected between the connecting cable 11 and the connecting cable 22, the flow of an electric current generated by static electricity through the connecting cable 11 to the signal cable 3 is prevented, and thus damage to the signal cable 3 or the preamplifier 2 due to static electricity is effectively avoided.Furthermore, since a capacitor 5 is also connected between the connecting cable 22 and the connecting cable 23, any electric current generated by static electricity on the connecting cable 23 flows through the capacitor 5 to ground. This prevents the flow of electric current generated by static electricity from a connecting cable connected to the preamplifier 2 to the preamplifier 2 or signal cable 3, and similarly prevents damage to the signal cable 3 or the preamplifier 2 due to static electricity.

[0031] Furthermore, in the present embodiment, where a circuit element is not provided as a countermeasure against static electricity on the signal cable 3, an increase in the input capacitance of the preamplifier 2 due to a circuit element is avoided, thus keeping the input capacitance of the preamplifier 2 low. Accordingly, with respect to a radiation detector of the present invention, a sufficient countermeasure against static electricity is implemented, while keeping the input capacitance of the preamplifier low. Therefore, the radiation detector can achieve radiation detection with high energy resolution and exhibits excellent resistance to static electricity.

[0032] Furthermore, in the present embodiment, a plurality of capacitors 5 are mounted on the substrate 42, in contrast to the substrate 41, on which the radiation detection element 1 and the preamplifier 2 are mounted. Preferably, a capacitor 5 is arranged in a position where it does not negatively impair the detection of radiation. For example, a capacitor 5 is arranged in a position where no radiation is received, or in a position where radiation generated by radiation cannot be produced for the capacitor 5, so that radiation could strike the radiation detection element 1. In the Fig. In the example shown in Figure 2, the substrate 41 and the radiation indicator element 1 are arranged between the window element 74 and the substrate 42, such that radiation passing through the window element 74 primarily strikes the radiation indicator element 1 and less so the capacitors 5. Since a plurality of capacitors 5 are mounted on the substrate 42, as opposed to the substrate 41, the position of the corresponding capacitor 5 can be easily adjusted so that there is no negative impact on radiation detection. Furthermore, because the position of the capacitors 5 can be adjusted without changing the position of the radiation indicator element 1 and the preamplifier 2, it is easier to construct a radiation detector according to the present invention using a circuit layout of an existing radiation detector.

[0033] Next, another example of the structure of a radiation detector will be explained. Fig. 3 and Fig. Figure 4 shows schematic circuit diagrams illustrating examples of a radiation detector where the number of capacitors (5) is reduced. In the diagram shown... Fig. In the example shown in Figure 3, a capacitor 5 is connected between the connecting cable 11 and the connecting cable 22, without any further capacitor 5 being provided. In such an example, the flow of electric current generated by static electricity through the connecting cable 11 to the signal cable 3 is also prevented by the capacitor 5. In such an example, a component that is extremely sensitive to static electricity from the radiation detector is protected in a defined manner by the capacitor 5, whereby only a small number of capacitors 5 are implemented as a maximum countermeasure against static electricity. As in Fig. As shown in Figure 3, a radiation detector can have a configuration in which a capacitor 5 is connected between the connecting cable 11, which has the lowest electrical resistance with respect to the signal cable 3 of all the connecting cables connected to the radiation indicator element 1, and another connecting cable, with the other capacitors 5 being omitted.

[0034] In the Fig. In the example shown in Figure 4, a capacitor 5 is connected between the connecting cable 11 and the connecting cable 12, with no further capacitor 5 being provided. In such an example, the flow of electric current generated by static electricity through the connecting cable 11 to the signal cable 3 is also suppressed by the capacitor 5. As in Fig. As shown in Figure 4, a radiation detector can have a configuration where a capacitor 5 is connected between a connecting cable (other than connecting cable 22) and connecting cable 11. Furthermore, a radiation detector can have a configuration where a capacitor 5 is connected between connecting cable 11 and each of a plurality of other connecting cables. When a capacitor 5 is connected between connecting cable 11 and another connecting cable, a component that is extremely sensitive to static electricity is protected in a defined manner, and thus a radiation detector exhibits resistance to static electricity. Furthermore, a radiation detector can have a configuration where a capacitor 5 is connected between connecting cables other than connecting cable 11.In such a configuration, the flow of electric current generated by static electricity through a connecting cable, which is connected to the capacitor 5, to the signal cable 3 is also suppressed.

[0035] Fig. Figure 5 is a schematic circuit diagram illustrating an example of a radiation detector where a substrate is provided. As shown in Fig. As shown in Figure 5, a radiation detector can have a configuration in which capacitors 5 are attached to the substrate 41 as a countermeasure against static electricity, on which the radiation indicator element 1 and the preamplifier 2 are mounted. A radiation detector can also have a configuration in which a capacitor 5 is not attached to a substrate but is provided directly on a connecting cable. A radiation detector can also have a configuration in which a capacitor 5 is connected between connection terminals 6, which are connected by corresponding connecting cables.

[0036] A radiation detector can also have a configuration where an amplifier, which is to be used as part of a preamplifier, is provided. Fig. Figure 6 is a schematic circuit diagram illustrating an example of a radiation detector, including part of a preamplifier. In the diagram shown... Fig. In the example shown in Figure 6, the radiation detector is provided with a FET 20, which acts as an amplifier. The FET 20 is connected to the signal cable 3 and is further connected to the output line 21 and the connecting cable 22. The connecting cable 22 is a ground cable. The output line 21 is connected to the other part of the preamplifier, which is provided on the outside, via a connection terminal 6. For example, the radiation detector is arranged in an X-ray detection apparatus, which is equipped with the other part of the preamplifier. When a signal from the radiation indicator 1 is input to the FET 20 through the signal cable 3, the FET 20 amplifies the signal and outputs a signal through the output line 21 to the other part of the preamplifier.Furthermore, a capacitor 5 is connected between connecting cable 11 and connecting cable 22, and another capacitor 5 is connected between connecting cable 12 and connecting cable 22. With such an arrangement, a radiation detector is also protected against static electricity by the capacitors 5.

[0037] It is noted that a radiation detector may have a configuration where a circuit element, as opposed to a capacitor, is used as a countermeasure against static electricity, provided the circuit element has capacitance. For example, a radiation detector may use a diode or varistor as a circuit element to counteract static electricity. Since the radiation indicator element 1 is a semiconductor detection element, a constant DC voltage is applied to it during operation. Therefore, it is advantageous for the circuit element used as a countermeasure against static electricity to be designed such that it is not driven by a voltage applied to it. On the other hand, to effectively protect the signal cable 3, or...To protect the preamplifier 2 from damage caused by an electric current generated by static electricity, a circuit element is preferably operated at a low voltage itself as a countermeasure against static electricity when static electricity is generated. Accordingly, a circuit element used as a countermeasure against static electricity, such as a diode or a varistor, preferably has the property of not conducting electric current at a DC voltage below a predetermined voltage value and of conducting electric current at a pulsating voltage at a voltage value lower than the predetermined voltage value. Furthermore, it is advantageous that a circuit element, such as...a diode or varistor, having sufficient capacitance to prevent electric current generated by static electricity from flowing through a connecting cable to the signal cable 3.

[0038] Furthermore, a radiation detector can have a configuration where a plurality of circuit elements are used at one location to implement a countermeasure against static electricity. For example, a radiation detector can have a configuration where a plurality of capacitors 5 are connected between connecting cable 11 and connecting cable 22. In another example, a radiation detector can have a configuration where a circuit, as a countermeasure against static electricity, is arranged between connecting cable 11 and connecting cable 22, composed of a plurality of types of circuit elements, including a capacitor.Preferably, a capacitance is achieved by a combination of a plurality of circuit elements which are provided at one location to prevent a flow of electric current which has been generated by static electricity, namely through a connecting cable to the signal cable 3.

[0039] Furthermore, a radiation detector is not limited to a configuration where a discrete circuit element is used as an implementation of a countermeasure against static electricity, but can have a configuration where a circuit element is provided using parasitic capacitance as a capacitance for a countermeasure against static electricity. Fig. Figure 7 is a schematic perspective view illustrating an example of a radiation detector improved by using a parasitic capacitance as a countermeasure against static electricity. Part of a radiation detector is shown in Fig. Figure 7 shows the radiation indicator element 1 being attached to the insulating substrate 41, with the connecting cable 11 being formed from conductive wiring. The connecting cable 11 is connected to the radiation indicator element 1 and a connection terminal 6 by means of a connection point and a wire. The substrate 41 is a multilayer substrate in which a conductive wiring layer is provided. The connecting cable 12 is formed on the wiring layer in the substrate 41. The connecting cable 12 is in Fig. Figure 7 is shown with dashed lines. The connecting cable 12 is connected via a through-hole to a connection point provided on the substrate 41 and is connected to the radiation indicator element 1 and a connection terminal 6 by means of the connection point and a wire. It should be noted that the connecting cable 12 can be located on the back side of the substrate 41.

[0040] A rectangular plate section 111 is provided in the middle of the connecting cable 11. Plate section 111 is a metal plate with a specific surface. A rectangular plate section 121 is also provided in the middle of the connecting cable 12. Plate section 121 is a metal plate with a surface corresponding to that of plate section 111. Plate section 121 is positioned directly below plate section 111, i.e., in a position where it overlaps plate section 111 when projected vertically onto the upper surface of the substrate 41. Plate section 111 and plate section 121 are substantially parallel to each other. It should be noted that plate section 111 and plate section 121 can have shapes other than rectangles.

[0041] Since part of the insulating substrate 41 is located between the conductive plate part 111 and the conductive plate part 121, a parasitic capacitance is generated between plate part 111 and plate part 121. Such a condition is similar to a state where a capacitor is formed with a pair of electrodes in the form of plate part 111 and plate part 121 and dielectrics of part of the substrate 41 connected between connecting cable 11 and connecting cable 12. That is, a circuit of a Fig. The radiation detector shown in Figure 7 corresponds to a circuit where a capacitor is connected between connecting cable 11 and connecting cable 12, as shown in Figure 7. Fig. 4 is shown. In such a configuration, the radiation detector is protected from static electricity, as shown in the Fig. This is the case as shown in example 4. The plate part 111 and the plate part 121 are dimensioned in such a way as to provide sufficient capacity to prevent electric current generated by static electricity from flowing through a connecting cable 3.

[0042] A capacitor with a pair of electrodes, composed of plate part 111 and plate part 121, is a circuit element connected between connecting cable 11 and connecting cable 12 and exhibits capacitance. As explained above, a circuit element connected between connecting cables as a countermeasure against static electricity is not limited to a specific circuit element, but can be any circuit element, including part of a connecting cable, using parasitic capacitance between connecting cables as capacitance. Similarly, a circuit element using parasitic capacitance can be used to implement a countermeasure against static electricity, in contrast to the one described in Fig. 7. For example, a countermeasure against static electricity can be implemented by providing a circuit element using parasitic capacitance between connecting cable 11 and connecting cable 22. Furthermore, a radiation detector can have a configuration where a countermeasure against static electricity is implemented by a combination of a circuit element using parasitic capacitance and a specific circuit element.

[0043] It has been established that in Fig. Figures 1 to 7 show a minimal structure of a radiation detector, wherein a radiation detector may have a configuration which includes a further circuit element or wiring not shown in the figures, for a use which relates mainly to a countermeasure against static electricity.

Claims

[1] Radiation detector comprising: a radiation indicator element (1) for detecting radiation and outputting a signal; an amplifier (2) into which the signal from the radiation indicator element (1) can be input; and a plurality of connecting wires (11, 12, 22, 23) which are each connected to the radiation indicator element (1) or the amplifier (2) and which are each to be connected to an external power supply or ground, respectively. characterized by a circuit element (5) which is connected between at least one of the plurality of connecting wires (11, 12, 22, 23) and another connecting wire (11, 12, 22, 23) and has a capacitance; and a signal wire (3) through which a signal is transmitted from the radiation indicator element (1) to the amplifier (2), wherein the signal wire (3) is connected only to the radiation indicator element (1) and the amplifier (2), and the circuit element (5) is not connected to the signal wire (3). [2] Radiation detector according to claim 1, wherein the circuit element (5) is connected between a connecting wire (22) which is connected to the amplifier (2) and another connecting wire (11, 12, 23) which is connected to the radiation indicator element (1). [3] Radiation detector according to claim 1 or 2, where the circuit element (5) is switchable between the connecting wire (11), which has the lowest electrical resistance to the signal wire (3) under one or more connecting wires connected to the radiation indicator element (1), and the other connecting wire (12, 22, 23), which is connected to the radiation indicator element (1) or the amplifier (2). [4] Radiation detector according to any one of claims 1 to 3, further comprising: a plurality of substrates (41, 42), wherein the radiation indicator element (1) and the amplifier (2) are mounted on one (41) of the plurality of substrates, and the circuit element (5) is attached to another substrate (42). [5] Radiation detector according to one of claims 1 to 4, wherein the circuit element (5) has the property of not conducting electric current in a predetermined direction when the DC voltage is below a predetermined voltage value, and of conducting electric current when the voltage is pulsating at a voltage value which is lower than the predetermined voltage value. [6] Radiation detector according to any one of claims 1 to 5, wherein the circuit element (5) is a capacitor which is formed using parasitic capacitance between one connecting wire and another connecting wire. [7] Radiation detector according to any one of claims 1 to 6, further comprising: a sealed housing (73) which has a reduced negative internal pressure or contains a noble gas enclosed therein, wherein the sealed housing (73) contains the radiation indicator element (1), the amplifier (2) and the circuit element (5). [8] Radiation detector according to claim 7, wherein the sealed housing (73) has a window part (74) through which radiation passes, and the circuit element (5) is provided at a location where it is not reached by the radiation passing through the window part (74).

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