JP2014240770A - Radiation detecting device and radiation analyzing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation detecting device capable of improving an S/N ratio by suppressing the generation of a noise.SOLUTION: A radiation detecting device 100 has a housing 10 having a window 12 provided with a transmission film 13 that allows a radiation to transmit, a generation unit 22 for generating a signal by an incident radiation, a collection unit 24 for collecting a signal generated by the generation unit 22, and an amplification unit 26 for amplifying the signal collected by the collection unit 24, and includes a detector 20 stored in the housing 10, and an insulation unit 30 provided so as to be overlapped with at least one of the collection unit 24 and the amplification unit 26 when viewed from an incident direction A of the radiation incident on the detector 20 and lower in transmission factor of the radiation than the transmission film 13.

Description

  The present invention relates to a radiation detection apparatus and a radiation analysis apparatus.

  Radiation detectors mounted on scanning electron microscopes (SEM), transmission electron microscopes (TEM), scanning transmission electron microscopes (STEM), fluorescent X-ray analyzers (XRF) and the like are generally detectors that detect radiation. , A field effect transistor (FET), a chamber, a transmission window that transmits radiation, and the like.

  A silicon drift detector (Silicon Drift Detector, SDD) is known as a detector. The silicon drift detector, for example, efficiently introduces electrons generated in (N-type) Si depleted by reverse bias by incident X-rays to the anode by an electrode structure having a concentric potential gradient. is there.

  As such a silicon drift detector, for example, Patent Document 1 discloses a device in which an FET (field effect transistor) for amplifying a generated signal (electron) is incorporated. A silicon drift detector incorporating an FET is effective for amplifying a generated signal with little noise.

JP 2010-169659 A

  However, in such a silicon drift detector, when radiation is incident on the FET or the anode, it causes noise. Such noise deteriorates the SN ratio of the output signal of the radiation detection apparatus.

  The present invention has been made in view of the above points, and one of the objects according to some aspects of the present invention is to detect radiation that can suppress the generation of noise and improve the SN ratio. An apparatus and a radiation analysis apparatus are provided.

(1) A radiation detection apparatus according to the present invention includes:
A housing having a window portion provided with a permeable membrane that transmits radiation;
A generator that generates a signal by the incident radiation; a collector that collects the signal generated by the generator; and an amplifier that amplifies the signal collected by the collector; A detector with
A shielding unit that is provided so as to overlap at least one of the collection unit and the amplification unit as viewed from the incident direction of the radiation incident on the detector, and has a lower transmittance of the radiation than the transmission film;
including.

  According to such a radiation detection apparatus, it is possible to prevent radiation from entering the collection unit and the amplification unit by the shielding unit. Thereby, generation | occurrence | production of noise can be suppressed and the S / N ratio of an output signal can be improved.

(2) In the radiation detection apparatus according to the present invention,
The shielding part may be provided so as not to overlap at least a part of the generation part as seen from the incident direction.

(3) In the radiation detection apparatus according to the present invention,
Including a support for supporting the permeable membrane,
The shielding part may be provided integrally with the support part.

  According to such a radiation detection apparatus, the shielding part and the support part can be manufactured in the same process, and the manufacturing process can be simplified.

(4) In the radiation detection apparatus according to the present invention,
The thickness of the shielding part may be larger than the thickness of the support part.

  According to such a radiation detection device, it is possible to increase the transmittance of the support portion with respect to the radiation while increasing the shielding rate of the shielding portion with respect to the radiation.

(5) In the radiation detection apparatus according to the present invention,
The shield may be in contact with the detector.

  According to such a radiation detection apparatus, it is possible to improve the SN ratio of the output signal while suppressing a decrease in the sensitivity of the detector.

(6) In the radiation detection apparatus according to the present invention,
The shield may be in contact with the permeable membrane.

(7) In the radiation detection apparatus according to the present invention,
The shielding part may be a metal film.

(8) In the radiation detection apparatus according to the present invention,
The shield may be provided between the permeable membrane and the detector.

  According to such a radiation detection apparatus, it is possible to improve the SN ratio of the output signal while suppressing a decrease in the sensitivity of the detector.

(9) In the radiation detection apparatus according to the present invention,
The detector may be a silicon drift detector.

(10) In the radiation detection apparatus according to the present invention,
The collector is an anode;
The amplifying unit may be a field effect transistor.

(11) A radiation analyzer according to the present invention includes:
A radiation detection apparatus according to the present invention is included.

  According to such a radiation analysis apparatus, since the radiation detection apparatus according to the present invention is included, the SN ratio of the output signal can be improved.

Sectional drawing which shows typically the radiation detection apparatus which concerns on 1st Embodiment. FIG. 2 is a plan view schematically showing the radiation detection apparatus according to the first embodiment. The top view which shows typically the detector of the radiation detection apparatus which concerns on 1st Embodiment. The top view which shows typically the detector which concerns on a reference example. The graph which shows the relationship between the detection probability of X-rays, and the energy of X-rays. Sectional drawing which shows typically the radiation detection apparatus which concerns on a 1st modification. Sectional drawing which shows typically the radiation detection apparatus which concerns on a 2nd modification. The top view which shows typically the radiation detection apparatus which concerns on a 2nd modification. Sectional drawing which shows typically the radiation detection apparatus which concerns on a 3rd modification. The top view which shows typically the radiation detection apparatus which concerns on a 3rd modification. Sectional drawing which shows typically the radiation detection apparatus which concerns on a 4th modification. The top view which shows typically the radiation detection apparatus which concerns on a 4th modification. The top view which shows typically the detector of the radiation detection apparatus which concerns on a 4th modification. Sectional drawing which shows typically the radiation detection apparatus which concerns on a 5th modification. The top view which shows typically the radiation detection apparatus which concerns on a 5th modification. Sectional drawing which shows typically the radiation detection apparatus which concerns on a 6th modification. The top view which shows typically the radiation analyzer which concerns on 2nd Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are essential constituent requirements of the present invention.

1. 1. First embodiment 1.1. Configuration of Radiation Detection Apparatus First, the radiation detection apparatus according to the first embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing the radiation detection apparatus 100 according to the first embodiment. FIG. 2 is a plan view schematically showing the radiation detection apparatus 100. 1 is a cross-sectional view taken along the line II of FIG.

  As shown in FIG. 1, the radiation detection apparatus 100 includes a housing (chamber) 10, a detector 20, a shielding unit 30, a support unit (grit unit) 40, a cooling element 50, a heat pipe 60, And an electrode terminal substrate 70.

  The radiation detection apparatus 100 is an apparatus that detects radiation. The radiation detected by the radiation detection apparatus 100 is, for example, X-rays or γ-rays. Here, a case where the radiation detection apparatus 100 detects X-rays will be described.

  The housing 10 has a window portion 12 provided with a permeable film 13 that transmits X-rays. The permeable membrane 13 is, for example, a thin film made of a polymer or an inorganic material. The material of the permeable membrane 13 is not particularly limited. Further, the permeable membrane 13 may be a single layer or a multilayer. The permeable membrane 13 is provided on the support portion 40 and the shielding portion 30. The permeable membrane 13 is supported by the support portion 40. The permeable membrane 13 is provided on the support portion 40 in the illustrated example, but may be provided between the beam portions 40 a and 40 b of the support portion 40. The permeable membrane 13 transmits X-rays and can isolate the environment inside the housing 10 from the external environment.

The housing 10 further includes a base 14 that supports a support portion (grid portion) 40 and a cylindrical body 16. The detector 20, the cooling element 50, the heat pipe 60, and the electrode terminal substrate 70 are accommodated in a space surrounded by the permeable membrane 13, the base 14, and the cylindrical body 16. The material of the base 14 and the cylinder 16 is, for example, SUS, brass, aluminum, copper, lead, or an alloy thereof.

  The detector 20 is accommodated in the housing 10. The detector 20 includes a generation unit 22, a collection unit 24, and an amplification unit 26. The detector 20 is a semiconductor detector, for example, a silicon drift detector (SDD).

  The generator 22 generates a signal (electrons) by the incident X-ray. The generation unit 22 includes, for example, a (N-type) Si single crystal that is depleted by a reverse bias, and a multistage ring electrode (not shown) that creates a concentric potential gradient (drift electric field). The ring electrode is provided in a ring shape centered on the center position of the detector 20, for example.

  The generating unit 22 includes a first portion 22a and a second portion 22b. The first portion 22a is a portion that overlaps the collection unit 24, the amplification unit 26, and the region 25 between the collection unit 24 and the amplification unit 26 in plan view. As shown in FIG. 2, the first portion 22 a is a region inside the collecting unit 24 (including the region on the collecting unit 24) provided in a ring shape in plan view. In the region 25 of the generation unit 22, for example, a separation unit (not shown) for electrically separating the amplification unit (FET) 26 is provided.

  The second portion 22b is a portion that does not overlap with the collection unit 24, the amplification unit 26, and the region 25 between the collection unit 24 and the amplification unit 26 in plan view. As shown in FIG. 2, the second portion 22 b is a region outside the collection unit 24 provided in a ring shape in plan view. That is, the second portion 22b is a region other than the first portion 22a of the generating unit 22. The signal (electrons) generated in the second portion 22b is guided to the collecting unit 24 by the drift electric field.

  The first portion 22 a overlaps the shielding unit 30 when viewed from the incident direction A of X-rays incident on the detector 20. Further, the second portion 22b does not overlap the shielding portion 30 when viewed from the incident direction A of X-rays. Note that a part of the second portion 22 b may overlap the shielding portion 30 when viewed from the X-ray incident direction A. The incident direction A of X-rays is, for example, a direction along the normal of the incident surface 20a of the detector 20.

  The collection unit 24 is an electrode for collecting signals (electrons) generated by the generation unit 22. The collecting unit 24 is an anode. The collector (anode) 24 is electrically connected to the gate electrode of the amplifier (FET) 26 by, for example, wiring (not shown). As shown in FIG. 2, the collection unit 24 has a ring shape and is provided so as to surround the amplification unit 26. The collecting unit 24 is provided on the back surface 20b (surface opposite to the incident surface 20a on which X-rays are incident) of the detector 20 side.

  The amplifying unit 26 amplifies the signal (electrons) collected by the collecting unit 24. The amplification unit 26 is a field effect transistor (FET). The amplifying unit 26 is disposed at the center of the detector 20. The amplifying unit 26 is provided on the back surface 20 b side of the detector 20.

  As shown in FIG. 2, the shielding unit 30 is provided so as to overlap the collection unit 24 and the amplification unit 26 when viewed from the incident direction A of the X-rays incident on the detector 20. In the illustrated example, the shielding unit 30 is provided so as to overlap all of the collection unit 24 and the amplification unit 26. That is, when viewed from the incident direction A, the collection unit 24 and the amplification unit 26 are located inside the outer edge of the shielding unit 30.

In addition, the shielding unit 30 is provided so as not to overlap the generation unit 22 when viewed from the incident direction A. That is, when viewed from the incident direction A, the generation unit 22 is located outside the outer edge of the shielding unit 30. Note that the shielding unit 30 may overlap a part of the generation unit 22 when viewed from the incident direction A. The shape of the shielding unit 30 is not particularly limited as long as it is provided so as to overlap the collection unit 24 and the amplification unit 26 and not to overlap at least a part of the generation unit 22 when viewed from the incident direction A. In the example shown in FIG. 2, the shield 30 is circular when viewed from the incident direction A.

  The shielding unit 30 is provided between the permeable membrane 13 and the detector 20. The shielding unit 30 is provided in the housing 10. In the example shown in the figure, the shielding part 30 is in contact with the permeable membrane 13.

  The shielding part 30 is provided integrally with the support part 40 for supporting the permeable membrane 13. For example, the shielding portion 30 and the support portion 40 can be integrally formed by patterning a silicon substrate using wet etching (anisotropic or isotropic), dry etching, micro-discharge machining, or the like. .

  The transmittance of the shielding unit 30 for X-rays is lower than the transmittance of the transmissive film 13 for X-rays. Here, the transmittance refers to a rate at which X-rays pass through an object (here, the shielding unit 30 or the permeable film 13). That is, the transmittance refers to the ratio between the transmission intensity and the incident intensity when entering the object. In addition, a shielding factor means 100-transmittance. The transmittance of the shielding unit 30 with respect to X-rays is desirably 0%. That is, it is desirable that the shielding rate of the shielding unit 30 against X-rays is 100%.

  The material of the shielding part 30 is not particularly limited as long as it is a substance lower than the transmittance of the permeable film 13. For example, a semiconductor such as silicon, a metal such as Sn and Mo, a polymer material, and the like are combined. is there. Further, the thickness of the shielding unit 30 (the size in the incident direction A) is, for example, about several nm to 1 mm.

  The support part 40 supports the permeable membrane 13. The material of the support portion 40 is, for example, a semiconductor such as silicon, a metal such as Sn or Mo, or a polymer material. The thickness of the support part 40 is the same as the thickness of the shielding part 30 in the illustrated example. In the example shown in FIG. 2, the support portion 40 includes a plurality of (eight in the illustrated example) beam portions 40 a extending in the radial direction from the shielding portion 30 as viewed from the incident direction A, and the shielding portion 30 extending in the circumferential direction. And a plurality of (two in the illustrated example) beam portions 40b. The shape of the support part 40 is not specifically limited.

  The shielding part 30 and the support part 40 may be covered with a conductive material (Al, graphite carbon, etc.). Thereby, it can prevent that the shielding part 30 and the support part 40 are charged.

  The cooling element 50 is an element for cooling the detector 20. The cooling element 50 is, for example, a Peltier element. The cooling element 50 is disposed on the back surface 20 b side of the detector 20. The heat released from the cooling element 50 is transmitted to the heat radiating plate (not shown) by the heat pipe 60 and released.

  The electrode terminal board 70 is disposed between the detector 20 and the cooling element 50. The electrode terminal board 70 includes a connection terminal for electrically connecting the detector 20 and an external circuit (not shown).

  The operation of the radiation detection apparatus 100 will be described.

For example, X-rays (characteristic X-rays and fluorescent X-rays) generated by irradiating the sample with electron beams or X-rays pass through the transmission film 13 of the window 12 and enter the generator 22 of the detector 20. To do. At this time, the shielding unit 30 prevents X-rays from entering the first portion 22a of the generation unit 22. When X-rays enter the second portion 22b of the generator 22 through the transmissive film 13, electrons are generated in the second portion 22b. The electrons move by a drift electric field generated by the ring electrode of the generator 22 and are collected by the collector 24. The amount of electrons collected by the collection unit 24 is proportional to the energy of incident X-rays. The electrons collected by the collection unit 24 are amplified by an amplification unit (FET) 26. Thereby, the radiation detection apparatus 100 outputs an output signal corresponding to the energy of the incident X-ray. The output signal of the detector 20 is sent from the electrode terminal board 70 to an external signal processing unit (not shown) via wiring (not shown).

  The radiation detection apparatus 100 has the following features, for example.

  In the radiation detection apparatus 100, the shielding unit 30 is provided so as to overlap the collection unit (anode) 24 and the amplification unit (FET) 26 when viewed from the incident direction A. Thereby, it is possible to prevent X-rays from entering the collection unit (anode) 24 and the amplification unit (FET) 26. For example, when X-rays are incident on the collection unit (anode) 24 and the amplification unit (FET) 26, noise may be caused and the SN ratio of the output signal may be deteriorated. According to the radiation detection apparatus 100, the shielding unit 30 can prevent X-rays from being incident on the collection unit (anode) 24 and the amplification unit (FET) 26. Therefore, the SN ratio of the output signal can be improved.

  In the radiation detection apparatus 100, the shielding unit 30 is further provided so as to overlap the first portion 22 a of the generation unit 22 when viewed from the incident direction A. Thereby, the incidence of X-rays on the first portion 22a can be prevented. For example, when X-rays are incident on the first portion 22a, the generated electrons cannot be collected accurately by the collecting unit (anode) 24, causing noise and deteriorating the SN ratio of the output signal. There is. According to the radiation detection apparatus 100, since the shielding part 30 can prevent the X-ray from entering the first portion 22a, the SN ratio of the output signal can be improved.

  In the radiation detection apparatus 100, the shielding unit 30 is provided so as not to overlap at least a part of the generation unit 22 when viewed from the incident direction A. Therefore, for example, the amount of X-rays incident on the generation unit 22 can be increased as compared with the case where the shielding unit 30 overlaps the entire generation unit 22.

  In the radiation detection apparatus 100, since the shielding part 30 is provided integrally with the support part 40, the shielding part 30 and the support part 40 can be manufactured in the same process, and the manufacturing process can be simplified.

  In the radiation detection apparatus 100, as described above, the shielding unit 30 can prevent X-rays from entering the collection unit (anode) 24, the amplification unit (FET) 26, and the first portion 22a. An anode) 24 and an amplifying unit (FET) 26 can be arranged in the center of the detector 20. As a result, the measurement time can be shortened while improving the S / N ratio of the output signal. The reason will be described below.

  FIG. 3 is a plan view schematically showing the detector 20. FIG. 4 is a plan view schematically showing a detector 20d according to the reference example. In the detector 20d shown in FIG. 4, an amplifying unit (FET) 26 is disposed at the end of the detector 20d. 3 and 4 are views seen from the incident direction A. FIG.

  In the detector 20d of the reference example shown in FIG. 4, the collection unit (anode) 24 and the amplification unit (FET) 26 are provided at the end of the detector 20d, and the collection unit (anode) 24 and the amplification unit (FET) 26 are provided. X-rays are prevented from entering.

However, the collector (anode) 24 and the amplifier (FET) at the end of the detector 20d
When 26 is provided, an area where the distance from the amplifying unit (FET) 26 is greatly separated is generated in the generating unit 22. When light is received in such a distance region, the time until the electrons e reach the amplifying unit (FET) 26 becomes longer. As a result, the number of signal processes per unit time is reduced, leading to a longer measurement time. Such a problem becomes particularly noticeable as the area of the detector 20 increases. Increasing the area of the detector 20 has an advantage in improving the detection sensitivity and shortening the measurement time, but this effect may be counteracted by the above problem.

  On the other hand, in the detector 20 of the radiation detection apparatus 100 shown in FIG. 3, the shielding unit 30 can prevent the X-ray from entering the collection unit (anode) 24 and the amplification unit (FET) 26. A collecting part (anode) 24 and an amplifying part (FET) 26 can be arranged in the central part of the vessel 20. Therefore, the above problem does not occur. Therefore, according to the radiation detection apparatus 100, it is possible to shorten the measurement time while improving the SN ratio.

  In the radiation detection apparatus 100, the shielding unit 30 is provided between the permeable membrane 13 and the detector 20. Thereby, it is possible to improve the SN ratio while suppressing a decrease in sensitivity of the detector 20. For example, when the shielding unit 30 is provided outside the housing 10, the distance between the shielding unit 30 and the detector 20 is increased. Therefore, in order to reliably shield the collecting unit (anode) 24 and the amplifying unit (FET) 26, the area of the shielding unit 30 must be increased. However, if the area of the shielding part 30 is increased, the ratio of shielding the second portion 22b of the generating part 22 is also increased, so that the sensitivity is lowered. On the other hand, in the radiation detection apparatus 100, since the shielding part 30 is provided between the permeable membrane 13 and the detector 20, compared with the case where the shielding part 30 is provided outside the housing 10. Thus, the distance between the shielding unit 30 and the detector 20 can be reduced. Therefore, the S / N ratio can be improved while suppressing a decrease in sensitivity of the detector 20.

1.2. Experimental Example Next, the effect of the shielding unit 30 will be specifically described.

  FIG. 5 shows that the material of the shielding part 30 is silicon, the thickness of the shielding part 30 is 400 μm, and the thickness of the detector (silicon drift detector) 20 is 400 μm. It is a graph which shows the result of having calculated | required the relationship between the detection probability and the X-ray detection probability in the 2nd part 22b, and the energy of X-ray | X_line by simulation. Note that the graph of FIG. 5 does not consider attenuation due to the permeable membrane. The detection probability in the first portion 22a is expressed as follows.

(Detection probability in the first part 22a) ≈ {1- (shielding rate in the shielding part 30)} × (shielding rate in the first part 22a)
As can be seen from FIG. 5, when the X-ray energy is 10 keV or less, the X-ray detection probability in the first portion 22a is 0, and the X-ray detection probability in the second portion 22b is 1. That is, the shielding part 30 shields almost all X-rays of 10 keV or less (transmittance of the shielding part 30≈0%).

  Even when the X-ray energy is greater than 10 keV, the X-ray detection probability in the first portion 22a is smaller than the detection probability in the second portion 22b. That is, it can be seen that the shielding part 30 prevents the X-ray from entering the first portion 22a.

  Thus, it has been found that the shielding part 30 can prevent the incidence of X-rays.

1.3. Modified Example Next, a modified example of the radiation detection apparatus according to the present embodiment will be described. Hereinafter, in each modified example, members having the same functions as the constituent members of the radiation detection apparatus 100 described above are denoted by the same reference numerals, and detailed description thereof is omitted.

(1) First Modification First, a first modification will be described. FIG. 6 is a cross-sectional view schematically showing the radiation detection apparatus 200 according to the first modification.

  In the radiation detection apparatus 100 described above, as shown in FIG. 1, the thickness of the shielding part 30 and the thickness of the support part 40 are the same.

  On the other hand, in the radiation detection apparatus 200, the thickness of the shielding part 30 is larger than the thickness of the support part 40 as shown in FIG. Thereby, the transmittance | permeability of the support part 40 with respect to X-rays can be raised, improving the shielding rate of the shielding part 30 with respect to X-rays. Therefore, according to the radiation detection apparatus 200, even when the support unit 40 and the shielding unit 30 are provided integrally, the first shielding unit 30 prevents the X-ray from entering the second portion 22 b by the support unit 40. The incidence of X-rays on the portion 22a can be prevented.

  When the shielding part 30 and the support part 40 having different thicknesses are integrally formed, for example, first, the silicon substrate is etched so as to have the thickness of the shielding part 30. Next, a mask is formed in a region to be the shielding portion 30 and etching is performed, and the silicon substrate is thinned except for the region where the mask is formed. Next, the support part 40 is formed by patterning the thinned region of the silicon substrate. Thereby, the shielding part 30 and the support part 40 from which thickness differs can be formed integrally.

  The shielding unit 30 and the support unit 40 may be separated.

(2) Second Modification Next, a second modification will be described. FIG. 7 is a cross-sectional view schematically showing a radiation detection apparatus 300 according to the second modification. FIG. 8 is a plan view schematically showing the radiation detection apparatus 300. 7 is a cross-sectional view taken along line VII-VII in FIG.

  In the radiation detection apparatus 100 described above, as shown in FIGS. 1 and 2, the shielding part 30 is provided integrally with the support part 40.

  On the other hand, in the radiation detection apparatus 300, as shown in FIGS. 7 and 8, the shielding unit 30 is provided on the permeable membrane 13. The shielding unit 30 is in contact with the permeable membrane 13.

  The shielding unit 30 is formed, for example, by forming a metal film on the transmission film 13. The material of the metal film used as the shielding unit 30 is a heavy metal such as Al, Ni, Au, Pt, Sn, or Mo, for example. Since such heavy metal has a high shielding rate against X-rays, the shielding part 30 can be made thin.

  The radiation detection apparatus 300 does not include the support unit 40 in the illustrated example, but may include the support unit 40.

(3) Third Modification Next, a third modification will be described. FIG. 9 is a cross-sectional view schematically showing a radiation detection apparatus 400 according to the third modification. FIG. 10 is a plan view schematically showing the radiation detection apparatus 400. 9 is a cross-sectional view taken along line IX-IX in FIG.

In the radiation detection apparatus 100 described above, as shown in FIGS. 1 and 2, the shielding part 30 is provided integrally with the support part 40.

  On the other hand, in the radiation detection apparatus 400, the shielding part 30 is provided on the detector 20, as shown in FIG. 9 and FIG. More specifically, the shielding unit 30 is provided on the first portion 22 a of the generation unit 22. The shield 30 is in contact with the detector 20.

  The shielding unit 30 is formed, for example, by forming a metal film on the detector 20. The material of the metal film used as the shielding unit 30 is a heavy metal such as Al, Ni, Au, Pt, Sn, or Mo, for example. Thereby, the shielding part 30 can be thinned.

  In the radiation detection apparatus 400, since the shielding unit 30 is provided on the detector 20, the distance between the shielding unit 30, the collection unit 24, and the amplification unit 26 can be reduced. Therefore, the S / N ratio can be improved while suppressing a decrease in sensitivity of the detector 20.

(4) Fourth Modification Next, a fourth modification will be described. FIG. 11 is a cross-sectional view schematically showing a radiation detection apparatus 500 according to the fourth modification. FIG. 12 is a plan view schematically showing the radiation detection apparatus 500. 11 is a cross-sectional view taken along line XI-XI in FIG. FIG. 13 is a plan view schematically showing the detector 20 of the radiation detection apparatus 500.

  In the radiation detection apparatus 100 described above, as shown in FIGS. 1 and 2, the collection unit 24 is provided so as to surround the amplification unit 26.

  On the other hand, in the radiation detection apparatus 500, as shown in FIGS. 11 to 13, the collection unit 24 is provided in the generation unit 22 of the detector 20, and the amplification unit 26 is outside the generation unit 22 (non-collection unit 23). ). The shielding unit 30 is provided so as to overlap the collection unit 24 when viewed from the incident direction A of X-rays. In the illustrated example, the shielding unit 30 does not overlap the amplification unit 26 when viewed from the incident direction A of X-rays.

  In the radiation detection apparatus 500, the detector 20 has a non-collecting unit 23 as shown in FIGS. The non-collecting unit 23 is a region where generated electrons are not collected by the anode even when X-rays are incident. The non-collecting unit 23 is, for example, a region where a potential gradient (drift electric field) of Si single crystal is not applied. In the detector 20, the non-collection unit 23 is a region outside the generation unit 22. In the illustrated example, the generator 22 is provided at the center of the detector 20, and the non-collector 23 is provided at the end of the detector 20.

  The collection unit 24 and the amplification unit 26 are electrically connected to each other by a wiring 28 such as a bonding wire, for example.

  In the radiation detection apparatus 500, since the shielding unit 30 is provided so as to overlap the collection unit 24 when viewed from the incident direction A of X-rays, generation of noise can be suppressed and the SN ratio can be improved.

  In the radiation detection apparatus 500, the amplifying unit 26 is provided in a region (non-collecting unit 23) where electrons generated even when X-rays are incident are not collected by the anode. Therefore, in the first place, there is no problem that electrons generated in the first portion 22a of the generating unit 22 overlapping the amplifying unit 26 cannot be accurately collected by the collecting unit 24 and cause noise. Therefore, in the radiation detection apparatus 500, even if the shielding unit 30 is not provided so as to overlap the amplification unit 26, generation of noise can be suppressed.

  Although not shown, for example, the base 14 or the beam portions 40a and 40b of the support portion 40 may overlap the amplification portion 26 when viewed from the incident direction A of X-rays. That is, the base 14 or the beam portions 40 a and 40 b of the support portion 40 may have the same function as the shielding portion 30. Thereby, generation | occurrence | production of noise can be suppressed and SN ratio can be improved.

(5) Fifth Modification Next, a fifth modification will be described. FIG. 14 is a cross-sectional view schematically showing a radiation detection apparatus 600 according to the fifth modification. FIG. 15 is a plan view schematically showing the radiation detection apparatus 600. 14 is a cross-sectional view taken along line XIV-XIV in FIG.

  In the radiation detection apparatus 100 described above, as shown in FIGS. 1 and 2, the collection unit 24 and the amplification unit 26 are arranged at the center of the detector 20.

  On the other hand, in the radiation detection apparatus 600, as shown in FIGS. 14 and 15, the collection unit 24 and the amplification unit 26 are arranged at the end of the detector 20. The positions of the collection unit 24 and the amplification unit 26 are not particularly limited.

(6) Sixth Modification Next, a sixth modification will be described. FIG. 16 is a cross-sectional view schematically showing a radiation detection apparatus 700 according to the sixth modification.

  In the radiation detection apparatus 100 described above, as shown in FIGS. 1 and 2, the shielding unit 30 is provided between the permeable membrane 13 and the detector 20.

  On the other hand, in the radiation detection apparatus 200, the shielding part 30 is provided outside the housing 10 as shown in FIG.

  The shielding unit 30 is supported by a collimator unit 710 for aligning the incident direction of X-rays. In addition, the member for supporting the shielding part 30 is not specifically limited.

2. Second Embodiment Next, a radiation analyzer according to a second embodiment will be described with reference to the drawings. FIG. 17 is a diagram illustrating a configuration of the radiation analysis apparatus 1 according to the second embodiment.

  The radiation analysis apparatus 1 includes a radiation detection apparatus according to the present invention. Here, a case where the radiation analysis apparatus 1 is configured to include the radiation detection apparatus 100 will be described.

  As shown in FIG. 17, the radiation analyzer 1 further includes an electron beam source 2, a focusing lens 3, a scanning deflector 4, an objective lens 5, a sample stage 6, and an electron detector 7. It consists of

  The radiation analyzer 1 scans the electron beam E1 on the sample S, detects the electron E2 emitted from the sample S when the electron beam E1 is scattered in the sample S, and displays an image (scanned electron image). get. That is, the radiation analysis apparatus 1 is a scanning electron microscope (SEM) on which the radiation detection apparatus 100 is mounted.

The electron beam source 2 generates an electron beam (primary electron beam) E1. The electron beam source 2 is, for example, a known electron gun, and accelerates electrons emitted from the cathode at the anode to emit an electron beam E1. The electron gun used as the electron beam source 2 is not particularly limited, and for example, a thermionic emission type, a thermal field emission type, a cold cathode field emission type, or the like can be used. The electron beam E1 emitted from the electron beam source 2 travels along the optical axis Z of the optical system of the radiation analyzer 1.

  The converging lens 3 is disposed downstream of the electron beam source 2 (on the downstream side of the electron beam E1). The focusing lens 3 is a lens for focusing the electron beam E1.

  The scanning deflector (scanning coil) 4 is arranged at the rear stage of the focusing lens 3. The scanning deflector 4 is an electromagnetic coil for scanning the sample S with the electron beam E <b> 1 focused by the focusing lens 3 and the objective lens 5. The scanning deflector 4 deflects the electron beam E1 based on the scanning signal generated by the scanning signal generation unit (not shown), and scans the electron beam E1 on the sample S.

  The objective lens 5 is disposed at the rear stage of the scanning deflector 4. The objective lens 5 is a lens for focusing the electron beam E1 and irradiating the sample S.

  The sample stage 6 can hold the sample S and move the sample S. The sample stage 6 can perform operations such as horizontal movement, vertical movement, rotation, and tilting of the sample S, for example.

  The electron detector 7 detects secondary electrons and reflected electrons emitted from the surface of the sample S based on scanning of the focused electron beam E1. The intensity signals of secondary electrons and reflected electrons detected by the electron detector 7 are stored in a frame memory (not shown) as image data synchronized with the scanning signal. A scanned image is generated based on the image data stored in the frame memory.

  The radiation detection apparatus 100 detects characteristic X-rays generated by irradiating the sample S with the focused electron beam E1. The radiation detection apparatus 100 functions as, for example, an energy dispersive detector.

  Since the radiation analysis apparatus 1 includes the radiation detection apparatus 100, the SN ratio can be improved.

  In addition, although the case where the radiation analyzer 1 is a scanning electron microscope equipped with the radiation detection device according to the present invention has been described here, the radiation analysis device 1 is, for example, a transmission equipped with the radiation detection device according to the present invention. It may be an electron microscope, a scanning transmission electron microscope, a fluorescent X-ray analyzer, an electron probe microanalyzer, or the like.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Radiation analyzer, 2 ... Electron beam source, 3 ... Condensing lens, 4 ... Scanning deflector, 5 ... Objective lens, 6 ... Sample stage, 7 ... Electron detector, 10 ... Housing | casing, 12 ... Window part, 13 DESCRIPTION OF SYMBOLS ... Permeation | transmission film | membrane, 14 ... Base, 16 ... Cylindrical body, 20 ... Detector, 20a ... Incident surface, 20b ... Back surface, 20d ... Detector, 22 ... Generating part, 22a ... 1st part, 22b ... 2nd part, 23 ... non-collection part, 24 ... collection part, 25 ... area, 26 ... amplification part, 28 ... wiring, 30 ... shielding part, 40 ... support part, 40a ... beam part, 40b ... beam part, 50 ... cooling element, 60 ... Heat pipe, 70... Electrode terminal board, 100, 20
0, 300, 400, 500, 600, 700 ... radiation detection device, 710 ... collimator section

Claims (11)

A housing having a window portion provided with a permeable membrane that transmits radiation;
A generator that generates a signal by the incident radiation; a collector that collects the signal generated by the generator; and an amplifier that amplifies the signal collected by the collector; A detector with
A shielding unit that is provided so as to overlap at least one of the collection unit and the amplification unit as viewed from the incident direction of the radiation incident on the detector, and has a lower transmittance of the radiation than the transmission film;
A radiation detection device. In claim 1,
The radiation detection apparatus, wherein the shielding part is provided so as not to overlap at least a part of the generation part when viewed from the incident direction. In any one of Claim 1 or 2,
Including a support for supporting the permeable membrane,
The said shielding part is a radiation detection apparatus provided integrally with the said support part. In claim 3,
The thickness of the said shielding part is a radiation detection apparatus larger than the thickness of the said support part. In claim 1 or 2,
The said shielding part is a radiation detection apparatus which is in contact with the said detector. In claim 1 or 2,
The said shielding part is a radiation detection apparatus which is in contact with the said permeable film. In claim 5 or 6,
The radiation detecting apparatus, wherein the shielding part is a metal film. In any one of Claims 1 thru | or 7,
The said shielding part is a radiation detection apparatus provided between the said permeable film and the said detector. In any one of Claims 1 thru | or 8,
The radiation detector according to claim 1, wherein the detector is a silicon drift detector. In any one of Claims 1 thru | or 9,
The collector is an anode;
The amplifying unit is a radiation detection device, which is a field effect transistor.   A radiation analysis apparatus comprising the radiation detection apparatus according to claim 1.

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