BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a photomultiplier tube for detecting incident light
from outside.
Related Background Art
[0002] US 2010/0213838 discloses a photomultiplier tube comprising the preamble portion of claim 1 of the
present invention.
[0003] Conventionally, compact photomultiplier tubes by utilization of fine processing technology
have been developed. For example, there is known a thin-type photomultiplier tube
where a photocathode, dynodes, an anode, etc., are arranged on a substrate constituting
a casing (refer to Patent Document 1 given below). The above-described structure makes
it possible to realize fine processing of a device in a two-stage manufacturing process.
Patent Document 1:
U.S. Patent No. 5,568,013
SUMMARY OF THE INVENTION
[0004] However, in the above-described conventional photomultiplier tube, there is a case
where some of the photoelectrons emitted from the photocathode are not made incident
onto electron multiplying parts but onto a side pipe, a substrate, etc., constituting
the casing depending on a potential of the casing. Therefore, the photoelectrons are
made incident away from the electron multiplying part, which is then the cause for
a decrease in detection sensitivity.
[0005] Under these circumstances, the present invention has been made in view of the above
problem, an object of which is to provide a photomultiplier tube capable of enhancing
the detection sensitivity by causing photoelectrons emitted from a photocathode to
be made efficiently incident onto electron multiplying parts.
[0006] In order to solve the above problem, the photomultiplier tube of the present invention
is provided with a first substrate and a second substrate which are arranged so as
to oppose each other, with the respective opposing surfaces made with an insulating
material, a side wall part which constitutes a casing together with the first and
the second substrates, a plurality of stages of electron multiplying parts which are
arrayed so as to be spaced away sequentially from a first end side to a second end
side on the opposing surface of the first substrate, a photocathode which is installed
on the first end side so as to be spaced away from the electron multiplying parts,
converting incident light from outside to photoelectrons to emit the photoelectrons,
an anode part which is installed on the second end side so as to be spaced away from
the electron multiplying parts to take out electrons multiplied by the electron multiplying
parts as a signal, and a wall-like electrode which is arranged so as to enclose the
photocathode when viewed from a direction directly opposite to the opposing surface
extending so as to run along an inner wall of the side wall part from the photocathode,
and having a notched part at a site opposing the electron multiplying parts on the
second end side.
[0007] According to the above-described photomultiplier tube, incident light is made incident
onto the photocathode, by which the light is converted to photoelectrons, these photoelectrons
are made incident onto a plurality of stages of electron multiplying parts on the
opposing surface of the first substrate and multiplied accordingly, and thus multiplied
electrons are taken out from the anode part as an electric signal. Here, the photocathode
is enclosed with the wall-like electrode when viewed from a direction directly opposite
to the opposing surface of the substrate, and the notched part is formed on the second
end side of the wall-like electrode. Therefore, photoelectrons from the photocathode
are efficiently guided into the electron multiplying parts and, as a result, it is
possible to enhance the detection sensitivity of incident light onto the photocathode.
[0008] It is preferable that the photocathode is electrically connected to the wall-like
electrode. In this instance, since there is formed an electric field preferable in
guiding photoelectrons from the photocathode into the electron multiplying parts,
the photoelectrons can be efficiently guided into the electron multiplying parts to
further enhance the detection sensitivity of incident light.
[0009] It is also preferable that the notched part is formed at a site corresponding to
a region of electron multiplying channels of the electron multiplying parts. The above
constitution makes it possible to guide more efficiently the photoelectrons into an
electron multiplying region at the electron multiplying parts and further enhance
the detection sensitivity of incident light.
[0010] Further, it is preferable that focusing electrodes for focusing photoelectrons emitted
from the photocathode and guiding them into the electron multiplying parts are installed
inside the notched part. In this instance, the photoelectrons can be guided more efficiently
into the electron multiplying parts to further enhance the detection sensitivity of
incident light.
[0011] It is also preferable that the wall-like electrode is provided with a connecting
part for electrically connecting to the photocathode. Further, it is also preferable
that there are provided conductive layers installed on the upper surface of the connecting
part and at a part of the opposing surface, the connecting part is formed in a flat-plate
shape which is thinner than a plate-like part enclosing the photocathode of the wall-like
electrode, and the photocathode is installed on the opposing surface and on the conductive
layers. In this instance, the wall-like electrode can be reliably electrically connected
to the photocathode.
[0012] Still further, it is preferable that the conductive layer installed on the upper
surface of the connecting part is electrically connected to the conductive layer installed
at a part of the opposing surface by using a wire member made with a conductive material.
In this instance, even where there is a bump between the connecting part and the photocathode,
the wall-like electrode can be reliably electrically connected to the photocathode.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013]
Fig. 1 is a perspective view of a photomultiplier tube which is related to one preferred
embodiment of the present invention.
Fig. 2 is an exploded perspective view of the photomultiplier tube shown in Fig. 1.
Fig. 3 is a plan view which shows a side wall frame of Fig. 1.
Fig. 4 (a) is a bottom view of an upper frame of Fig. 1 when viewed from the back
surface side, and Fig. 4 (b) is a plan view of the side wall frame of Fig. 1.
Fig. 5 is a perspective view showing a state which connects the upper frame to the
side wall frame as shown in Fig. 4.
Fig. 6 is an exploded perspective view which shows a photomultiplier tube related
to a modified example of the present invention.
Fig. 7 is an exploded perspective view of a photomultiplier tube related to another
modified example of the present invention.
Fig. 8 is an exploded perspective view of a photomultiplier tube related to still
another modified example of the present invention.
Fig. 9 is an exploded perspective view of a photomultiplier tube related to a further
modified example of the present invention.
Fig. 10 is a plan view of a side wall frame in which a wall-like electrode is removed
from the side wall frame of Fig. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] Hereinafter, a detailed description will be given for preferred embodiments of the
photomultiplier tube related to the present invention by referring to drawings. In
addition, in describing the drawings, the same or corresponding parts will be given
the same reference numerals to omit overlapping description.
[0015] Fig. 1 is a perspective view of a photomultiplier tube 1 related to one preferred
embodiment of the present invention. Fig. 2 is an exploded perspective view of the
photomultiplier tube 1 shown in Fig. 1. Fig. 3 is a plan view of the side wall frame
3 of Fig. 1.
[0016] The photomultiplier tube 1 shown in Fig. 1 is a photomultiplier tube having a transmission-type
photocathode and provided with a casing constituted with an upper frame (a second
substrate) 2, a side wall frame (a side wall part) 3, and a lower frame (a first substrate)
4 which opposes the upper frame 2, with the side wall frame 3 kept therebetween. The
photomultiplier tube 1 is an electron tube such that when light is made incident from
a direction at which a light incident direction onto the photocathode intersects with
a direction at which electrons are multiplied at electron multiplying parts, that
is, a direction indicated by the arrow A in Fig. 1, photoelectrons emitted from the
photocathode are made incident onto the electron multiplying parts, thereby secondary
electrons are subjected to cascade amplification in a direction indicated by the arrow
B to take out a signal from the anode part.
[0017] It is noted that in the following description, the upstream side of an electron multiplying
channel (the side of the photocathode) along a direction at which electrons are multiplied
is given as "a first end side," while the downstream side (the side of the anode part)
is given as "a second end side." Further, a detailed description will be given for
individual constituents of the photomultiplier tube 1.
[0018] As shown in Fig. 2, the upper frame 2 is constituted with a wiring substrate 20 made
mainly with rectangular flat-plate like insulating ceramics as a base material. As
the above-described wiring substrate, there is used a multilayer wiring substrate
such as LTCC (low temperature co-fired ceramics) in which microscopic wiring can be
designed and also wiring patterns on front-back both sides can be freely designed.
The wiring substrate 20 is provided on a main surface 20b thereof with a plurality
of conductive terminals 201A to 201D electrically connected to the side wall frame
3, a photocathode 41, focusing electrodes 31, a wall-like electrode 32, electron multiplying
parts 33, and the anode part 34 which are described later, to supply power from outside
and take out a signal. The conductive terminal 201A is installed for supplying power
to the side wall frame 3, the conductive terminal 201B for supplying power to the
photocathode 41, the focusing electrodes 31 and the wall-like electrode 32, the conductive
terminal 201C for supplying power to the electron multiplying parts 33, and the conductive
terminal 201D for supplying power to the anode part 34 and taking out a signal respectively.
These conductive terminals 201A to 201D are mutually connected to conductive layers
and the conductive terminals (details will be described later) on an insulating opposing
surface 20a which opposes the main surface 20b inside the wiring substrate 20, by
which these conductive layers and the conductive terminals are connected to the side
wall frame 3, the photocathode 41, the focusing electrodes 31, the wall-like electrode
32, the electron multiplying parts 33 and the anode part 34. Further, the upper frame
2 is not limited to a multilayer wiring substrate having the conductive terminals
201 but may include a plate-like member made with an insulating material such as a
glass substrate on which conductive terminals for supplying power from outside and
taking out a signal are installed so as to penetrate.
[0019] The side wall frame 3 is constituted with a rectangular flat-plate like silicon substrate
30 as a base material. A penetration part 301 enclosed by a frame-like side wall part
302 is formed from a main surface 30a of the silicon substrate 30 toward an opposing
surface 30b thereto. The penetration part 301 is provided with a rectangular opening
and an outer periphery of which is formed so as to run along the outer periphery of
the silicon substrate 30.
[0020] Inside the penetration part 301, the wall-like electrode 32, the focusing electrodes
31, the electron multiplying parts 33 and the anode part 34 are arranged from the
first end side to the second end side. The wall-like electrode 32, the focusing electrodes
31, the electron multiplying parts 33 and the anode part 34 are formed by processing
the silicon substrate 30 according to RIE (Reactive Ion Etching) processing, etc.,
and mainly made with silicon.
[0021] The wall-like electrode 32 is a frame-like electrode which is formed so as to enclose
a photocathode 41 to be described later when viewed from a direction completely opposite
to an opposing surface 40a of the glass substrate 40 to be described later (a direction
approximately perpendicular to the opposing surface 40a and a direction opposite to
a direction indicated by the arrow A of Fig. 1). Further, the focusing electrode 31
is an electrode for focusing photoelectrons emitted from the photocathode 41 and guiding
them to the electron multiplying parts 33 and installed between the photocathode 41
and the electron multiplying parts 33.
[0022] The electron multiplying parts 33 are constituted with N stages (N denotes an integer
of two or more) of dynodes (electron multiplying parts) set different in potential
along a direction at which electrons are multiplied from the photocathode 41 to the
anode part 34 and provided with a plurality of electron multiplying channels (electron
multiplying channels) so as to be astride individual stages. Further, the anode part
34 is arranged at a position holding the electron multiplying parts 33 together with
the photocathode 41.
[0023] The wall-like electrode 32, the focusing electrodes 31, the electron multiplying
parts 33 and the anode part 34 are individually fixed to the lower frame 4 by anode
bonding, diffusion joining and joining, etc., using a sealing material such as a low-melting-point
metal (for example, indium), by which they are arranged on the lower frame 4 two-dimensionally.
[0024] The lower frame 4 is constituted with the rectangular flat-plate like glass substrate
40 as a base material. The glass substrate 40 forms an opposing surface 40a which
opposes the opposing surface 20a of the wiring substrate 20, by use of glass which
is an insulating material. The photocathode 41 which is a transmission-type photocathode
is formed at a site opposing a penetration part 301 of the side wall frame 3 on the
opposing surface 40a (a site other than a joining region with a side wall part 302)
and at the end part opposite to the side of the anode part 34. Further, a rectangular
recessed part 42 which prevents multiplied electrons from being made incident onto
the opposing surface 40a is formed at a site where the electron multiplying parts
33 and the anode part 34 on the opposing surface 40a are loaded.
[0025] A further detailed description will be given for an internal structure of the photomultiplier
tube 1 by referring to Fig. 3. The electron multiplying parts 33 inside the penetration
part 301 are constituted with a plurality of stages of dynodes arrayed so as to be
spaced away sequentially from the first end side to the second end side on the opposing
surface 40a (in a direction indicated by the arrow B which is a direction at which
electrons are multiplied). The plurality of stages of dynodes are provided in parallel
with a plurality of electron multiplying channels C constituted with the N number
of electron multiplying holes installed so as to continue along a direction indicated
by the arrow B from a 1
st stage dynode 33a on the first end side to a final stage (the N
th stage) dynode 33b on the second end side.
[0026] Further, the photocathode 41 is installed so as to be spaced away from the 1
st stage dynode 33a on the first end side to the first end side on the opposing surface
40a behind the focusing electrode 31. The photocathode 41 is formed on the opposing
surface 40a of the glass substrate 40 as a rectangular transmission-type photocathode.
When incident light transmitted from outside through the glass substrate 40, which
is the lower frame 4, arrives at the photocathode 41, photoelectrons corresponding
to the incident light are emitted, and the photoelectrons are guided into the 1
st stage dynode 33a by the wall-like electrode 32 and the focusing electrodes 31.
[0027] Further, the anode part 34 is installed so as to be spaced away from the final stage
dynode 33b on the second end side to the second end side on the opposing surface 40a.
The anode part 34 is an electrode for taking outside electrons multiplied inside the
electron multiplying channels C of the electron multiplying parts 33 in a direction
indicated by the arrow B as an electric signal.
[0028] Still further, the wall-like electrode 32 is a rectangular frame-like electrode constituted
with a plurality of plate-like parts 32a extending substantially in a perpendicular
direction only by as thick as the side wall part 302 inside the penetration part 301
so as to run along the inner wall of the side wall part 302 from the opposing surface
40a to the upper frame 2 and installed upright on the opposing surface 40a in a state
that encloses a region of forming the photocathode 41 on the opposing surface 40a.
An approximately rectangular notched part 35 which has been notched is formed at a
site which is the second end side wall part of the wall-like electrode 32 and opposes
a region where the electron multiplying channel C is formed at the 1
st stage dynode 33a. Then, a columnar focusing electrode 31 is formed so as to extend
substantially in a perpendicular direction from a thin plate-like member 35a installed
so as to connect both end parts of the notched part 35 on the opposing surface 40a
to the side of the upper frame 2. It is noted that in the present embodiment, the
wall-like electrode 32, the thin plate-like member 35a and the focusing electrodes
31 are formed in an integrated manner. However, they may be formed individually.
[0029] Next, a description will be given for a wiring structure of the photomultiplier tube
1 by referring to Fig. 4 and Fig. 5. In Fig. 4, (a) is a bottom view when the upper
frame 2 is viewed from the side of a back surface 20a, and (b) is a plan view of the
side wall frame 3. Fig. 5 is a perspective view which shows a state connecting the
upper frame 2 with the side wall frame 3.
[0030] As shown in Fig. 4(a), the back surface 20a of the upper frame 2 is provided with
a plurality of conductive layers 202 electrically connected to the respective conductive
terminals 201B, 201C, 201D inside the upper frame 2, and a conductive terminal 203
electrically connected to the conductive terminal 201A inside the upper frame 2. Further,
as shown in Fig. 4(b), power supplying parts 36, 37 for connecting to the conductive
layers 202 are installed upright respectively at the end parts of the electron multiplying
parts 33 and the anode part 34, and a power supplying part 38 for connecting to the
conductive layers 202 is installed upright at a corner of the wall-like electrode
32. Still further, the focusing electrodes 31 are integrated with wall-like electrode
32 on the lower frame 4 side, together with the thin plate-like member 35a, thereby
electrically connected to the wall-like electrode 32. In addition, a rectangular flat-plate
like connecting part 39 which is thinner than the plate-like part 32a of the wall-like
electrode 32 is formed in an integrated manner at the wall-like electrode 32 on the
opposing surface 40a side of the lower frame 4. A conductive layer 39a made with a
conductive material such as aluminum is formed so as to continue to a part of the
opposing surface 40a from the upper surface of the connecting part 39. Further, since
there is a bump between the connecting part 39 and the opposing surface 40a, the continuity
is discontinued at the bump portion which may result in the possibility that the conductive
layer 39a on the connecting part 39 may not be electrically connected to the conductive
layer 39a on the opposing surface 40a. Therefore, the conductive layer 39a on the
connecting part 39 and the conductive layer 39a on the opposing surface 40a are wire-bonded
by using a wire (a wire member) 39b made with a conductive material such as gold (Au),
by which the conductive layer 39a is made equal in potential as a whole. Then, the
photocathode 41 formed on the opposing surface 40a enclosed with the wall-like electrode
32 is formed also on the conductive layer 39a and the wire 39b, by which the wall-like
electrode 32 is reliably electrically connected to the photocathode 41. It is noted
that when the photocathode is formed also on an inner wall surface of the wall-like
electrode 32, that is, on the surface of the plate-like part 32a on the side of the
photocathode 41, it functions as a reflection-type photocathode as well. In this instance,
for example, light which is transmitted without being converted to electrons by the
photocathode 41 is subjected to photoelectric conversion, thus making it possible
to detect the light more efficiently.
[0031] The above constituted upper frame 2 and the side wall frame 3 are joined, by which
the conductive terminal 203 is electrically connected to the side wall part 302 of
the side wall frame 3. Also, the power supplying part 36 of the electron multiplying
part 33, the power supplying part 37 of the anode part 34 and the power supplying
part 38 of the wall-like electrode 32 are respectively connected to the corresponding
conductive layers 202 independently via conductive members made with gold (Au), etc.
The above-described connecting structure makes it possible to electrically connect
the side wall part 302, the electron multiplying part 33 and the anode part 34 respectively
to the conductive terminals 201A, 201C, 201D. Also, the wall-like electrode 32 is
electrically connected to the conductive terminal 201B together with the focusing
electrodes 31 and the photocathode 41 (Fig. 5).
[0032] According to the photomultiplier tube 1 which has been so far described, incident
light is transmitted through the lower frame 4 and made incident onto the photocathode
41, thereby converted to photoelectrons, and the photoelectrons are made incident
onto the plurality of stages of electron multiplying parts 33 on the opposing surface
40a of the lower frame 4 and multiplied accordingly, and the multiplied electrons
are taken out from the anode part 34 as an electric signal. Here, the photocathode
41 is enclosed by the wall-like electrode 32, when viewed from a direction directly
opposite to the opposing surface 40a, and the notched part 35 is formed on the second
end side of the wall-like electrode 32. Therefore, the photoelectrons from the photocathode
41 are prevented from being made incident onto the casing such as the side wall frame
3 and the photoelectrons are guided efficiently into the electron multiplying part
33. As a result, it is possible to enhance the detection sensitivity of incident light
onto the photocathode 41.
[0033] Here, effects of the present embodiment will be described in detail by referring
to Fig. 3 and Fig. 10. Fig. 10 is a plan view of the side wall frame 903 in which
the wall-like electrode 32 is removed from the side wall frame 3 shown in Fig. 3.
Where a side wall frame 903 is used, photoelectrons generated from the photocathode
41 by incident light are mostly made incident onto the 1
st stage dynode 33a, but a portion is guided in directions to the side wall part 302
(directions indicated by the arrows E
1, E
2 in Fig. 10) and may not contribute to the detection of a signal. This will be made
more apparent in a state that the potential of the side wall part 302 is not stable.
In addition, of the photoelectrons generated from the photocathode 41, those from
a region closer to the side wall part 302 are influenced to a greater extent by the
side wall part 302. That is, within the photocathode 41, a region less influenced
by the side wall part 302 is a substantially effective region, and therefore, a substantially
effective area of the photocathode 41 is decreased. In order to cope with the above
problem, there is an idea that a potential equal to that of the photocathode 41 is
given to the side wall part 302. However, in this instance, there is a greater difference
in potential among the side wall part 302, the electron multiplying part 33 and the
anode part 34, which may result in a failure of withstand voltage. This problem is
apparent in particular at the anode part 34 and then more apparent at a further subsequent
stage of the electron multiplying parts 33. In order to prevent such a withstand voltage
failure, it is necessary to secure a sufficient space. As a result, there is an increase
in area of a material used in manufacturing one chip, which may result in an increase
in cost. Further, there is a case that light may be emitted at the second end side
inside the penetration part 301, etc., by collision of multiplied secondary electrons
against an insulating body. When the light advances as indicated by the arrow E
3 and arrives at the photocathode 41, photoelectrons which are not related to incident
light are emitted and there is a concern that noise will be generated in a detection
signal to decrease an SN ratio.
[0034] On the other hand, in the present embodiment, photoelectrons generated from the photocathode
41 can be efficiently made incident onto the 1
st stage dynode 33a (a direction indicated by the arrow E
4 in Fig. 3), irrespective of a potential of the side wall part 302, due to the presence
of the wall-like electrode 32 which is set to be stable in potential. Further, even
when the light generated on the second end side, etc., inside the penetration part
301 advances in a direction toward the photocathode 41 (a direction indicated by the
arrow E
5 in Fig. 3), the light can be blocked by the wall-like electrode 32 and prevented
from being made incident onto the photocathode 41. Thereby, it is possible to maintain
the detection sensitivity when a potential of the side wall part 302 is set to be
free and also enhance an SN ratio by improving noise characteristics. For example,
the side wall part 302 is set to be a ground potential as a desired potential, thus
making it possible to enhance electric noise characteristics of the photomultiplier
tube 1. In particular, a noise-reduction effect can be maximized by being set to the
ground potential and a possible risk of electrification of humans can be also decreased.
Further, since a region enclosed by the wall-like electrode 32 is a substantially
effective region of the photocathode, an appropriate light incident region can be
easily specified when the photomultiplier tube 1 is viewed from outside.
[0035] Further, the photocathode 41 is electrically connected to the wall-like electrode
32 and set to be equal in potential. Therefore, there is formed an electric field
where photoelectrons from the photocathode 41 are favorably guided into the electron
multiplying part 33 without being made incident onto the wall-like electrode 32, by
which the detection sensitivity is further enhanced.
[0036] Still further, the notched part 35 of the wall-like electrode 32 is formed at a site
opposing a region of the electron multiplying channels C of the electron multiplying
parts 33, by which photoelectrons guided into the electron multiplying parts 33 can
be efficiently multiplied to further enhance the detection sensitivity of incident
light.
[0037] It is noted that the present invention shall not be limited to the embodiments so
far described. For example, as shown in a photomultiplier tube 1A in Fig. 6, which
is a modified example of the present invention, a photocathode 41A may be installed
on the back surface (an opposing surface 50a) side of an upper frame 2A. In this instance,
as the upper frame 2A, that in which power supplying terminals are buried into a translucent
insulating substrate such as a glass substrate can be used. As a lower frame 4A, various
insulating substrates can be used other than a glass substrate. Then, a wall-like
electrode 32 is arranged so as to enclose the photocathode 41A when viewed from a
direction directly opposite to the opposing surface 50a of the upper frame 2A (a direction
approximately perpendicular to the opposing surface 50a).
[0038] Further, as shown in a photomultiplier tube 1B in Fig. 7, which is a modified example
of the present invention, the photocathode may be a reflection-type photocathode.
For example, a translucent insulating substrate is used as an upper frame 2B and an
inclined surface which is inclined to the second end side with respect to an opposing
surface 40a is formed inside a wall-like electrode 32B of a side wall frame 3B. A
photocathode 41B is formed from the inclined surface to the opposing surface 40a.
A configuration of the inclined surface may include a flat surface or a curved surface
as long as it is such a configuration that photoelectrons generated from the photocathode
41B by incident light which has been transmitted through the upper frame 2B move toward
electron multiplying parts 33.
[0039] Further, various modified modes can be adopted in a wiring structure of the present
embodiment. For example, as shown in Fig. 8, such a structure may be provided that
conductive terminals 401 are formed so as to penetrate through the lower frame 4C,
and power is supplied via the conductive terminals 401 to the photocathode 41, the
wall-like electrode 32, the focusing electrodes 31, the electron multiplying parts
33 and the anode part 34. This structure makes it possible to supply power independently
to the conductive layers 202 (Fig. 4(a)) formed on the upper frame 2 and each of the
electrodes.
[0040] Still further, as shown in Fig. 9, the lower frame 4C having the conductive terminals
401 may be combined with the upper frame 2C from which the conductive terminals 201A
to 201D are removed. In this instance, an insulating substrate having a plurality
of conductive layers 202 on the back surface side is used as the upper frame 2C. The
wiring structure described by referring to Fig. 4 is used in the above combination,
thus making it possible to supply power from the conductive terminals 401 of the lower
frame 4C to the conductive layers 202 of the upper frame 2C via the wall-like electrode
32, the electron multiplying parts 33 and the anode part 34.
[0041] In addition, in any of the embodiments and the modified examples, it is not always
necessary that the wall-like electrode 32 encloses the photocathode 41 as a whole,
but may be arranged so as not to enclose an edge part if it encloses a substantially
effective region that can guide emitted photoelectrons into the electron multiplying
parts 33.
1. A photomultiplier tube comprising:
a first substrate (4) and a second substrate (2) which are arranged so as to oppose
each other, with the respective opposing surfaces made with an insulating material;
a side wall part (302) which constitutes a casing together with the first and the
second substrates;
a plurality of stages of electron multiplying parts (33) which are arrayed so as to
be spaced away sequentially from a first end side to a second end side on the opposing
surface of the first substrate (4);
a photocathode (41) which is installed on the first end side so as to be spaced away
from the electron multiplying parts (33), converting incident light from outside to
photoelectrons to emit the photoelectrons; and
an anode part (34) which is installed on the second end side so as to be spaced away
from the electron multiplying parts (33) to take out electrons multiplied by the electron
multiplying parts as a signal;
characterized in that
a wall-like electrode (32) which is arranged so as to enclose the photocathode (41)
when viewed from a direction directly opposite to the opposing surface (40a), extending
so as to run along an inner wall of the side wall part (302) from the photocathode
(41), and having a notched part (35) at a site opposing the electron multiplying parts
(33) on the second end side, and electrically connected to the photocathode (41).
2. The photomultiplier tube according to claim 1, wherein the notched part (35) is formed
at a site corresponding to a region of electron multiplying channels (C) of the electron
multiplying parts (33).
3. The photo multiplier tube according to claim 1, wherein focusing electrodes (31) for
guiding the photoelectrons emitted from the photocathode (41) into the electron multiplying
parts (33) are installed inside the notched part (35).
4. The photomultiplier tube according to claim 1, wherein a connecting part (39) for
electrically connecting to the photocathode (41) is installed at the wall-like electrode
(32).
5. The photomultiplier tube according to claim 4 which is further provided with conductive
layers (202) installed on the upper surface of the connecting part and at a part of
the opposing surface, wherein
the connecting part (39) is formed in a flat-plate shape which is thinner than a plate-like
part enclosing the photocathode (41) of the wall-like electrode (32), and
the photocathode (41) is installed on the opposing surface and on the conductive layers.
6. The photomultiplier tube according to claim 5, wherein the conductive layer (202)
on the upper surface of the connecting part (39) is electrically connected to the
conductive layer installed at a part of the opposing surface by using a wire member
made with a conductive material.
7. The photomultiplier tube according to claim 1, wherein the wall-like electrode (32)
includes a plurality of parts (32a) extending in a direction perpendicular to the
opposing surface (40a) and runs along the inner wall of the side wall part (302) from
the opposing surface (40a) to the second substrate (2) and installed in an upright
position over the opposing surface (40a) in a state to enclose the photocathode (41).
1. Photovervielfacherröhre, die umfasst:
ein erstes Substrat (4) und ein zweites Substrat (2), die so angeordnet sind, dass
sie einander gegenüberliegen, wobei die jeweiligen einander gegenüberliegenden Flächen
aus einem isolierenden Material bestehen;
einen Seitenwand-Teil (302), der zusammen mit dem ersten und dem zweiten Substrat
ein Gehäuse bildet;
eine Vielzahl von Stufen von Elektronenvervielfachungs-Teilen (33), die strukturiert
so angeordnet sind, dass sie sequenziell von einer Seite des ersten Endes zu einer
Seite des zweiten Endes an der gegenüberliegenden Fläche des ersten Substrats (4)
beabstandet sind;
eine Photokathode (41), die an der Seite des ersten Endes so installiert ist, dass
sie von den Elektronenvervielfachungs-Teilen (33) beabstandet ist, und die auftreffendes
Licht von außen in Photoelektronen umwandelt und die Photoelektronen emittiert; sowie
einen Anoden-Teil (34), der an der Seite des zweiten Endes so installiert ist, dass
er von den Elektronenvervielfachungs-Teilen (33) beabstandet ist und durch die Elektronenvervielfachungs-Teile
vervielfachte Elektronen als ein Signal aufnimmt;
dadurch gekennzeichnet, dass
eine wandartige Elektrode (32), die so angeordnet ist, dass sie, in einer der gegenüberliegenden
Fläche (40a) direkt entgegengesetzten Richtung gesehen, die Photokathode (41) umschließt,
sich so erstreckt, dass sie von der Photokathode (41) aus an einer Innenwand des Seitenwand-Teils
(302) entlang verläuft, und die einen eingekerbten Teil (35) an einer den Elektronenvervielfachungs-Teilen
(33) gegenüberliegenden Position an der Seite des zweiten Endes hat und elektrisch
mit der Photokathode (41) verbunden ist.
2. Photovervielfacherröhre nach Anspruch 1, wobei der eingekerbte Teil (35) an einer
Position ausgebildet ist, die einem Bereich von Elektronenvervielfachungs-Kanälen
(C) der Elektronenvervielfachungs-Teile (33) entspricht.
3. Photovervielfacherröhre nach Anspruch 1, wobei Fokussier-Elektroden (31), die die
von der Photokathode (41) emittierten Photoelektronen in die Elektronenvervielfachungs-Teile
(33) leiten, im Inneren des eingekerbten Teils (35) installiert sind.
4. Photovervielfacherröhre nach Anspruch 1, wobei ein Verbindungs-Teil (39) zum elektrischen
Verbinden der Photokathode (41) an der wandartigen Elektrode (32) installiert ist.
5. Photovervielfacherröhre nach Anspruch 4, die des Weiteren mit leitenden Schichten
(202) versehen ist, die an der oberen Fläche des Verbindungs-Teils und an einem Teil
der gegenüberliegenden Fläche installiert sind, wobei
der Verbindungs-Teil (39) in Form einer flachen Platte ausgebildet ist, die dünner
ist als ein plattenartiger Teil der wandartigen Elektrode (32), der die Photokathode
(41) umschließt, und
die Photokathode (41) an der gegenüberliegenden Fläche sowie an den leitenden Schichten
installiert ist.
6. Photovervielfacherröhre nach Anspruch 5, wobei die leitende Schicht (202) an der oberen
Fläche des Verbindungs-Teils (39) unter Verwendung eines Drahtelementes, das aus einem
leitenden Material besteht, elektrisch mit der leitenden Schicht verbunden ist, die
an einem Teil der gegenüberliegenden Fläche installiert ist.
7. Photovervielfacherröhre nach Anspruch 1, wobei die wandartige Elektrode (32) eine
Vielzahl von Teilen (32a) enthält, die sich in einer Richtung senkrecht zu der gegenüberliegenden
Fläche (40a) erstrecken, und sie von der gegenüberliegenden Fläche (40a) zu dem zweiten
Substrat (2) an der Innenwand des Seitenwand-Teils (302) entlang verläuft und in einer
aufrechtstehenden Position in einem Zustand über der gegenüberliegenden Fläche (40a)
installiert ist, in dem sie die Photokathode (41) umschließt.
1. Tube photomultiplicateur comprenant :
un premier substrat (4) et un second substrat (2) qui sont agencés de façon à se faire
face, les surfaces respectives en regard étant constituées d'un matériau isolant,
un composant formant paroi latérale (302) qui constitue un boîtier avec le premier
et le second substrat,
une pluralité d'étages de composants de multiplication d'électrons (33) placés en
réseau de sorte à être espacés séquentiellement depuis un premier côté jusqu'à un
second côté sur la surface en regard du premier substrat (4),
une photocathode (41) placée sur le premier côté de façon à être écartée des composants
de multiplication d'électrons (33), convertissant la lumière incidente provenant de
l'extérieur en photoélectrons afin d'émettre les photoélectrons, et
un composant formant anode (34) placé sur le second côté de façon à être écarté des
composants de multiplication d'électrons (33) dans le but de prélever des électrons
multipliés par les composants de multiplication d'électrons sous forme d'un signal,
caractérisé en ce que
une électrode de type paroi (32), qui est agencée de façon à enfermer la photocathode
(41) lorsqu'elle est vue depuis une direction directement opposée à la surface en
regard (40a), s'étend de façon à courir le long d'une paroi interne du composant formant
paroi latérale (302) depuis la photocathode (41), et comporte un composant à encoche
(35) au niveau d'un site faisant face aux composants de multiplication d'électrons
(33) sur le second côté, et est reliée électriquement à la photocathode (41).
2. Tube photomultiplicateur selon la revendication 1, dans lequel le composant à encoche
(35) est formé au niveau d'un site correspondant à une zone de canaux (C) de multiplication
d'électrons appartenant aux composants de multiplication d'électrons (33).
3. Tube photomultiplicateur selon la revendication 1, dans lequel des électrodes de concentration
(31), destinées à guider les photoélectrons émis de la photocathode (41) dans les
composants de multiplication d'électrons (33), sont installées à l'intérieur du composant
à encoche (35).
4. Tube photomultiplicateur selon la revendication 1, dans lequel un composant de raccordement
(39), destiné à se relier électriquement à la photocathode (41), est installé au niveau
de l'électrode de type paroi (32).
5. Tube photomultiplicateur selon la revendication 4, qui est en outre muni de couches
conductrices (202) placées sur la surface supérieure du composant de connexion et
au niveau d'un composant de la surface en regard, dans lequel
le composant de connexion (39) présente une forme de plaque plate qui est plus mince
qu'un composant de type plaque enfermant la photocathode (41) de l'électrode de type
paroi (32), et
la photocathode (41) est placée sur la surface en regard et sur les couches conductrices.
6. Tube photomultiplicateur selon la revendication 5, dans lequel la couche conductrice
(202) sur la surface supérieure du composant de connexion (39) est reliée électriquement
à la couche conductrice placée au niveau d'un composant de la surface en regard en
utilisant un élément de fil constitué d'un matériau conducteur.
7. Tube photomultiplicateur selon la revendication 1, dans lequel l'électrode de type
paroi (32) inclut une pluralité de composants (32a) s'étendant dans une direction
perpendiculaire à la surface en regard (40a) et court le long de la paroi interne
du composant formant paroi latérale (302) depuis la surface en regard (40a) jusqu'au
second substrat (2), et est placée dans une position droite au-dessus de la surface
en regard (40a) afin d'enfermer la photocathode (41).