CN101165843A

CN101165843A - Photomultiplier

Info

Publication number: CN101165843A
Application number: CNA2007101624996A
Authority: CN
Inventors: 大村孝幸; 山口晃彦
Original assignee: Hamamatsu Photonics KK
Current assignee: Hamamatsu Photonics KK
Priority date: 2006-10-16
Filing date: 2007-10-16
Publication date: 2008-04-23
Also published as: CN101165845A; CN101165844A; CN101165842A

Abstract

The present invention relates to a photomultiplier that realizes significant improvement of response time properties with a structure enabling mass production. The photomultiplier comprises a sealed container, and the sealed container includes a hollow body section, extending along a tube axis, and a faceplate. The faceplate has a light incidence surface and a light emission surface on which a photocathode is formed. In particular, the light emission surface is constituted by a flat region, and a curved-surface processed region that is positioned at a periphery of the flat region and that includes edges of the light emission surface. A surface shape of the peripheral region of the light emission surface of the faceplate is thus intentionally changed in order to adjust the angles of emission of photoelectrons from the photocathode positioned at the peripheral region. Thus, the spread of transit times of photoelectrons propagating from the photocathode to a first dynode is thus reduced effectively and made not to depend on the emission positions of the photoelectrons.

Description

Photomultiplier

Technical field

The present invention relates to a kind of photomultiplier, this photomultiplier can carry out the cascade-multiplied of secondary electron in response to photoelectronic incident by the multistage continuous emission of secondary electron.

Background technology

In recent years, as PET of future generation (positron emission fault is taken a picture, Positron EmissionTomography) device, the development of TOF-PET (flight time FET, Time-of-Flight PET) was subjected to promoting energetically in the field of nuclear medicine always.In the TOF-PET device, because will measure two gamma rays that the radioisotope that gives health sends simultaneously, so, use the photomultiplier that has characteristics such as highly sensitive, that response speed is fast in a large number as checkout gear be arranged in target to be measured around.

Particularly in order to realize the more high-speed response characteristic of high stability, the multichannel photoelectricity multiplier tube that the multiplication of using a plurality of electron multiplication passages and making electronics produces in this multiplication passage concurrently will be applied in the PET device of future generation, such as, the above-mentioned quantity of mentioning is just at ever-increasing device.For example, a kind of multichannel photoelectricity multiplier tube of mentioning among the open No.WO2005/091332 of international monopoly, its structure is as follows: a panel is encapsulated in the single glass tube, is divided into a plurality of incident light districts territory (each zone is the photocathode that is assigned an electron multiplication passage) and is arranged on a plurality of electron multiplication portions (each electron multiplication portion has by a plurality of dynodes and the dynode unit that anode constitutes) in a plurality of incident light districts territory as the electron multiplication passage.Photomultiplier with structure like this is about to a plurality of photomultipliers and is encapsulated in the interior photomultiplier of single glass tube, is commonly referred to multichannel photoelectricity multiplier tube.

As mentioned above, therefore multichannel photoelectricity multiplier tube has a kind of like this structure, it is the function of single channel photomultiplier, that is to say, be arranged at photoelectron that the photocathode on the panel launches by the multiplication of single electron multiplication portion, export the function of anode then to, shared by a plurality of electron multiplication passages.For example, in a multichannel photoelectricity multiplier tube, Two dimensional Distribution four incident light districts (corresponding to the photocathode of electron multiplication passage), because concerning an electron multiplication passage, photoelectron emissions zone (effective coverage of corresponding photocathode) only account for panel 1/4 or still less, thereby the difference of the transit time of the electronics between each electron multiplication passage just is easy to improve.Therefore, compare with the difference of electron transit time of whole single channel photomultiplier, the remarkable improvement of the difference of the electron transit time of whole multichannel photoelectricity multiplier tube can be predicted.

Summary of the invention

The inventor studies the multichannel photoelectricity multiplier tube of above-mentioned routine, found that following problem.Promptly, in the multichannel photoelectricity multiplier tube of routine, because the electron multiplication passage that carries out electron multiplication discharges photoelectronic position according to photocathode and is provided with, thereby go out the position of each best electrode, to reduce the difference of electron transit time according to each electron multiplication channels designs.According to the method, the difference of the electron transit time by improving each electron multiplication passage just can be improved the difference of the electron transit time of whole multichannel photoelectricity multiplier tube, thereby improve the high-speed response characteristic of whole multichannel photoelectricity multiplier tube.

But in this multichannel photoelectricity multiplier tube, the discrete of the difference of average electron transit time must be improvement yet in the electron multiplication passage.And, light emission surface (being positioned at the surface of sealed container interior) about the panel that is formed with photocathode, at the external zones that surrounds central area (tubular axis that comprises airtight container), especially at light emission surface and the crossing boundary member (edge of light emission surface) of inboard wall of tube body, the shape of light emission surface can deform.Therefore, the equipotential lines between photocathode and dynode or photocathode and focusing electrode is distorted, even in single passage, the position because of photoelectron emissions may produce spuious photoelectron sometimes.To further improve high response characteristic and just can not ignore this spuious photoelectronic appearance.

In addition, need a large amount of photomultipliers, so the photomultiplier that people wish to be applied to device such as TOF-PET has a kind of structure that is more suitable for producing in enormous quantities owing to produce the TOF-PET device.

The present invention is suggested in order to address the above problem, its purpose is, reduce crosstalking between the electron multiplication passage by a kind of structure that is more suitable for producing in enormous quantities, thereby provide a kind of such as TTS (transit time spread, Transit Time Spread) and the photomultiplier that is significantly improved of the whole response time properties of CTTD (negative electrode transit time difference, Cathode Transit Time Difference).

Recently, PET device has increased TOF (flight time, Time-of-Flight) function.In the photomultiplier that is applied to this TOF-PET device, CRT (coincidence resolving time, the Coincidence Resolving Time) response time is also very important.Conventional photomultiplier can not satisfy the requirement of TOF-PET device to the CRT response characteristic.Therefore, in the present invention, in view of doing the basis with the conventional PET device of a cover, thus the vacuum tube peripheral diameter of present use kept, and the design of carrying out track makes the CRT test satisfy the requirement of TOF-PET device.Specifically, in order to improve the TTS relevant with the CRT response characteristic, the design of carrying out track improves the TTS of whole front panel and the TTS of each incidence zone.

The photomultiplier that the present invention relates to comprises airtight container, photocathode and electron multiplication portion, and the former is equipped with a pipe to reduce internal tank pressure to predetermined vacuum degree in its bottom, and both all place the back in the closed container.Airtight container is made up of panel, body (vacuum tube) and base, and wherein, panel is fused to an end of body, and extends along predetermined tube axial direction, and base is fusion welded to the bottom of the other end of body as airtight container.Panel has light entrance face and light emitting surface on the other side, and photocathode just forms on the light emitting surface that is positioned at the airtight container inboard.Airtight container can have shell, and it is as a whole that panel and body are formed, and in this case, the base welding has just been obtained airtight container on the opening of shell.

The installation site of the electron multiplication portion on the tube axial direction in airtight container is determined by the pin that extends to from base in the airtight container.Electron multiplication portion comprises focusing electrode unit and dynode unit, and the former is used to revise from photocathode and is transmitted into photoelectronic tracks in the airtight container, and the latter is used to realize photoelectronic cascade-multiplied.

In photomultiplier involved in the present invention, dynode unit has a pair of insulation supporting member, and at least one carries out the electrode group of cascade-multiplied their support focusing electrode unit and clamping to the photoelectron from photocathode.Especially two or more electrode assembly by the situation of these two insulation supporting member clampings under, these electrode groups and tubular axis are and intersect distribution.Each electrode group can form one or more electron multiplication passages, and the electron multiplication passage correspondence of each formation an anode.

Particularly, as architectural feature, the photomultiplier that the present invention relates to has a demarcation strip, this demarcation strip along second dynode vertically with the second dynode separated into two parts.Second dynode is set to electromotive force and is higher than first dynode, and is set at the position that secondary electron arrived from first dynode, and first dynode is launched secondary electron in response to the photoelectronic incident from photocathode.Utilization is configured in the demarcation strip in second dynode, can reduce crosstalking between the electron multiplication passage of the mutual vicinity that is formed by a dynode group effectively.In other words, along a plurality of dynodes continuously the track of ELECTRON OF MOTION reduced in this process, to traverse into the possibility (crosstalking between the contiguous electron multiplication passage significantly reduces) of contiguous electron multiplication passage greatly.

Preferably, demarcation strip is a metal bump of focusing electrode unit, and the focusing electrode configuration of cells is between photocathode and dynode unit, and it is identical with second dynode to be set to electromotive force.In this case, the metal bump of focusing electrode unit is extended on the direction from the photocathode to the dynode.

Because the metal bump of focusing electrode unit has at least a part to be placed in second dynode, so preferred second dynode has finedraw, the front surface and the rear surface on the other side that will be formed with secondary electron emission surface connect.Because the finedraw of the tip of the metal bump of focusing electrode unit by second dynode is inserted in the space between first dynode and second dynode, thereby two electron multiplication passages have just been formed a dynode group.

Can understand the present invention from following detailed description more fully with relevant accompanying drawing, these explanations and accompanying drawing only are presented as example, can not be understood that to limit the present invention.

From detailed description described later, the scope of application widely of the present invention becomes clear.Yet, must be clear and definite be, when describing at preferred implementation of the present invention, detailed explanation and concrete example only are presented as example, this be because, be derived from the variations and modifications that do not break away from main idea of the present invention of this detailed description, will be readily apparent to persons skilled in the art.

Description of drawings

Fig. 1 is the partial sectional view of general arrangement of the execution mode of the photomultiplier that the present invention relates to.

Fig. 2 A and 2B are respectively the assembling process figure and the sectional views of structure that is used to illustrate the airtight container of the photomultiplier that the present invention relates to.

Fig. 3 is the assembling process figure of structure that is used to illustrate the electron multiplication portion of the photomultiplier that the present invention relates to.

Fig. 4 is the figure of structure that is used to illustrate a pair of insulation supporting member of a part that constitutes electron multiplier shown in Figure 3 portion.

Fig. 5 A is the schematic diagram that is used to illustrate the structure that connects focusing electrode unit and a pair of insulation supporting member, and Fig. 5 B is the schematic diagram that is used to illustrate the structure that connects gain control unit and a pair of insulation supporting member.

Fig. 6 is the perspective view that is used for illustrating the cross section structure after electron multiplication portion is broken away along the I-I line of Fig. 1.

Fig. 7 A and 7B are the sectional views that is used to illustrate the architectural feature of the photomultiplier that the present invention relates to.

Fig. 8 A is the sectional view of effect that is used to illustrate the architectural feature of the photomultiplier that the present invention relates to 8C.

Fig. 9 A is the perspective view of the electron orbit of the photomultiplier (not having architectural feature) that is used for illustrating that comparative example relates to 9C, and this comparative example is used to illustrate the effect of the architectural characteristic of the photomultiplier that the present invention relates to.

Embodiment

Below, with reference to the accompanying drawings 1,2A-2B, 3-4,5A-5B, 6 and 7A-9C explain the execution mode of the photomultiplier that the present invention relates in detail.In the explanation of accompanying drawing, with the mutually the same part of identical numeral, and the repetitive description thereof will be omitted.

Fig. 1 is the partial sectional view of general arrangement of the execution mode of the photomultiplier that the present invention relates to.Fig. 2 A and 2B are respectively assembling schematic diagram and the partial schematic diagrams that is used to illustrate the sealed container structure of the photomultiplier that the present invention relates to.

As shown in Figure 1, the photomultiplier that the present invention relates to has an airtight container 100, there is one to be used to make internal pressure to be reduced to the pipe 600 (it is blocked to vacuumize the back tube interior) of predetermined vacuum level at sealing container bottom, in airtight container 100, also has photocathode 200 and electron multiplication portion 500.

Shown in Fig. 2 A, airtight container 100 is by panel 110, body (vacuum tube) 120, form with base 130, wherein, panel 110 weldings are at an end of body 120, and the predetermined tubular axis AX direction in edge is extended, base 130 weldings are at the other end of electron tube body 120, and composition has the bottom part of the airtight container 100 of pipe 600.Fig. 2 B is the sectional view after airtight container 100 is broken away along the I-I line among Fig. 2 A, has shown that specially panel 110 is welding in an end that part of of body 120.Panel 110 has light incident surface 110a and the light emission surface 110b relative with light incident surface 110a, and photocathode 200 forms on the light emission surface 110b that is positioned at airtight container 100 inboards.Body 120 is cavity members, is the center and expands along tubular axis AX with tubular axis AX.Panel 110 weldings are at an end of this cavity member, and base 130 weldings are at the other end.Base 130 is equipped with the through hole that extends along tubular axis AX direction, and the inside and outside of airtight container 100 communicated.Pin 700 distributes around this through hole.In order to extract the air in the airtight container 100, pipe 600 links to each other with base 130 at the through hole place.

Be positioned at the installation site of electron multiplication portion 500 of the tubular axis AX direction of airtight container 100, by determining to the airtight container 100 inner pins that extend 700 from base 130.Electron multiplication portion 500 comprises focusing electrode unit 300 and dynode unit 400 equally, and the former is used to revise the photoelectronic track that is transmitted into airtight container 100 from photocathode 200, and the latter is used for photoelectronic cascade-multiplied.

Following separating is right, annotate as the execution mode of the photomultiplier that the present invention relates to multichannel photoelectricity multiplier tube, described multichannel photoelectricity multiplier tube has four electron multiplication channel C H1 being made up of two groups of electrodes (dynode) that clip tubular axis AX to CH4.

Fig. 3 is the assembling process figure of structure that is used to illustrate the electron multiplication portion 500 of the photomultiplier that the present invention relates to.In Fig. 3, electron multiplication portion 500 has focusing electrode unit 300 and dynode unit 400.

Focusing electrode unit 300 is formed by mesh electrode 310, shield member 320 and elastic electrode 330 laminated configuration.Mesh electrode 310 has the metal framework of opening, and this opening allows to pass through from the photoelectron of photocathode 200.By the opening that the frame part of mesh electrode 310 is determined, the wire netting with many openings covers.Shield member 320 has a metal framework that has opening, and this opening allows to pass through from the photoelectron of photocathode 200.Determine this frame part of the opening of shield member 320, be equipped with towards barricade 323a, the 323b of photocathode 200 extensions and barricade 322a, the 322b that extends towards base 130.Barricade 323a, 323b can control photoelectron respectively and incide first pair of position on the dynode DY1, are adjusted at the electric field lens that forms between photocathode 200 and the focusing electrode unit 300, to improve the response characteristic of CTTD (being TTS).Barricade 322a, 322b are located respectively, to surround a space in the relative both ends open of the first dynode DY1.Barricade 322a, 322b are set at than the high electromotive force of the electromotive force of the first dynode DY1 (equaling the electromotive force of the second dynode DY2), and effect is to strengthen the electric field between the first dynode DY1 and the second dynode DY2.Therefore, improved from the first dynode DY1 and incided effect on the second dynode DY2, reduced the discrete of the transit time of secondary electron between the first dynode DY1 and the second dynode DY2 to the secondary electron of second dynode DY2 motion.Elastic electrode 330 has a metal framework that is equipped with opening, and this opening allows to pass through from the photoelectron of photocathode 200.The frame part of elastic electrode 330 is equipped with metal spring 331 (electrode part), this metal spring 331 has the electron multiplication portion 500 of focusing electrode unit 300 to be fixed on the predefined position of airtight container 100 inside whole erection by pressing to the inwall of airtight container 100.The frame part of elastic electrode 330 also is equipped with demarcation strip 332, the second dynode DY2 separated into two parts under its longitudinal direction along the second dynode DY2 will be positioned at.Demarcation strip 332 is set at the identical electromotive force with the second dynode DY2, effect be to reduce effectively mutual vicinity by crosstalking between the electron multiplication passage that forms with a series of electrode groups.

On the other hand, dynode unit 400 has a pair of insulation supporting member (the first insulation supporting member 410a and the second insulation supporting member 410b), this insulation support member support has the focusing electrode unit 300 of said structure, and at least two electrode groups of the photoelectron from photocathode 200 being carried out cascade-multiplied in clamping.Specifically, the a pair of first dynode DY1 in the first and second insulation supporting member 410a, the common clamping of 410b, the a pair of second dynode DY2, a pair of the 3rd dynode DY3, a pair of the 4th dynode DY4, a pair of the 5th dynode DY5, a pair of the 7th dynode DY7, and a pair of

gain control unit

430a, 430b, the every pair of dynode or unit tubular axis AX configuration and relative in tubular axis AX both sides.Metal pins 441,442 is fixed on the first and second insulation supporting member 410a, the 410b, is used for separately electrode is set in predetermined electromotive force.Except electrode separately, the first and second

insulation supporting member

410a, 410b also clamping a bottom metal 440, and this metallic plate electromotive force is set to earth potential (0V).

The a pair of first dynode DY1 is installed in the top of the first and second

insulation supporting member

410a, 410b, and makes metal fixed

component

420a, 420b be welded on its two ends.Two gain control unit 430a, any one among the 430b all has an insulating base plate 431, and fixing the 6th relevant dynode DY6 on this insulating base plate 431, and anode 432 and octuple increase electrode DY8.Here, each the 6th dynode DY6 is installed on the insulating base plate 431 by two and the electrode that is in electric released state is formed.Each anode 432 is installed on the insulating base plate 431 by two and the electrode that is in electric released state is formed.Each octuple increases that electrode DY8 is two electrodes forming the 6th dynode DY6 and two electrodes forming anode 432 is common.

As mentioned above, each

gain control unit

430a, 430b all belong to one group that clips in two electrode groups that tubular axis AX is provided with.Therefore, by with

gain control unit

430a, 430b and demarcation strip 332 fit together, thereby form the four-way photomultiplier, constitute two electron multiplication passages by an electrode group.The 6th dynode DY6 among each

gain control unit

430a, 430b also is made up of two electrodes, and therefore, photomultiplier is done as a whole, and four electrodes are disposed respectively to the electron multiplication passage as the 6th dynode DY6.Dispose electromotive force by adjusting respectively, can under gain is independent of other situation, adjust each electron multiplication passage to the electrode of each electron multiplication passage as the 6th dynode DY6.

Fig. 4 is the figure of structure that is used to illustrate a pair of insulation supporting member 410a, the 410b of a part that constitutes electron multiplication shown in Figure 3 portion.Because the first insulation supporting member 410a and the second insulation supporting member 410b are of similar shape, below only the first insulation supporting member 410a is described, and the explanation of the second insulation supporting member 410b will be omitted.

The first insulation supporting member 410a is made of main part and projection.The former supports the first electrode group and the second electrode group, wherein, the first electrode group comprises the first dynode DY1 to the, five dynode DY5, the 7th dynode DY7 and gain control unit 430a, and the second electrode group comprises the first dynode DY1 to the, five dynode DY5, the 7th dynode DY7 and gain control unit 430b; The latter is 200 extensions from main part towards photocathode.

The main part of the first insulation supporting member 410a is equipped with fixed

slit

412a, 413a and fixed slit 412b, 413b.The former is used for fixing the first electrode group, and the latter is used for fixing the second electrode group (identical fixed slit also is set at the main part of the second insulation supporting member 410b).

With regard to the first electrode group, with one that is configured in two fixed lobes at the second dynode DY2 two ends, dispose in two fixed lobes at the 3rd dynode DY3 two ends, dispose in two fixed lobes at the 4th dynode DY4 two ends, dispose in two fixed lobes at the 5th dynode DY5 two ends, dispose in two fixed lobes at the 7th dynode DY7 two ends, all insert among the fixed slit 412a, thereby make these electrode members by the first and second

insulation supporting member

410a, 410b integral retaining.In addition, shown in Fig. 5 B, be arranged on the fixed lobe of the end in the fixed lobe on the two ends of gain control unit 430a of the electrode group that belongs to first series, be inserted among the fixed slit 413a.With regard to the second electrode group, with one that is configured in two fixed lobes at the second dynode DY2 two ends, be configured in two fixed lobes at the 3rd dynode DY3 two ends, be configured in two fixed lobes at the 4th dynode DY4 two ends, be configured in two fixed lobes at the 5th dynode DY5 two ends, be configured in two fixed lobes at the 7th dynode DY7 two ends, all insert among the fixed slit 412b, thereby make these electrode members by the first and second

insulation supporting member

410a, 410b integral retaining.In addition, be arranged on the fixed lobe of the end in the fixed lobe on the two ends of gain control unit 430b of the electrode group that belongs to first series, be inserted among the fixed slit 413b.

In addition, otch 415 is configured in the bottom of the first insulation supporting member 410a, is used for clamping bottom metal 440 (the second insulation supporting member 410b has identical fixture).And, the bearing part 411 that the first electrode DY1 is installed is formed at the part that is clipped by the projection of the first insulation supporting member 410a, and the otch 414 of fixed-focus electrode unit 300 forms (the second insulation supporting member 410b has identical fixture) on each projection.Specifically, shown in Fig. 5 A, insert otch 414 on the first insulation supporting member 410a respectively at the otch that forms on the focusing electrode unit 300, so focusing electrode unit 300 is just by the first and second

insulation supporting member

410a, 410b integral retaining.Fig. 5 A is the schematic diagram that connects the structure of focusing electrode unit 300 and a pair of

insulation supporting member

410a, 410b, and Fig. 5 B is the schematic diagram that connects the structure of

gain control unit

430a, 430b and a pair of

insulation supporting member

410a, 410b.

Fig. 6 is the perspective view that is used for illustrating the cross section structure after electron multiplication portion is broken away along the I-I line of Fig. 1.As shown in Figure 6, electron multiplication portion 500 has two covers to clip the electrode group that tubular axis AX is provided with.In each of this two electrode groups, can be independent of the electron multiplication passage of the mutual vicinity of adjusting under other the situation in gain, the configuration of the demarcation strip 332 that provides by the elastic electrode 330 of a part that constitutes focusing electrode unit 300 and relevant

gain control unit

430a or 430b and determining.Therefore, in electron multiplication portion 500 as shown in Figure 6, according to four electron multiplication passages of photoelectron emissions position formation of photocathode 200.

Clip in the electrode group that comprises gain control unit 430a (the first electrode group) in two electrode groups that tubular axis AX is provided with, increase to octuple from the first dynode DY1 on each dynode of electrode DY8 and all be formed with secondary emission surface.The setting electromotive force that increases each dynode of electrode DY8 from the first dynode DY1 to octuple increases according to the order that increases electrode DY8 from the first dynode DY1 to octuple, arrives the next stage dynode continuously with the guiding secondary electron.The electromotive force of anode 432 is higher than the electromotive force that octuple increases electrode DY8.For example, setting photocathode 200 is-1000V, setting the first dynode DY1 is-800V, setting the second dynode DY2 is-700V, setting the 3rd dynode DY3 is-600V, setting the 4th dynode DY4 is-500V, setting the 5th dynode DY5 is-400V, to set the 6th dynode DY6 and to be-300V (adjust be set in order gaining adjustable), setting the 7th dynode DY7 is-200V, set octuple and increase electrode DY8 and be-100V, setting anode 432 is earth potential (0V).Be equipped with the focusing electrode unit 300 of demarcation strip 332 to be set to, electromotive force is identical with the second dynode DY2.

Photoelectron from photocathode 200 is launched behind the netted window by focusing electrode unit 300, arrives the first dynode DY1, and it is identical with second dynode DY2 that focusing electrode unit 300 is set to electromotive force.The barricade 322b that electromotive force is identical with the second dynode DY2, be configured in along in the space that the first dynode DY1 vertically opens wide, like this, electric field between the first dynode DY1 and the second dynode DY2 is strengthened, move to the efficient that the secondary electron of the second dynode DY2 incides on the second dynode DY2 from the first dynode DY1 and can improve the discrete minimizing of the secondary electron transit time between the first dynode DY1 and the second dynode DY2.Secondary electron emission surface forms on the electronics arrival surface of the first dynode DY1, and, in response to photoelectronic incident, launch secondary electron from the first dynode DY1.The secondary electron of launching from the first dynode DY1 moves towards the second dynode DY2 that electromotive force is higher than the first dynode DY1.The second dynode DY2 is by 300 extended demarcation strips 332 are divided into two electron multiplication passages from the focusing electrode unit, and formed a kind of structure, it is by adjusting the track from the secondary electron of the first dynode DY1, with crosstalking between the electron multiplication passage that suppresses vicinity.The electronics of the second dynode DY2 arrives on the surface and also is formed with secondary electron emission surface, and the secondary electron of launching from the secondary electron emission surface of second dynode DY2 moves towards the 3rd dynode DY3 that electromotive force is higher than the second dynode DY2.Along with electronics according to the 4th dynode DY4, the 5th dynode DY5, the sequential advancement of the 6th dynode DY6, the secondary electron of launching from the secondary electron emission surface of the 3rd dynode DY3 similarly is cascaded multiplication.The 6th dynode DY6 is made up of two electrodes of a part that constitutes gain control unit 430a, and by the setting voltage of these two electrodes is done suitable adjustment, can adjust the gain of contiguous electron multiplication passage separately.The secondary electron of launching from the secondary electron emission surface of the electrode that constitutes the 6th dynode DY6 separately arrives the 7th dynode DY7, and the secondary electron of launching from the secondary electron emission surface of the 7th dynode DY7 is towards anode 432 motions that are equipped with mesh openings.Octuple increases electrode DY8 and is set to electromotive force and is lower than anode 432, and works as the conversion dynode of an emission secondary electron, and these secondary electrons pass anode 432, get back to anode 432 then.Comprise another electrode group of gain control unit 430b, also work in an identical manner.

Next, use Fig. 7 A, the architectural feature of the photomultiplier that the present invention relates to is described to 9C.According to architectural feature, photomultiplier has been equipped with demarcation strip 332, and this demarcation strip is divided into two parts along the vertical of the corresponding second dynode DY2 with the corresponding second dynode DY2.Fig. 7 A and 7B are the perspective views that the architectural feature of the photomultiplier that the present invention relates to is described, in the present embodiment, demarcation strip 332 is configured in 300 places, focusing electrode unit that are positioned on the second dynode DY2.By this arrangement, it is identical with the corresponding second dynode DY2 that demarcation strip 332 is set to electromotive force.In addition, in the present embodiment, each electrode group all has been equipped with demarcation strip 332, and the demarcation strip of preparing by two electrode groups that clip that tubular axis AX is provided with for each electrode group 332 has been formed four electron multiplication passages.

Specifically, demarcation strip 332 is configured on the elastic electrode 330 of a part that constitutes focusing electrode unit 300.Shown in Fig. 7 A, elastic electrode 330 has metal framework, the opening that this metal framework is equipped with permission to pass through from the photoelectron of photocathode 200.The frame part of elastic electrode 330 is equipped with metal spring 331 (electrode part), this metal spring 331 is by pressing to the inwall of airtight container 100, whole electron multiplication portion 500 is fixed on precalculated position in the airtight container 100, and the electromotive force of photocathode 200 and focusing electrode unit 300 is equated.The frame part of elastic electrode 330 also is equipped with demarcation strip 332, and each demarcation strip 332 is after the direction bending shown in the arrow S3 among Fig. 7 A, and the second dynode DY2 under vertically will being positioned at of corresponding second dynode is separated into two parts.Each second dynode DY2, the fixed lobe DY2a, the DY2b that are welded on its two ends are all arranged, and be equipped with a slit 333 that is used to insert demarcation strip 332, when focusing electrode unit 300 is fixed on this to insulation supporting member 410a, when 410b is last, each 322 while of demarcation strip also is inserted among the corresponding second dynode DY2 by slit 333.By this configuration, crosstalking between the electron multiplication passage of the mutual vicinity that is formed by the electrode group of a series reduced effectively.

Fig. 8 A is the sectional view of the effect of the architectural feature (demarcation strip 332) that is used to illustrate the photomultiplier that the present invention relates to 8C.Fig. 9 A is the sectional view of the electron orbit of the photomultiplier (structure that does not have demarcation strip) that is used for illustrating that comparative example relates to 9C, and this comparative example is used to illustrate the effect of the architectural characteristic of the photomultiplier that the present invention relates to.Among each figure from Fig. 8 A to 9C, A1 represents photoelectronic track, and E1 represents equipotential lines.In addition, among each figure from Fig. 8 A to 9C, CH1 represents first respectively to quadrielectron multiplication passage to CH4.

Fig. 8 A is the sectional view that is equipped with after demarcation strip 332 is broken away along the VIII-VIII line among Fig. 8 C as the cross section structure of the photomultiplier of architectural feature.On the contrary, Fig. 8 C is the sectional view after photomultiplier (having architectural feature) is broken away along the X-X line among Fig. 8 A.Fig. 8 B is the sectional view after photomultiplier is broken away along the IX-IX line among Fig. 8 C.Can understand from Fig. 8 A to 8C, because the second dynode DY2 is higher than the second dynode DY2 demarcation strip 332 by electromotive force and separates, thereby significantly improve (crosstalking between the contiguous electron multiplication passage is considerably reduced) from the photocathode 200 arrival first dynode DY1 and according to the possibility that the further photoelectron that moves of the order of the second dynode DY2, the 3rd dynode DY3 traverses into contiguous electron multiplication passage.

On the other hand, to shown in the 9C, in the photomultiplier that the comparative example that does not have architectural feature (demarcation strip) relates to, crosstalking occurs between the contiguous electron multiplication passage as Fig. 9 A.Arrive the first dynode DY1 and according to the further photoelectron of motion of the order of the second dynode DY2, the 3rd dynode DY3 from photocathode 200, traverse into contiguous electron multiplication passage the getting over of the 3rd dynode DY3 moving to from the second dynode DY2.Therefore, according to the photomultiplier that the comparative example that does not dispose demarcation strip relates to, crosstalking and to be reduced effectively between the contiguous electron multiplication passage.Fig. 9 A is the sectional view that the cross section structure of the photomultiplier that relates to of comparative example (not having demarcation strip) is broken away along the XI-XI line among Fig. 9 C.On the contrary, Fig. 9 C is the sectional view after photomultiplier that comparative example relates to is broken away along the XIII-XIII line among Fig. 9 A.Fig. 9 B is the sectional view after photomultiplier that comparative example relates to is broken away along the XII-XII line among Fig. 9 C.

Shown in Fig. 2 B, in the photomultiplier that the present invention relates to, the light emission surface 110b of panel 110 is made up of plane domain and Machining of Curved Surface zone, and this Machining of Curved Surface zone is positioned at the periphery of plane domain and comprises the edge of light emission surface 110b.So the surface configuration of the neighboring area of the light emission surface 110b of panel 110 is changed artificially, purpose is to adjust the angle that photoelectron is launched from the photocathode 200 that is positioned at the neighboring area.Therefore photoelectron moves to the first dynode DY1 from photocathode 200 the discrete of transit time reduced effectively, and do not rely on photoelectronic transmitting site.

And as shown in Figure 6, the first dynode DY1 that belongs to two electrode groups respectively is set to back-to-back relatively and clips tubular axis AX.In this case, the photoelectronic collection efficiency that arrives the first dynode DY1 periphery is improved significantly.For example, owing between the photocathode 200 and the first dynode DY1, do not need the direct light electronics to move to the electrode of the first dynode DY1 from photocathode 200, thereby, compare with traditional technology, neighboring area at photocathode 200 can access stronger electric field strength, and it is even that the spacing of equipotential lines also becomes.The photoelectron of launching from the neighboring area of photocathode 200 when not reaching the first dynode DY1, can directly not arrive the second dynode DY2.

In addition, preferred first dynode DY1 width in the vertical is greater than this insulation support member 430a, the space between the 430b.In this case, the active surface that arrives of the photoelectron of launching from photocathode 200 is expanded thereupon.And, as Fig. 3 and shown in Figure 6, being positioned at the shielding construction of the first dynode DY1 periphery,

i.e. barricade

322a, 322b are configured in the position in the space closure of the first dynode DY1 both ends open.Barricade 322a, 322b are set to electromotive force and are higher than the first dynode DY1 (equaling the electromotive force of the second dynode DY2), and effect is to strengthen the electric field between the first and second dynode DY1, the DY2.So, move to the efficient that the secondary electron of the second dynode DY2 incides on the second dynode DY2 from the first dynode DY1 and be improved, and the discrete of the transit time of the secondary electron between the first and second dynode DY1, the DY2 also reduced.

As mentioned above, according to the photomultiplier that the present invention relates to, can reduce crosstalking between the electron multiplication passage that constitutes an electrode group effectively, and improve TTS, CTTD and other response time properties thus significantly.Therefore and a part and the anode of gain control unit and dynode integrate, and can reduce the number of components in the assembling process, and are simple structure with a plurality of electron multiplication channel arrangement.

It is evident that in the foregoing invention that this working of an invention mode can change in many ways.These variations can not be considered to exceed scope of the present invention, and all similarly are out of shape to it will be apparent to one skilled in the art that it all is conspicuous, and are included in the scope of claim.

Claims

1. photomultiplier comprises:

Airtight container (100) comprises along the hollow bulb (120) of predetermined tubular axis (AX) extension and the panel (110) of reporting to the leadship after accomplishing a task with tubular axis (AX) light of described panel (110) transmission predetermined wavelength;

Photocathode (200) is arranged in the described airtight container (100), in response to the incident of light with predetermined wavelength, and emission photoelectron in described airtight container (100);

Dynode unit (400), be arranged in the described airtight container (100), the photoelectron that described photocathode (200) is launched carries out cascade-multiplied, described dynode unit (400) comprises a dynode group at least, this dynode group is made up of a plurality of dynodes that have secondary electron emission surface respectively

It is characterized in that:

Has the demarcation strip (332) that constitutes by electric conducting material, the described demarcation strip (332) of a described dynode unit (400), be set to electromotive force and be higher than first dynode (DY1) of launching secondary electron in response to photoelectronic incident, and vertical with described second dynode (DY2) separated into two parts along second dynode (DY2), described second dynode (DY2) is positioned at the position that the photoelectron from described first dynode (DY1) arrives.

2. photomultiplier according to claim 1 is characterized in that:

Also comprises focusing electrode unit (300), be set between described photocathode (200) and the described dynode unit (400), and it is identical with second dynode (DY2) to be set to electromotive force,

Wherein, described demarcation strip (332) comprises, in a metal bump pointing to the upwardly extending described focusing electrode unit, side (300) of described dynode unit (400) from described photocathode (200).

3. photomultiplier according to claim 2 is characterized in that:

Described second dynode (DY2) possesses and will be formed with the front surface of secondary electron emission surface and the slit (333) that rear surface on the other side connects,

The described metal bump of described focusing electrode unit (300), extend in the direction of pointing to described dynode unit (400) from described photocathode (200), make the described slit (333) of its tip, and be positioned at the space between described first dynode (DY1) and described second dynode (DY2) by described second dynode (DY2).