CA1139821A - Electron multipliers with discrete dynode separating elements - Google Patents
Electron multipliers with discrete dynode separating elementsInfo
- Publication number
- CA1139821A CA1139821A CA000329423A CA329423A CA1139821A CA 1139821 A CA1139821 A CA 1139821A CA 000329423 A CA000329423 A CA 000329423A CA 329423 A CA329423 A CA 329423A CA 1139821 A CA1139821 A CA 1139821A
- Authority
- CA
- Canada
- Prior art keywords
- dynode
- separating elements
- plates
- dynodes
- elements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J43/00—Secondary-emission tubes; Electron-multiplier tubes
- H01J43/04—Electron multipliers
- H01J43/06—Electrode arrangements
- H01J43/18—Electrode arrangements using essentially more than one dynode
- H01J43/22—Dynodes consisting of electron-permeable material, e.g. foil, grid, tube, venetian blind
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/88—Mounting, supporting, spacing, or insulating of electrodes or of electrode assemblies
Abstract
-10- PHB. 32,626.
ABSTRACT:
An electron multiplier using a laminated channel plate assembly. The electron multiplier is usable in display tubes and image intensifiers. A problem in channel plate electron multipliers is to space apart accurately the dynodes in a sim-ple and inexpensive way. In the present invention this problem is overcome by using discrete separating elements such as ballotini to space apart the dynodes. The elements are bonded to the surface of one dynode of adjacent pairs of dynodes and is either bonded to or clamped against the other dynode of the pair. Various methods of making the laminated channel plate assembly are disclosed.
ABSTRACT:
An electron multiplier using a laminated channel plate assembly. The electron multiplier is usable in display tubes and image intensifiers. A problem in channel plate electron multipliers is to space apart accurately the dynodes in a sim-ple and inexpensive way. In the present invention this problem is overcome by using discrete separating elements such as ballotini to space apart the dynodes. The elements are bonded to the surface of one dynode of adjacent pairs of dynodes and is either bonded to or clamped against the other dynode of the pair. Various methods of making the laminated channel plate assembly are disclosed.
Description
1139~321 - 1 - P~B. 32,626.
The present invention relates to electron multipliers and more particularly to electron multipliers of the channel plate type which may be used in electronic imaging and display applications.
In present practice a channel plate is a secondary-emissive electron multiplier device which can be in the form of a glass plate having a first conductive layer on its input face and a separate second conductive layer on its output face to act respectively as input and output electrodes and a large number of channels with resistive walls passing through its thickness so that the electric field inside each channel varies uniformly along its length. The multipller device can also be in the form of a channel plate structure comprising a plurality of discrete dynode metal channel plates in a stack, each plate being separated from the others.
Different types of channel plate structures are known for example from British Patent Specifications 1,401,969, 1,402,549 and 1,434,053 which are all assigned to Mullard Ltd. and were published on August 6, L975, August 13, 1975 and April 28, 1978 respectively. Figures 5 and 6 of British Patent Specification No. 1,402,549 disclose the use of screen printed glass dots as a means of separating adjacent channel plates of a stack. In order to bond the plates together to form a channel plate structure it is necessary partly to melt the glass dots. A problem may arise here in that accurate spacing between the channel plates may be lost due to the glass dots changing shape when partly melted. In order to avoid this problem it is proposed in that Specification to form spacing separating elements from a high melting point glass, which separating elements may be machined to an accurate thickness after application. Thereafter bonding separating elements of a low melting point glass are applied to the same surface of each channel plate as the spacing separating elements.
The plates are then arranged in a stack with the channels in the plates being aligned as desired and the stack is heated to a temperature to melt partly the lcw melting point ~B
-., I
The present invention relates to electron multipliers and more particularly to electron multipliers of the channel plate type which may be used in electronic imaging and display applications.
In present practice a channel plate is a secondary-emissive electron multiplier device which can be in the form of a glass plate having a first conductive layer on its input face and a separate second conductive layer on its output face to act respectively as input and output electrodes and a large number of channels with resistive walls passing through its thickness so that the electric field inside each channel varies uniformly along its length. The multipller device can also be in the form of a channel plate structure comprising a plurality of discrete dynode metal channel plates in a stack, each plate being separated from the others.
Different types of channel plate structures are known for example from British Patent Specifications 1,401,969, 1,402,549 and 1,434,053 which are all assigned to Mullard Ltd. and were published on August 6, L975, August 13, 1975 and April 28, 1978 respectively. Figures 5 and 6 of British Patent Specification No. 1,402,549 disclose the use of screen printed glass dots as a means of separating adjacent channel plates of a stack. In order to bond the plates together to form a channel plate structure it is necessary partly to melt the glass dots. A problem may arise here in that accurate spacing between the channel plates may be lost due to the glass dots changing shape when partly melted. In order to avoid this problem it is proposed in that Specification to form spacing separating elements from a high melting point glass, which separating elements may be machined to an accurate thickness after application. Thereafter bonding separating elements of a low melting point glass are applied to the same surface of each channel plate as the spacing separating elements.
The plates are then arranged in a stack with the channels in the plates being aligned as desired and the stack is heated to a temperature to melt partly the lcw melting point ~B
-., I
- 2 _ 1 glass bonding elements which bond themselves to the surface of an adjacent plate. In the case of plates not made of ~ ece ssa a secondary emissive material, for example mild steel, it lS~
to provide a secondary emissive material in each channel.
S The repeated heating of the plates in order to apply high melting point and low melting point glass separating elements to the plates and the heating to bond the elernents to adjacent plates can affect adversely the secondary emissive material. miS can have the effect that the channels do not behave uniformly over the area o~
the channel plate structure.
Accordingly it is an object of the present invention to space apart accurately the channel plates in a reliable and simple way.
According to one aspect of the present invention there is provided a channel plate structure comprising a stack of discrete electrically conductive dynodes separated from each other by an array of discrete separating elements distributed -across the area of tha channel plate, which elements æe less conductive than the dynodes.
According to a second asp~ct of the present invention there is provided a method of manu*acturing a channel plate st-ucture, c~mprising applying a glass enarnel to a surface of at least some of a plurality o~ perforate, electricall~
conductive dynode forming sheets, firing the glass enamel, temporarily positioning discrete separating elements on the enamelled surfaces, bonding the spherical elements to tlle en~nelled surraces by rnelting the glass enamel thereon, and arranging the sheets in a stack with the free surfaces of the spherical elements contacti~g a surface of an adjacent sheet.
m e discrete separating elernents may be spherical and comprise s~all glass spheres krown as ballotini. The provision of the discrete elements enables a s~eater consistency to be achieved in the electrical characteristics of the char~el plate structure and in the spacing of adjacent channel plates, !
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~- 1139821
to provide a secondary emissive material in each channel.
S The repeated heating of the plates in order to apply high melting point and low melting point glass separating elements to the plates and the heating to bond the elernents to adjacent plates can affect adversely the secondary emissive material. miS can have the effect that the channels do not behave uniformly over the area o~
the channel plate structure.
Accordingly it is an object of the present invention to space apart accurately the channel plates in a reliable and simple way.
According to one aspect of the present invention there is provided a channel plate structure comprising a stack of discrete electrically conductive dynodes separated from each other by an array of discrete separating elements distributed -across the area of tha channel plate, which elements æe less conductive than the dynodes.
According to a second asp~ct of the present invention there is provided a method of manu*acturing a channel plate st-ucture, c~mprising applying a glass enarnel to a surface of at least some of a plurality o~ perforate, electricall~
conductive dynode forming sheets, firing the glass enamel, temporarily positioning discrete separating elements on the enamelled surfaces, bonding the spherical elements to tlle en~nelled surraces by rnelting the glass enamel thereon, and arranging the sheets in a stack with the free surfaces of the spherical elements contacti~g a surface of an adjacent sheet.
m e discrete separating elernents may be spherical and comprise s~all glass spheres krown as ballotini. The provision of the discrete elements enables a s~eater consistency to be achieved in the electrical characteristics of the char~el plate structure and in the spacing of adjacent channel plates, !
-........................................................................ !
~- 1139821
- 3 ~
1 otherwise known as dynodes, from each other. In the case of using ballotin~ as insulating separators higher values of resistance and ~oltage breakdown limits between adjacent dynodes, compared with screen printed glass, are obtained.
By way of comparison, laboratory-made channel plates having a working area of 150 x 200 mm , a chan~el pitch of the order 0.8 mm. and a spacer thickness of the ordor of 0.1 gave the following typical results:
Separator Dynode-dynode resistancë Voltage brea~down limit __ Ballotini consistently ~ 10 l_Jl_ > 1000 Volts Screen printed ~ariable, usually 105-109~ 40a Volts(a~s~x) glass sometimes much lower Another advantage of using discrete elements as insulating or resistive separators is that their small size means that any electrons which drop-out in passing from one dynode to the next are unlikely to land on the elements causing a negative charge to build-up, w~ich charge will oppose the passage of further electrons through the channels. Rather any drop-out electrons are likely to land on thæ dynode surface which is conducting - and thæreby they do not cause charging.
If it is desired that the separating elements should be resistive, that is be slightly conductive, rather than insulating, - the elemer.ts~ such as ballotini may be made a glass containing a high lead content which when heated in a reducing atmosphere of hydrogen causes a resistive surface to be produced thereon.
The resistive elements thus formed act as part o a resistor chain for biasing the dynodes.
The discrete separating elements may be arranged singly or in clusters as desired. Further they may be arranged more densely at the edse o each dynode than at the centre thereof. Such a distribution of the elements enables a greater bond strength to be given at the edges thereby minimising the risk of adjacent dynodes peeling apart and - 1139~
1 otherwise known as dynodes, from each other. In the case of using ballotin~ as insulating separators higher values of resistance and ~oltage breakdown limits between adjacent dynodes, compared with screen printed glass, are obtained.
By way of comparison, laboratory-made channel plates having a working area of 150 x 200 mm , a chan~el pitch of the order 0.8 mm. and a spacer thickness of the ordor of 0.1 gave the following typical results:
Separator Dynode-dynode resistancë Voltage brea~down limit __ Ballotini consistently ~ 10 l_Jl_ > 1000 Volts Screen printed ~ariable, usually 105-109~ 40a Volts(a~s~x) glass sometimes much lower Another advantage of using discrete elements as insulating or resistive separators is that their small size means that any electrons which drop-out in passing from one dynode to the next are unlikely to land on the elements causing a negative charge to build-up, w~ich charge will oppose the passage of further electrons through the channels. Rather any drop-out electrons are likely to land on thæ dynode surface which is conducting - and thæreby they do not cause charging.
If it is desired that the separating elements should be resistive, that is be slightly conductive, rather than insulating, - the elemer.ts~ such as ballotini may be made a glass containing a high lead content which when heated in a reducing atmosphere of hydrogen causes a resistive surface to be produced thereon.
The resistive elements thus formed act as part o a resistor chain for biasing the dynodes.
The discrete separating elements may be arranged singly or in clusters as desired. Further they may be arranged more densely at the edse o each dynode than at the centre thereof. Such a distribution of the elements enables a greater bond strength to be given at the edges thereby minimising the risk of adjacent dynodes peeling apart and - 1139~
- 4 - PHB. 32,626.
affecting adversely the uniformity in the performance of the channel plate structure. The separating elements may be arranged regularly between the channels of each dynode and where the borders of the dynodes are imperforate, the density of the elements may be much greater.
The discrete separating elements may be bonded to adjacent dynodes and thereby form an integrated stack.
Alternatively the elements may be bonded to one side of a plate forming a dynode and the channel plate structure is assembled by arranging the separated dynodes as a stack which is then clamped.
The present invention will now be described, by way of example, with reference to the accompanying drawings, wherein Figure 1 is a diagrammatic cross section through a portion of a stack of four dynodes having spherical separa-ting elements, each dynode comprising a single, perforate electrically conductive plate of the type shown in Figure 1 of British Patent Specification No. 1,402,549, Figure 2 is a diagrammatic cross section through a por-tion of a stack of four dynodes having spherical separating elements, each dynode comprising a pair of mating, perforate electrically conductive plates of the type shown in Figure 4 of British Patent Specification No. 1,434,053, and Figure 3 is a diagrammatic sectional view of an image display tube having a channel plate structure made in accordance with the present invention.
In the interests of brevity, the description of Figures 1 and 2 will be confined to only that which is necessary to understand the present invention. For details of the fabrication of the dynodes and their various alternative arrangements of the dynodes, reference is made to British Patent Specifications Nos. 1,401,969, 1,402,549 and 1,434,053.
`--B
` 113982~
affecting adversely the uniformity in the performance of the channel plate structure. The separating elements may be arranged regularly between the channels of each dynode and where the borders of the dynodes are imperforate, the density of the elements may be much greater.
The discrete separating elements may be bonded to adjacent dynodes and thereby form an integrated stack.
Alternatively the elements may be bonded to one side of a plate forming a dynode and the channel plate structure is assembled by arranging the separated dynodes as a stack which is then clamped.
The present invention will now be described, by way of example, with reference to the accompanying drawings, wherein Figure 1 is a diagrammatic cross section through a portion of a stack of four dynodes having spherical separa-ting elements, each dynode comprising a single, perforate electrically conductive plate of the type shown in Figure 1 of British Patent Specification No. 1,402,549, Figure 2 is a diagrammatic cross section through a por-tion of a stack of four dynodes having spherical separating elements, each dynode comprising a pair of mating, perforate electrically conductive plates of the type shown in Figure 4 of British Patent Specification No. 1,434,053, and Figure 3 is a diagrammatic sectional view of an image display tube having a channel plate structure made in accordance with the present invention.
In the interests of brevity, the description of Figures 1 and 2 will be confined to only that which is necessary to understand the present invention. For details of the fabrication of the dynodes and their various alternative arrangements of the dynodes, reference is made to British Patent Specifications Nos. 1,401,969, 1,402,549 and 1,434,053.
`--B
` 113982~
- 5 -1 ~igure 1 shows a channel plate structure 10 in which each of the dynodes 11, 12, 13 and 14 comprises a single, perforated metal plate. Channels 15 in the dyncdes 11 to 14 converge in the direction of electron multiplication and are aligned with each other. The dyncdes 11 to 14 are separated by spherical separating elements 16 in the form of ballotini which are bonded by glass enamel 17 ~o adjacent dynodes. By way of illustration the density of the elements 16 at the im?erforate edges of the dynodes 11 to 14 is greater than in the centre thereof. Further although the eleme~ts 16 are shown positioned between each char~el opening of a dynode, they could be spaced apart by integral multiples of the distance between the centres of adj~cent channels 15 of a dynods.
~5 As the illustrated separating elements 16 are electrically insulatir~ it is necessary that each dynode be biassed separately by a power supply 18.
~ igure 2 shows an alternative embodLment of a channel plate stn:cture 10 to that shown in Figure 1. Dynodes 20 to 23 each comprise two, juxtaposed, mating perforated metal plates 25, 26 of ~hich at least the channels 15 in the plate 26 of each dvnode is secondary emissive as is illustrated diagrammaticaly by the electron multiplication of an electron beam ir.ciden' in the channel of the dynode 21. The separating elements 16 comprise ballotini arranged at suitable intervals between the channels. Once again taps of the po-~er supply 18 are connected to respecti~e dynodes.
An example of one method for manuacturing channel plate structure of ~igure 2 will now be given, which method can readily be adapted to manufacture the structure of Figure 1.
- Pairs of metal plates 25, 26, ~or example mild steel plates, having matching arrays of convergent apertures therein are cleaned. A high yield secondary emissive surface is deposited by way of evaporation in the apertures of at least the plates 26~ The plates 25, 26 are then assembled to form d~odes with the smaller di~,eter operings of the apertures .
.. . . . ................................................... .
.
~5 As the illustrated separating elements 16 are electrically insulatir~ it is necessary that each dynode be biassed separately by a power supply 18.
~ igure 2 shows an alternative embodLment of a channel plate stn:cture 10 to that shown in Figure 1. Dynodes 20 to 23 each comprise two, juxtaposed, mating perforated metal plates 25, 26 of ~hich at least the channels 15 in the plate 26 of each dvnode is secondary emissive as is illustrated diagrammaticaly by the electron multiplication of an electron beam ir.ciden' in the channel of the dynode 21. The separating elements 16 comprise ballotini arranged at suitable intervals between the channels. Once again taps of the po-~er supply 18 are connected to respecti~e dynodes.
An example of one method for manuacturing channel plate structure of ~igure 2 will now be given, which method can readily be adapted to manufacture the structure of Figure 1.
- Pairs of metal plates 25, 26, ~or example mild steel plates, having matching arrays of convergent apertures therein are cleaned. A high yield secondary emissive surface is deposited by way of evaporation in the apertures of at least the plates 26~ The plates 25, 26 are then assembled to form d~odes with the smaller di~,eter operings of the apertures .
.. . . . ................................................... .
.
- 6 -1 being arranged remote from each other.
The outer surface of each pair of part-dynodes are coated with a bonding medium which at a later stage, is used to bond the ballotini to the dynodes. 'me bonding medium conveniently-comprises a thin layer of glass enamel applied for exam~ple byscreen printing or settling from a suspension. If the dynode material and the bonding medium have matchir.g coefficients of expansion the bonding ~edium e.g. glass enamel may be applied all over the outer dynode surface, otherwise it should be applied locally in the form of dots which coincide with the subsequent positions of the ballotini to prevent the risk of the dynodes curling with te~perature changes. The enamel is ~ired to a glassy state, the temperature being typically in the rarge 350 to 450 C. One of each adjacent pair of part-dynodes from adjacent dynodes is then coated with a sticky medium such as pine oil, the purpose of which ls to hold the ballotini temporarily in place. A stencil or the other dynode plate is then placed over the sticky mediu~
and ballotini having for example a nominal diameter of 100 microns are brushed across the surface of the stencil.
~he stencil consists of a thin sheet of perforated metal, the perforations being so located and of such a diameter that one sl2ss sphere (o- a cluster of a small number of ballotini if so desired) is placed at each of the required locations. The stencil is removed leaving correctly located ballotini adher~ng to the part-dynode by means of the sticky medium~ The part-dynode is taken through a heating cycle to remove the sticky medium by volat~lisation and to allow the ~lass layer to melt so that the balloti~,li are permanently bonded to the part-dynode. The next step is to place an en2mel coated part-dynode against a ballotini coated part-dynode in a jig which holds them in register ~hilst they are taken through a further heating cycle. The temperature is rais2d until the enamel melts and the two part-dynodes become bonaed with ballotini sep~rating them. Care has to he exercised to ensure that the ena~el does not cover the ballotini so as to cause a bridge to be formed between the two dynodes adversely affecting the insulation , .~ . .
~_,
The outer surface of each pair of part-dynodes are coated with a bonding medium which at a later stage, is used to bond the ballotini to the dynodes. 'me bonding medium conveniently-comprises a thin layer of glass enamel applied for exam~ple byscreen printing or settling from a suspension. If the dynode material and the bonding medium have matchir.g coefficients of expansion the bonding ~edium e.g. glass enamel may be applied all over the outer dynode surface, otherwise it should be applied locally in the form of dots which coincide with the subsequent positions of the ballotini to prevent the risk of the dynodes curling with te~perature changes. The enamel is ~ired to a glassy state, the temperature being typically in the rarge 350 to 450 C. One of each adjacent pair of part-dynodes from adjacent dynodes is then coated with a sticky medium such as pine oil, the purpose of which ls to hold the ballotini temporarily in place. A stencil or the other dynode plate is then placed over the sticky mediu~
and ballotini having for example a nominal diameter of 100 microns are brushed across the surface of the stencil.
~he stencil consists of a thin sheet of perforated metal, the perforations being so located and of such a diameter that one sl2ss sphere (o- a cluster of a small number of ballotini if so desired) is placed at each of the required locations. The stencil is removed leaving correctly located ballotini adher~ng to the part-dynode by means of the sticky medium~ The part-dynode is taken through a heating cycle to remove the sticky medium by volat~lisation and to allow the ~lass layer to melt so that the balloti~,li are permanently bonded to the part-dynode. The next step is to place an en2mel coated part-dynode against a ballotini coated part-dynode in a jig which holds them in register ~hilst they are taken through a further heating cycle. The temperature is rais2d until the enamel melts and the two part-dynodes become bonaed with ballotini sep~rating them. Care has to he exercised to ensure that the ena~el does not cover the ballotini so as to cause a bridge to be formed between the two dynodes adversely affecting the insulation , .~ . .
~_,
- 7 -1 An alternative technique involves clamping the part-dynodes together instead of bonding them. In this case one part-dynode is coated with ballotini as described above. The other part-dynode is not coated with enamel however~ Because of the S flexible nature o~ part-dynodes this method may only be adequate for multipliers with an area no greater than a few hundred cm (for a part-dynode thickness of about 0.15 ~).
In the above-mentioned examples the bond between ballotini and a dynode is effected by a glass enamel. However glass is not the only suitable bonding medium, others may include potassium silicate solution~ polyimide adhesive and Silvac (a propriatary vacuum-compatible adhesive)~
The above methods are also relevant to resistive spacers~
Resistive separating elements can be provided by using ballotini made of lead-containing glass and reducing the surface of each sphere by heating in hydrogen. Where resistive elements are used, the dynodes need not be coupled separately to the power supply 18 as shown in Figures 1 and 2. Instead th2 power supply can be connected between the first and last dynode and the resistive elements act as a potential di~ider enabling each dynode to be bias as required.
Figure 3 diagrammatically illustrates a chan~el plate cathode ray ~ube 30 comprising a metal, for example mild steel~ cone 31 having a substantially flat plate glass screen 32 closing the open end of the cone 31. A channel plate 10 made ~n accordance with the present invention is disposed at a small distance, for example 10 mm~ from the screen 32. An electron gun 33 is disposed adjacent th~ closed end of the cone 31 and a deflection coil assembly 34 is disposed adjacent to, but spaced from, the electron gun 33.
In operation a low energy electron beam 35 from thR
electron sun 33 is deflected in raster fashion across the input side of the channel plate structure lO by the coil assembly 34. m e beam undergoes electron multiplication in the struc.ure 10 and the output electrons are applied substantially normally to the screen 32.
I --- , .
.... . . .
~1398~1
In the above-mentioned examples the bond between ballotini and a dynode is effected by a glass enamel. However glass is not the only suitable bonding medium, others may include potassium silicate solution~ polyimide adhesive and Silvac (a propriatary vacuum-compatible adhesive)~
The above methods are also relevant to resistive spacers~
Resistive separating elements can be provided by using ballotini made of lead-containing glass and reducing the surface of each sphere by heating in hydrogen. Where resistive elements are used, the dynodes need not be coupled separately to the power supply 18 as shown in Figures 1 and 2. Instead th2 power supply can be connected between the first and last dynode and the resistive elements act as a potential di~ider enabling each dynode to be bias as required.
Figure 3 diagrammatically illustrates a chan~el plate cathode ray ~ube 30 comprising a metal, for example mild steel~ cone 31 having a substantially flat plate glass screen 32 closing the open end of the cone 31. A channel plate 10 made ~n accordance with the present invention is disposed at a small distance, for example 10 mm~ from the screen 32. An electron gun 33 is disposed adjacent th~ closed end of the cone 31 and a deflection coil assembly 34 is disposed adjacent to, but spaced from, the electron gun 33.
In operation a low energy electron beam 35 from thR
electron sun 33 is deflected in raster fashion across the input side of the channel plate structure lO by the coil assembly 34. m e beam undergoes electron multiplication in the struc.ure 10 and the output electrons are applied substantially normally to the screen 32.
I --- , .
.... . . .
~1398~1
- 8 - P~s. 32,626 In an alternative construction of the display tube, the channel plate structure may be placed like a shadow mask in a conventional cathode ray tube having a glass envelope.
The channel plate structure described above may be used in other practical applications such as electron multipliers, image intensifier tubes, data display tubes, x-ray image intensifiers and certain types of gas discharge tubes.
Although the spherical elements conveniently comprise ballotini because they are readily available, the elements may be of any compatible material having a sufficiently high resistance and a melting point sufficiently high such that the elements will not be deformed during the normal processing of the channel plate assembly.
Further although one technique has been described for laying down the ballotini, other techniques using currently known technology for handling such materials may be used.
The discrete separating elements may have other shapes besides spherical, such as cylindrical, ellipsoidal pris-matic and cubic. Irrespective of the precise shape of the elements, the technique for laying them down must ensure that they are in the desired positions and orientates so that the dynodes are separated by a substantially constant distance from each other.
.~
.~
The channel plate structure described above may be used in other practical applications such as electron multipliers, image intensifier tubes, data display tubes, x-ray image intensifiers and certain types of gas discharge tubes.
Although the spherical elements conveniently comprise ballotini because they are readily available, the elements may be of any compatible material having a sufficiently high resistance and a melting point sufficiently high such that the elements will not be deformed during the normal processing of the channel plate assembly.
Further although one technique has been described for laying down the ballotini, other techniques using currently known technology for handling such materials may be used.
The discrete separating elements may have other shapes besides spherical, such as cylindrical, ellipsoidal pris-matic and cubic. Irrespective of the precise shape of the elements, the technique for laying them down must ensure that they are in the desired positions and orientates so that the dynodes are separated by a substantially constant distance from each other.
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Claims (9)
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFUNED AS FOLLOWS:
1. A channel plate structure comprising a stack of substantially parallel discrete, electrically conductive apertured dynode plates, each dynode plate being separated from an adjacent dynode plate by separating elements distributed across the area of the dynode plate, the apertures in the dynode plates being aligned to form channels, the separating elements which are less conductive than the dynode plates being placed as individual entities on at least some of the dynode plates and being bonded to them, prior to being placed on the dynode plates the individual entities in one dimension being of a size corresponding substantially to the desired spacing between adjacent dynode plates and in a dimension transverse to said one dimension being smaller than the space between adjacent apertures in the dynode plates.
2. A structure as claimed in Claim 1, wherein the separating elements are substantially spherical.
3. A structure as claimed in Claim 2, wherein the substantially spherical elements comprise ballotini.
4. A structure as claimed in Claim 1, 2 or 3, wherein the ele-ments are made of glass having a surface comprising a lead film.
5. A structure as claimed in Claim 1, 2 or 3, wherein each dynode plate comprises a perforate electrically conductive sheet having a regular array of apertures.
6. A structure as claimed in Claim 1, 2 or 3, wherein each dynode plate comprises two perforate, electrically conductive mating sheets in electrical contact with each other.
7. A structure as claimed in Claim 1, 2 or 3, wherein the separating elements are arranged in clusters.
8. A structure as claimed in Claim 1, 2 or 3, wherein the separating elements are arranged more densely at the edge of each dynode sheet than at the centre thereof.
9. A structure as claimed in Claim 1, 2 or 3, wherein the dynodes are clamped together to form the stack.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7826877A GB2023332B (en) | 1978-06-14 | 1978-06-14 | Electron multipliers |
| GB26.877/78 | 1978-06-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1139821A true CA1139821A (en) | 1983-01-18 |
Family
ID=10497954
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000329423A Expired CA1139821A (en) | 1978-06-14 | 1979-06-07 | Electron multipliers with discrete dynode separating elements |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0006267B1 (en) |
| JP (1) | JPS5516392A (en) |
| CA (1) | CA1139821A (en) |
| DE (1) | DE2964009D1 (en) |
| GB (1) | GB2023332B (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2124017B (en) * | 1982-06-16 | 1985-10-16 | Philips Electronic Associated | A deflection colour selection system for a single beam channel plate display tube |
| GB2129205A (en) * | 1982-10-22 | 1984-05-10 | Philips Electronic Associated | Colour display tube |
| GB2138627A (en) * | 1983-04-20 | 1984-10-24 | Philips Electronic Associated | Display apparatus |
| GB2154053A (en) * | 1984-02-08 | 1985-08-29 | Philips Electronic Associated | High resolution channel multiplier dynodes |
| DE3660879D1 (en) * | 1985-05-28 | 1988-11-10 | Siemens Ag | Channel structure of an electron multiplier |
| GB2181319A (en) * | 1985-10-04 | 1987-04-15 | Philips Electronic Associated | Colour display apparatus |
| GB2181677B (en) * | 1985-10-21 | 1988-12-29 | Philips Electronic Associated | Method of making a colour selection deflection structure, and a colour picture display tube including a colour selection deflection structure made by the method |
| FR2608316B1 (en) * | 1986-12-12 | 1995-07-28 | Radiotechnique Compelec | SHEET TYPE ELECTRON MULTIPLIER WITH INTEGRATED DIVIDER BRIDGE |
| GB2213632A (en) * | 1987-12-11 | 1989-08-16 | Philips Electronic Associated | Flat cathode ray tube display apparatus |
| GB2215962A (en) * | 1988-03-23 | 1989-09-27 | Philips Electronic Associated | Flat crt with stepped deflection and interlace |
| US5227691A (en) * | 1989-05-24 | 1993-07-13 | Matsushita Electric Industrial Co., Ltd. | Flat tube display apparatus |
| JPH072165A (en) * | 1993-02-26 | 1995-01-06 | Nkk Corp | Ship hull structure for oil tanker |
| US6380674B1 (en) | 1998-07-01 | 2002-04-30 | Kabushiki Kaisha Toshiba | X-ray image detector |
| JP4246879B2 (en) | 2000-04-03 | 2009-04-02 | 浜松ホトニクス株式会社 | Electron and photomultiplier tubes |
| JP4108905B2 (en) * | 2000-06-19 | 2008-06-25 | 浜松ホトニクス株式会社 | Manufacturing method and structure of dynode |
| CN104269338B (en) * | 2014-09-17 | 2016-04-06 | 中国工程物理研究院激光聚变研究中心 | For variable orifice footpath microchannel plate that photoelectronic imaging and signal strengthen and preparation method thereof |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1401969A (en) * | 1971-11-17 | 1975-08-06 | Mullard Ltd | Electron multipliers |
| GB1402549A (en) * | 1971-12-23 | 1975-08-13 | Mullard Ltd | Electron multipliers |
| GB1405256A (en) * | 1972-04-20 | 1975-09-10 | Mullard Ltd | Electron multipliers |
| GB1434053A (en) * | 1973-04-06 | 1976-04-28 | Mullard Ltd | Electron multipliers |
| GB1446774A (en) * | 1973-04-19 | 1976-08-18 | Mullard Ltd | Electron beam devices incorporating electron multipliers |
| GB1431490A (en) * | 1973-06-13 | 1976-04-07 | Mullard Ltd | Electron multipliers |
| GB1523730A (en) * | 1974-12-13 | 1978-09-06 | Mullard Ltd | Secondaryemissive layers |
| GB1457213A (en) * | 1975-01-30 | 1976-12-01 | Mullard Ltd | Electron multipliers |
-
1978
- 1978-06-14 GB GB7826877A patent/GB2023332B/en not_active Expired
-
1979
- 1979-06-07 CA CA000329423A patent/CA1139821A/en not_active Expired
- 1979-06-11 DE DE7979200291T patent/DE2964009D1/en not_active Expired
- 1979-06-11 EP EP19790200291 patent/EP0006267B1/en not_active Expired
- 1979-06-14 JP JP7515779A patent/JPS5516392A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB2023332A (en) | 1979-12-28 |
| GB2023332B (en) | 1982-10-27 |
| EP0006267B1 (en) | 1982-11-10 |
| JPS6141097B2 (en) | 1986-09-12 |
| JPS5516392A (en) | 1980-02-05 |
| DE2964009D1 (en) | 1982-12-16 |
| EP0006267A1 (en) | 1980-01-09 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |