US2216282A - Secondary electron amplifier - Google Patents
Secondary electron amplifier Download PDFInfo
- Publication number
- US2216282A US2216282A US124936A US12493637A US2216282A US 2216282 A US2216282 A US 2216282A US 124936 A US124936 A US 124936A US 12493637 A US12493637 A US 12493637A US 2216282 A US2216282 A US 2216282A
- Authority
- US
- United States
- Prior art keywords
- electrodes
- electrode
- electrons
- emitting
- amplifier
- 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 - Lifetime
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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
- H01J43/20—Dynodes consisting of sheet material, e.g. plane, bent
Definitions
- the invention relates to amplifier tubes in which the emission'of secondary electrons from anode surfaces is used for amplification, These tubes usually operate in the, mannerthat electrons of a certain velocity liberate secondaries from an electrode. These liberated electrons im pact a second secondary-emitting electrode, and these secondaries impact a third secondaryemitting electrode, and so forth.
- Electrodes then have the shape of plane circular rings or truncated cones of increasing diameters, instead of the usual electrodes which have the same area in all stages.
- auxiliary electrodes for instance, grids or other permeable electrodes, are incorporated, and the distances between these auxiliary electrodes and the emitting electrodes is chosen in such a manner that in spite of a large field strength in front of the emitting electrode, the primary electrons 40 still impact the secondary emitting electrode.
- Figure 1 shows an amplifier with secondary emission according to the invention.
- Figures 2 and 3 show another example of a multi-stage amplifier.
- Figure 4 shows an amplifier tube with secondary emission with a magnetic field according to the invention.
- FIG. 5 shows another embodiment.
- vacuum receptacle l5 contains the thermionic cathode [6 for emitting primary electrons which are varied in number by the control grid IT.
- the primaries impact the cone-shaped 55 first secondary-emitting electrode l8, and liberate secondary electrons which leave the cone 3 substantially perpendicularly to the axis of the cone, and impact the second secondary-emitting electrode IS.
- the latter has the shape of a truncated cone, whereby its inside surface is impacted by electrons, so that further secondary electrons are liberated. These are accelerated in the direction of the third electrode 29, also having the shape of a truncated cone, and impact the outer wall of this electrode.
- the electrodes 2!, 22 and 23 are similar to the electrodes i9 and 2t, and fulfill the same functions.
- and 23 complement each other to form two concentric cones.
- the cloud of secondary electrons swings in the space between these two cones, and is finally collected by the collecting anode 24. It may be seen from Figure 1 that the area of the secondary-emitting surfaces increases from stage to stage, whereby space 2% charge and stress of the emitting electrodes is lower than in any previously known arrangements.
- the voltages applied to the emitting electrodes are chosen in such a manner that the gain of secondary electrons is as large as possible in every stage of the amplifier.
- the electrode I 8 is, for instance, given a positive voltage of 450 volts with respect to the cathode; the electrode I9, 900 volts; the electrode 20, 1350 volts; the electrode 2
- the auxiliary electrodes I, 8, 9, l0 and M if incorporated in the tube to insure drawing of the secondaries away from the emitting surface, are, for instance, given the potential of the next following emitting electrode and may be directly connected with the latter.
- the electrodes consist of concentric flat cylindrical rings.
- the first emitting electrode l is given the shape of a round plate.
- Secondary-emitting electrodes 2, 3, 4, 5 and B have the shape of a fiat cylindrical ring, so that the areas of the electrodes increase proportionally to the radius with increasing number of stages.
- the collecting anode 24 is given the shape of a cylinder.
- the invention is not limited to amplification by means of secondary emission with electrostatic fields. Devices in which the paths of the secondary electrons are controlled by means of magnetic deflection fields are also within the scope of the invention.
- the cylindrical metal receptacle has welded or soldered to the middle of the bottom of it a vertical metal pin 26; a direct current source 21 is connected between the end of this metal pin 26 and the upper end of the metal receptacle 25, so that a magnetic field may be formed in the receptacle and its axis, the magnetic lines of force filling out the entire interior of the receptacle in the form of complete circles. It is naturally possible to substitute a coil of suitable shape for this metal receptacle, in order to decrease the direct current required in the arrangement.
- receptacle 25 may be either directly placed into a vacuum receptacle, or a vacuum receptacle 38 may be arranged in the interior of the metal vessel.
- this vacuum vessel there are concentric fiat cylindrical plates 29, 30 and 3i as secondary emitting electrodes, an electron source, as for example a thermionic or photo-cathode 32, and the accelerating electrodes 33, 34 and 35.
- an electron source as for example a thermionic or photo-cathode 32
- the accelerating electrodes 33, 34 and 35 The combination of the magnetic field and the electrostatic field between the electrodes causes semi-circular paths of the primary electrons on which they travel to the following secondary emitting electrode.
- the electron paths will have a greater radius as they come nearer to the outside of the receptacle, and the width of the individual fiat circular rings will be accordingly increased, in order to insure that the primary electrons of one ring impact the following secondary-emitting electrode.
- the electrodes have a semi-circular shape, and are placed in a semi-circular vacuum vessel 36.
- the magnetic field is generated by a U-shaped magnet 31 in the front of the poles of which the vacuum vessel is arranged.
- the magnetic field has an approximately semi-circular shape within the range of the vacuum vessel, so that the electrons may have arch-shaped paths.
- An electron multiplier comprising a source of primary electrons, a series of secondary-emissive truncated cone-shaped electrodes of increasing mean diameter supported concentrically about a common axis with the inner surfaces of alternate truncated cone-shaped electrodes exposed to electron bombardment by electrons from the outer surfaces of electrodes intermediate said alternate electrodes, a secondary-emissive coneshaped electrode supported at a point on said axis and responsive to electrons from said primary source for bombarding the first of said truncated cone-shaped electrodes in the series with secondary electrons, and a collector electrode for collecting electrons from the last of said truncated cone-shaped electrode in said series.
- An electron multiplier comprising an envelope having therein a plurality of secondaryemissive electrodes of truncated cone shape, each of said electrodes having a mean diameter greater than that of the preceding electrode in the series, the inner surfaces of alternate ones of said electrodes being exposed to bombardment by electrons from the outer surfaces of those of said electrodes intermediate said alternate electrodes.
- An electron multiplier comprising an envelope having therein a plurality of secondaryemissive electrodes of truncated cone shape, each of said electrodes having an area greater than that of the preceding electrode in the series, the inner surfaces of alternate ones of said electrodes being exposed to bombardment by electrons from the outer surfaces of those of said electrodes intermediate said alternate electrodes.
- An electron multiplier comprising an envelope having therein a plurality of secondaryemissive electrodes of annular shape, each of said electrodes having an area greater than that of the preceding electrode in the series, the inner surfaces of alternate ones of said electrodes being exposed to bombardment by electrons from the outer surfaces of those of said electrodes intermediate said alternate electrodes.
Landscapes
- Electron Tubes For Measurement (AREA)
- Physical Vapour Deposition (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE490229X | 1936-02-10 |
Publications (1)
Publication Number | Publication Date |
---|---|
US2216282A true US2216282A (en) | 1940-10-01 |
Family
ID=6544082
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US124936A Expired - Lifetime US2216282A (en) | 1936-02-10 | 1937-02-09 | Secondary electron amplifier |
Country Status (4)
Country | Link |
---|---|
US (1) | US2216282A (fi) |
FR (1) | FR817566A (fi) |
GB (1) | GB490229A (fi) |
NL (1) | NL47938C (fi) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3506868A (en) * | 1967-05-22 | 1970-04-14 | Bendix Corp | Positive-type electron multiplier channels connected in series |
US4143291A (en) * | 1976-04-22 | 1979-03-06 | S.R.C. Laboratories, Inc. | Dynode for a photomultiplier tube |
US4184098A (en) * | 1976-04-22 | 1980-01-15 | S.R.C. Laboratories, Inc. | Cone type dynode for photomultiplier tube |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE750071C (de) * | 1939-06-21 | 1944-12-12 | Verfahren zur Herstellung von Elektronenvervielfachern mit Elektroden verschiedenen Sekundaeremissionsgrades |
-
0
- NL NL47938D patent/NL47938C/xx active
-
1937
- 1937-02-09 US US124936A patent/US2216282A/en not_active Expired - Lifetime
- 1937-02-10 GB GB4030/37A patent/GB490229A/en not_active Expired
- 1937-02-10 FR FR817566D patent/FR817566A/fr not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3506868A (en) * | 1967-05-22 | 1970-04-14 | Bendix Corp | Positive-type electron multiplier channels connected in series |
US4143291A (en) * | 1976-04-22 | 1979-03-06 | S.R.C. Laboratories, Inc. | Dynode for a photomultiplier tube |
US4184098A (en) * | 1976-04-22 | 1980-01-15 | S.R.C. Laboratories, Inc. | Cone type dynode for photomultiplier tube |
Also Published As
Publication number | Publication date |
---|---|
GB490229A (en) | 1938-08-10 |
FR817566A (fr) | 1937-09-06 |
NL47938C (fi) |
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