EP0908917A2 - Revêtement à émission secondaire pour tube photomultiplicateur - Google Patents

Revêtement à émission secondaire pour tube photomultiplicateur Download PDF

Info

Publication number
EP0908917A2
EP0908917A2 EP98308254A EP98308254A EP0908917A2 EP 0908917 A2 EP0908917 A2 EP 0908917A2 EP 98308254 A EP98308254 A EP 98308254A EP 98308254 A EP98308254 A EP 98308254A EP 0908917 A2 EP0908917 A2 EP 0908917A2
Authority
EP
European Patent Office
Prior art keywords
substrate
secondary electron
diamond
diamond film
dynode
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.)
Granted
Application number
EP98308254A
Other languages
German (de)
English (en)
Other versions
EP0908917B1 (fr
EP0908917A3 (fr
Inventor
Robert Caracciolo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Burle Technologies Inc
Original Assignee
Burle Technologies Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Burle Technologies Inc filed Critical Burle Technologies Inc
Publication of EP0908917A2 publication Critical patent/EP0908917A2/fr
Publication of EP0908917A3 publication Critical patent/EP0908917A3/fr
Application granted granted Critical
Publication of EP0908917B1 publication Critical patent/EP0908917B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • H01J43/10—Dynodes
    • 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
    • H01J1/02—Main electrodes
    • H01J1/32—Secondary-electron-emitting electrodes

Definitions

  • This invention deals generally with electron discharge devices, and more specifically with a secondary electron emitting surface constructed with diamond film and used in photomultiplier tubes.
  • Photomultiplier tubes have become commonly used for detecting low radiation levels.
  • Typical such tubes consist of a glass envelope with an electron emitting photocathode located on the inside surface of a faceplate on the envelope. When radiation strikes the photocathode, electrons emitted from it are directed toward and collected by an electron multiplier.
  • the electron multiplier consists of several dynodes with secondary electron emitting surfaces, with the first dynode receiving the electrons from the photocathode.
  • the electron multiplier has an electrical output which is directly related to the quantity of electrons collected by the first dynode, and increasing the ratio of the quantity of electrons at the output of the electron multiplier to the quantity of the electrons received by the first dynode is a continuing design goal. This ratio is largely determined by the gain of the individual dynodes, expressed in a simple number ratio, which indicates the number of secondary electrons emitted for every electron striking the dynode secondary emitter surfaces.
  • gallium phosphide requires special thermal activation in a vacuum during tube processing and it also requires the use of hazardous gases during its processing.
  • the present invention furnishes a modified diamond layer, a diamond layer with p-doping, applied to a standard substrate, preferably of molybdenum, for use as a secondary emitter in photomultiplier tube dynodes.
  • the diamond layer is p-doped with boron.
  • the p-doped diamond layer provide higher gain, but a substantial additional advantage of such a p-doped diamond secondary emitter layer is that it has lower hysteresis and greater pulse rate stability than prior art secondary emitters, even the undoped diamond emitters.
  • the p-doped diamond film of the invention can also be placed on the substrate before being put into the tube.
  • antimony in-situ Such antimony coating are applied from special sources installed in the tube which are activated while the tubes are being processed on the exhaust system. This method results in high secondary emission in the first dynode position, but since the antimony is evaporated in-situ, it is not uniform and hence can have a negative effect on pulse height resolution and sensitivity to external magnetic fields.
  • Gallium phosphide dynodes which also provide exceptionally high secondary emission, require a hazardous fabrication process and require thermal activation during the exhaust process. Diamond deposition is not a hazardous process, and the dynodes do not require any special activation process.
  • the invention thereby provides a secondary electron emitter surface for use in photomultiplier tubes with a gain equivalent to or greater than the prior art devices and with superior stability, but the surface is easier and less hazardous to manufacture.
  • the high secondary emission p-doped diamond layer dynode of the present invention can be used in various applications.
  • tubes are designed with large, high collection and high gain dynodes at the front end of the tubes. This lends itself to improved pulse height resolution, an important parameter for scintillation detection.
  • P-doped diamond coated dynodes are uniform over large areas with secondary emission, and that satisfies such design criteria.
  • the applications for p-doped diamond coated dynodes can also be extended to latter stages of the electron multiplier.
  • the higher gain of the dynode results in a lower number of dynodes required to achieve the desired tube gain.
  • Electron multipliers with fewer stages require less physical space, leading to more compact and less massive imaging systems, a benefit in both medical imaging technology and photon counting applications.
  • the invention also provides a complete photomultiplier tube as well as a method for its manufacture as defined in the annexed claims.
  • FIGURE is a simplified drawing of the preferred embodiment of the secondary emitting surface of the invention.
  • the FIGURE is a drawing of the very simple preferred embodiment of the invention in which secondary emitter 10 is formed only from p-doped diamond film 12 coated by chemical vapor deposition upon base substrate 14.
  • Alkali metal layer 16 is then conventionally produced upon p-doped diamond film 12 during the generation of the photocathode within the tube.
  • the alkali metal layer may be caesium, potassium, sodium, or rubidium for example. This layer may be produced after assembly of the photomultiplier tube or other devices in which the invention is used. In this case, the device is assembled with untreated diamond dynode surfaces.
  • the device enclosed in a glass or metal envelope is evacuated, and any of the above mentioned alkali is introduced in its metallic form at a temperature, 150°C to 250°C, where the metals exist as a vapour.
  • the alkali metals deposit on the dynode surfaces yielding an activated diamond surface with high secondary emission. It should be recognised that even at higher temperatures, alkali metal will still be present on the dynode surface, maintaining its activation.
  • Base substrate 14 is selected from materials that promote the growth of tetrahedrally coordinated or sp3 carbon, such as refractory metals (e.g. molybdenum, tungsten, tantalum) or other carbide formers. These materials react with carbon to form carbides. These carbides have a molecular structure or chemical bonding geometry similar to that of diamond, and so the formation of such a carbide at the substrate surface promotes the growth of diamond. In addition, the thermal expansion of, for example, molybdenum is close to that of diamond, minimising interfacial stresses that might cause the diamond to separate from the substrate.
  • refractory metals e.g. molybdenum, tungsten, tantalum
  • Conventional substrate 14 is typically .005 inch thick and p-doped diamond film 12 is 1-10 microns thick.
  • P-doped diamond or diamond-like-carbon film 12 is typically applied to base substrate 14 by chemical vapor deposition or plasma deposition processes.
  • the microstructure of the film is polycrystalline, exposing facets of a preferred crystallographic plane.
  • the p-dopant is typically boron, and the dopant level is such that the modified resistivity of the diamond film is in the range between 600 and 1600 ohm/square.
  • the diamond is grown from the gas phase using a hydrocarbon such as butane, and the gas BH 3 is simultaneously admitted to the growth chamber in the appropriate amount so as to generate the desired doping level.
  • a hydrocarbon such as butane
  • Secondary emitter 10 of the FIGURE can be completely prepared and processed outside the tube in which it will be used after substrate 14 is first shaped into the appropriate dynode surface, and then, after the dynode is installed within a tube, tube processing can proceed as usual.
  • secondary emitter 10 of the preferred embodiment of the invention When tested as a photomultiplier dynode, secondary emitter 10 of the preferred embodiment of the invention demonstrated that its gain is almost linear with incident beam energy, with gains of 29 at 600 volts and 48 at 1000 volts. Such a high first dynode gain results in improved pulse height resolution in tubes used for medical imaging applications.
  • p-dopants may be sued instead of boron, and, of course, other materials may be used for the substrate.

Landscapes

  • Crystals, And After-Treatments Of Crystals (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
EP98308254A 1997-10-10 1998-10-09 Revêtement à émission secondaire pour tube photomultiplicateur Expired - Lifetime EP0908917B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US94749797A 1997-10-10 1997-10-10
US947497 1997-10-10

Publications (3)

Publication Number Publication Date
EP0908917A2 true EP0908917A2 (fr) 1999-04-14
EP0908917A3 EP0908917A3 (fr) 2000-03-22
EP0908917B1 EP0908917B1 (fr) 2005-04-20

Family

ID=25486238

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98308254A Expired - Lifetime EP0908917B1 (fr) 1997-10-10 1998-10-09 Revêtement à émission secondaire pour tube photomultiplicateur

Country Status (2)

Country Link
EP (1) EP0908917B1 (fr)
DE (1) DE69829816T2 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005006734A1 (fr) * 2003-07-09 2005-01-20 Council For The Central Laboratory Of The Research Councils Dispositif de generation d'image faisant appel a un multiplicateur d'electrons a grande surface
EP1400293A3 (fr) * 2002-07-16 2006-04-12 Seco Tools Ab Outil de coupe revêtu par dépôt en phase gazeuse par procédé physique
WO2011157810A1 (fr) * 2010-06-18 2011-12-22 Photonis France Detecteur a multiplicateur d'electrons forme d'une couche de nanodiamant hautement dope
FR2964785A1 (fr) * 2010-09-13 2012-03-16 Photonis France Dispositif multiplicateur d'électrons a couche de nanodiamant.
WO2020227785A1 (fr) * 2019-05-16 2020-11-19 Adaptas Solutions Pty Ltd Dynode à mode de réflexion améliorée

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69030145T2 (de) * 1989-08-18 1997-07-10 Galileo Electro Optics Corp Kontinuierliche Dünnschicht-Dynoden
US5619091A (en) * 1994-10-03 1997-04-08 Universities Research Association, Inc. Diamond films treated with alkali-halides
US5886465A (en) * 1996-09-26 1999-03-23 Hamamatsu Photonics K.K. Photomultiplier tube with multi-layer anode and final stage dynode

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1400293A3 (fr) * 2002-07-16 2006-04-12 Seco Tools Ab Outil de coupe revêtu par dépôt en phase gazeuse par procédé physique
WO2005006734A1 (fr) * 2003-07-09 2005-01-20 Council For The Central Laboratory Of The Research Councils Dispositif de generation d'image faisant appel a un multiplicateur d'electrons a grande surface
WO2011157810A1 (fr) * 2010-06-18 2011-12-22 Photonis France Detecteur a multiplicateur d'electrons forme d'une couche de nanodiamant hautement dope
FR2961628A1 (fr) * 2010-06-18 2011-12-23 Photonis France Détecteur a multiplicateur d'électrons forme d'une couche de nanodiamant hautement dope.
US9035540B2 (en) 2010-06-18 2015-05-19 Photonis France Electron multiplier detector formed from a highly doped nanodiamond layer
FR2964785A1 (fr) * 2010-09-13 2012-03-16 Photonis France Dispositif multiplicateur d'électrons a couche de nanodiamant.
WO2012034948A1 (fr) * 2010-09-13 2012-03-22 Photonis France Dispositif multiplicateur d'électrons a couche de nanodiamant
US8912526B2 (en) 2010-09-13 2014-12-16 Photonis France Electron multiplier device having a nanodiamond layer
WO2020227785A1 (fr) * 2019-05-16 2020-11-19 Adaptas Solutions Pty Ltd Dynode à mode de réflexion améliorée
CN114072893A (zh) * 2019-05-16 2022-02-18 艾德特斯解决方案有限公司 改进的反射模式倍增极
US12198915B2 (en) 2019-05-16 2025-01-14 Adaptas Solutions Pty Ltd Reflection mode dynode

Also Published As

Publication number Publication date
DE69829816T2 (de) 2006-01-26
DE69829816D1 (de) 2005-05-25
EP0908917B1 (fr) 2005-04-20
EP0908917A3 (fr) 2000-03-22

Similar Documents

Publication Publication Date Title
US5680008A (en) Compact low-noise dynodes incorporating semiconductor secondary electron emitting materials
US8686733B2 (en) Ionization gauge having electron multiplier cold emission source
KR101907223B1 (ko) 나노 다이아몬드층을 가지는 전자 증배기 장치
US6566884B2 (en) Ionization vacuum pressure gauge
Plumlee et al. Mass Spectrometric Study of Solids I. Preliminary Study of Sublimation Characteristics of Oxide Cathode Materials
US8410433B2 (en) Mass spectrometer
EP0908917B1 (fr) Revêtement à émission secondaire pour tube photomultiplicateur
EP1260616A1 (fr) Film mince en diamant polycristallin, photocathode et tube electronique l'utilisant
US6670752B2 (en) Cathode for emitting photoelectron or secondary electron, photomultiplier tube, and electron-multiplier tube
US5619091A (en) Diamond films treated with alkali-halides
JPH0244639A (ja) 光電子増倍管の製造方法
US12198915B2 (en) Reflection mode dynode
US4407857A (en) Method for processing a lithium-sodium-antimony photocathode
US11901169B2 (en) Barrier coatings
US20240136139A1 (en) A uv sensitive photocathode, a method for producing a uv sensitive photocathode, and a detector for measuring uv radiation
JPH11120899A (ja) 二次電子放出装置及びそれを用いた電子管
Mackie et al. Emission and processing requirements for carbide films on Mo field emitters
GB2040553A (en) Dynode
Anderson et al. Diamond films treated with alkali-halides
Testerman et al. Cold Electron Sources for Mass Spectrometric Applications
HK40065143A (en) Improved reflection mode dynode
Vroom et al. Cross sections for charge transfer between mercury ions and other metals
Koryukin Change in the properties of the electrodes of thermionic single-element EGC at the initial stage of operation
Warshawsky Classified abstracts 6094-6102
McWane et al. 530. He* afterpulses in photomultipliers: their effect on atomic and molecular lifetime determinations.(USA)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

17P Request for examination filed

Effective date: 20000728

AKX Designation fees paid

Free format text: DE FR GB

17Q First examination report despatched

Effective date: 20020626

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 69829816

Country of ref document: DE

Date of ref document: 20050525

Kind code of ref document: P

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

ET Fr: translation filed
26N No opposition filed

Effective date: 20060123

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 18

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 19

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20171025

Year of fee payment: 20

Ref country code: DE

Payment date: 20171027

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20171027

Year of fee payment: 20

REG Reference to a national code

Ref country code: DE

Ref legal event code: R071

Ref document number: 69829816

Country of ref document: DE

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20

Expiry date: 20181008

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20181008