US2994782A - Device for stabilizing the gain of photomultiplier tubes - Google Patents

Device for stabilizing the gain of photomultiplier tubes Download PDF

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Publication number
US2994782A
US2994782A US859531A US85953159A US2994782A US 2994782 A US2994782 A US 2994782A US 859531 A US859531 A US 859531A US 85953159 A US85953159 A US 85953159A US 2994782 A US2994782 A US 2994782A
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United States
Prior art keywords
gain
voltage
dynode
tube
stabilizing
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Expired - Lifetime
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US859531A
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English (en)
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Gouyon Arthur Marcel
Kermagoret Marcel
Pascal Andre
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/52—Circuit arrangements for protecting such amplifiers
    • H03F1/54—Circuit arrangements for protecting such amplifiers with tubes only
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J43/00—Secondary-emission tubes; Electron-multiplier tubes
    • H01J43/04—Electron multipliers
    • H01J43/30—Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for

Definitions

  • the present invention relates to photomultiplier tubes, that is to say to tubes for transforming incident photons into electrical pulses adapted to be used for measuring the number and/or the energy of these photons.
  • a photomultiplier tube comprises, inside an evacuated vessel: a photocathode emitting a bunch of electrons in response to an incident photon striking said photocathode, a series of intermediate electrodes or dynodes every dynode emitting, in response to the primary electrons coming from the preceding electrode (photocathode or dynode) that strike said first mentioned dynode, a great number of secondary electrons (multi plication effect by secondary emission), and a collecting electrode or anode which receives the electrons emitted by the last dynode and supplies the electrical pulses to be used.
  • a high voltage feed source inserted between the anode and the photocathode and of a voltage divider device also inserted between the anode and the photocathode, the respective dynodes being all fed from said voltage divider so as to be brought to potentials which increase progressively in the order in which they are disposed between the photocathode and the anode.
  • the gain of a photomultiplier tube varies very quickly as a function of the supply or feed high voltage. It is known for instance that variations of 1% of the feed high voltage produce gain variations ranging approximately from 8 to 12% and that it is difficult, in industrial applications of this apparatus, to use high voltage feed sources having a stability corresponding to maximum variations lower than 1%.
  • the object of the present invention is to achieve a stabilization of the gain of photomultiplier tubes making use of feed sources, even little stabilized (having for instance voltage variations which may be as high as through means which are simple, efiicient, unexpensive and require only an easy adjustment, which is quite necessary for industrial applications of photomultiplier tubes (measurement of X-rays intensity, counting of nuclear particles in combination with scintillators, and so on).
  • the present invention for stabilizing the gain of a photomultiplier tube including n dynodes, n being at least equal to two, located between a photocathode and an anode, said tube being fed from a high voltage source having its two terminals connected respectively to said photocathode and said anode and also from a voltage divider connected between said terminals of said source, consists in feeding only n-l dynodes in the known manner from said voltage divider and feeding the remaining dynode with a stabilizing voltage derived from said high voltage and which is an increasing linear function of said high voltage.
  • the tube capable of maintaining a constant potential dilference between its terminals is a voltage stabilizing tube of the corona eifect type and the dynode fed from the potentiometer is the fourth, fifth or sixth dynode from the photocathode.
  • FIGS. 1 to 4 show four curves representing the variations of the gain of a photomultiplier tube as a function of the feed voltage and of the voltage applied to a given dynode, these curves facilitating the explanation of the principle of stabilization of the gain according to the invention.
  • FIG. 5 is a diagram illustrating the gain stabilization of a photomultiplier tube by the method according to the invention.
  • FIG. 6 shows a photomultiplier tube cooperating with a device made according to the present invention for regulating the gain.
  • FIG. 7 shows curves of adjustment of the device of FIG. 6.
  • FIG. 1 When the feed voltage of one of the dynodes of a photomultiplier tube is modified, there is produced a gain variation shown by FIG. 1.
  • the gain G is plotted in ordinates (with a logarithmic scale) and the voltage Vd of the dynode in abscissae.
  • This figure shows that the same gain G may be obtained for two values (such as Vn-l and Vn+l) of the voltage Vd which are substantially symmetrical with respect to the normal potential V of the nth dynode.
  • FIG. 3 shows, with the same references as on FIG. 1, the variations of the gain of a photomultiplier tube due to the modification of potential of the nth dynode, resulting exclusively from the variations of the secondary emission coefi'icient; the curve in dotted lines shown on the same figure represents the gain variation that has been experimentally observed.
  • FIG. 5 shows a photomultiplier tube comprising, in an evacuated vessel 1 provided with a transparent window 1a, a photocathode 2, a series of dynodes 3 and a collecting electrode or anode 4.
  • the electrodes 2, 3 and 4 of this tube are fed from a high voltage source 5, the postitive terminal of which is connected with anode 4, the negative terminal, connected to photocathode 2, being grounded and from a voltage divider 6 (constituted by a number of resistances in series) inserted between photocathode 2 and anode 4, this voltage divider serving to the feed of dynode 3 with the exception of a single one, to wit dynode 3a.
  • this dynode 3a is fed with a voltage which is an increasing linear function of the voltage delivered by source 5.
  • a voltage which is an increasing linear function of the voltage delivered by source 5.
  • the feed voltage of dynode "3a is collected through a potentiometer 10 shunting tube 8, the two terminals of this potentiometer being connected to points 11 and 12, whereas its slider 13 is connected to dynode 3a.
  • Equation I represents the upper and lower branches of the constant gain curves.
  • V the voltage across the terminals of tube 8 between 11 and 12, a
  • V V +m-V (with m ranging from 0 to l) we have:
  • V V V R i+mV As 2 c v V,
  • (a) tube 8 so that it permits a relatively large modification of voltage for the regulated dynode, without exceeding 1,000 volts; preferably a corona efiect tube is used; we might also make use of a neon tube but there are two important drawbacks inherent in this kind of tubesz-its low regulation voltage volts) and its high consumption.
  • the voltage stabilization tube 8 is constituted by a corona effect tube and resistor 7 is divided into two portions, to wit a fixed resistor 7a and an adjustable resistor 7b (consisting for instance of a rheostat); in a likewise manner, potentiometer 10 is advantageously replaced by a series arrangement including, in addition to a potentiometer 10b, two fixed resistors 10a and 100, which makes it possible'to use a potentiometer 1% adapted for a narrower resistance band.
  • R will include resistors 7a and 7b and m is no longer variable between 0 and l, but between two values m m such as m 0 and m' 1.
  • Calculation of the values of the resistances to be used in the gain stabilizing arrangement according to the invention may be effected in the following manner.
  • the adjustment of the gain may be performed very quickly in the following manner:
  • a photomultiplier tube including a photocathode, n dynodes located behind one another after said photocathode and an anode located behind said dynodes, a high voltage source having its two terminals connected respectively to said photocathode and said anode and a voltage divider device connected between said source terminals, a device for stabilizing the gain of said photomultiplier tube which comprises conventional means for feeding n-l of said dynodes from said voltage divider and means for supplying the remaining dynode with a stabilizing voltage derived :from said high voltage and the value of which is an increasing linear function of said high voltage, said last mentioned means including a network disposed between said terminals of said high voltage source, said network comprising in series at least one first resistor, a tube capable of maintaining a constant potential difference between its terminals and at least one second resistor, at least one of said resistors being adjustable, and a potentiometer connected in shunt with said last mentioned
  • a device in which said tube maintaining a constant potential difference between its terminals is a corona efiect tube.
  • n is an integer close to ten, said remaining dynode being the fourth starting from said cathode.
  • n is an integer close to ten, said remaining dynode being the starting from said cathode.
  • n is an integer close to ten, said remaining dynode being the sixth starting from said cathode.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Measurement Of Radiation (AREA)
US859531A 1958-12-16 1959-12-14 Device for stabilizing the gain of photomultiplier tubes Expired - Lifetime US2994782A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR781754A FR1222536A (fr) 1958-12-16 1958-12-16 Nouveau mode de stabilisation du gain des photomultiplicateurs

Publications (1)

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US2994782A true US2994782A (en) 1961-08-01

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US859531A Expired - Lifetime US2994782A (en) 1958-12-16 1959-12-14 Device for stabilizing the gain of photomultiplier tubes

Country Status (7)

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US (1) US2994782A (fr)
BE (1) BE585528A (fr)
CH (1) CH362713A (fr)
FR (1) FR1222536A (fr)
GB (1) GB927757A (fr)
LU (1) LU38035A1 (fr)
NL (1) NL246387A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3197642A (en) * 1961-11-20 1965-07-27 Latronics Corp Feedback circuit for electromagnetic control of photomultiplier tube
US3243588A (en) * 1962-08-17 1966-03-29 Serge A Scherbatskoy Scintillation detector system using a white light as a standard to stabilize the system

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5453610A (en) * 1994-05-20 1995-09-26 Summit World Trade Corporation Electronic gain control for photomultiplier used in gamma camera
US5512755A (en) * 1994-05-20 1996-04-30 Summit World Trade Corp. Gamma camera device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3197642A (en) * 1961-11-20 1965-07-27 Latronics Corp Feedback circuit for electromagnetic control of photomultiplier tube
US3243588A (en) * 1962-08-17 1966-03-29 Serge A Scherbatskoy Scintillation detector system using a white light as a standard to stabilize the system

Also Published As

Publication number Publication date
NL246387A (fr)
LU38035A1 (fr)
BE585528A (fr) 1960-06-10
FR1222536A (fr) 1960-06-10
CH362713A (fr) 1962-06-30
GB927757A (en) 1963-06-06

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