RU2046446C1 - Photoelectric multiplier - Google Patents

Abstract

FIELD: nuclear physics. SUBSTANCE: photoelectric multiplier has case with optical input window houses dynode system composed of dynodes with circular arrangement. Photocathode is made transparent with conducting plates and is applied on to inner surface of optical input window. Two focusing electrodes are placed along photocathode. Last dynode is produced with at least two electrically insulated sections having independent leads-out. EFFECT: facilitated manufacture, improved operational characteristics. 1 dwg

Description

 The invention relates to nuclear physics and high energy physics, in particular to photomultiplier tubes (PMTs).

 Known photomultiplier tube for working with plate scintillators of PMT 50 (Katznelson BV Kalugin AM Larionov AS Electrovacuum electronic and ionic devices. Handbook. M. Energy, 1976, S. 386), [1] PMT 50 consists of a cylindrical body with an entrance window, on the inner surface of which a translucent photocathode is applied; two focusing electrodes placed along the photocathode; dynode system with trough dinodes and anode.

 The known design is single-channel, i.e. the device does not allow determining the place of formation of the light flash along the photocathode. The large diameter of the PMT 50 flask and the relatively low temporal characteristics create great difficulties for using the PMT in a number of problems.

 A known design of a photomultiplier tube, selected as a prototype, consisting of a cylindrical body with a side optical input window; massive photocathode. deposited on a metal electrode; of a dynode system with a circular arrangement of dynodes and a reflex anode [2] The circular arrangement of dynodes is the most rational for working with plate scintillators.

 Known design is single-channel. The disadvantages include the reduced detection efficiency of scintillation radiation due to the lack of optical contact between the scintillator and the photocathode. The device has a small optical input window, which also limits its use for recording scintillation radiation.

 The essence of the invention lies in the fact that in the known design of the PMT, comprising a housing with a lateral optical input window, inside of which there is a dynode system consisting of dynodes with a circular arrangement, the last dynode is made of at least two electrically isolated sections with independent terminals. A translucent photocathode and conductive plates are applied to the inner surface of the optical window. Two focusing electrodes are placed along the photocathode.

 The execution of the last dynode of a circular dynode system from several electrically isolated sections having independent outputs for signal collection allows one to determine the particle passage. The application of a translucent photocathode with conductive plates to the inner surface of the optical window and the placement of two focusing electrodes along the photocathode increase the efficiency of scintillation radiation registration.

 The claimed technical solution allows to obtain a multichannel (the number of channels is equal to the number of isolated sections of the last dynode) photoelectronic multiplier with high detection efficiency.

 The drawing shows the design of the proposed device.

 The multi-channel photoelectronic multiplier contains a glass cylindrical housing 1, an optical input window 2, on the inner surface of which a translucent photocathode 3 and conductive plates 4 are applied. Focusing electrodes 5 are placed along the photocathode. Nine dynodes 6-14 with a circular arrangement are oriented along the axis of the housing. Moreover, the first dynode is located directly under the optical input window 2. Sectional tenth dynode 15. Reflex anode 16.

 Multichannel photoelectric multiplier works as follows. A charged particle or γ-ray, falling into the scintillator, excites electrons, accompanied by their radiative transitions to the normal state. Light flashes passing into the input optical window 2 and falling into the translucent photocathode 3 knock the photoelectrons into vacuum. The photoelectrons are focused by electrodes 5 to the first dynode 6. When they hit the first dynode, they knock out secondary electrons, which are then sequentially multiplied by subsequent dynodes. The voltage at the PMT dynodes is applied in such a way that an electric field is created between each pair of dynodes, accelerating the electrons from the previous dynode to the next and sufficient for multiplication. Ultimately, an electron avalanche falls on one of the sections of the dynode 15, multiplies and falls on the common reflex anode 16. The known location of the section relative to the scintillator allows you to determine the passage of the particle.

Claims (1)

 A photoelectronic multiplier comprising a housing with a lateral optical window, inside of which there is a photocathode and a dynode system, consisting of circularly arranged dynodes, characterized in that two focusing electrodes and conductive plates are additionally introduced into it, the photocathode is made translucent and deposited on the inner surface of the optical window bounded by conductive plates, two focusing electrodes are placed along the photocathode, and the last dynode is made of at least two electrically isolated bath sections with independent conclusions.

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