CS215428B1 - Gas-filled scintillation detector - Google Patents

Abstract

The invention relates to a gas-filled scintillation detector with an exit window covered on the outside with an optical converter layer which is in optical contact with the used photomultiplier. The optical converter layer is formed by either an inorganic or organic converter and its placement does not cause contamination of the gas filling of the detector, therefore no flushing device is required and the permanent stability of the scintillation detector is ensured.

Description

(54) Gas filling scintillation detector

The present invention relates to a gas-filled scintillation detector having an exit window coated on the outside with an optical converter layer in optical contact with the rotary multiplier used. The optical converter layer consists of either an inorganic or organic converter and its location does not contaminate the gas charge of the detector, therefore no flushing device is required and the scintillation detector is permanently stable.

215428 X

The invention relates to a gas-filled scintillation detector with an output window coated on the outside with an optical converter in optical contact with a photomultiplier.

Scintillation detectors filled with noble gas or mixtures thereof - as a working medium - are particularly suitable for the detection and spectrometry of heavy charged particles including fission products. By using suitable additives, eg ¹⁰ B, ⁶ Li, they can also be used for neutron detection.

Essentially, the gas-filled scintillation detector consists of a cylindrical body of vacuum-tight material, one base of which is an inlet window of radiation-permeable material and the other base is an outlet window of short-wave UV-radiation material. The workload consists of a rare gas or a mixture of these gases, which causes ionization of gases and excitation of atoms and ions. When excited states disappear and recombination occurs, light quantities are emitted. The emission spectrum of inert gases is composed of a set of lines and bands and extends over the wavelength range from 200 nm to 600 nm.

The maximum cathode sensitivity of commonly used photomultipliers lies in the wavelength range from 350 to 600 nm. Therefore, optical converters are used to register the noble gas emission, converting the noble gas emission into longer wavelength radiation and corresponding to the maximum sensitivity of the photocathode. The optical converters used, however, have a high vapor pressure and their layers deposited on the inside of the scintillator body contain a large amount of adsorbed and absorbed undesirable gases and vapors. This requires the use of getter or continuous flushing of the gas detection volume with the aid of complex special equipment.

These drawbacks are eliminated by the gas-filled scintillation detector according to the invention, which is based on the outer window of the detector being provided with an optical converter layer which is in optical contact with the photobaser. Scintillation detector exit window

A gas-filled scintillation detector consisting of a cylindrical body with a radiation-permeable input window and a short-wave-emitted output window, characterized in that the output window of the detector is provided on the outside with an optical converter layer consisting of either an organic converter, e.g. -phenyl, or inorganic gas-filled inorganic con215428 consisting of lithium fluoride, magnesium fluoride or calcium fluoride, is covered externally with either a layer of organic optical converter, eg p-terphenyl, p-quaterphenyl, diphenylstilbene, sodium salicilane, or a layer of an organic optical converter such as sodium, calcium, magnesium, cadmium, gallium doped gallium: and others. The optical converter layer may also be in the form of a scintillation activator dissolved in polyvinyltoluene or polystyrene, e.g. polyvinyltoluene + p-terphenyl + POPOP, which layer is in optical contact with the photomultiplier.

The gas-filled scintillation detector with an output window, equipped with both an optical and a converter from outside, shifts the short-wave emitted radiation to the maximum sensitivity of the photocathode of the photomultiplier used. Since the optical converter is located outside the working volume of the detector, there is no contamination of the gas filling of the detector and it is not necessary to use any flushing devices to ensure the proper functioning of the detector. This also ensures the permanent stability of the gas-filled scintillation detector. The optical converter layer applied from the outside to the exit window of the gas-filled scintillation detector also allows easy optical connection with the photomultiplier used.

Claims (2)

The present invention has been verified on a specific embodiment of a gas-filled scintillation detector with an exit window provided with an optical converter layer on the outside. The detector body consisted of a glass cylinder with a diameter of 25 mm, the entrance window of the detector was of mica and the exit window of the detector of lithium fluoride with a thickness of 2 mm. A p-quaterphenyl layer having a basis weight of 1 gm ^-2 was applied from the outside of the exit window to form an optical converter. The scintillation detector with gas filling was long pumped to a pressure of 10 ^-4 Pa, and was filled with xenon at a pressure of 100 kPa and a deposition rate of pumping and filling apparatus. ! INVENTION! a vertor, e.g. sodium tungstate, which is: in optical contact with the photomultiplier used. 2. Gas-filled scintillation detector according to claim 1, characterized in that the optical converter layer consists of a scintillation activator dissolved in polyvinyltoluene or polystyrene, eg polyvinyltoluene + p-terphenyl + POPOP, and is in optical contact with the photomultiplier used.