Pr-containing single crystal for scintillator, process for producing the same, radiation detector and inspection apparatus

Abstract

The present invention provides an oxide-base scintillator single crystal having an extremely large energy of light emission, adoptable to X-ray CT and radioactive ray transmission inspection apparatus, and more specifically to provide a Pr-containing, garnet-type oxide single crystal, a Pr-containing perovskite-type oxide single crystal, and a Pr-containing silicate oxide single crystal allowing detection therefrom light emission supposedly ascribable to 5d-4f transition of Pr.

Description

technical field [0001] The present invention relates to a single crystal for a scintillator containing praseodymium (Pr), a method for producing the same, a radiation detector and an inspection device using the single crystal for a scintillator. Background technique [0002] In positron radionuclide tomography (PET), since high-energy gamma rays (annihilation gamma rays: 511keV) are detected by coincidence counting, scintillation detection with high sensitivity and high-speed response has been used device. Among the characteristics of the detector, high count rate characteristics and high time resolution for eliminating random coincidence count noise are required, and excellent energy resolution is also required for eliminating scattered rays from the body. [0003] Therefore, as a scintillator suitable for a detector meeting the above requirements, it is desired to have a high density and a large atomic number (high photoelectric absorption ratio) in terms of detection eff...

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Problems solved by technology

In addition, the service life of the Ir crucible is also short, and the huge cost of recasting the crucible becomes a great burden for the manufacturer.

Also, in order to achieve this ultra-high temperature, the high-frequency oscillator must also achieve high output, thus resulting in an increase in the overall running cost

[0008] On the other hand, in Ce:GSO and Ce:LSO used as light-emitting materials for scintillators, if a large amount of Ce as a light-emitting element is contained, the amount of light emitted increases, but if it exceeds a certain %, the phenomenon of concentration quenching (concentration extinction) is obvious. , cannot present the scintillator effect

[0009] Moreover, Ce is second only to La among the rare earth ions, and must be larger than the representative rare earth ions (Y, Gd, Lu) in the parent crystal. Therefore, the effective segregation coefficient of Ce deviates greatly from 1.

That is, the compositional variation of Ce along the growth direction cannot be avoided

This phenomenon causes changes in physical parameters such as fluorescence decay time and luminescence amount, and becomes a serious problem when used in high-precision PET, etc.

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