Radiation monitor

Patent metadata

Field	Value
Publication number	US-10908301-B2
Application number	US-201916415052-A
Country	US
Kind code	B2
Filing date	May 17, 2019
Priority date	Aug 21, 2018
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

A radiation monitor according to the present invention includes: a radiation sensing unit which includes phosphors emitting a photon with respect to an incident radiation; and a photon sending unit which sends the photon emitted from the phosphors of the radiation sensing unit, wherein the phosphors form a multilayer structure including a first phosphor and a second phosphor, and a photon absorbing layer absorbing a photon emitted from a phosphor is provided between the first phosphor and the second phosphor.

First claim

What is claimed is:

1. A radiation monitor comprising:
a plurality of radiation sensing units which includes phosphors emitting photons in response to an incident radiation; and
a plurality of photon sending units which sends the photons emitted from the phosphors of the radiation sensing unit;
an optical filter which attenuates a number of photons sent from the photon sending units;
a photodetector which converts the photons sent from the optical filter into an electric pulse signal; and
a light selection unit which is controlled to select any one of light sent from a first optical fiber and light sent from a second optical fiber as light to be acquired by the photodetector to be converted into an electric pulse signal,
wherein the phosphors form a multilayer structure including a first phosphor and a second phosphor, and a photon absorbing layer absorbing a photon emitted from the phosphor is provided between the first phosphor and the second phosphor,
wherein the optical filter is connected to the photon sending unit and the photodetector,
wherein radiation dose rates at a plurality of different positions are measured, and
wherein the optical filter is connected to the light selection unit and the photodetector.

2. The radiation monitor according to claim 1 , wherein
the first phosphor and the second phosphor form a nested structure.

3. The radiation monitor according to claim 2 , wherein
the phosphors each have a cylindrical shape.

4. The radiation monitor according to claim 2 , wherein
the phosphors each have a prism shape.

5. The radiation monitor according to claim 2 , wherein
the phosphors each have a hemispherical shape.

6. The radiation monitor according to claim 2 , wherein
a transmittance of the first phosphor and a transmittance of the second phosphor are different from each other.

7. The radiation monitor according to claim 2 , wherein
a density of the first phosphor and a density of the second phosphor are different from each other.

8. The radiation monitor according to claim 1 , further comprising:
a plurality of optical filters, including a first optical filter and a second optical filter,
wherein the optical filter is connected to the first optical fiber and the light selection unit, and
wherein the second optical filter is connected to the second optical fiber and the light selection unit.

9. A radiation monitor comprising:
a plurality of radiation sensing units which includes phosphors emitting photons in response to an incident radiation; and
a plurality of photon sending units which sends the photons emitted from the phosphors of the radiation sensing unit;
an optical filter which attenuates a number of photons sent from the photon sending units;
a photodetector which converts the photons sent from the optical filter into an electric pulse signal; and
a light selection unit which is controlled to select any one of light sent from a first optical fiber and light sent from a second optical fiber as light to be acquired by the photodetector to be converted into an electric pulse signal;
wherein the phosphors form a nested structure including a first phosphor and a second phosphor, and a transmittance of the first phosphor and a transmittance of the second phosphor are different from each other;
wherein the optical filter is connected to the photon sending unit and the photodetector,
wherein radiation dose rates at a plurality of different positions are measured, and
wherein the optical filter is connected to the light selection unit and the photodetector.

Assignees

• Hitachi Ltd

Inventors

• Hatakeyama Shuichi
• Tadokoro Takahiro
• Ueno Yuichiro
• Nagumo Yasushi
• Ueno Katsunori
• Okada Kouichi

Classifications

• G01T1/2006 Primary

  using a combination of a scintillator and photodetector which measures the means radiation intensity · CPC title

• G01T1/023 Primary

  Scintillation dose-rate meters · CPC title

• G01T1/2008

  using a combination of different types of scintillation detectors, e.g. phoswich · CPC title