# US 8,785,875 B2 · Positron annihilation characteristics measurement system and method for measuring positron annihilation characteristics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,875 B2 - Document ID: US8785875B2 - Status: Granted - Kind: B2 - Application number: 13/302,496 - Filed: 2011-11-22 - Published: 2012-06-21 - Granted: 2014-07-22 - Earliest claimed: 2010-11-24 - Assignees: National Institute of Advanced Industrial Science and Technology; Toyo Seiko Co., Ltd. - Applicants: Masato Yamawaki; Yoshinori Kobayashi; Yoshihiro Watanabe; Kanehisa Hattori - Inventors: Masato Yamawaki; Yoshinori Kobayashi; Yoshihiro Watanabe; Kanehisa Hattori - Web page: https://patentgrep.com/patent/US8785875B2 ## CPC - G01T 1/2985: {In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); (using external radiation sources A61B6/02)} - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) ## Abstract A positron annihilation characteristics measurement system 10 comprises a positron source; radiation detection means 14 for detecting radiation emitted when a positron generated by the positron source is annihilated; and a positron detector 40 that detects a positron that is not injected into a measured sample S after being generated by the positron source. The positron source is disposed between the measured sample S and the positron detector. An arithmetic device 50 calculates the annihilation characteristics of the positron in the measured sample S after eliminating the radiation that is detected by the radiation detection means 14 and is expected to be emitted when the positron detected by the positron detector 40 is annihilated. ## Claims ### Claim 1 A positron annihilation characteristics measurement system for measuring annihilation characteristics of a positron that is injected into a measured sample and is annihilated in the measured sample, the system comprising: a positron source disposed at a position where the positron source is close to or adhered to a surface of the measured sample; a first radiation detector that detects radiation emitted when the positron generated by the positron source is annihilated; a positron detector that detects a positron that is not injected into the measured sample after being generated by the positron source; and an arithmetic device that calculates annihilation characteristics of the positron in the measured sample based on a detection result obtained by the first radiation detector and a detection result obtained by the positron detector, wherein the positron source is disposed between the measured sample and the positron detector, and the arithmetic device calculates the annihilation characteristics of the positron in the measured sample after eliminating a radiation that is detected by the first radiation detector and is expected to be emitted when the positron detected by the positron detector is annihilated. ### Claim 2 (depends on 1) The positron annihilation characteristics measurement system according to claim 1, further comprising a second radiation detector that detects a radiation emitted when the positron is generated by the positron source, wherein the arithmetic device calculates the annihilation characteristics based on a lifetime of the positron obtained from a time difference between a time point at which the second radiation detector detects a radiation and a time point at which the first radiation detector detects the radiation, and the arithmetic device calculates the annihilation characteristics of the positron in the measured sample after eliminating a radiation that is detected by the second radiation detector and is expected to be emitted when the positron detected by the positron detector is generated. ### Claim 3 (depends on 2) The positron annihilation characteristics measurement system according to claim 2, wherein the positron detector includes: a scintillator that emits scintillation light when struck by the positron; an optical sensor that detects the scintillation light emitted by the scintillator; and a light tight cover that restricts injection of light other than the scintillation light into the optical sensor. ### Claim 4 (depends on 3) The positron annihilation characteristics measurement system according to claim 3, wherein the positron source is a sheet coated with a positron emitting nuclide, the sheet being disposed so as to be adhered to the surface of the measured sample, and the light tight cover is adhered to the surface of the measured sample and covers the scintillator, the optical sensor, and the positron source. ### Claim 5 (depends on 1) The positron annihilation characteristics measurement system according to claim 1, wherein the first radiation detector measures energy of gamma ray produced when the positron is annihilated, and the arithmetic device calculates the annihilation characteristics of the positron in the measured sample from a distribution of energy spectrum of the gamma ray obtained from the detection result obtained by the first radiation detector. ### Claim 6 A positron annihilation characteristics measurement method for measuring annihilation characteristics of a positron that is injected into a measured sample and is annihilated in the measured sample, comprising: a step of disposing a positron source at a position where the positron source is close to or adhered to a surface of the measured sample, and disposing a positron detector in such manner that the positron source is placed between the measured sample and the positron detector; a detection step of detecting, by radiation detecting means, a radiation emitted when the positron generated by the positron source is annihilated, alter the positron source and the positron detector are disposed relative to the measured sample, and detecting, by the positron detector, the positron that is not injected into the measured sample after being generated by the positron source; and a calculation step of calculating annihilation characteristics of the positron in the measured sample based on a detection result obtained by the radiation detection means and a detection result obtained by the positron detector in the detection step, wherein the calculation step calculates the annihilation characteristics of the positron in the measured sample after eliminating radiation that is detected by the radiation detection means and is expected to be emitted when the positron detected by the positron detector is annihilated.