| 摘要 |
A reference cell simulating the light amplitude spectrum of an alpha scintillation cell containing radon222. The cell includes a gas-tight container having a transparent window. The interior of the container, aside from the window, has a coating of a luminescent material. Inside of the container lies an amount of radium226. The radium radioactively decays to produce alpha particles and radon222. The radon222 and its daughter particles also undergo radioactive decay to produce further alpha particles. The 1620-year half life of the radium226 assures an adequate supply of the radon222 for a greater time period than radon's 3.825-day half life. The production rate of the alpha particles within the container increases for a period of approximately 22 years after the cell's construction. Although the radium226 generally has a nonuniform distribution in the cell, the produced radon assumes a gaseous form and uniformly diffuses throughout the entire cell. The decay products of the radon222 return to the solid state and deposit uniformly on the cell's walls. The cell may allow the alpha particles from the radium226 to contact the luminescent material and produce light. Alternately, the cell may prevent the utilization of these alpha particles by interposing a barricade between the radium and the luminescent material. Making the cell involves coating the inside of the container with luminescent material while leaving the window clear. After placing the radium226 inside, the cell undergoes permanent sealing against the ingress or egress of gaseous components.
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