Long-lived reference cell simulating the. cap alpha. scintillation of radon-222

Patent · Tue Dec 04 04:00:00 EST 1979

OSTI ID:5407429

Stevens, W M

A reference cell simulating the light amplitude spectrum of an alpha scintillation cell containing radon/sup 222/ is described. 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 radium/sup 226/. The radium radioactively decays to produce alpha particles and radon/sup 222/. The radon/sup 222/ and its daughter particles also undergo radioactive decay to produce further alpha particles. The 1620-year half life of the radium/sup 226/ assures an adequate supply of the radon/sup 222/ 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 radium/sup 226/ 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 radon/sup 222/ return to the solid state and deposit uniformly on the cell's walls. The cell may allow the alpha particles from the radium/sup 226/ 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 radium/sup 226/ inside, the cell undergoes permanent sealing against the ingress or egress of gaseous components.

• Assignee: Randam Electronics, Inc.
• Patent Number(s): US 4177378
• OSTI ID: 5407429
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
070201 -- Radiation Sources-- Design
Fabrication & Operation
655002* -- Medical Physics-- Radiation Source Calibration & Standardization
ACCURACY
ALKALINE EARTH ISOTOPES
ALPHA DECAY
ALPHA DECAY RADIOISOTOPES
ALPHA PARTICLES
CALIBRATION
CALIBRATION STANDARDS
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
DECAY
EVEN-EVEN NUCLEI
HEAVY NUCLEI
ISOTOPES
LUMINESCENCE
MEASURING INSTRUMENTS
NUCLEI
RADIATION DETECTORS
RADIOISOTOPES
RADIOLUMINESCENCE
RADIUM 226
RADIUM ISOTOPES
RADON 222
RADON ISOTOPES
SCINTILLATION COUNTERS
SCINTILLATIONS
SPECIFICATIONS
STANDARDIZATION
STANDARDS
YEARS LIVING RADIOISOTOPES