Mixed Gamma Standard
Mixed Gamma Standard (Basic 8-isotope mixture) Advantages
The Mixed Gamma Standard contains carefully selected radionuclides for minimum spectral interference.
The use of multiple gamma-ray-emitting radionuclides with simple spectra (single or at most twin gamma-ray emissions) allows the activities of each component to be adjusted to give approximately equal counting statistics across the entire energy range. The result is that all regions of the energy-versus-efficiency curve will have equal precision.
This mixture minimizes coincident summing effects, which is particularly important when counting close to large, high-efficiency, germanium detectors. For more information on problems with coincidence summing consult "The Counting Room: Special Edition," Radioact. Radiochem., McFarland, T., Ed; Caretaker Communications, 1994; pp 67-86.
The calibration is performed by germanium spectrometry on the final mixture. This procedure provides verifiable final calibrations and uncertainty values for each component. Typical uncertainties are in the range of 3 - 4%, relative expanded uncertainty (k=2).
Matrices
- Over the past twenty-five years Analytics has prepared custom-made standards in hundreds of different geometries utilizing many different matrices.
- Water-equivalent solid standards are prepared in hundreds of different geometries. These standards are individually traceable and much safer to handle in the counting room than liquid standards. There is no possibility of leakage, spillage or plate-out of the radioactive material. Matrix density is 1.15 g/cc.
- Air filter standards are uniformly deposited to your specifications and sealed in customer supplied counting configurations.
- Charcoal and silver zeolite cartridge standards are prepared in customer supplied cartridges loaded to your specifications.
- Soil or sand standards are prepared in customer supplied counting containers. Matrix density ranging from 1.5 g/cc to 1.7 g/cc.
- High density solids with density range from 1.5 to 2.0 g/cc.
- Vegetation or simulated vegetation standards are prepared in customer supplied counting containers with an approximate density of 0.6 g/cc.
- Simulated gas standards are prepared in customer supplied gas counting containers. These low-density (0.02 g/cc) standards have the same gamma-ray attenuation characteristics as actual gas standards and greatly extend the energy range and useful life of the calibration standard.
- Point sources are mounted in various geometries, again to your specifications.
- click to enlarge
Mixed Gamma-Ray Standards Table
