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  IPL offers radiation standards in many different geometries which can be generally categorized as Point Source Standards, Planar Standards, and Large Volume Standards.
Point Source Standards Point Source Standards are radiation standards in which the active element is very small. Gamma point sources are offered in our GF series in the Type D disk and the Type M disk. The Type D is 1 inch diameter by approximately 0.25 inch thick with the activity centered in a 0.2 inch spot. A Type M is also 1 inch in diameter but is approximately 0.03 inches thick providing an ideal precision point standard. GF series are widely used throughout the world as but check sources and a calibration standards. The GF series also includes Test Tube standards and Rod Standards that are typically used in well counters.
Planar Standards IPL offers a number of planar sources and standards to meet most every need. Planar sources come in both circular and rectangular configurations. The typical source consists of radioactive material deposited onto a substrate and covered with a thin window material. This type of source is generally used to calibrate survey instrumentation in a laboratory. In addition to this construction technique, IPL offers electro-plated sources and filter paper sources. Plated sources provide the least amount of spectral distortion for precise Alpha and Beta energy measurement while Filter paper standards are used to simulate survey wipes for removable contamination. All types of planar sources are offered in the EAB series and the LDS series. In general, the EAB series sources are circular and the LDS series sources are rectangular. The table below defines standard sizes for both EAB and LDS series sources. Sources are provided with both contained activity and emissions in 2 pi.
Filter Paper Sources Filter Paper Standards have their activity incorporated into the surface of a filter paper, typically used for smear samples and for air sampling. Filter Paper standards are prepared in a unique manner that provides a surface deposit of active salts rather than saturating the filter paper with activity. This simulates the active loading one would find in air samples and in dry smear samples of bench tops, floors, and tools. Filter Paper standards are not recommended for field use due to their delicate nature.
Plated Sources Plated sources are those in which the activity is incorporated into a metallic substrate typically by electro-deposition. The activity is then diffusion bonded into the substrate yielding a very thin active layer on the surface of the substrate. These standards are typically used for alpha emitters in which thicker active layers would severely perturb the emission spectra. Plated sources are recommended for laboratory or primary calibration use, not for rugged field applications.
Large Volume Standards Large Volume Standards (EG series) are used to calibrate Germanium and NaI detectors, to name a few, used in the assay of soil, gas, vegetation, and water samples. These standards are gamma sources and are offered with any available gamma emitting nuclide or mixture thereof. They are offered in standard sampling configurations such as Marinelli Beakers, sampling bottles, and air sampling cartridges. A variety of matrices can be used to simulate samples being measured. The most popular configuration is a 1 Liter Marinelli Beaker with a water equivalent solid matrix containing a nine nuclide mixture with gamma peaks from 60 keV to 1836 keV. This wide range allows for the development of accurate efficiency curves. |
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