US 4,286,165 AGranted

Dosimeter for measuring skin dose and more deeply penetrating radiation

AssigneeThe United States of America as represented by the United States Department of Energy

InventorsDonald E. Jones, DeRay Parker, Paul R. Boren

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Abstract

A personnel dosimeter includes a plurality of compartments containing thermoluminescent dosimeter phosphors for registering radiation dose absorbed in the wearer's sensitive skin layer and for registering more deeply penetrating radiation. Two of the phosphor compartments communicate with thin windows of different thicknesses to obtain a ratio of shallowly penetrating radiation, e.g. beta. A third phosphor is disposed within a compartment communicating with a window of substantially greater thickness than the windows of the first two compartments for estimating the more deeply penetrating radiation dose. By selecting certain phosphors that are insensitive to neutrons and by loading the holder material with netruon-absorbing elements, energetic neutron dose can be estimated separately from other radiation dose. This invention also involves a method of injection molding of dosimeter holders with thin windows of consistent thickness at the corresponding compartments of different holders. This is achieved through use of a die insert having the thin window of precision thickness in place prior to the injection molding step.

Claims12

Dependent claims

A personnel dosimeter for measuring radiation dose to a wearer within a skin layer defined between density thickness limits comprising:

a holder of thermoplastic material having a front face and a rear wall, said rear wall having an opening therein for access to a plurality of wells;
a plug adapted to seat within said rear wall opening, said plug having a plurality of posts each of which corresponding to one of said plurality of wells to define a plurality of compartments for containing TLD phosphors behind windows of predetermined density thicknesses from the front face of said holder;
a first window, within said front face at a first compartment, having a density thickness of at least about that of the lesser limit of said skin layer but no more than about the deeper limit of said skin layer;
a second window, within said front face at a second compartment, having a density thickness substantially greater than that of said first window and that of the deeper limit of said skin layer, said second window density thickness is greater than that of said first window by at least 5% but no more than 100% of the average density thicness of the phosphors contained within said first and second compartments;
a third window, within said front face at a third compartment, having a density thickness of more than that of said second window and more than that of the average density thickness of the phosphors within said first and second compartments to permit estimation of the dose of penetrating radiation into the body of the wearer and thereby determine the ratio of the net dose passing through said first and said second windows being absorbed within the thickness of phosphors within said first and second compartments whereby radiation dose to said defined skin layer can be determined as a function of said ratio of net dose.

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Dependencies are inferred from the claim text.