GB811492A - Device for measurement of individual ray dose and ray dose rate and for identification - Google Patents

Abstract

811,492. Radiation dose-meters. KERR & CO. (MANCHESTER) Ltd., J. (Total Komm-Ges Foerstner & Co.). Jan. 9, 1956 [Oct. 8, 1954], No. 28983/54. Class 98(1) In a radiation dose-meter consisting of an identification tag combined with a holder for at least one recorder of the amount of incident radiation and means on the holder which enable details thereon in respect of the person concerned to be transferred to part of each recorder which registers radiation received in a given period, a recorder for registering radiation received cumulatively being also preferably provided, the holder(s) are capable of being removed, cut or broken off from the identification, tag along a given line and the recorder(s) are capable of being marked, as by perforations to be identifiable with the holder (and hence the bearer). As shown in Figs. 2, 3, the holder 1 is made of sheet steel and may be broken along the line of slots 2. A plastic cover 3 has turned-over edges 4 engaging the holder 1, and a dosemeter 6, consisting of a piece of photographic film and protected by a foil 6a, is placed between the cover 3 and the holder 1. The cover 3 is fastened to the holder 1 by a rivet 5. The upper part of the holder bears identification data and similar data are reproduced in a form of code perforations on its lower part. The perforations allow film 6 to be pierced by a pin to convey the coded data from holder to the film. A reduced reproduction 10 of the personal register card of the bearer is mounted at the back of the holder and is covered by a convex lens 11. In an alternative form the holder carries a sheet of phosphorus glass which indicates the total radiation to which the holder has been exposed as well as two removable dose-meters which may be partially covered by strips of metal, e.g. lead foil, which in another form may be separated from the film by plastic spacers. When several dose-meters are used, they may have different markings or colours. Each cover and each film has a cut-off corner, to ensure that the films are inserted right way round. The perforations may be filled with a radiopaque substance, which may be coloured to make it easy to see where it has been pierced. Alternatively the holder may, at certain points, be made of, or have recesses filled with, material differing in transparency to radiation from the main part of the holder; or the holder may have teeth or points to transfer the data to the film when pressure is applied. When several films are used, they may be separated as by distance pieces and metal (e.g. lead or aluminium) foil interposed to reduce the effects of secondary electron emission. Filters or fluorescent layers may be provided preferably partially covering the dosemeters, to enable an estimate of the quality of radiation received to be made. Alternatively, the dose-meter films may be of varying sensitivity to varying radiations.