X-ray dose and dose distribution intercomparisons using mailed LiF and BeO thermoluminescent dosimeters

After a first series of measurements of the X-ray dose and dose distribution, carried out in 1971 at a number of biological and biomedical institutes cooperating within the European Late Effects Project Group, a second intercomparison has been performed to check the improvements made after the first series. These measurements were more directed to the actual exposure conditions at the participating institutes. A test phantom with the size of a mouse and containing LiF and BeO thermoluminescent (TL) dosimeters had to be exposed up to an absorbed dose of 200 rad, together with additional mouse phantoms in the cage used for mice irradiations at the institutes. From the TL reading of the dosimeters at the entrance, central and exit position in the phantom and the TL reading of similar dosimeters exposed at a standardization laboratory the absorbed dose really given has been calculated, taking into account a possible change in effective energy inside the phantom due to scattered radiation. A comparison of LiF data for the absorbed dose and dose distribution in the phantom resulting from the measurements performed in 1971 and 1973 will be given. The simultaneous exposure of LiF and BeO dosimeters made it possible to compare the absorbed dose data from both systems. The BeO system seems to offer perspectives for this type of intercomparisons. (author)