Assessment of the linear reference air kerma rate of 192Ir wires.

In this study, a procedure to test the linear reference air kerma rate of 192Ir wires using a well-type chamber is described. The method is based on a special lead insert with a 1 cm acrylic aperture that provides a differential response of the well chamber. The wire is considered divided into 1 cm parts. Using an external positioning system it is possible to place every part of the wire at the aperture position in the lead insert allowing measurement of each 1 cm making up the length of the wire. By means of a set of equations that take into account the contribution of all parts of the wire, in all possible positions, the relative linear reference air kerma rate is obtained. The estimated uncertainties of this procedure are about 2 to 3%. So, a well chamber and the specific inserts allow the measurements of total and linear reference air kerma rate for 192Ir wires.