Determination of the initial approximation for the kinematical parameters of a charged particle

Abstract

In order to obtain the kinematical parameters of a charged particle, which moves with ionization losses in a medium placed in a nonuniform magnetic field, it is necessary to have their initial estimates as precise as possible. Usually one approximates the measured points of a track by a parabola and then obtains with some accuracy the momentum and angles considering a constant value of the magnetic field and a constant value of the ionization losses along the track. In the present paper it is shown that one can obtain more precise values of these kinematical parameters using the same parabola. In order to check the accuracy of the method the kinematical parameters have been determined for artificial tracks in a propane bubble chamber with a 20% nonuniformity of the magnetic field. The results are shown in table 1.