Calculation of magnetic fields in spiral slowing-down systems with electric current

On the basis of Biot-Savart-Laplas formula, analytical expressions are obtained and the computer calculations of configurations of magnetic fields caused by direct current flowing in decelerating systems of the single and double spiral type, is made. On the basis of results obtained the conclusion in made that current passage through spiral decelerating systems of the type considered is an effective method of generating a focusing magnetic field of one or several beams of charged particles for systems with phase velocities not more than 0.1 s when the field is practically axis-symmetric and uniform in the region of particle motion