Magnetic field transport routines

Once the step size has been decided, transport proceeds along a straight lines for all neutral particles and for charged particle in absence of magnetic field. When magnetic field is present, the direction of charged particles will change along the step. The routine GUSWIM calculates the deviation in magnetic field over a given step. Depending on the tracking medium parameter IFIELD the GUSWIM routine calls:

• GRKUTA for inhomogeneous fields, IFIELD=1;
• GHELIX for quasi-homogeneous fields, IFIELD=2;
• GHELX3 for uniform fields along the z axis, IFIELD=3).