Cyclotron collimator time step

Summary

Cyclotron collimator needs that each particle has own time step

Steps to reproduce

Collimator in BANDRF cyclotron without acceleration: particulas_1000_xUyUzU_pxpypz.dat BField_0T_const.dat trackingColl.in

What is the current bug behavior?

In ParallelCyclotronTracker time step is not an attribute not null for each particle, so the simulations breaks in CollimatorPhysics::copyFromBunch, because stepWidth=0

What is the expected correct behavior?

dt[i] should be equal to general timestep

Relevant logs and/or screenshots

Error> 
Error> *** Error:
Error>     Internal OPAL error: 
Error>     Assertion 'tau >= 0.0' failed. 
Error>     tau = -inf, 0.0 = 0.000000
Error>     in 
Error>     OPAL/src/src/Classic/Solvers/CollimatorPhysics.cpp, line  554

Possible fixes

For ParallelTTracker, dt[i] is update throught PartBunchBase<T, Dim>::switchToUnitlessPositions