Multiple showers

Hello, I didn't find a specific example which generates multiple showers. I tried to add a loop but it was created some troubles :

terminate called after throwing an instance of 'std::runtime_error'
  what():  Interaction: GetCrossSection: CoM energy outside range for Sibyll!
Abandon (core dumped)

If I take example "cascade_example" and I start my loop just before :

setup::Stack stack;
stack.Clear();

It should work. I should't save results correctly but I can take some first performances measures technically.

For my experiments, I use 1 TeV for E0, 1GeV for cut energy (like CTA experiments) and theta=20 degrees / phi=180 degrees

My problem with other experiments is they haven't phi angle like em_shower and vertical_EAS. It should be great if they have this. I tried to add phi component but I'm not sure all is right. In my branch, it's em_shower_cherenkov and vertical_EAS_cherenkov. Compilation is ok but only em_shower_cherenkov "work" without photons (with energy cut with 1MeV). vertical_EAS generate a message while execution :

vertical_EAS_cherenkov: /home/mcarrere/Documents/git/cerenk_project/Processes/Proposal/PROPOSAL/src/PROPOSAL/propagation_utility/PropagationUtilityInterpolant.cxx:59: virtual double PROPOSAL::UtilityInterpolant::GetUpperLimit(double, double): Assertion `rnd >= 0' failed.

Thank you.