flat foil with exponential ramp

[ktippey-hzdr]

Introducing flat foil with exponential ramps

[dpgrote]

Thanks for the PR! One question though is could this foil be described using an analytic expression, with PICMI_AnalyticDistribution?

[ktippey-hzdr]

Technically yes, but the same is true for all other already existing distributions (for example PICMI_GaussianBunchDistribution, PICMI_UniformDistribution and PICMI_UniformFluxDistribution) and every other analytically definable distribution. My understanding is that PICMI is supposed to standardize common use cases. Foils would be the standard distribution for ion acceleration experiments and staged channel wakefield acceleration.

[dpgrote]

This looks good overall. I've left some comments to make the documentation consistent with the style of other classes.

[ktippey-hzdr]

Have implemented all requested fixes @dpgrote Please review and let me know if anything further is suggested?