titancollaboration/ebitsim

EBIT simulator for ionization

ebitsim's Issues

Bad error reporting for a bad config file

If the speciesList and beamList do not match what is actually given, the simulation crashes and the error it gives is confusing. Example:

speciesList = Mo98

beamList = BeamAndTrap, BeamAndTrap2

[BeamAndTrap]
blah blah
blah

[Mo98]
blah blah
blah

Charge breeding bare ions

I believe I've found an issue in the code when trying to charge breed bare ions. I have not seen this behavior at any of the lower charge states so any charge breeding below the ionization threshold required for bare ions should still give good results. The following graph illustrates the issue:

It is a charge breeding simulation of Ar-36, using 4.5 keV, which is just above the ionization energy for bare argon. Plotting for all possible charge states ranging from neutral to 18+ is turned on. From breeding time of 0 up to 1 ms we see expected behavior for the evolution of charge state of the Ar ions. As we breed past 1 ms, the 16+ population decreases, but the population of 17+ increases as expected, indicating 16+ is being ionized to 17+. At this point the population of 16+ and 17+ pretty much accounts for 100% of the total population. Just past 10ms, a kink in 16+ coincides with the peak of 17+ and then they both are dropping. However, none of the other possible charge states are increasing, so the population of all of the possible charge states does not add up to 100%. I do not know a way to explain this other than it being a bug because I can't account for the rest of the population.

Beam changing

Write code that allows for the beams parameters (probably just the beam's energy) to change mid simulation.

Beta decay not tested

Need to just test it...

Negative energy

I just implemented heat transfer due to charge changing reactions. While not useful right now, it will be needed in the future when the other heat transfer mechanisms are used. Right now it's primary effect is on the CX rate calculation because the average velocity of the ions are a factor in the rate and are derived from the temperature of the distribution.

In a very simple configuration I have going right now, the SCI start with 25 eV of energy. As charge breeding occurs, every other charge state which has a population picks up this 25 eV of energy... as expected. At some points this energy can randomly drop to around 14 eV, and then most recently I saw it drop to -8 eV. This of course gives an error when we try to calculate the ion velocity because the sqrt() operator can't do it.

I looked in to it and I found that the underlying reason is that while the population of a charge state is very small, it can sometimes fluctuate negative simply because of the way the RK4 algorithm is implemented. This negative value then turns up in the calculation for heat transfer and can lead to a negative temperature. I'm not sure how to resolve this issue because this isn't an inherently bad thing about the RK4 algorithm... it's just that we're dealing with pretty small numbers (like 1x10^-13). In the context of the number of ions than can be stored in an EBIT, these are effectively zero, so maybe we can implement some sort of cutoff...

Or I need to find a new way of calculating the heat transfer due to charge changing reactions.

Auto-optimizer

Need to write code so that it can optimize a charge states breeding

Write code to export results as CSV file

Instead of matplotlib there should be an option of csv to give the raw data.