Beam current dropped to 85 epA at the start of the shift, operator checked for reasons and decided to change
stripper foil. That brought the current back up, but it started decreasing again, so from run to run slits were
gradually opened further to keep FC0 current at about 100 epA.
I forgot the part about saving and clearing the spectra after every run, so runs 171-177 were summed together.