What happens if you set ECUT less than 1 keV?

[rtownson]

I ask because we typically set ECUT=0.512 MeV to get a 1 keV cutoff, but the electron rest mass is larger than exactly 0.511 MeV. Is there an extrapolation on the data tables? Or is the smallest value in the table used when energy drops below 1 keV?

[Jaap1957]

The code uses:
E = 0.5109989461 MeV + kinetic_E
Wiki says : 0.51099895000 MeV rest mass

So the rest mass is actually a little below 0.511

[mchamberland]

@rtownson looks like there were new CODATA values published in 2018. Time to update the rest mass?

[ftessier]

Yes, indeed we should update to the most recent CODATA 2018 recommended value: 0.510 998 950 00(15) MeV.

[rtownson]

Feels like we just did this! Yes we should take a look.