I had a very asymmetric spectra (see the snapshot in log scale where the landau falls like a straight line more or less) with another sample of diamond (i use mainly Element Six diamonds) and this, i think, is the first time this feature is actually measured or at least pointed out. Normally when you borrow Strontium from the radioactive guys, you only think about the main energetic decay at 2.28 MeV which passes through (a typical) thickness of sample. Since a lot of guys work with two triggers people use to select only the through going beta. At the begining my setup was easier and i did not include a second trigger (you clearly need another channel or another digitizer if you have money enough). Then i took both the decays and recorded them together. The energy release follows bethe block. The distribution is best approximated with a landau (but you need to cut at high energy to be physically acceptable). ROOT provides such a function. I took two since no theoretically difference must hold between the 0.5 and 2.3 MeV beta. The first one of course remains inside the bulk… Then i noticed that with only two landau it is really unlikely that you can take care of the long tail going to zero. Then i remembered i forgot the gaussian noise… this is the story more or less… 
