General remarks to the MOCADI simulations:

1. scraper size vertically > (p,g) spot at the scraping position --> (p,g) can be separated by truncating the backscattered Rutherford events in the energy.


2. replacing the atomic masses to nuclear masses does not change significantly the absolute positions of the (p,g) and the Rutherford. However, the (p,g) spot in the simulation seems bigger using the nuclear masses, than in the 124Xe experiment with a factor ~1.6.


3. going for lighter elements, the separation between (p,g) and Rutherford getting better, than slit can be placed even more far from the beam in x (radial) direction. For 124Xe the minimal distance from the beam axis is <4cm, for 73As it is <7.5cm.


4. in the simulations the scraping is mostly until x=-inf. However, if the scraping is incomplete in x, we can end up with underlying background events below the p,g peak (see the last slides)! The Rutherford cone gets bigger by going down with A,Z. For 91Nb the minimal width of the scraper: x>6cm, for 73As x>7cm. Therefore, I suggest to have a scraper width x=9cm. For the y, y=6cm should be safe.


5. for lighter elements, the (p,g) spot size increases: in the simulation for 73As it reaches the detector size. However, the (p,g) spot size might be overestimated, please read the 2. point.