Dear Fluka experts:

I am trying to use the SPOTBEAM source in a radiation protection calculations for proton thearpy facility.

I set eight beam spots, the energy and relative intensity (beam current) of this beam spots were specified separately. The total beam current is 12.74 nA, and the last beam spot is 2.0 nA. Based on the above settings, I obtained the dose rate distribution of a certain plane ( the USRBIN Scoring 26bin) through simulation calculation. And draw a one-dimensional dose distribution passing through the maximum point on the plane.

Then, I only keep one beam spots （the last one）, and set the current is 2.0 nA, so other spots to zero. In the end, I obtained the results at the same position mentioned above. Both the resluts are respectively multiplied by the beam intensity（12.4 and 2.0）.

Unfortunately， these two results are not consistent, as can be clearly seen from the following two graphs.

Meanwhile, I have attached my input file.

multiple_source.inp (69.6 KB)

single_source.inp (78.0 KB)

Therefore, could you please help me check if there are any settings errors.

[Thank you very much！