notes: from program Sim NRA kinematic factor @ 2.000 ±0.001 MeV 150 degrees Cu: 1885.05 ± 0.01 Si: 1749.21 ± 0.01 can find a ratio between the lithium and flourine cross-sections taking the ratio of the yields and cross-sections allows things like target thickness to drop out what you're after: the yield and the cross-section are basically proportional to each other in lab write-up A big danger: Flourine curve very sensitive to different in energy of about .1, so this could change your ratio greatly this would be a systematic error that caused an energy shift to explain wrong values