Bremsstrahlung induced by proton and helium-3 ion impact

Continuous X-ray spectra from a thin aluminium target produced by MeV proton and helium-3 ion impact have been measured with a Si(Li) detector. The observed spectra can be well reproduced with a simple model where it is assumed that these continuous X-rays originate from bremsstrahlung due to secondary electrons ejected from the target. The calculated angular distribution of these continuous X-rays is not isotropic but generally intense at 90°, which is also qualitatively in agreement with the experimental measurement.