[en] Background X-rays from an Al target bombarded with protons of 0.5, 0.75 and 1.0 MeV and α-particles of 0.5 MeV/amu from the 2.5 MV Van de Graff accelerator were measured with a Si(Li) detector. Production cross section and spectra of continuum X-rays are compared with predictions from the atomic bremsstrahlung(AB) and the secondary electron bremsstrahlung(SEB). Good agreements are obtained. Atomic bremsstrahlung is the most predominant process in this projectile-energy region. The experimental angular distribution of 2.85 - 3.00 keV X-rays for 0.5-MeV proton bombardment is also in good agreement with the calculation of atomic bremsstrahlung. This distribution is symmetric about 90 deg with respect to the incident beam. These results make possible to estimate the sensitivity of the trace-element analysis by PIXE. (author)