Comment on Observation of annual modulation by $gamma$ rays from ($alpha$,$gamma$) reactions at the Soudan Underground Laboratory

Tiwari {it et al.} have identified an annual modulation of the $gamma$-ray flux at the Soudan Underground Laboratory which is strongly correlated to the radon concentration. The $gamma$-ray flux results from ($alpha$,$gamma$) reactions which are induced by the $alpha$ activity of radon and its daughters. Unfortunately, the quantitative analysis of the $gamma$-ray flux is based on unrealistic ($alpha$,$gamma$) cross sections, and thus the calculated $gamma$-ray fluxes are not reliable.