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

Abstract

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.