  Recently, Jenkins, et al. have reported the detection of correlations between
fluctuations in nuclear decay rates and Earth-Sun distance, which suggest that
nuclear decay rates can be affected by solar activity. In this paper, we report
the detection of a significant decrease in the decay of 54Mn during the solar
flare of 13 December 2006, whose x-rays were first recorded at 02:37 UT (21:37
EST on 12 December). Our detector was a 1 uCi sample of 54Mn, whose decay rate
exhibited a dip coincident in time with spikes in both the x-ray and proton
fluxes recorded by the GOES-10 and 11 satellites. A secondary peak in the x-ray
and proton fluxes on 17 December at 12:40 EST was also accompanied by a
coincident dip in the 54Mn decay rate. These observations support the claim by
Jenkins, et al. that nuclear decay rates vary with Earth-Sun distance.
