interesting, and are included in [**Figure \[fig:raincompare\]**]{} for comparison. This suggests that the radioactivity was spread uniformly in the precipitation as the storm front passed through northern California over the course of several hours.

![Comparison of rainwater samples collected during the same time period at two locations approximately 120 miles apart. The hollow points represent rainwater collected in the east San Francisco Bay Area by Norman et. al. and replotted from [@Norman2011]. The solid points represent rainwater collected and analyzed by the LBF in Oroville, CA as seen in [**Figures \[fig:raincompare\]**]{} and [**\[fig:ororainloglog\]**]{}. The data shows remarkably similar activities in both locations, despite their distance form one another and time between rainstorms passing through each.[]{data-label="fig:raincompare"}](ORO-EastBay-Compare){width="\linewidth"}

The Search for Strontium-90
===========================

The rainwater samples in Norman, et al. [@Norman2011] contained the man-made isotopes $^{131}$I, $^{132}$I,$^{132}$Te,$^{134}$Cs,$^{136}$Cs, and $^{137}$Cs. They were collected between March 16-26, 2011 in Oakland, Albany, and Berkeley, California on the eastern side of the San Francisco Bay. Samples were placed directly into Marinelli beakers for gamma ray counting, with no additional preparation prior to gamma ray counting on a 60% relative efficient HPGe gamma spectrometer. An efficiency calibration utilizing natural La, Lu, and K isotopes was used for analysis 