– which often have strict requirements for radiopurity. Of primary concern in these experiments are the natural primordial radioisotopes and their decay chains ($^{238,235}$U,$^{232}$Th, $^{40}$K), common man-added radioactivity ($^{60}$Co, $^{137}$Cs, etc.), and various cosmogenic radioisotopes. Other services include neutron activation analysis for trace analysis of many stable isotopes, neutron flux/transmutation doping, radon emanation, R&D hosting, environmental measurements, and other various applications such as accelerator characterization and radiological waste assay. More information on the Low Background Facility at LBNL can be found in [@Thomas2013] and [@ThomasLRT].

Air Sampling
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An air sampler was put into operation outside LBNL LBF on 3/14/2011, to track the arrival and continued presence at LBNL of gamma-emitting fission products from the Fukushima Daiichi nuclear power plant disaster that was caused by the earthquake/tsunami on 3/11/2011. This sampling station has continued operation to the present and results through the end of 2012 are summarized here.

Air sampling began on the morning of 3/14/11, using a nominal 24-hr collection period, followed by immediate counting on an ORTEC low-background packaged HPGe detector (2.26 kg n-type HPGe crystal, relative efficiency of 115%). Air flow through the sampler is actively regulated at a constant flow rate, producing 244.7 m$^{3}$ throughput in 