A controlled field pilot has been developed in Bozeman, Montana, USA, to study near surface CO 2 transport and detection technologies. A slotted horizontal well divided into six zones was installed in the shallow subsurface. The scale and CO 2 release rates were chosen to be relevant to developing monitoring strategies for geological carbon storage. The field site was characterized before injection, and CO 2 transport and concentrations in saturated soil and the vadose zone were modeled. Controlled releases of CO 2 from the horizontal well were performed in the summers of 2007 and 2008, and collaborators from six national labs, three universities, and the U.S. Geological Survey investigated movement of CO 2 through the soil, water, plants, and air with a wide range of near surface detection techniques. An overview of these results will be presented.

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The effects of boric acid admixture on the intensity and line structure of EPR spectra of free radicals produced in alanine by thermal neutrons are presented. The EPR signal enhancement, up to a factor of 40 depending on the boron concentration, is related to additional energy deposition in alanine crystals by the disintegration products resulting from the capture of a thermal neutron by boron, 10B(n,alpha)7Li. The changes in the shape of the EPR spectra observed by changing the microwave power are due to the differences in the microwave power saturation of the free radicals produced by a low-LET radiation and those produced by the high-LET components of the radiation after the neutron capture reaction.

Microcrystalline samples of L-alanine irradiated with energetic high-LET cobalt and iron ions had different EPR spectra compared to alanine samples irradiated with low-LET photons. The differences in the shapes of the EPR spectra and their dependence on the microwave power are related to the differences in the microwave power saturation of the radicals induced by the various types of ionizing radiation. The changes in the shape of the EPR spectra, which were caused by increasing microwave power, were more pronounced in samples irradiated with low-LET radiation than with high-LET particles. This effect showed a long-term stability and can be used to monitor radiation quality.

Calculations of the energy response of an electron paramagnetic resonance (EPR) signal induced by gamma radiation in an agar-alanine phantom dosimeter are presented. Theoretically calculated slopes of the EPR signal calibration lines are comparable with those obtained experimentally for low-(50 kVp), medium-(662 keV), and high-(15 MVp) energy photons. The sensitivity of the phantom dosimeter (EPR signal amplitude/Gray) varies less than 2% within the 150- to 20-MeV energy range. For energies above 150 keV, the influence of variations in the size of alanine crystals is negligible.