The Gamma ray/Neutron instrument is crude and low resolution (200-400km field of view, and it measures an average). It also neds to integrate counts over months to years to get anything like good statistics.

I discussed this instrument with one of the team members at U. Arizona when I visited there in August. He seemed fairly sure that the instrument could detect the 30% CO2 in the permanent northern polecap if it were made of clathrate.

So the answer is, wait 2 years and ask again!

For THEMIS, this is a slightly "better" version of TES. I expect broadly similar results, i.e. nothing earth-shattering.