# Coherent detection of low energy neutrinos using a topological insulator

**George Chapline**

LLNL

The question of whether it is possible to make use of coherent atomic effects to increase the detection cross section for neutrinos has been in the air since Weber"s 1985 suggestion that coherent scattering of neutrinos from a crystal would lead to an interaction cross section varying as N-squared rather than N. The Jason"s looked at this circa 1985-88 and concluded that, at least for MeV neutrinos, coherent effects were of no practical use. We have recently reconsidered Dthis question for low energy neutrinos. In particular, we have considered whether using coherenc backscattering off a 3-dimensional topological insulator such as Bi2Te3 could be used to detect cosmological neutrinos. Estimates of the coherent cross section for 2K neutrinoes scattering off Bi2Te3 suggest that a 1m dismeter mosiac of 1mm crystals could detect - 1 CMB neutrino per hour.