Toward coherent neutrino detection using low-background micropattern gas detectors

The detection of low energy neutrinos (< few tens of MeV) via coherent nuclear scattering remains a holy grail of sorts in neutrino physics. This uncontroversial mode of interaction is expected to profit from a sizeable increase in cross section proportional to neutron number squared in the target nucleus, an advantageous feature in view of the small probability of interaction via all other channels in this energy region. A coherent neutrino detector would open the door to many new applications, ranging from the study of fundamental neutrino properties to true "neutrino technology." Unfortunately, present-day radiation detectors of sufficiently large mass (>1 kg) are not sensitive to sub keV nuclear recoils like those expected from this channel. The advent of micropattern gas detectors (MPGDs), new technologies originally intended for use in high energy physics, may soon put an end to this impasse. We present first tests of MPGDs fabricated with radioclean materials and discuss the approach to assessing their sensitivity to these faint signals. Applications are reviewed, in particular their use as a safeguard against illegitimate operation of nuclear reactors. A first industrial mass production of gas electron multipliers (GEMs) is succinctly described.