Anomaly..?



[link to arstechnica.com]

[snip]

The data obtained by the researchers show clear spikes in the low-energy neutron detectors at the same time as the electrical discharges from a storm. Unfortunately, the time resolution of the neutron detectors is only 1 minute, so it is impossible to extract any detailed information about the neutron flux. The use of the three shielded detectors, however, shows the expected decay behavior, indicating that the neutrons are not generated within the detectors themselves.

The high-energy neutron detector also showed some activity during the storm, but this is because the detector still has some sensitivity for low-energy neutrons. Once this was taken into account, the four detectors all agreed. In short, cosmic rays are not the source for the neutron flux observed during lightning strikes.

The new detectors also allowed the researchers to calculate the neutron flux from the storm activity. In the previous experiments, it had been assumed that each detection event corresponded to a single neutron. In a surprising turn up, the new data show that up to 5000 neutrons per cubic meter are produced every second by lightning strikes.

This is very high, and not very compatible with the alternate explanation, neutron production by high energy photons (gamma rays). To generate the number of neutrons the researchers observe would take about 10 million gamma ray photons m-3s-1.

Unfortunately, lightning strikes only generate a tiny fraction of that.