An Experimental Search for Gamma Radiation Associated . With Thunderstorm Activity*

This eZp&iment is a repeat of an earlier experiment,’ but with more sensitive appaTatus and in a location with a higher incidence of thunderstorm activity. The experiment of Ref. (1) was undertaken by Ashby and Whitehead (AW) to investigate the theory that ball lightning might be associa.ted with the annihilation of small amounts of antimatter, and it yielded some very int.eresting but inconclusive results. In the course of about 12 months of da.ta taking, four high rate bqsts of gamma radiation were detected. 2 These events la.sted a. few seconds and had many thousands of counts (16500, 5000, 3700, and > 7700). Unfortunately, the association of these gamma ray bursts with thunderstorms or ball lightning was not clearly established, although one of the bursts did occur during a local thunderstorm in rough coincidence with a lightning bolt striking a flagpole3 about l-00 yards from the gamma ray detection crystals. A pulse height spectrum taken for this burst (no spectrum was taken for the other three) exhibited a significant peak, well above background, the energy of which appeared to be compatible with the 511 key positron annihilation line. While the peak could not, be unambigu.ously %&ribtited to positron annihilation, this certainly a.ppeared to be the most likely source.