Number 41 (Story #3), July 17, 1991 by Phillip F. Schewe and Ben Stein EVIDENCE FOR THE 17-KEV NEUTRINO has been seen in an electron-capture experiment. A team of scientists at Boskovic Institute in Zagreb, Yugoslavia reports in the 29 July Physical Review Letters (preliminary results appeared at a nuclear physics meeting in December 1990) that the spectrum of gamma photons radiated by electrons as they are captured by germanium-71 nuclei suggests that in 1.6% of the capture events, a 17.2-keV neutrino is being emitted. This particular nuclear reaction, called internal bremsstrahlung in electron capture (IBEC), is a sort of beta decay in reverse; Eric Norman at LBL used IBEC reactions in iron-55 (as well as beta-decay reactions in carbon-14) to find evidence for a 17-keV neutrino.