Focardi, S., et al., "Evidence of electromagnetic radiation from Ni-H Systems," in Eleventh International Conference on Condensed Matter Nuclear Science (2004).
Summary: Three Ni-H systems emitted gamma radiation after hydrogen was introduced. The first system showed excess heat, and the second showed none. When the third system underwent thermal excitation, the rate of photon emission increased for a short period of time.
In three different experiments, nickel plates were interleaved with heating elements in a closed chamber. The chamber was first evacuated and then hydrogen gas was introduced. Emissions in one experiment lasted forty-five days after degassing. Gamma emission did not always depend on temperature. In the second experiment, which showed marked gamma activity above background, samples were kept for fifty-two days in a vacuum while measurements were taken of photon emission, before hydrogen was introduced. They obtained photon emission but not excess heat. The spectrum lasted for twenty-six days after hydrogen was added. In the third experiment there was no difference in spectra during the degassing period and the introduction of H2. In all three experiments, the peak energy in the spectra was the same. The first system showed excess heat at one point, and Cr and Mn turned up in the nickel samples. The second system showed no excess heat or neutron emission and nothing unusual was found in the surface analysis.
There are two databases that can help in determining what is happening in a spectrum at a given energy range: GAMQUEST (Lawrence Berkeley National Laboratory) and NUDAT (Brookhaven National Laboratory).
An important possibility here is that what is emitted by the system depends upon how the system is set up. Questions: The difference curve in figure 4 is small; is it statistically significant? What is degassing? Were there transmutations in the third experiment? Why were there no transmutations in the second experiment?