UPDATE #2 - Stoyan Sarg comments
http://www.quantumheat.org/index.php/en/follow/follow-2/347-gamma
In my book “Structural Physics of Nuclear Fusion” I did extensive analysis of LENR experiments, Rossi method and Defkalion method. I stated clearly in my latest article in Foreign Policy Journal (with more details in my book) why must use the Ni(62) and Ni(64) isotopes. The fusion reactions with these isotopes will lead mainly to a stable copper and partly to an unstable zinc isotope. The latter will decay to a copper by beta decay. The released beta particle serves as a catalyst for these reactions. Therefore, this is the cleanest nuclear process with a known gamma radiation without alpha particles or neutrons. Low energy (X-ray) olso may exist.
Rossi uses these isotopes and for this reason no neutron radiation is measured. He also does not produce a lot of transmutations like in the case with Defkalion method. At his initial public tests with the hydrogen gas in 2011 he probably used some triggering process by applying a HV discharge. In Hyperion reactor of Defkalion HV discharge is used all the time, but Rossi needed this only at the beginning to start the process. That’s why he did this privately and the strong gamma burst that was detected in 2011 might be from this. After the initial start (and at proper temperature) the process becomes self-sustainable, because the needed beta particles are generated by the decay of zinc. I am not sure does Rossi need such start in his E-cat HT in which he uses a metal hydrate instead of a hydrogen gas.
If you not use the above mentioned isotopes you will get different nuclear transmutations with a larger spectrum of radiation and may be also neutrons. But this will not help in revealing the secret of Rossi. Until this secret is not revealed he will be much ahead of others.
This was the reason of my recommendation.
Stoyan Sarg