There are obvious reasons why you will have to present a "need to know" for this information.
You can start your search with the inventor of the Mark 1 and 2 triggers, referred to here. http://pubs.acs.org/cen/priestley/recipients/1972kistiakowsky.html From: James Bowery Still awaiting the cite from Jones about H+Cl => HCl producing neutrons.
