During this time I had the singular good fortune of being able to discuss the problem constantly with Einstein. Some experiments done at Einstein's suggestion yielded no decisively new result.
This result was confirmed by different researchers using various experimental arrangements.
Rossi was the first to describe another system working with valves in parallel; it has the advantage that it can easily be extended to coincidences between more than two events, and is therefore predominantly used today.
Our arrangement therefore consisted of two needle counters, past the common front wall of which, without touching it, swept a beam of X-rays.
During conversion, the newly formed nucleus is not always immediately in the ground state, but is at times in one of the possible activated states.
Film consumption however was so enormous that our laboratory with the film strips strung up for drying sometimes resembled an industrial laundry.