his mind on trivia, keep him from thinking about what was going on
inside that reactor.

He should have known automatically that it was building toward Fermium
256. It was the most logical, easiest, and simplest way for a D-H
reactor to go off the deep end.

A Ditmars-Horst reactor took advantage of the fact that any number can
be expressed as the sum of powers of two--and the number of nucleons in
an atomic nucleus was no exception to that mathematical rule.

Building atoms by adding nucleons wasn't as simple as putting marbles in
a bag because of the energy differential, but the energy derived from
the fusion of the elements lighter than Iron 56 could be compensated for
by using it to pack the nuclei heavier than that. The trick was to find
a chain of reactions that gave the least necessary energy transfer. The
method by which the reactions were carried out might have driven a
mid-Twentieth Century physicist a trifle ga-ga, but most of the
reactions themselves would have been recognizable.

There were several possible reactions which Ferguson and Metty could
have used to produce Hg-203, but de Hooch was fairly sure he knew which
one it was. The five-branch, double-alpha-addition scheme was the one
that was easiest to use--and it was the only one that started the
damnable doubling chain reaction, where the nuclear weights went up
exponentially under the influence of the peculiar conditions within the
reactor. 2-4-8-16-32-64-128-256 ... Hydrogen 2 and Helium 4 were stable.
So were Oxygen 16 and Sulfur 32. The reaction encountered a sticky spot
at Beryllium 8, which is highly unstable, with a half life of ten to
the minus sixteenth seconds, spontaneously fissioning back into two
Helium 4 nuclei. Past Sulfur 32, there was a lot of positron emission as
the nuclei fought to increase the number of neutrons to maintain a
stable balance. Germanium 64 is not at all stable, and neither is
Neodymium 128, but the instability can be corrected by positive beta
emission. When two nuclei of the resulting Xenon 128 are forced
together, the positron emission begins long before the coalescence is
complete, resulting in Fermium 256.

But not even a Ditmars-Horst reactor can stand the next step, because
matter itself won't stand it--not even in a D-H reactor. The trouble is
that a D-H reactor _tries_. Mathematically, it was assumed that the
resulting nucleus did exist--for an infinitesimal instant of time.
Literally, mathematically,