s follows:

{94}Pu<239> (n, [gamma]) {94}Pu<240> (n, [gamma]) {94}Pu<241> [beta]
--> {95}Am<241>.

The notation (n, [gamma]) means that the plutonium absorbs a neutron and
gives off some energy in the form of gamma rays (very hard x rays); it
first forms {94}Pu<240> and then {94}Pu<241>, which is unstable and gives
off fast electrons ([beta]), leaving {95}Am<241>.

Berkelium and californium, elements 97 and 98, were produced at the
University of California by methods analogous to that used for curium,
as shown in the following equations:

{95}Am<240> + [alpha] --> {97}Bk<243> + {0}n<1>,

and {96}Cm<241> + [alpha] --> {98}Cf<244> + {0}n<1>.

The next two elements, einsteinium ({99}Es) and fermium ({100}Fm), were
originally found in the debris from the thermonuclear device "Mike,"
which was detonated on Eniwetok atoll November 1952. (This method of
creating new substances is somewhat more extravagant than the mythical
Chinese method of burning down a building to get a roast pig.)

These elements have since been made in nuclear reactors and by
bombardment. This time the "bullet" was N<14> stripped of electrons till it
had a charge of +6, and the target was plutonium.

Researchers at the University of California used new techniques in
forming and identifying element 101, mendelevium. A very thin layer of
{99}Es<253> was electroplated onto a thin gold foil and was then bombarded,
from behind the layer, with 41-MeV [alpha] particles. Unchanged {99}Es<253>
stayed on the gold, but those atoms hit by [alpha] particles were
knocked off and deposited on a "catcher" gold foil, which was then
dissolved and analyzed (Fig. 3). This freed the new element from most of
the very reactive parent substances, so that analysis was easier. Even
so, the radioactivity was so weak that the new element was identified
"one atom at a time"; this is possible because its daughter element,
fermium, spontaneously fissions and releases energy in greater bursts
than any possible contaminant.

[Illustration: Fig. 3. The production of mendelevium.]

In 1957, in Stockholm, element 102 was reported found by an
international team of scientists (who called it nobelium), but diligent
and extensive research failed to duplicate the Stockholm findings.
However, a still newer technique developed at Berkeley showed the
footprints--if not the living presence--of 102 (see Fig. 4). The rare
isotope curium-246 is coated on a small piece of