For convenient holding irregularly sized
and shaped biological and gemological samples which
were hard to hold vertically, the machine was in a vertical
setup so that the samples could be placed horizontally and
even without fixing. For a high beam current and intensity
and a simple structure, the machine was a non-mass-
analyzing ion implanter using mixed molecular and
atomic nitrogen (N) ions so that material modifications
could be more effective. For a homogeneous ion
implantation, the machine was equipped with a
focusing/defocusing lens and an X-Y beam scanner. For
fast evacuation and short vacuum exposure to better
maintain biological living samples surviving, the target
chamber was made relatively small while supported by a
powerful pump. To save equipment materials and costs,
most of the components of the machine were taken from
abandoned ion beam facilities, while the IAEA supported
two main power supplies. The total maximum
accelerating voltage of the accelerator could be up to 100
kV, which was ideally necessary for crop mutation
induction and gem modification by ion beams from our
experience. The entire facility consisted of, from the top
to the bottom, a modified duoplasmatron ion source, an
Einzel lens, a home-made accelerating tube, a small beam
diagnosis chamber, an X-Y electrical scanner, and a target
chamber. Inside the target chamber there were a sample
holder stage and a beam current measurement plate which
coordinated a Faraday cup in the beam diagnosis chamber
to check the beam current. A stack of power supplies and
controllers managed the operation of the facility. The
whole system was housed in an appropriately-sized air-
conditioned room to reduce the humidity from the tropical
environment. The total height of the machine was about 2
meters. The N-ion beam current could be hundreds of µA
and the maximum beam spot at the target was 8 cm in
diameter. N-ion implantation of local rice seeds and cut
gemstones was carried out. Various phenotype changes of
grown rice from the ion-implanted seeds and
improvements in gemological quality of the ion-
bombarded gemstones were observed, demonstrating the
IAEA-supported ion accelerator/implanter successfully
completed and working satisfactorily. The success in
development of such a low-cost and simple-structured ion
accelerator/implanter provides developing countries with
a model of utilizing our limited resources to develop
novel accelerator-based technologies and applications.