A neutron generator includes a modular arrangement of a high current electron
bombardment
ion source, providing deuterium(D) and/or tritium(T) ions, a high voltage acceleration
stage to accelerate the ions and raise the ion energy to the order of 100 keV,
and an occluded reaction target containing T and/or D to produce the nuclear reactions.
Neutrons are produced in the target using the D-D and/or D-T reaction. The invention
is designed to allow the target to be located at the end of a needle and thereby
is useful for treating cancers by the Brachy therapy method. The ion source of
the neutron generator is a modified version of the electron bombardment type used
in mass spectrometers for gas analysis. This source uses an electron beam running
through an ionization chamber to ionize gas molecules that are extracted out of
the chamber by electric fields. The ion source has been redesigned for higher current
by providing a larger electron beam and enlarging the extraction slit and subsequent
focusing element apertures to 3 mm or more. This modified source provides microamperes
of ion current at operating pressures in the 10-;4 torr range, whereas
a typical mass spectrometer source for radio frequency instruments (0.1 mm extraction
orifice), produces many decades lower output. An embodiment particularly suited
for treating tumors as well as methods for using it are disclosed.
