  Recently, there is an increasing need for $H_{2}^+$ and $H_{3}^+$ ion
sources. One example are ion therapy facilities, where $C^{4+}$ and $H_{3}^+$
ion beams along the linac are of great interest. Another example is a $H_{2}^+$
test beam for linacs finally operated with intense deuteron beams. At
Frankfurt, a simple proton ion source is needed to test a new kind of beam
injection into a magnetic storage ring\cite{EPAC08}\cite{EPAC06}. This article
describes a volume type ion source which can deliver upto $3.05~mA$ beam
current at $10~keV$ in stable dc operation. It is a hot filament driven ion
source which can provide high fractions of $p$, $H_{2}^+$ or $H_{3}^+$,
depending on the operation settings.
