  We present results on a free-space atom interferometer operating on the first
order magnetically insensitive |F=1,mF=0> -> |F=2,mF=0> transition of
Bose-condensed 87Rb atoms. A pulsed atom laser is output-coupled from a
Bose-Einstein condensate and propagates through a sequence of two internal
state beam splitters, realized via coherent Raman transitions between the two
interfering states. We observe Ramsey fringes with a visibility close to 100%
and determine the current and the potentially achievable interferometric phase
sensitivity. This system is well suited to testing recent proposals for
generating and detecting squeezed atomic states.
