  Superconformal `type B' quantum mechanical sigma models arise in a variety of
interesting contexts, such as the description of D-brane bound states in an
AdS$_2$ decoupling limit. Focusing on $N=2B$ models, we study superconformal
indices which count short multiplets and provide an alternative to the standard
Witten index, as the latter suffers from infrared issues. We show that the
basic index receives contributions from lowest Landau level states in an
effective magnetic field and that, due to the noncompactness of the target
space, it is typically divergent. Fortunately, the models of interest possess
an additional target space isometry which allows for the definition of a
well-behaved refined index. We compute this index using localization of the
functional integral and find that the result agrees with a naive application of
the Atiyah-Bott fixed point formula outside of it's starting assumptions. In
the simplest examples, this formula can also be directly verified by explicitly
computing the short multiplet spectrum.
