Von Hamos (VH) spectrometers are widely used in several fields, ranging from pure physics
applications to very different types of practical ones. However, these type of Bragg spectrometers
are usally implied in high rate - high resolution experiments, where the typical source size can be
as low as few tens of microns. These limitations prevented them to be used as X-ray detectors for
high precision exotic atoms spectroscopy, except for cases where extremly high flux beams could
be employed, like in the case of pionic atoms at PSI. Recently, we developed a VH spectrometer,
within the VOXES collaboration at the INFN Laboratories of Frascati, making use of Highly
Annealed Pyrolitic Graphite (HAPG) mosaic crystals and a X-ray beam optics optimization,
which could be used for source sizes up to few mm, (in the Bragg plane), some tens of mm in
the sagittal plane and, if gaseous sources are used, of several tens of cm in the X-ray propagation
direction. Such kind of a spectrometer could be used, for example, to open a new era in the field
of exotic (kaonic) atoms precision measurements, delivering data with unprecedented precision
to the (strangeness) nuclear physics community. In this paper we present, together with an overall
description of the VOXES spectrometer and of its main characteristics in terms of resolution and
efficiencies, a comparison between a kaonic helium 3𝑑 → 2𝑝 transition spectrum measured with
Silicon Drift Detectors and ray tracing simulated spectra of how the same transition would appear
if measured with our apparatus.