  Bragg spectroscopy is one of the best established experimental methods for
high energy resolution X-ray measurements and has been widely used in several
fields, going from fundamental physics to quantum mechanics tests, synchrotron
radiation and X-FEL applications, astronomy, medicine and industry. However,
this technique is limited to the measurement of photons produced from well
collimated or point-like sources and becomes quite inefficient for photons
coming from extended and diffused sources like those,for example, emitted in
the exotic atoms radiative transitions. The VOXES project's goal is to realise
a prototype of a high resolution and high precision X-ray spectrometer, using
Highly Annealed Pyrolitic Graphite (HAPG) crystals in the Von Hamos
configuration, working also for extended sources. The aim is to deliver a cost
effective system having an energy resolution at the level of eV for X rays
energies from about 2 keV up to tens of keV, able to perform sub-eV precision
measurements with non point-like sources. In this paper, the working principle
of VOXES, together with first results, are presented.
