In the future hadron facility FAIR the HESR ring will supply antiprotons in the
momentum range 1.5-15 GeV/c as projectiles for charm, strangeness and Form Factor physics.
For all the reactions it will be necessary to use internal targets and in particular, for the
double strangeness production, a solid 12C target will be used. Inserting a solid target inside
an antiproton ring creates two main problems: a large background on the detectors due to the
overwhelming amount of annihilations and a strong depletion of the beam due to all the hadronic
and Coulomb interactions of the antiprotons with the 12C nuclei. The width of the target plays
a crucial role in minimizing these unwanted eects. Two wire-shaped prototypes have been
already realized, starting from a thin diamond disk. The wire shape has been obtained by using
a femto-edge laser. One prototype has been submitted to irradiation by protons of 1.5 MeV and
to simultaneous Back-Scattering control to test the impurity level, the surface 12C density, the
radiation hardness and eventual phase modications during irradiation. Both the prototypes
have been submitted to Micro-Raman spectroscopy in order to scan the carbon phases along
the width. The results show performances which satisfy the experimental requirements.