  We report the first detection of the J = 1 - 0 (102.6 GHz) rotational lines
of CF+ (fluoromethylidynium ion) towards CygX-N63, a young and massive
protostar of the Cygnus X region. This detection occurred as part of an
unbiased spectral survey of this object in the 0.8-3 mm range, performed with
the IRAM 30m telescope. The data were analyzed using a local thermodynamical
equilibrium model (LTE model) and a population diagram in order to derive the
column density. The line velocity (-4 km s-1) and line width (1.6 km s-1)
indicate an origin from the collapsing envelope of the protostar.
  We obtain a CF+ column density of 4.10e11 cm-2. The CF+ ion is thought to be
a good tracer for C+ and assuming a ratio of 10e-6 for CF+/C+, we derive a
total number of C+ of 1.2x10e53 within the beam. There is no evidence of carbon
ionization caused by an exterior source of UV photons suggesting that the
protostar itself is the source of ionization. Ionization from the protostellar
photosphere is not efficient enough. In contrast, X-ray ionization from the
accretion shock(s) and UV ionization from outflow shocks could provide a large
enough ionizing power to explain our CF+ detection.
  Surprisingly, CF+ has been detected towards a cold, massive protostar with no
sign of an external photon dissociation region (PDR), which means that the only
possibility is the existence of a significant inner source of C+. This is an
important result that opens interesting perspectives to study the early
development of ionized regions and to approach the issue of the evolution of
the inner regions of collapsing envelopes of massive protostars. The existence
of high energy radiations early in the evolution of massive protostars also has
important implications for chemical evolution of dense collapsing gas and could
trigger peculiar chemistry and early formation of a hot core.
