  Production of neutrinos is abundant at LHC. Flavour composition and energy
reach of the neutrino flux from proton-proton collisions depend on the
pseudorapidity $\eta$. At large $\eta$, energies can exceed the TeV, with a
sizeable contribution of the $\tau$ flavour. A dedicated detector could
intercept this intense neutrino flux in the forward direction, and measure the
interaction cross section on nucleons in the unexplored energy range from a few
hundred GeV to a few TeV. The high energies of neutrinos result in a larger
$\nu$N interaction cross section, and the detector size can be relatively
small. Machine backgrounds vary rapidly while moving along and away from the
beam line. Four locations were considered as hosts for a neutrino detector: the
CMS quadruplet region (~25 m from CMS Interaction Point (IP)), UJ53 and UJ57
(90 and 120 m from CMS IP), RR53 and RR57 (240 m from CMS IP), TI18 (480 m from
ATLAS IP). The potential sites are studied on the basis of (a) expectations for
neutrino interaction rates, flavour composition and energy spectrum, (b)
predicted backgrounds and in-situ measurements, performed with a nuclear
emulsion detector and radiation monitors. TI18 emerges as the most favourable
location. A small detector in TI18 could measure, for the first time, the
high-energy $\nu$N cross section, and separately for $\tau$ neutrinos, with
good precision, already with 300 fb$^{-1}$ in the LHC Run3.
