Impact of the layout of the ITER Radial Neutron Camera in-port system on the measurement of the neutron emissivity profile

The Radial Neutron Camera (RNC), located in the ITER Equatorial Port Plug 1 (EPP1), is designed to provide the neutron emissivity profile through the measurement of the neutron flux along several collimated channels. The present design of the RNC is based on collimating structures: an ex-port system viewing the plasma core and an in-port system composed by two detector cassettes viewing the upper and lower plasma edges. gn of the EPP1 in which the diagnostics are installed in three completely independent vertical drawers is under study. In this frame, space optimization and integration issues suggest two possible solutions for the layout of the in-port RNC cassettes: the first one in which both cassettes are located in a side drawer; the second one in which the two cassettes lie in the central drawer, on opposite sides of the ex-port RNC cut-out. aper describes the work performed to assess the impact of the two different in-port system layouts on the capability of the RNC to measure the neutron emissivity profile by means of MCNP and diagnostic performance calculations. sults of the analysis provide guidelines for the integration of the RNC into the EPP1 showing that the proximity of the in-port cassettes to the ex-port cut-out strongly increases the amount of uncollimated and scattered neutrons at the detector positions, thus reducing the diagnostic measurement capability.