Unidirectional carbon-carbon (C-C) composite tiles have been designed, manufactured, and tested to be used as thermal imaging diagnostic of high energy particle beams. The tiles intercept the particle beam eroding the carbon surface and producing debris, while a plasma forms due to beam-gas interaction in front of the tiles. Carbon fibres are aligned along the tile thickness in order to transfer the thermal pattern from the front to the rear surface. Thermal pattern divergence is limited by the very high thermal conductivity of carbon fibre and pattern aspect ratio is preserved by applying the same manufacturing parameters in any transversal direction. Thermal radiation is detected at the tile rear surface by thermographic cameras producing thermograms correlated to particle beam energy, distribution, and exposure time [1]. Different manufacturers have been involved in the project to develop the unidirectional C-C composite and tile prototypes have been tested [2]. Thermal patterns with spatial resolution of few mm and time resolution of 100 ms have been measured on C-C tiles exposed to hydrogen accelerated to produce up to 10 MW/m2 in the GLADIS ion beam test facility by observing material heterogeneousness and temperature distribution with maximum value of 800 °C in vacuum. Multiphysics transient non-linear parametric finite element models have been developed to simulate thermal transfer inside tiles, thermal patterns at surfaces, and thermal deformations of tiles by varying distribution and peak of the power density. Screening shields have been simulated to investigate experimental effects on tested tiles. Thermal gradients, heat fluxes through the thermal path, characteristic time constant, and hoop deformations around the applied power density have been analysed and discussed to recognise the tile behaviour. Models have been validated by comparing outputs from analytical calculations and experimental measurements. Then, model geometry and parameters can be changed to extrapolate the behaviour of the full diagnostic to be used in the ITER Neutral Beam Test Facility with expected specific power up to 20 MW/m2 [3].