a b s t r a c tThis work evaluates the changes in radiative properties of two decomposing carbonaceous porous materials, each composed of two semi-transparent, homogeneous and isotropic phases. The understanding of the complex dependence of macroscopic optical behaviour on material microstructure, bulk phase properties and the wavelength of incoming radiation is paramount for modelling, design and optimisation of systems incorporating such media. Experimental and numerical techniques were combined to solve the homogenised radiative transfer equations using Monte Carlo ray tracing in the limit of geometrical optics. Effective radiative properties required by these equations were determined by Monte Carlo techniques using the exact 3D microstructures of the samples, obtained through high-resolution synchrotron computed tomography. This methodology is applied to a medium density carbon phenolic and a high density graphite reinforced polymer composite, each composed of semi-transparent solid and fluid phases. The extent of material decomposition is seen to affect the absorption behaviour of both samples. This effect is more obvious in the lower density carbon phenolic, where an 18% increase in absorptance is observed due to decomposition, compared to an increase of just 2% for the graphite. A library of absorption data is presented for use in continuum heat transfer modelling of similar chemically reacting macroporous carbon composites.

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A radiation hard image sensor HAS2 was chosen for the Juice Monitoring Camera, an important instrument to monitor the status of the JUpiter ICy moons Explorer (JUICE) spacecraft and to take wide-angle images of the Jovian system. To improve the perception, a radiation-hardened, non-organic color filter array (CFA) was deposited on the sensor silicon, with four colors: red, green, blue, and yellow. In this paper we present the results of the radiation tests on these customized image sensors. First, results on the total ionizing dose (TID) test up to 57 krad confirm that both the image sensor and the deposited CFA are resistant to gamma radiation in the measured range. Also, single event effects (SEE) measurements up to LET of 100 MeV•cm 2 /mg were performed. Three types of events were considered: single event latch-up (SEL), single event upset (SEU), and finally single event functional interruption (SEFI). Since only one SEL was registered on one of the samples at 62.5 MeV•cm 2 /mg there was no further analysis on this event. Based on the experimental results, the cross sections have been calculated for SEU and SEFI. These results were used as input for the SEE analysis with the CRÈME96 software. The rates of about 10 -4 and 10 -5 events/device/day were obtained for SEU and SEFI for quiet environment, respectively.

The effects of phenolic pyrolysis on flow radiation were investigated experimentally in the X2 expansion tube for a Venus entry flow. A carbon phenolic aeroshell was subjected to a flow with a flight equivalent velocity of 9.59 km/s. Emission spectroscopy was used to measure boundary layer radiation in part of the visible wavelength range (615-700 nm) and compared to measurements taken with a cold steel model. The spectral radiance measured off the carbon phenolic model was seen to increase for C (658.942 nm) and N (672.262 nm) atomic lines, demonstrably due to surface reactions and outgassing. These experimental spectra were compared to numerical spectra produced by 2D axisymmetric CFD simulations coupled to a radiation solver. Nomenclature ρDensity, kg m −3 ∂vBounding surfacê n Outward-facing normal of control surface V Volume, m 3

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