The diffusion properties of graphite targets with 1, 4 and 15 micron microstructures were measured for He and Ar isotopes. A large enhancement of the diffusion efficiency for the smaller microstructure was observed. A releasing efficiency of the order of 100% was obtained for 6He (T1/2 = 806ms) at a temperature of 1600K.

Recent Results at the Sira Test Bench: Diffusion Properties of Carbon Graphite and B4C Targets. Landré-Pellemoine, F., Angelique, J.C., Bajeat, O., Barué, C., Bennett, R., Clapier, F., Ducourtieux, M., Gaubert, G., Gibouin, S., Huguet, Y., Jardin, P., Kandri-Rody, S., Lau, C., Lecesne, N., Leroy, R., Lewitowicz, M., Lichtenthäler, R., Marry, C., Maunoury, L., Obert, J., Orr, N.A., Pacquet, J.Y., Saint-Laurent, M.G., Stodel, C., Rataud, J.P., Villari, A.C.C.: Nuclear Physics A, 2002, 701[1-4], 491c-4