This work showed how it was possible to extract diffusion coefficients for 35Ar atoms diffusing out of graphite targets from release time measurements by using an analytical description of the release times. The diffusion coefficients and efficiencies were compared with results obtained by using a so-called continuous method. Agreement was obtained with regard to 4 points: 1) the release of 35Ar from 1µ grain-size graphite was faster than that from graphite with a larger grain size, 2) in this graphite, the release efficiency of 35Ar was close to 100% at above 1500C, 3) the response time of the ion source had to be taken into account in order to extract the diffusion coefficient from the time-response of the production system, and 4) in spite of efforts to make systematic measurements of the diffusion coefficient using a dedicated system, the differences between the results emphasized the difficulty of obtaining absolute values of this coefficient.

Measurement of the Ar Diffusion Coefficient in Graphite at High Temperature by the ISOL Method. Eléon, C., Jardin, P., Thomas, J.C., Saint-Laurent, M.G., Huet-Equilbec, C., Alvès Condé, R., Angélique, J.C., Boilley, D., Cornell, J., Dubois, M., Franberg, H., Gaubert, G., Jacquot, B., Köster, U., Leroy, R., Maunoury, L., Orr, N., Pacquet, J.Y., Pellemoine, F., Stodel, C., Turrion, M.: Nuclear Instruments and Methods in Physics Research B, 2008, 266, 4284-8