Curium-244 alpha-sources for space research

Special alpha-proton-X-ray spectrometric complexes (APXS) have been develop ed in order to perform chemical analyses of the Mars atmosphere and rock su rface compounds by alpha back-scattering, alpha-proton measurements, and X- ray fluorescence. The sources were prepared by high temperature condensatio n of metal curium vapour onto silicon substrates. They are silicon disks wi th curium-244 fixed on their surfaces as a silicide. The sources have overa ll dimensions as follows: disk diameter 8 mm; thickness 0.3 mm; and 6 mm di ameter active spot. The source activities are 5 +/- 1 mCi and the alpha-lin e half-widths are equal to (1.7-2.5) and (2.9-4.5)% of full width at 10% of Maximum (Maximum is equal to 5.8 MeV). Thermovacuum (from 196 to 1000 degr ees C), mechanical, and resource tests were performed and demonstrated that the sources maintained their characteristics. The applicability of the sou rces for the above-mentioned analytical purposes was confirmed during NASA Mars Pathfinder mission. (C) 2000 Published by Elsevier Science Ltd.