Small-angle X-ray scattering measurements of helium-bubble formation in borosilicate glass

Author(s) of this paper may load this reprint on their own web site provided that this cover page is retained. Republication of this article or its storage in electronic databases or the like is not permitted without prior permission in writing from the IUCr. Small-angle X-ray scattering (SAXS) measurements have been performed to study helium-bubble formation in borosilicate glass. Helium was introduced by He + implantation over an energy range of 1 to 2 MeV to give a uniform distribution over $1 mm depth. The implanted dose was varied from 9 Â 10 13 to 2.8 Â 10 16 ions cm À2 , corresponding to a local concentration range of 40 to 11200 atomic parts per million (a.p.p.m.) averaged over the implantation depth. The SAXS response was fit with the Percus–Yevick hard-sphere interaction potential to account for interparticle interference. The fits yield helium-bubble radii and helium-bubble volume fractions that vary from 5 to 15 A ˚ and from 10 À3 to 10 À1 , respectively, as the dose increased from 9 Â 10 13 to 2.8 Â 10 16 cm À2. The SAXS data are also consistent with maximum helium solubility with respect to bubble formation between 40 and 200 a.p.p.m. in the borosilicate glass matrix.