X-ray diffraction experiments show that solid 4He grown in aerogel is highly polycrystalline, with a hcp crystal structure (as in bulk) and a crystallite size of approximately 100 nm. In contrast to the expectation that the highly disordered solid will have a large supersolid fraction, torsional oscillator measurements show a behavior that is strikingly similar to high purity crystals grown from the superfluid phase. The low temperature supersolid fraction is only ~3x10-4 and the onset temperature is ~ 100 mK.
@article{arxiv.0808.2871,
title = {Torsional oscillator and synchrotron x-ray experiments on solid 4He in aerogel},
author = {N. Mulders and J. T. West and M. H. W. Chan and C. N. Kodituwakku and C. A. Burns and L. B. Lurio},
journal= {arXiv preprint arXiv:0808.2871},
year = {2009}
}