The Yutu rover traversed the lunar surface near the Chang'e 3 lander. The Yutu rover was equipped with a device, called the Active Particle-induced X-ray Spectrometer, that used radiation to measure the abundances of elements in rocks and soil. Along its traverse path, the Yutu rover made several measurements with the Active Particle-induced X-ray Spectrometer providing researchers with new data about the composition of the lunar surface.

http://www.raa-journal.org/raa/index.php/raa/article/view/1942