15 September 2017
Vol 357, Issue 6356

About The Cover

Cover image expansion

COVER Two-kilogram prototype of a 14.6-kilogram cesium iodide crystal used for coherent neutrino detection. The scintillator is encapsulated in ultrapure electroformed copper developed at Pacific Northwest National Laboratory. Ancient, radioisotope-free lead recovered from a Spanish galleon is used to block radioactive emissions from electronic components above the photomultiplier. See pages 1098 and 1123. For more on the process behind the cover image, see
Photo: Jean Lachat/University of Chicago