Silicon Photomultipliers (SiPMs) are attractive candidates for light
detectors for next generation liquid xenon double-beta decay experiments, like
nEXO. In this paper we discuss the requirements that the SiPMs must satisfy in
order to be suitable for nEXO and similar experiments, describe the two test
setups operated by the nEXO collaboration, and present the results of
characterization of SiPMs from several vendors. In particular, we find that the
photon detection efficiency at the peak of xenon scintillation light emission
(175-178 nm) approaches the nEXO requirements for tested FBK and Hamamatsu
devices. Additionally, the nEXO collaboration performed radioassay of several
grams of bare FBK devices using neutron activation analysis, indicating levels
of 40K, 232Th, and 238U of the order of <0.15, (6.9e10-4 - 1.3e10-2), and <0.11
mBq/kg, respectively.Comment: Version as accepted to Transaction of Nuclear Science. 12 pages, 15
figures (one figure removed following peer review), 8 tables (1 table added
following peer review