Richard A. Muller is an American physicist and emeritus professor of physics at the University of California, Berkeley. He was also a faculty senior scientist at the Lawrence Berkeley National Laboratory. In early 2010, Muller and his daughter Elizabeth Muller founded the group Berkeley Earth, an independent 501(c)(3) non-profit aimed at addressing some of the major concerns of the climate change skeptics, in particular the global surface temperature record. In 2016, Richard and Elizabeth Muller co-founded Deep Isolation, a private company seeking to dispose of nuclear waste in deep boreholes.

Accelerator mass spectrometry (AMS) is a form of mass spectrometry that accelerates ions to extraordinarily high kinetic energies before mass analysis. The special strength of AMS among the different methods of mass spectrometry is its ability to separate a rare isotope from an abundant neighboring mass. The method suppresses molecular isobars completely and in many cases can also separate atomic isobars. This makes possible the detection of naturally occurring, long-lived radio-isotopes such as 10Be, 36Cl, 26Al and 14C.