Editing Alpha particle X-ray spectrometer (section)

== Sources ==

Several forms of radiation are used in APXS. They include [[alpha particles]], [[protons]], and [[X-ray]]s. Alpha particles, protons, and X-rays are emitted during the radioactive decay of unstable atoms. A common source of alpha particles is [[curium-244]]. It emits particles with an energy of 5.8 [[MeV]]. X-rays of 14 and 18 keV are emitted in the decay of [[plutonium-240]]. The [[Mars Exploration Rover]]s' Athena payload uses curium-244 with a source strength of approximately {{convert|30|mCi|GBq|lk=on}}.<ref>{{cite web |url=http://athena.cornell.edu/pdf/tb_apxs.pdf |title=Alpha Particle X-Ray Spectrometer (APXS) (2 pages) |author=unknown}}</ref>