Editing Curium (section)

===X-ray spectrometer===
The most practical application of <sup>244</sup>Cm—though rather limited in total volume—is as α-particle source in [[alpha particle X-ray spectrometer]]s (APXS). These instruments were installed on the [[Mars Pathfinder|Sojourner]], [[Mars rover|Mars]], [[Mars 96]], [[Mars Exploration Rover]]s and [[Philae (spacecraft)|Philae comet lander]],<ref>{{cite web|url=http://www.bernd-leitenberger.de/philae.shtml |title=Der Rosetta Lander Philae |publisher=Bernd-leitenberger.de |date=2003-07-01 |access-date=2011-03-25}}</ref> as well as the [[Mars Science Laboratory]] to analyze the composition and structure of the rocks on the surface of planet [[Mars]].<ref>{{cite journal|bibcode=1996DPS....28.0221R|title=An Alpha Proton X-Ray Spectrometer for Mars-96 and Mars Pathfinder|author=Rieder, R.|author2=Wanke, H.|author3=Economou, T.|journal=Bulletin of the American Astronomical Society|volume=28|page=1062|date=September 1996}}</ref> APXS was also used in the [[Surveyor program|Surveyor 5–7]] moon probes but with a <sup>242</sup>Cm source.<ref name="LA2">[http://www.ead.anl.gov/pub/doc/curium.pdf Human Health Fact Sheet on Curium] {{Webarchive|url=https://web.archive.org/web/20060218162709/http://www.ead.anl.gov/pub/doc/curium.pdf |date=2006-02-18 }}, Los Alamos National Laboratory</ref><ref>Leitenberger, Bernd [http://www.bernd-leitenberger.de/surveyor.shtml Die Surveyor Raumsonden] (in German)</ref><ref>{{cite book|chapter-url=https://history.nasa.gov/SP-480/ch9.htm |author=Nicks, Oran |
chapter=Ch. 9. Essentials for Surveyor|publisher=NASA|date=1985|title=SP-480 Far Travelers: The Exploring Machines}}</ref>

An elaborate APXS setup has a sensor head containing six curium sources with a total decay rate of several tens of [[Curie (unit)|millicuries]] (roughly one [[gigabecquerel]]). The sources are collimated on a sample, and the energy spectra of the alpha particles and protons scattered from the sample are analyzed (proton analysis is done only in some spectrometers). These spectra contain quantitative information on all major elements in the sample except for hydrogen, helium and lithium.<ref>[https://web.archive.org/web/20060302040531/http://athena.cornell.edu/pdf/tb_apxs.pdf Alpha Particle X-Ray Spectrometer (APXS)], Cornell University</ref>