Editing Alpha particle X-ray spectrometer (section)

{{Use dmy dates|date=September 2021}}
:''APXS is also an abbreviation for '''AP'''ache e'''X'''ten'''S'''ion tool, an extension for [[Apache HTTP Server|Apache]] web servers.''

{{multiple image|perrow = 2|total_width=300
| image1 = MER APXS PIA05113.jpg
| image2 = Back of Sojourner and its Alpha Proton X-Ray Spectrometer.png
| image3 = MSL - Alpha Particle X-ray Spectrometer (APXS).jpg
| footer = Alpha particle X-ray spectrometer ''(top left)'', APXS at the back of the Mars Pathfinder [[Sojourner rover|''Sojourner'' rover]] ''(top right)'', MSL [[Curiosity (rover)|''Curiosity'']]'s alpha particle X-ray spectrometer, with a ruler ''(bottom)''.
}}

An '''alpha particle X-ray spectrometer''' ('''APXS''') is a [[spectrometer]] that analyses the chemical element composition of a sample from scattered [[alpha particle]]s and fluorescent [[X-ray]]s after a sample is irradiated with alpha particles and X-rays from radioactive sources.<ref>
{{cite journal
 |title=The Alpha-Scattering Technique of Chemical Analysis
 |author=Economou, T.E. 
 |author2=Turkevich, A.L. 
 |author3=Sowinski, K.P. 
 |author4=Patterson, J.H. 
 |author5=Franzgrote, E.J.
 |journal=Journal of Geophysical Research 
 |date=1970
 |volume=75
 |issue=32
 |doi=10.1029/JB075i032p06514| pages = 6514
 |bibcode=1970JGR....75.6514E
}}
</ref> This method of analysing the elemental composition of a sample is most often used on space missions, which require low weight, small size, and minimal power consumption. Other methods (e.g. [[mass spectrometry]]) are faster, and do not require the use of radioactive materials, but require larger equipment with greater power requirements. A variation is the '''alpha proton X-ray spectrometer''', such as on the [[Mars Pathfinder|Pathfinder mission]], which also detects [[protons]].

Over the years several modified versions of this type of instrument such as APS (without X-ray spectrometer) or APXS have been flown: [[Surveyor program|Surveyor 5-7]],<ref>
{{cite journal
 |title=Alpha-scattering experiment on Surveyor 7 – Comparison with Surveyors 5 and 6
 |author=Patterson, J.H. 
 |author2=Franzgrote, E.J. 
 |author3=Turkevich, A.L. 
 |author4=Anderson, W.A. 
 |author5=Economou, T.E. 
 |author6=Griffin, H.E. 
 |author7=Grotch, S.L. 
 |author8=Sowinski, K.P.
 |journal=Journal of Geophysical Research 
 |date=1969
 |volume=74
 |issue=25 
 |pages=6120–48
 |doi=10.1029/JB074i025p06120
 |bibcode=1969JGR....74.6120P
}}
</ref> [[Mars Pathfinder]],<ref>
{{cite journal
 |title=Determination of the chemical composition of Martian soil and rocks:The alpha proton X ray spectrometer
 |author=R. Rieder
 |author2=H. Wänke
 |author3=T. Economou
 |author4=A. Turkevich
 |journal=Journal of Geophysical Research
 |date=1997
 |volume=102
 |issue=E2 
 |pages=4027–4044
 |doi=10.1029/96JE03918
 |bibcode=1997JGR...102.4027R|doi-access=free
 }}
</ref> [[Mars 96]],<ref>
{{cite journal
 |title=An Alpha Proton X-Ray Spectrometer for Mars-96 and Mars Pathfinder
 |author=Rieder, R.
 |author2=Wanke, H.
 |author3=Economou, T.
 |journal=American Astronomical Society
 |date=1997
 |volume=28 
 |pages=1062
 |bibcode=1996DPS....28.0221R
 }}</ref> [[Mars Exploration Rover]],<ref>
{{cite journal
 |title =The new Athena alpha particle X-ray spectrometer for the Mars Exploration Rovers
 |author = R. Rieder
 |author2 = R. Gellert
 |author3 = J. Brückner
 |author4 = G. Klingelhöfer
 |author5 = G. Dreibus
 |author6 =  A. Yen
 |author7 = S. W. Squyres
 |journal = Journal of Geophysical Research
 |date = 2003
 |volume = 108
 |issue =E12
 |pages = 8066
 |doi = 10.1029/2003JE002150
 |bibcode=2003JGRE..108.8066R
|doi-access = free
 }}</ref> [[Phobos program|Phobos]],<ref name=phobos>
{{cite journal
 |title=In-Situ Measurement of the Surface Composition of the Mars Moon Phobos: The Alpha-X Experiment on the Phobos Mission
 |journal=Abstracts of the Lunar and Planetary Science Conference
 |date=1988
 |volume=19
 |pages=511
 |bibcode=1988LPI....19..511H
 |last1=Hovestadt
 |first1=D.
 |last2=Andreichikov
 |first2=B.
 |last3=Bruckner
 |first3=J.
 |last4=Economou
 |first4=T.
 |last5=Klecker
 |first5=B.
 |last6=Kunneth
 |first6=E.
 |last7=Laeverenz
 |first7=P.
 |last8=Mukhin
 |first8=L.
 |last9=Prilutskii
 |first9= A.
 |display-authors=8
}}</ref> [[Mars Science Laboratory]] and the [[Philae (spacecraft)|Philae comet lander]].<ref name="philae-jgu" /><ref name=Philae>
{{cite web
 |title=Alpha Proton X-ray Spectrometer (APXS) – Mission Name: Philae
 |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=2004-006C-03
 |publisher=[[NASA]]
 |date= 26 August 2014
}}</ref> APS/APXS devices will be included on several upcoming missions including the [[Chandrayaan-2]] [[lunar rover]].<ref>
{{cite web
 |title=Payloads for Chandrayaan-2 Mission Finalised 
 |url=http://www.isro.gov.in/pressrelease/scripts/pressreleasein.aspx?Aug30_2010 
 |date=2010-08-30 
 |accessdate=2012-08-07 
 |work=isro.gov.in 
 |publisher=[[Indian Space Research Organisation]] 
 |url-status=dead 
 |archiveurl=https://web.archive.org/web/20121015032050/http://isro.gov.in/pressrelease/scripts/pressreleasein.aspx?Aug30_2010 
 |archivedate=15 October 2012 
}}</ref>