Instrumentation development for planetary in situ 40Ar/39Ar geochronology

Morgan, L., Davidheiser-Kroll, B., Munk, M., van Bibber, K., Harkness, P. , Lee, M., Wright, I., Gupta, S. and Mark, D. (2014) Instrumentation development for planetary in situ 40Ar/39Ar geochronology. In: Goldschmidt Conference, Sacramento, CA USA, 8-13 June 2014,

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The key to understanding the history of planetary and asteroidal bodies is the accurate and precise determination of the timescale over which they developed. Absolute dating of planetary materials remains a primary goal of planetary research. Given the success of recent unmanned missions to Mars (e.g., Spirit, Opportunity, Curiosity) in understanding geological processes, development of an <i>in situ</i> numerical dating instrument packages for future robotic missions is a logical next step. Several ongoing programs of research are seeking to develop instrument packages for <i>in situ</i> application of the K-Ar technique (e.g., [1,2]). For terrestrial rocks, the K-Ar method has largely been replaced by the <sup>40</sup>Ar/<sup>39</sup>Ar technique, which can determine thermal histories and provide internal reliability assurance. The <sup>40</sup>Ar/<sup>39</sup>Ar method is the most promising geochronometer for obtaining accurate ages and thermal histories for rocks on the Martian surface but relies on the <sup>39</sup>K(n,p)<sup>39</sup>Ar reaction so that <sup>39</sup>Ar can be measured as a proxy for the parent element K. As the mass and power requirements of a nuclear reactor are not compatible with spaceflight, an alternative neutron source must be employed. Here, we examine the potential of <sup>252</sup>Cf, which generates neutrons through its decay by spontaneous fission. We will present initial results from neutron modeling and technological considerations towards the development of an <i>in situ</i> dating package, including a <sup>252</sup>Cf neutron source, a subcritical <sup>235</sup>U neutron multiplier, quadrupole noble gas mass spectrometry, and sample drilling and handling strategies.

Item Type:Conference Proceedings
Glasgow Author(s) Enlighten ID:Morgan, Dr Leah and Mark, Professor Darren and Harkness, Professor Patrick
Authors: Morgan, L., Davidheiser-Kroll, B., Munk, M., van Bibber, K., Harkness, P., Lee, M., Wright, I., Gupta, S., and Mark, D.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
College of Science and Engineering > Scottish Universities Environmental Research Centre

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