Genesis : the search for origins : the curation and contamination control of returned solar wind samples

The purpose of the studies carried out in this thesis was to aid in the curation of samples of solar wind returned to earth on the Genesis spacecraft. An experimental study was carried out to aid development of a set of protocols for the laser scribing and subdivision of the Genesis silicon collector array materials. Optimisation of the scribing speed and the positioning of the focal point of the laser were carried out. It was found that scribe width was independent of both factors. Slower scribing speeds were found to produce deeper scribes, while heating effects were minimised with faster speeds. Vertical movement of the stage of 5 pm/pass was found to optimise the focal point of the laser, and minimise heating effects. A procedure to measure the flexural modulus of samples was proposed to quantify the success of the optimisation of the scribing parameters. A theoretical study was carried out to develop a predictive kinetic model for the oxidation of the silicon collector arrays during flight. The mechanism proposed for the increase in oxide thickness over that present pre-flight was the formation of a less-dense suboxide at the SiO₂/Si interface. The driving force is the elevated temperature of the collectors during collection, in the vacuum of space.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Jackson, Benjamin K

Advisor dc:contributor.advisor

• Samuel M. Allen.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/33615

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/33615