| Title |
Monitoring of laser-induced contamination on anti-reflective coating used in mars organic molecule analyzer / |
| Translation of Title |
Marso organinių molekulių analizatoriui skirtos skaidrinančios dangos tyrimas, stebint lazerine spinduliuote sukeltą taršą. |
| Authors |
Šablovskaja, Agneška |
| Full Text |
|
| Pages |
53 |
| Keywords [eng] |
Laser-induced contamination, Mars Organic Molecule Analyzer, anti-reflective coating, UV laser, lazerine spinduliuote sukelta tarša, Marso Organinių Molekulių Analizatorius, skaidrinanti danga, UV lazeris |
| Abstract [eng] |
Monitoring of Laser-Induced Contamination on Anti-reflective Coating Used in Mars Organic Molecule Analyzer New ExoMars rover mission led by ESA will launch on 2018 with the aim of seeking for the manifestations of life. For molecular compound characterization ExoMars rover contains Mars Organic Molecule Analyser (MOMA). To ensure efficient sample preparation nanosecond-pulsed frequency quadrupled (266 nm) passively Q-switched Nd:YAG laser with the intensities of tens to hundreds of Mega Watts in squared centimetre (MW/cm2) is used. Development of high-power laser systems for space applications is not straightforward, analysis of previously failed space missions showed that the lifetime of ultraviolet laser optics in space is lowered due to the vacuum impact on material outgassing rates and laser-induced contamination (LIC). The development of MOMA laser-system and for the qualification of used optical components and materials regarding LIC are entrusted to The Laser Zentrum Hannover e.V. Monitoring of laser-induced contamination growth under near-operation MOMA environmental conditions on AR-coated substrates was performed using two in-situ and one ex-situ investigation methods. Two possible MOMA laser-system contamination sources were tested: epoxy “Loctite Ablestik 2151” and electrical plugs that might contain small amount of organic compounds. After approximately 2,6 mln. laser pulses (72 hours), neither of contaminants cause measurable laser induced contamination growth on optics exposed to 266 nm wavelength, it is confirmed by complementary investigation units. Synthetic air containing oxygen (O2) is used to pressurize Mars Organic Molecule Analyser’s laser compartment for reduction of LIC effect. O2 is known as mitigating LIC factor and plausibly even under 100 mBar pressure oxygen content is sufficient to supress contamination growth. Comparative LIC measurements in different kind of gas mixture and vacuum environments are needed to confirm the mitigation effect. |
| Dissertation Institution |
Vilniaus universitetas. |
| Type |
Master thesis |
| Language |
English |
| Publication date |
2016 |
