In Situ Raman Spectroscopy Monitoring of Material Changes During Proton Irradiation

Area of Science:

• Astrobiology
• Materials Science
• Planetary Science

Background:

• Organic molecules are key biosignatures in the search for extraterrestrial life.
• Understanding organic molecule preservation under space radiation is crucial for astrobiology.
• Ionic irradiation fluences on planetary bodies like Mars can span millions to billions of years.

Purpose of the Study:

• To assess the preservation and detectability of organic molecules under ionic irradiation.
• To validate an in situ Raman spectroscopy setup for studying irradiated materials.
• To investigate the effects of proton irradiation on polymer samples.

Main Methods:

• In situ Raman spectroscopy was used to monitor polymer samples during proton irradiation.
• A novel Raman optical probe was employed within a dedicated irradiation chamber.
• Proton irradiation was conducted with a final fluence of 3.10^14 particles/cm^2.

Main Results:

• Proton irradiation increased the background signal level in Raman spectra.
• This increase is attributed to polymer chain scission and defect creation from atom displacements.
• The feasibility of in situ Raman analysis under irradiation conditions was demonstrated.

Conclusions:

• The developed Raman setup is suitable for in situ analysis of organic materials under irradiation.
• Further improvements, including micro-Raman and temperature control, are needed for enhanced resolution and analysis.
• This research contributes to understanding the fate of organic molecules in space environments.