Calibration of the SHERLOC Deep Ultraviolet Fluorescence-Raman Spectrometer on the Perseverance Rover.

Area of Science:

• Planetary Science
• Spectroscopy
• Astrochemistry

Background:

• The Perseverance Rover's SHERLOC instrument analyzes Martian surface samples using deep ultraviolet Raman and fluorescence (DUV R/F) spectroscopy.
• DUV R/F spectroscopy employs a 248.6 nm laser to detect and classify chemical and mineralogical compositions by analyzing scattered photons and fluorescence emission.

Purpose of the Study:

• To describe the wavelength calibration of the SHERLOC spectrometer.
• To ensure accurate analysis of mineralogy and chemistry of Martian materials.

Main Methods:

• Utilized a compact DUV R/F spectrometer with a spectral range of 249.9 nm to 353.6 nm.
• Developed a custom design to project high-resolution Raman and low-resolution fluorescence spectra onto a single charge-coupled device.
• Implemented a segmented, nonlinear wavelength calibration to account for curved spectral illumination.

Main Results:

• The SHERLOC spectrometer optimizes resolution for Raman spectra and wavelength range for fluorescence spectra.
• The calibration method addresses the curved spectral illumination on the charge-coupled device.
• Accurate calibration is essential for interpreting the mineralogy and chemistry of Martian samples.

Conclusions:

• The described wavelength calibration is critical for the SHERLOC instrument's success in analyzing Martian samples.
• Accurate spectral data enables a deeper understanding of the potential for past life on Mars.