Simulcam Instrument. a Standof Raman Setup for Planetary Exploration Simulation.

This setup is based on previous developments from our group to demonstrate the feasibility of standoff Raman spectroscopy in planetary exploration. In this setup, called SimulCam, the instrument performs Time Resolved Raman Spectroscopy and Time Resolved Luminiscence, in certain experiments a side mounted system can be used to acquire standoff LIBS (200-850 nm in atmosphere). The spectrometer is a transmission spectrometer with two tracks, covering a range from 532 nm to 690 nm, which corresponds to a coverage of up to 4300 cm-1 for Raman spectroscopy, enough for the most common Raman features from minerals and organics. This spectrometer uses an Andor iStar intensified camera as detector, that includes the synchronism electronics between the laser and the photocatode. Time resolving ability in this setup goes down to a 3 ns in gatewidth, amd allows us to select between different emissions (Raman or luminescence) or adapt to different distances of the target or to the intrinsic jitter times in the system. The system can also integrate several discharges of the intensifier in one readout of the CCD, or capture single laser shots. For collection optics this instrument uses a SLR lens from Canon, with 300 mm focal at f:4. This objective is attached to a Raman probe where the Rayleigh emission is filtered before its conduction to the spectrometer through a fibre bundle.

The final element in play, the laser, is a frequency-doubled Nd:YAG, providing pulses of 120 mJ and 6 ns width in 532 nm. With the ability to adapt the irradiance thanks to its electronically controlled power (from 60% to 100%) and the use of a variable beam expander. With this setup we are participating in different experiments, lately mostly related to scientific support of SuperCam. In this line we have been able to detect organics associated to sulfates in concentrations down to a 1%, evaluate the detections of salts such as perchlorates or re-evaluate the analytical method in literature for the determination of FoFa ratio in olivines, or the identification of feldspars, adapting these methods to the reality of a standoff instrument, that usually provides lower SNR and resolution than benchtop instruments.