Raman Spectroscopy System for Mars Surface Studies PI Bruce McIntosh

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Raman Spectroscopy System for Mars Surface
StudiesPI Bruce McIntosh

• OBJECTIVES
• Development of a Raman spectrometer
• system suitable for Mars rover operation
• Science Mineral composition determination
• Technology Laser, Probe, Spectrograph, software
  and camera optimization for Mars rover system.
• Integration and testing of portable demonstration
  unit in environment similar to Mars surface

Co-Investigators   Requirements and Instrument
Specs. M. Bonner Denton (U. Ariz.
Tucson) Robert Downs (U. Ariz. Tucson . . .
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FY04 Milestones

• Assembly of Smart Raman Demonstrator Unit (SRDU)
• Specify and procure custom spectrograph and probe
• Receive and integrate custom spectrograph
• Receive and integrate custom Raman probe
• Receive and integrate diode laser module
• Receive and integrate CCD camera assembly
• Design and construct hardware interface subsystem
• Create and Integrate Operating Software Suite
• Customize existing Raman interface for new
  spectrograph
• Create autofocus and hardware I/O program
• Customize existing FTIR search software for Raman
  application
• Format UofA Gem and Mineral Library for search
  module
• Create overall system user interface program

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Technical Accomplishments

• All components for the complete SRDU have been
  received, tested and integrated.
• All subsystems met purchase or design
  specifications
• All custom and modified software operates with
  the hardware
• High quality Raman spectra of reference materials
  and minerals were obtained.
• A set of comparison tests were run on the SRDU
  and a commercial system.
• SRDU performed equally or significantly better on
  all tests including resolution, spectral
  coverage, frequency accuracy, band shape and
  signal to noise ratio.
• All components of required software are complete
  or nearing completion.
• Only UI, auto-focus and search remain to be
  completed

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Integration of SRDU System

• System components received integrated and tested
  as complete Raman analyzer.
• Performance goals for all components were met
  resulting in very high overall spectroscopic
  performance
• Spectrometer, camera and camera controller
  -gt
• Probe and laser in test enclosure -gt

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Testing of Performance with Reference Materials

• Spectra of a set of Raman standard materials was
  performed on SRDU and commercial System
• SRDU has higher resolution.
• SRDU has better band shape.
• SRDU and commercial system both agreed with
  reference frequency values.
• SRDU required lower power and shorter exposures
  to fill A/D converter range.
• Figure to right shows cyclohexane sample spectra
• 114mw 3 seconds Commercial (Purple)
• 29mw 1 second SRDU (Red)

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Testing of Performance with Mineral Samples

• 10 Mars surrogate mineral samples were measured
  with both systems
• SNR Figure of merit ranges from 3 to 50 times
  better than commercial system.
• Spectrum to right shows Olivine with both
  systems.
• RedSRDU PurpleCommercial

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Testing of Auto-focus subsystem

• Auto-focus subsystem
• Captures visible image of laser spot through
  range of focus positions.
• Calculates optimum focus by spot size.
• Captures visible image of sample and superimposes
  laser spot image.
• Olivine sample image is shown to right.
• Red spot near center is laser image.
• Image allows correlation of Raman signal with
  geometry of heterogeneous samples.
• Laser spot at focus is 100u.
• Note that image is through fast F/1.2 lens so
  focus is only clear around laser spot.

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Plans for Next Period

• Complete all remaining software integration tasks
• Optimize performance of auto-focus
• Perform further performance tests
• Complete configuration and specification for
  flight Raman spectrometer
• Prepare SRDU system for testing on NASA
  earthbound rover
• Perform field tests, evaluate results and prepare
  report

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Financial Status Obligations Cost
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Financial Summary

• Prior to June 04 spending was significantly below
  plan.
• This was due to the decision to obtain major
  subsystems (spectrograph and probe) outside
  rather than fabricating them in-house.
• These major items have now been received and
  accounted for bringing the spending and plan back
  into line.

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Action Items/Issues/Concerns

• All issues from last years report have been
  resolved
• Consult with JPL on completion requirements