New Mass Spectrometer Designs for Astrobiology Applications

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New Mass Spectrometer Designs for Astrobiology
Applications

• F. Scott Anderson
• NAI-UH

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Program Origins (AstroBio!)
Cryobot Mk 2
Cryobot Mk 1

• Need in-situ chemistry instrument for H2O from
  Cryobot
• In-situ ice coring-melting system for Mars,
  Europa, Earth
• Water chemistry, climate history, biomarkers

Banff Test
Svalbard Test
JPL Test
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Why Mass Spectroscopy (MS)

• Instead of other promising new technologies?
• MS benefits
• Capable of a broad range of measurements
• Detailed sensitive analysis of individual
  species
• Gold standard of laboratory analysis
• Elemental chemistry, organics, biomarkers
• Miniaturization for in-situ application remains a
  development area

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Program Origins

• This led to
• Proposals to develop a in-situ MS for liquids
• Proposals for other MS applications
• Success gt Facility In-Situ MS Design
• 2 Labs (one under construction)
• Leveraged funding
• MIDP, NAI, PIDDP, NSF, DIA, ONR
• 2.8M / year
• NAI funding 30K / yr PostDocs
• Partners SwRI, Sandia, PaceTech
• Intellectual leverage
• Ion Microprobe (NAI Co-I Keil/Huss)
• Microbiology (NAI PostDocs)
• Isotope Laboratory

New Lab
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Focus of In-Situ MS Facility

• Developing three mass spectrometers
• Vacuum assisted nano-ElectroSpray Ionization
  Rotating Field Mass Spectroscopy (ESI-RFMS)
• Liquid chemistry, heavy organics
• Electron Impact (EI)-RFMS for gases
• Laser Ablation Resonance Ionization Multi-Bounce
  Time of Flight Mass Spectroscopy (LA-RI-MB-TOF)
• Solid chemistry, radiometric dates
• Funded for additional future development (SI)
• Soon to be proposed
• Cycloidal Focus Mass Spectrometer (CFMS)
• Liquids, D/H ratio

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1.A ESI Astrobiology

• ESI-MS new but now common technique for studying
  heavy organic molecules
• Peptides
• Proteins
• DNA
• Low flow rates typically result in more
  sensitivity
• Demonstrated 10-18M detection _at_ lt10 nl / min
• Carbonic Anhydrase important enzyme for transport
  of CO2 by red blood cells

Valaskovic et al., Science, 1996
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1.A How ESI-RFMS works

• ESI provides soft ionization of liquids
• A liquid is sprayed through 1-100µm needle
  electrified _at_ 500-5000 V
• The droplets evaporate and explode to very small
  sizes, forming molecular ions
• RF dispersion uses quadrature to move ions
• A mass disperser (spectrograph)
• No upper limit to mass range
• Models indicate resolving power of 1000

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1.A ESI Schematic
Drying Gas
Drying Gas
MS
Skimmer
Fluid
Tip 1-100 µm
Detector
Evaporation
Explosion
HV
Molecular Ions
Atmosphere
Low Vacuum
High Vacuum
Mass Spectrometer
ESI Needle
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1.A RF Dispersion
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1.A ESI-RFMS Prototype
RF Disperser

• New Construction
• Mark V ESI Needle Connection
• Einzel lens for focusing ions
• RF Stage w/Aiming and RF
• Simple Faraday cup detector
• Data supports models shows promise

Lens
ESI
Detector
RF Disperser
Lens
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1.B Electron Impact (EI) Gases
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1.A/B RFMS 1000-g tolerant
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1.C LA-RI-MS

• Goal
• In-situ radiometric date (Rb/Sr)
• Elemental abundance
• Simple sampling strategy
• Relevance for Astrobiology
• Date
• Chemical environment
• Implications for geology
• Normative mineralogy
• Mantle evolution
• Relationships with meteorites

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1.C Rb/Sr Geochronology
l1.42x1011y1

• Requirement
• ID 87Rb-87Sr R300K
• 87Sr/86Sr .02
• 87Rb/86Sr 1

Faure, 1986
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1.C LA-RI-MB-TOF Method

• 87Rb-87Sr Resonance Ionization
• Ionizes only a single element
• Enables 87Sr/86Sr .02
• 87Rb/86Sr 1 Laser Ablation
• Proven to 0.6
• Using UV or fs/ps laser

Sr RI MS test, error 0.17, but integration time
x103 low, final error x30 better
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1.C How LA-RI-MS Works

• Laser ablation gt 99.9 Neutrals, 0.1 Ions
• Remove ions
• Use tuned laser to RI neutral element of choice
• Detect with MS

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1.C Microlaser Technology
Microchip Size 1 mm3
US Patent No. 5,394,413 Passively Q-Switched
Picosecond Microlaser by Zayhowski
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1.C Single-Pass Two-Stage Microchip YVO4 Amplifier

• Previous Megachip design illustrates 5-10X
  amplification/stage

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1.C Master Oscillator 5 PassPower Amplifier
Amplifier Stages
Phase Control Waveplates
Microchip Laser
Isolator to prevent frequency shifting due Cr4
Photo-Bleaching from re-imaged back reflected
light
Diode Bar
NdYVO4
NdYVO4
Diode Bar
NdYVO4
Diode Bar
5
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1.C Principle of MB-TOF-MS
6 bounce Ar spectrum
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2. Funded Development Path
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3. Future Cycloidal Focus MS

• Primarily for low AMU
• Use for in-situ studies of origin of H2O
  background D/H
• Climate change