1. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan A MINIATURE MASS SPECTROMETER AS A MELTING PROBE PAYLOAD INSTRUMENT S. Sheridan Planetary and Space Sciences Research Institute, Open University, Milton Keynes, MK7 6AA, U.K. s.sheridan@open.ac.uk

2. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan Talk overview Context: PSSRI research and instrumentation Previous missions Mass spectrometry background Proposed payload for a melting probe Results Future work and conclusions

3. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan PSSRI instrument heritage From sample analysis Lunar samples Meteorites Stardust, Genesis… …to in-situ instruments Cassini-Huygens –SSP, HASI, CDA Beagle 2 –ESS, GAP Rosetta –Ptolemy, MUPUS, GIADA And also enabling research: Medical/life sciences Next generation instruments MEMS

4. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan The Gap instrument GAP on Beagle2 (6 kg) High precision (<<1%) Solid sample inlet (carousel, MPAe) Chemical sample processing Chemical / getter pumps Onboard reference material Magnetic sector mass spectrometer (2kg, 5W) VERY complex sample preparation

5. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan The Ptolemy instrument Ptolemy on Rosetta lander (<5 kg) Medium precision (1 to 5 %) Solid sample inlet (carousel, MPAe) Chemical sample processing 3-4 channel gas chromatograph Ion trap mass spectrometer (500 g, 1 W) MEMS field emission electron source (CCLRC RAL) Digital ion counting (no noise) m/z 10-200 C, H, N, O, (S?) VERY complex sample preparation

6. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan Simple device : Low mass, low power & rugged 3 electrodes –3D trapping field –r.f. (approximately 1 MHz) Electron multiplier detector Ion source Fast scanning (m/z 10-250 in 100 ms) Operates under poor vacuum (1x10 -3 mbar) Software control of one parameter (r.f.) Limitations: Requires sophisticated drive electronics The Ion trap Mass Spectrometer

7. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan PSSRI Ion trap interests Melting probe instrument terrestrial (Lake vostock) Europa, Mars poles EVITA for an Instrumented mole Active EDLS – measuring atmospheric properties (pressure, density, composition during descent e.g. to Mars) Monitoring breathing air Venus Entry Probe, balloon, 100 gram microprobes –A batch of MEMS traps (due in next few weeks) PhD student (1 Oct 2006-) sub-1 kg MS for planetary missions Ongoing work in support of the Rosetta mission Wellcome trust project - Breath analyser

8. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan The EVITA instrument EVITA Evolved Volatiles Ion Trap Analyser Initially developed for instrumented mole deployment Modular system Mission specific sampling method Airless bodies : –Bepicolombo –NEO missions –Luna missions Mars missions –Miniature Turbo pump (130 grams)

9. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan Ion trap on a Melting Probe Instrument proposal: Miniature ion trap (EVITA type) mass spectrometer m/z of 10-200 amu measurement of –either gaseous volatile compounds (if sampling in a non- aqueous environment) –or dissolved organic compounds (if sampling in an aqueous environment) –the above measurements to PPM levels Use technology derived from previous projects Low mass (<500 g) and low power (<1 W)

10. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan Sample inlet / preparation (1) Direct sampling of the environment Feedback enables constant pressure (flow) > 1x10 -10 to 1x10 -4 mbar l sec -1 Very simple - a variable capillary leak Pressure tested to 150 bar (Helium) > Used on the Ptolemy instrument Will allow evacuation during cruse phase Limitations: no selective control of sample species > Lets everything into the mass spectrometer problem with aqueous environment > large gas load - Pumping requirement (1) Thermally actuated proportional valve

11. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan Sample inlet / preparation (2) Membrane is the interface between the liquid and the vacuum of the mass spectrometer very low gas load in aqueous environments >minimal pumping required Rugged / simple devices Negate extensive sample preparation Continuous monitoring possible Limitations: Sensitivity depends on hydrophobicity and volatility of the analyte. 2) Membrane inlet

12. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan Ion trap for a Melting Probe

13. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan The prototype ion trap Prototype electronicsPrototype hardware

14. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan Future work More representative system A vacuum vessel has been designed and is under construction to allow testing of the Ion trap with a MIMS and a direct inlet system –Sampling from liquids –investigation of pressure effects / length of operation with the mini chemical getter pump Replace the Filament used in the prototype ion trap: A batch of MEMS nanotip electron sources is being manufactured by RAL –testing and characterisation of these devices with the ion trap system A alternative batch of miniature, rugged and low power electron sources has been procured. – A testing programme is currently underway to evaluate these devices with the Ion trap Development of new electron multiplier devices Further development of the Ion trap drive electronics is now required: Funds required to enable a study to evaluate / design and manufacture an ASIC.

15. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan Conclusions PSSRI has an active, ongoing programme of missions and technology development involving small ion trap mass spectrometers and the associated inlet systems A prototype Ion trap instrument has been developed which is low mass, small, flexible in operation and could be carried by the proposed melting probe Two sampling methods have been discussed which are compatible with the envisaged environment in which the melting probe will operate Ongoing characterisation / development of the system is currently underway Further development of the electronics, with the aim of designing and the eventual manufacture of an ASIC solution (maybe part of a common electronics solution???) Looking for funding opportunities to achieve this

16. Melting Probe Review Simon Sheridan Melting Probe ReviewGraz 11 April 2006 Simon Sheridan Acknowledgements The PSSRI space instrumentation mass spectrometry group: A.D. Morse G.H.Morgan S.J.Barber I.P.Wright M.Javis