# Presentation: 325729

## ARGON GEOCHRONOLOGY EXPERIMENT (AGE) PI  Tim SwindleJuly 21, 2004

_**CO-INVESTIGATORS**_
***Mass Spectrometry***** (JPL)**
**Ara Chutjian**
**Murray Darrach**
***LIBS***** (LANL)**
**Dave Cremers**
**Roger Wiens**

_**OBJECTIVES**_
**Develop instrument to perform in-situ geochronology based on noble gases. Subsystems include:**
**Laser-Induced Breakdown Spectroscopy to measure elemental abundances**
**Furnace to heat rock to 1500****0****C**
**Sample mass determination (via volume determination and elemental composition)**
**Mass spectrometer (Paul ion trap) to measure noble gases**

- Sample acquisition and handling, volume determination (for mass determination) and oven vacuum volume (replaced by clear plastic shroud). Mass spectrometer will connect to left side, laser for LIBS will fire when sample is in arm in one of lower locations.

_**NOTE**_
**Modular nature means that development can go on in parallel, so different pieces are at different stages. Integrated testing now beginning**

## FY ’04 Milestones

- LIBS
- Successful environmental testing
- Demonstration of capabilities at Mars ambient pressure
- Calibration of multiple elements in basalt samples
- Mass Spectrometry
- Completion of Paul trap
- Completion of improved flight electronics
- Furnace construction
- Construction of improved versions
- Demonstration of reusable design (furnace, seal)
- Mass measurement (by volume)
- Extensive (successful) tests of three different basalts
- Demonstration of limitations for some mineralogies

## Laser-Induced Breakdown Spectroscopy (LIBS, at LANL)

- Successful environmental testing of Ocean Optics HR2000 spectrometer
- Vibration tests
- Passed MSL standards
- Some trouble at twice MSL standards, can be strengthened
- Thermal tests (prototype)
- -45 to +50C test
- No peak drift (right)

## LIBS (LANL)

- *elements seen in second order

**LIBS (LANL)**

- HR2000 Spectrograph
- Basalt spectrum in IR region
- 50 shots averaged
- 7 Torr CO2 (optimal pressure)
- Other elements can be obtained by adding spectrographs in other regions

## LIBS (LANL)

- Soil spectrum

**LIBS (LANL)**

- Resolution of HR2000 compares well with LLA ESA3000
- $80K high resolution lab echelle spectrograph (comparison below left)
- Calibration of multiple basalts samples gives <10% errors (below right)

| element | Accuracy* |
| --- | --- |
| Al | 5.4 |
| Ca | 4.9 |
| Mg | 3.2 |
| Fe | 6.3 |
| Si | 9.3 |
| K | 5.2 |

- Average of absolute value of % accuracy. Accuracy data generated by measuring 8 samples. For each sample, accuracy determined by comparing actual value to that generated by calibration curve constructed on basis of other 7 samples.

## Furnace (UA)

- Latest version approaching mechanical brassboard
- All seals metal gaskets or welds (except for one required to be reusable)

- Simplified schematic of AGE furnace

## Mass calibration

- Mass (of 5-10mg samples) measured by measuring volume and knowing density (by knowing elemental composition)
- Calibrated for three basalts melted in 1 atm. pressure
- Accurate to better than 10% (see figure)
- Samples with compositions with higher melting temperatures (e.g., dunites, analogs of Chassigny Martian meteorite) don’t fully melt, so technique not effective

- Data for calibration of basalt samples. “Calibration factor” is used to account for effects of meniscus, etc. After this is applied, standard deviation is 7%, well within 10% target for uncertainties.

## Mass spectrometry (JPL)

**Paul ion trap**
- Second generation Paul trap has been constructed
- Improved flight electronics completed
- Testing underway

- First generation of JPL Paul trap

## AGE Plans (7/2004)

**Continue current tests**
- Work toward integrated test of system
- Integrated furnace & mass spectrometer tests to assess performance of both, develop protocols
- Mass calibration, handling tests with potentially difficult samples
- Major concerns
- Background noble gas signal derived from furnace (species, size)
- Continue to explore limitations of components in terms of sample types

- Left: Oven attached to Quadrupole Mass Spectrometry Analyzer in April. Demise of QMSA delayed testing, but current round is with more sensitive Paul trap

## Geochronology with a Paul ion trap mass spectrometer 

**Status:  ****	****1.  Proof of Concept - Isotopic abundance measurements    ****	****          ****Done**
**	****     ****with an ion trap ****	****	****	****	**
**	**
**	****2.  Design, build, and test “low dead volume analysis chamber”         ****In progress**
**	**
**	****3.  Design, build and test miniature MS *****rf*****  Electronics****	****	****    ****In progress**

## 3He-4He mixture 1:1000 concentration

- 3He-4He mixture 1:1000 concentration

- Neon isotopes

- Krypton isotopes

- Xenon isotopes

## Financial issues

- Note: Due to funding mechanism, most of funding does not go through PI
- Arizona funding:
- Spending at budgeted pace
- Began 6 mos. late
- Completed PIDDP first
- No-cost extension discussed