Lawrence Livermore National Laboratory

The laboratory houses analytical systems for magnetic sector and quadrupole mass spectrometry, with a variety of sample heating and gas introduction systems.

Noblesse 6-Faraday/4-multiplier detector block.

Mass Spectrometry:

  1. The backbone of the laboratory is a Nu Instruments Noblesse mass spectrometer equipped with six Faraday cup detectors and four ion-counting, discrete dynode multiplier detectors. The Faraday-multiplier detector array provides the versatility to concurrently analyze high- and low-abundance noble gas isotopes.
  2. Quadrupole mass spectrometry is performed using a Pfeiffer Prisma Plus QME 220.

Sample Heating:

Noble gases are extracted from solid samples using a variety heating techniques.

  1. Precise, temperature-controlled heating experiments are performed using a Photon Machines Thermochron Fusions diode laser (either 75W or 150W; λ = 970 nm) equipped with a co-axially aligned optical pyrometer. This system is designed for the simultaneous acquisition of diffusion kinetics and isotopic data.
  2. Direct fusion of samples is performed using a Photon Machines Fusions CO2 laser (55W). The Fusions CO2 is designed for the direct heating and melting of samples, including optically transparent phases.
  3. In situ noble gas isotope measurements are performed using a Photon Machines Analyte G2 ultra-short pulse 193 nm Excimer laser ablation system. The Analyte G2 provides micron-scale, spatially resolved noble gas isotope ratios.
  4. A series of projector lamp – diffusion cell apparatuses are used for low temperature heating (<500 C) and helium gas extraction from some samples.

Gaseous Introduction Systems:

Eight automated pipette systems, variably equipped with getters and LN2 cryogenic traps, are available for controlled introduction of gaseous samples. Most of these pipettes are dedicated to gas standards, including atmospheric noble gases used for determining spectrometer mass discrimination and mono-isotopic compositions (e.g., 3He and 124Xe) used for high-precision abundance determinations.

Gas Processing:

The gas processing line is equipped with two Janis cryogenic separators (one bare metal and one charcoal trap), an ARS cryogenic water trap, and two SAES getters (one hot and one cold) for noble gas purification.