RADIOGENIC
ISOTOPES LABORATORY
The facilities
and personnel of this research laboratory which are on the third
floor of Mendenhall Laboratory, are supervised by Professor Ken Foland.
The Radiogenic Isotopes Laboratory is staffed by Research Associates Jeff
Linder and Fritz Hubacher. This laboratory is dedicated to isotopic
and geochronologic studies and is involved in diverse activities of involving
many kinds of systems and materials. The research emphasizes the
study of elements with radiogenic isotopes, in particular, Ca, Ar, Sr,
Nd, and Pb, and the related elements of their radioactive parents.
It specializes in high-precision determination of isotopic compositions
by magnetic-sector mass spectrometry currently with four mass spectrometers.
The laboratory rooms, which are supplied with HEPA filtered air, include:
two rooms that house thermal-ionization mass spectrometers; a state-of-the-art
cleanroom for low-blank separation of elements for mass analysis; a laboratory
for noble gas extraction and mass analysis housing two mass spectrometers;
a laboratory for the handling, counting, and storage of radioactive materials;
and, a mineral separation and sample processing room.
High-precision
isotopic analyses are conducted on a completely- equipped Finnigan-
MAT (model 261A) thermal ionization mass spectrometer. This instrument
is equipped for fully automatic operation with simultaneous multicollection
of different isotopes using an array of nine Faraday collectors and an
electron multiplier that are moveable for different elements. Mass
analyses of noble gases are performed on a recently acquired Mass
Analysers Products (model 215-50) mass spectrometer, which has both
Faraday and multiplier collectors with the ability for simultaneous measurements
of two masses. This machine is equipped with a low-blank, ultra high
vacuum gas extraction system for small samples (e.g., single crystals)
with resistive heating in a furnace or laser microsampling. Lasers
with infrared and ultraviolet radiation provide for microanalysis for rare
gases and Ar age determinations in geologic materials. Geochronologic
research with the both the
40Ar/39Ar
and K-Ar techniques is also conducted using a Nuclide
(SGA 6-60) mass spectrometer and two high-vacuum Ar extraction lines.
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