ISOTOPIC ANALYSIS OF LITHIUM BY MASS SPECTROMETRY

Journal Article · Thu Jan 01 04:00:00 EST 1959 · J. Sci. Instr.

DOI:https://doi.org/10.1088/0950-7671/36/1/312· OSTI ID:4279654

Bentley, P G; Bishop, J; Davidson, D F; Evans, P B.F.

A mass spectrometer has been built specially for the isotopic analkysis of lithium. Conventional solid-source techniques are used, but the tube unit and electronic system, have several novel features. Provtsion is made for pumping down two ion sources at once by having three arms in the mass spectrometer tube instead of the usual two; one arm takes the collector and the other two take ion sources, so that either source arm and the collector form a 60'-sector mass spectrometer. Each source arm is fitted with a vacuum lock to reduce pumping times. Measurements of the isotope ratio are made semi-automatically once ion beams are obtained. By scanning the magnetic field, each ion beam is brought alternately on to the collector, where it is amplified and "remembered" as a voltage on a capacitor. The araplifier sensitivity is adjusted for one beam until the two voltages are equal, and the isotope ratio is read directly as the ratio of the amplifier sensitivities for the two ion beams. Fractionation effects in the ion source are described. The precision of measurement of the isotope ratio is 0.7% at the 95% confidence level, and the absolute accuracy of these measurements is thought to be better than 2%. The instrument is reliable and simple to use, and analyses can be made at the continuous rate of one every twenty minutes. (auth)

• Research Organization: United Kingdom Atomic Energy Authority, Capenhurst, Chester, Eng.
• NSA Number: NSA-13-008872
• OSTI ID: 4279654
• Journal Information: J. Sci. Instr., Journal Name: J. Sci. Instr. Vol. Vol: 36
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AMPLIFIERS
BEAMS
CAPACITORS
CLOSURES
ELECTRIC POTENTIAL
ELECTRONIC EQUIPMENT
ERRORS
INSTRUMENTS
IONS
ISOTOPE SEPARATION
LITHIUM
MAGNETIC FIELDS
MASS SPECTROMETERS
PERFORMANCE
PLANNING
PUMPS
RADIATION SOURCES
SENSITIVITY
SOLIDS
VACUUM