Radiocarbon measurements by the direct detection of 14C atoms with the Tandetron accelerator mass spectrometer were begun in the autumn of 1983 at Nagoya University. The 14C dating of geological and archeological samples is routinely performed with a precision of ±1% (±83 years) using a carbon-silver target containing only 2–5 mg of carbon in measurements lasting 5 hours. The accuracy of a single 14C measurement was estimated by a reproducibility test to be ±1.34%. Radiocarbon ages measured with the Tandetron spectrometer for ten natural samples agreed well with those obtained by radioactivity measurements. The 14C background of the spectrometer limits the measurable age to less than 60000 y BP. The limit will be extended to about 82000 y BP if the 14C background is eliminated.

No abstract

A Bernas type ion source has been developed for Genus high energy ion implanters. The new source increases output by 50 YO and lifetime by 100 YO for boron applications, compared to the standard Genus PIG ion source. Up to 49 mA of total beam has been extracted from a BF, plasma through an aperture, 7.0 mm in diameter, and 14 mA of analyzed boron current ("B? has been obtained. This is equivalent to providing a 85 YO margin above the specified boron current for Genus 1510 implanters. In this paper, the source configuration, output performance and lifetime are presented.

No abstract

No abstract