¹⁴C Gas Counting: Is There Still a Future?

Abstract

ABSTRACT. Reviewed here are developments in low background proportional counters and chambers used for low-level internal gas counting of '4C. I have studied the influence of counter geometry and the nature of the gas filling on counter characteristics and describe in detail operational characteristics of multi-element proportional chambers. I also discuss detector developments for ultra-low-level gas counting based on a time projection chamber. My observations show that proportional and drift chambers, together with multichannel electronics operating on-line with a computer, open new possibilities in ultra-low-level gas counting.

Developments in Radiocarbon Technologies: From the Libby Counter to Compound-Specific AMS Analyses

“…1951;Houtermans and Oeschger 1955;Drever et al 1957;Nydal 1962;Geyh 1967;Povinec 1972aPovinec , 1992Moúcicki and Zastawny 1977;SrdoË et al 1977). This helped to optimize the detector design as the inner cathode of the detector with proper thickness could be chosen from a material with a minimum radioactive contamination.…”

High-Sensitivity Radiocarbon Dating in the 50,000 to 70,000 bp Range without Isotopic Enrichment

“…Longer counting times improve the statistical resolution of lowcount-rate samples, but the longer the counting time, the greater the probability of electronic shifts in background or efficiency. Approaches to this problem include: 1) development of special counters with extremely high active volumes and/or very low backgrounds (Oeschger & Wahlen 1975;Povinec 1992); 2) the use of isotopic enrichment to concentrate the 14C into normal volume gas proportional counters; and 3) the use of large volume (>10 g of carbon), high-stability, lowbackground liquid scintillation counting (LSC) systems. The high density of carbon and low cosmic-ray profile in a vial of benzene potentially give a high sample-to-background count-rate ratio.…”

The Conventional Method of Radiocarbon Dating☆

“…This can be avoided by dividing the sensitive volume into several wall-less counter elements, the so-called multielement counter (Povinec, 1992); however, in practice their operation is rather complex. The sensitivity in GPC can be improved by increasing the size of the counter and by increasing the gas pressure; however, increasing the diameter and/or the pressure would require higher voltages to be applied across the counter.…”