In:
Radiocarbon, Cambridge University Press (CUP), Vol. 58, No. 1 ( 2016-03), p. 213-225
Abstract:
The intracavity optogalvanic spectroscopy (ICOGS) method has been reported to quantify radiocarbon at subambient levels ( 〈 1 part per trillion). ICOGS uses a gas sample that is ionized in a low-pressure glow discharge located inside a 14 CO 2 laser cavity to detect changes in the discharge current under periodic modulation of the laser power to determine the 14 CO 2 concentration of the sample. When claims of detection thresholds below ambient levels were not verified by other researchers, we constructed a theoretical analysis to resolve differences between these conflicting reports and built and tested an ICOGS system to establish a lower limit of detection. Using a linear absorbance model of the background contribution of 12 CO 2 and data from the HITRAN database, we estimate that the limit of detection (3 σ x ) is close to 1.5×10 4 Modern. By measuring a 1.5×10 4 Modern enriched CO 2 sample in a cavity modulation ICOGS system without a clear signal, we conclude that for this system the limit of detection for ICOGS must be above 1.5×10 4 . The implications for previous ICOGS reports are discussed.
Type of Medium:
Online Resource
ISSN:
0033-8222
,
1945-5755
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2016
detail.hit.zdb_id:
2028560-7
SSG:
11
SSG:
13
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