scholarly journals Tartu Radiocarbon Dates XIII

Radiocarbon ◽  
1994 ◽  
Vol 36 (1) ◽  
pp. 153-158
Author(s):  
Arvi Liiva ◽  
Ilze Loze
Keyword(s):  
Standard Deviation ◽  
Oxalic Acid ◽  
Liquid Scintillation Counting ◽  
Half Life ◽  
Liquid Scintillation ◽  
Standard Sample ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
Academy Of Sciences ◽  
Modern Standard

This date list reports dates of archaeological samples of Mesolithic and Neolithic sites of Estonia, Latvia and Lithuania. We use liquid scintillation counting at the Geochemical and Statistical Laboratory of the Institute of Zoology and Botany, Estonian Academy of Sciences. Our modern standard is benzene enriched in 14C and its activity is checked with an NBS oxalic acid standard sample. Dates are given in conventional 14C years, based on the Libby half-life of 5570 ± 30 yr. AD 1950 is the reference year. Errors are based on one standard deviation calculated from count rates.

scholarly journals Tartu Radiocarbon Dates XI

Radiocarbon ◽  
1990 ◽  
Vol 32 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Evald Ilves
Keyword(s):  
Standard Deviation ◽  
Oxalic Acid ◽  
Half Life ◽  
Liquid Scintillation ◽  
Standard Sample ◽  
Single Channel ◽  
Radiocarbon Dates ◽  
Geologic Samples ◽  
Modern Standard

This list includes dates of geologic samples measured using a single-channel liquid scintillation 14C counter at the Geochemical and Statistical Laboratory, Tartu, Estonian SSR. Our modern standard is made of benzene enriched in 14C and its activity is checked with NBS oxalic acid standard sample. Dates are given in conventional radiocarbon years, based on the Libby half-life of 5570 ± 30 yr. AD 1950 is the reference year. Errors refer only to 1σ standard deviation calculated from count rates involved.

scholarly journals Quebec Radiocarbon Measurements III

Radiocarbon ◽  
1981 ◽  
Vol 23 (2) ◽  
pp. 241-251 ◽  
Author(s):  
Louis Barrette ◽  
Pierre La Salle ◽  
Claude Samson
Keyword(s):  
Standard Deviation ◽  
Oxalic Acid ◽  
Liquid Scintillation Counting ◽  
Half Life ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
The Given ◽  
Deviation Criterion ◽  
Modern Standard

The results presented in this list have been obtained by benzene synthesis and liquid scintillation counting: ages are calculated using the 14C half-life of 5570 yr with 0.95 activity of NBS oxalic acid as modern standard, with no correction. The given precision is obtained from a one-standard-deviation criterion.

scholarly journals Tartu Radiocarbon Dates XII

Radiocarbon ◽  
1991 ◽  
Vol 33 (3) ◽  
pp. 345-354
Author(s):  
Evald Ilves
Keyword(s):  
Standard Deviation ◽  
Oxalic Acid ◽  
Half Life ◽  
Liquid Scintillation ◽  
Standard Sample ◽  
Single Channel ◽  
Geological Samples ◽  
Radiocarbon Dates ◽  
Modern Standard

IntroductionThis list includes dates of geological samples measured using a single-channel liquid scintillation 14C counter at the Geochemical and Statistical Laboratory, Tartu, Estonia. Our modern standard is made of benzene enriched in 14C, and its activity is checked with NBS oxalic acid standard sample. Dates are given in conventional radiocarbon years, based on the Libby half-life of 5570 ± 30 years. A.D. 1950 is the reference year. Errors refer only to 1σ standard deviation calculated from count rates involved.

scholarly journals University of Texas at Austin Radiocarbon Dates VII

Radiocarbon ◽  
1970 ◽  
Vol 12 (1) ◽  
pp. 249-280 ◽  
Author(s):  
S. Valastro ◽  
E. Mott Davis
Keyword(s):  
Oxalic Acid ◽  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
Sample Count ◽  
Counting Statistics ◽  
Made In ◽  
Modern Standard

This list reports C14measurements made in dating projects completed in the year ending December, 1968, and some measurements for projects still in progress. Age calculations are based on C14half-life of 5568 yr and a modern standard of 95% of NBS oxalic acid. Deviations reported are based on counting statistics of sample, background, and modern, and are ±1σ except that when sample count approaches either modern or background, 2σ limits are reported. The laboratory uses liquid scintillation counting of benzene, with Li2C2and vanadium activated catalyst in preparation, as described in Texas IV (Radiocarbon, 1966, v. 8, p. 453–466) and earlier lists. Chemical yields average 85%.

scholarly journals University of Texas at Austin Radiocarbon Dates VIII

Radiocarbon ◽  
1970 ◽  
Vol 12 (2) ◽  
pp. 617-639 ◽  
Author(s):  
S. Valastro ◽  
E. Mott Davis
Keyword(s):  
Oxalic Acid ◽  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
Sample Count ◽  
Counting Statistics ◽  
Made In ◽  
Modern Standard

This list reports C14 measurements made in projects completed in the year ending October, 1969, and some measurements for projects still in progress. Age calculations are based on C14 half-life of 5568 years and a modern standard of 95% of NBS oxalic acid. Deviations reported are based on counting statistics of sample, background, and modern, and are ± 1σ except that when sample count approaches either modern or background, 2σ limits are reported. The laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium activated catalyst in preparation. Chemical yields average 88%.

scholarly journals University of Texas At Austin Radiocarbon Dates XIII

Radiocarbon ◽  
1979 ◽  
Vol 21 (2) ◽  
pp. 257-273 ◽  
Author(s):  
S Valastro ◽  
E Mott Davis ◽  
Alejandra G Varela
Keyword(s):  
Oxalic Acid ◽  
National Science Foundation ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
National Science ◽  
Sample Count ◽  
Counting Statistics ◽  
Modern Standard

This list reports certain 14C measurements completed by November 1978; other projects completed by this time will be reported later. Age calculations are based on 14C half-life of 5568yr and modern standard of 95% NBS oxalic acid, supplemented by tree rings of pre-industrial wood from a log cut in the 1850's (Tx-540; R, 1970, v 12, p 249). Deviations reported are based on counting statistics of sample, background and modern, and are ± 1σ, except that when sample count approaches either modern or background, 2σ limits are reported. Unless noted, 12C/13C measurements were not made and results are not corrected for 13C fractionation (assumed ratio = −25‰ WRT PDB). Our laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium-activated catalyst in preparation; chemical yields range between 95% and 99%. Three counters are employed; a Packard Tri-Carb Model 3002 and 2 Beckman LS320 spectrometers obtained through a grant from the National Science Foundation.

scholarly journals Tallinn Radiocarbon Dates VI

Radiocarbon ◽  
1980 ◽  
Vol 22 (1) ◽  
pp. 91-98 ◽  
Author(s):  
J M Punning ◽  
R Rajamäe ◽  
K Joers ◽  
H Putnik
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dates ◽  
Academy Of Sciences ◽  
Modern Standard

The following list includes samples dated at the Institute of Geology, Academy of Sciences of the Estonian SSR in 1978. The measurement of natural 14C activity is performed by 1-channel and 2-channel scintillation devices (Punning & Rajamäe, 1977). Ages are calculated using the half-life of 5568 ± 30 years and 0.95 NBS oxalic acid modern standard with ad 1950 as reference year.

scholarly journals University of Miami Radiocarbon Dates VII

Radiocarbon ◽  
1976 ◽  
Vol 18 (3) ◽  
pp. 371-375 ◽  
Author(s):  
J J Stipp ◽  
K L Eldridge ◽  
K Valenziano
Keyword(s):  
Standard Deviation ◽  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Shell Material ◽  
Soft Or ◽  
Radiocarbon Dates ◽  
Powdery Material ◽  
Partial List ◽  
Geologic Samples

The following radiocarbon measurements are a partial list of geologic samples from S Florida dated during the summer of 1975. The technique used is liquid scintillation counting of wholly synthesized benzene as indicated in R, v 16, p 402-408 and R, v 18, p 210-220. Dates are calculated using a 14C half-life of 5568 yr and errors are reported as one standard deviation. Before conversion, shell material was etched with HCl to remove all soft or powdery material. All wood and peat samples were treated with NaOH.

scholarly journals National Taiwan University Radiocarbon Measurements II

Radiocarbon ◽  
1973 ◽  
Vol 15 (2) ◽  
pp. 345-349 ◽  
Author(s):  
Yuin-Chi Hsu ◽  
Muh-Chen Chou ◽  
Yi-Chuan Hsu ◽  
Song-Yun Lin ◽  
Shih-Chong Lu
Keyword(s):  
Standard Deviation ◽  
Oxalic Acid ◽  
Proportional Counter ◽  
Half Life ◽  
Statistical Nature ◽  
Radiocarbon Dates ◽  
Disintegration Process ◽  
Modern Standard

The C14 dates given below have been obtained by counting CO2 at 2 atm pressure in a 1 L proportional counter. Details of procedure are given in our previous list (R., 1970, v. 12, p. 187–192). Radiocarbon dates in this list are based on 95% of activity of NBS oxalic acid as the modern standard and were calculated using 5570 yr as the half-life of C14. Errors quoted with the dates are standard deviation originating from the statistical nature of radioactive disintegration process. Results obtained during 1970 and 1971 are described here.

scholarly journals University of Miami Radiocarbon Dates VI

Radiocarbon ◽  
1976 ◽  
Vol 18 (2) ◽  
pp. 210-220 ◽  
Author(s):  
J J Stipp ◽  
K L Eldridge ◽  
R Cadwell
Keyword(s):  
Standard Deviation ◽  
Reaction Time ◽  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Correction Factors ◽  
Lithium Metal ◽  
Radiocarbon Dates ◽  
Partial List ◽  
Time Required

The following radiocarbon measurements are a partial list of projects and samples dated since the Spring of 1975. The technique used is liquid scintillation counting of wholly synthesized benzene as indicated in R, v 16, p 402-408. The intermediate chemical step of converting CO2 to Li2C2 has been modified so that the CO2 is reacted with the lithium metal at a temperature of 950° to 1000°C instead of the 600°C as formerly done (Tamers, 1975). This modification has had the effect of reducing occasional variable losses in conversion yields in this step, and reducing the reaction time required from 30 min to 10 min for a typical ¼ mole sample. Dates are calculated using a 14C half-life of 5568 yr and errors are reported as one standard deviation. No other correction factors are applied.

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