scholarly journals Geological Survey of Canada Radiocarbon Dates IV

Radiocarbon ◽  
1965 ◽  
Vol 7 ◽  
pp. 24-46 ◽  
Author(s):  
W. Dyck ◽  
J. G. Fyles ◽  
W. Blake
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Error Term ◽  
Geological Survey ◽  
Radiocarbon Dates ◽  
The Past ◽  
Average Variation

Most of the determinations reported here were obtained with the 2 L counter described in our first date list (GSC I). All age calculations are based on a C14 half-life of 5568 ± 30 yr and 0.95 of the activity of the NBS oxalic-acid standard, and the ages are quoted in years before 1950. The age errors include: counting errors of sample, background, and standard, the error in the half-life of C14, and an error term to account for the average variation of ±1.5% in the C14 concentration during the past 1100 yr. ‘Greater than’ ages are based on the 4 σ criterion (GSC II).

scholarly journals U. S. Geological Survey Radiocarbon Dates VI

Radiocarbon ◽  
1961 ◽  
Vol 3 ◽  
pp. 86-98 ◽  
Author(s):  
Meyer Rubin ◽  
Sarah M. Berthold
Keyword(s):  
Oxalic Acid ◽  
19Th Century ◽  
Half Life ◽  
Geological Survey ◽  
Radiocarbon Dates ◽  
Appreciable Difference ◽  
The 19Th Century ◽  
Modern Standard

Dates in this list have been determined at U. S. Geological Survey radiocarbon laboratory, Washington, since our 1960 date list (USGS V). Procedures for the preparation of acetylene gas used in the counting, and the method of counting, (two days in two separate counters) remain unchanged. However, the modern standard used is no longer wood grown in the 19th century, but 95% of the activity of NBS oxalic-acid radiocarbon standard, as recommended at the 1959 Groningen Radiocarbon Conference. Measurement of the oxalic-acid standard at our laboratory indicates 6.2 ± 1% more C14 activity than our modern wood standard; so use of the new standard should make no appreciable difference when comparing samples computed by the old method. W. F. Libby's (1955) half-life average for C14, 5568 ± 30 years, was used for the decay equation.

scholarly journals Geological Survey of Canada Radiocarbon Dates III

Radiocarbon ◽  
1964 ◽  
Vol 6 ◽  
pp. 167-181 ◽  
Author(s):  
W. Dyck ◽  
J. G. Fyles
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Geological Survey ◽  
Radiocarbon Dates

All C14 measurements in this date list were made with the 2 L counter described in our first date list (GSC I). Ages were calculated on a C14 half life of 5570 ± 30 yr and 0.95 of the activity of the NBS oxalic-acid standard, and are quoted in years before 1950.

scholarly journals Copenhagen Radiocarbon Dates VI

Radiocarbon ◽  
1964 ◽  
Vol 6 ◽  
pp. 215-225 ◽  
Author(s):  
Henrik Tauber
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dates ◽  
Unknown Sample ◽  
Minimum Sample ◽  
Standard Deviations

The following list comprises a selected number of measurements made up to November 1963. Age calculations are based on a contemporary value equal to 95% of the activity of the NBS oxalic-acid standard, and on a half life for C14 of 5570 ± 30 yr.Results are expressed in years before 1950 and in the b.c.-a.d. scales. Errors quoted include the standard deviations of the count rates for the unknown sample, the contemporary value, and the background. Calculated errors smaller than 100 yr have been increased by rounding to that figure as a minimum. Sample descriptions have been prepared in collaboration with collectors and submitters.

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 Tallinn Radiocarbon Dates V

Radiocarbon ◽  
1978 ◽  
Vol 20 (3) ◽  
pp. 461-468 ◽  
Author(s):  
J M Punning ◽  
R Rajamäe ◽  
M Ehrenpreis
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Reference Standard ◽  
Radiocarbon Dates

The following list comprises age measurements carried out during 1976 and 1977. The activity of 14C was computed by one- and two-channel scintillation devices (Punning et al, 1976; 1977). Ages are calculated using a half-life of 5568 ± 30 years for 14G with NBC oxalic acid as a reference standard. All dates are reported in years before 1950. 12C/13C measurements were not performed and results are not corrected for 13C fractionation.

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 US Geological Survey, Denver, Colorado Radiocarbon Dates III

Radiocarbon ◽  
1981 ◽  
Vol 23 (1) ◽  
pp. 24-32 ◽  
Author(s):  
I C Yang ◽  
R L McAvoy ◽  
R L Emerson
Keyword(s):  
Half Life ◽  
Geological Survey ◽  
Total Alkalinity ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
The Us ◽  
Age Limit

This list contains the results of measurements made during 1978 and 1979. Ages were computed on the radiocarbon half-life of 5568 ± 30 years. Statistical errors quoted herein are 1σ counting errors which include sample, background, and standard. The age limit reported is calculated on the basis of 3σ activity. The σ13C values in table 1 were measured by Krueger Enterprises, Inc, Geochron Laboratories Division1 and calculated based on Craig's Peedee Belemnite (PDB) limestone standard (Craig, 1957). The total alkalinity as bicarbonate values reported in table 1 was determined using techniques described by Brown, Skougstad, and Fishman (1970). Unless otherwise stated, all samples were collected and submitted by personnel of the US Geological Survey.

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 UCLA Radiocarbon Dates V

Radiocarbon ◽  
1966 ◽  
Vol 8 ◽  
pp. 467-497 ◽  
Author(s):  
Rainer Berger ◽  
W. F. Libby
Keyword(s):  
Oxalic Acid ◽  
Proportional Counter ◽  
Half Life ◽  
Count Rate ◽  
Radiocarbon Dates ◽  
Counting Error ◽  
Energy Channels ◽  
Sixth International

The measurements reported have been carried out during 1965 in the Isotope Laboratory of the Institute of Geophysics and Planetary Physics as a continuation of the UCLA date lists I through IV. Samples were analyzed as CO2-gas at one atm in a 7.5 L proportional counter with three energy channels. Dates have been calculated on the basis of a 5568 yr half-life as was recommended by the Sixth International C11 and H3 Dating Conference, June 1965, in Pullman, Washington. The standard for the contemporary biosphere remains as 95% of the count rate of NBS oxalic acid for radiocarbon laboratories. Background determinations have been made with CO2 obtained from marble. The error listed is always at least a one-sigma statistical counting error.

scholarly journals U. S. Geological Survey Radiocarbon Dates VII

Radiocarbon ◽  
1964 ◽  
Vol 6 ◽  
pp. 37-76 ◽  
Author(s):  
Patricia C. Ives ◽  
Betsy Levin ◽  
Richard D. Robinson ◽  
Meyer Rubin
Keyword(s):  
Solid State ◽  
External Field ◽  
Half Life ◽  
Geological Survey ◽  
Radiocarbon Dates ◽  
Solid State Electronics ◽  
Counting Error ◽  
Atmospheric Variations ◽  
The One

This date list contains the results of measurements made during 1961, 1962 and 1963. The method of counting, utilizing acetylene gas, remains essentially unchanged, except for the addition of some solid state electronics. The method of computation, using the Libby half-life of 5568 ± 30 yr, is continued. The error listed is always larger than the one-sigma statistical counting error commonly used, and takes into account known uncertainty laboratory factors, and does not include external (field or atmospheric) variations.Unless otherwise stated, collectors of all samples are members of the U. S. Geological Survey.

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