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 U. S. Geological Survey Radiocarbon Dates V

1960 ◽  
Vol 2 ◽  
pp. 129-185 ◽  
Author(s):  
Meyer Rubin ◽  
Corrinne Alexander
Keyword(s):  
19Th Century ◽  
Standard Procedure ◽  
Wood Charcoal ◽  
Geological Survey ◽  
Radiocarbon Dates ◽  
The 19Th Century ◽  
Modern Standard

The dates listed herein have been determined at the U. S. Geological Survey radiocarbon laboratory at Washington since our last date list (USGS IV) and up to the end of 1959. Acetylene continues to be the gas of our choice. Each sample is run for a period of two days in two separate counters with separate electronics. The modern standard used is wood grown in the 19th century, and the ages and errors have been computed in the same manner as before. Pretreatment of wood, charcoal, and peat samples by boiling in acid, alkali, and acid again, is standard procedure.

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 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 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 Dublin Radiocarbon Dates III

Radiocarbon ◽  
1980 ◽  
Vol 22 (4) ◽  
pp. 1028-1030 ◽  
Author(s):  
P Q Dresser
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dates ◽  
Physical Laboratory ◽  
Modern Standard

The dating equipment and operating procedures in the Physical laboratory remained as described previously (R, 1974, v 16, no. 1, p 6-9).Dates were calculated using the 5568-year half-life with 1950 as the reference year, the modern standard being 0.95 of the activity of the NBS oxalic acid standard. When done, δ13C was measured on CO2 produced in the combustion of samples, and results are given relative to the PDB standard. All samples were from Ireland.

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 University of Miami Radiocarbon Dates II

Radiocarbon ◽  
1975 ◽  
Vol 17 (1) ◽  
pp. 112-120 ◽  
Author(s):  
J J Stipp ◽  
K L Eldridge
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Liquid Scintillation ◽  
Liquid Scintillation Spectrometer ◽  
Radiocarbon Dates ◽  
Laboratory Procedures ◽  
University Of Miami ◽  
Modern Standard

The following list of dates are selected from geologic and archaeologic samples measured in late 1973. The laboratory procedures and techniques are the same as indicated in R, 1974, v 16, p 402–408, where sample is synthesized to benzene and counted for 24 hours in either a Beckman LS-100-C or Packard 2311 liquid scintillation spectrometer. Ages are calculated relative to 0.95 x NBS oxalic acid using a 14C half-life of 5568 years. The quoted error is 1σ, which includes only the counting uncertainties of the background, modern standard, and sample. Sample descriptions and comments were written in collaboration with collectors and submitters.

scholarly journals University of Granada Radiocarbon Dates III

Radiocarbon ◽  
1986 ◽  
Vol 28 (3) ◽  
pp. 1200-1205 ◽  
Author(s):  
Cecilio Gonzalez-Gomez ◽  
Purificacion Sanchez-Sanchez ◽  
Elena Villafranca-Sanchez
Keyword(s):  
Sample Preparation ◽  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Standard Sample ◽  
Research Project ◽  
Radiocarbon Dates ◽  
Preparation Techniques ◽  
Age Determinations ◽  
Modern Standard

The following list includes some measurements made from December 1982 to May 1985 in the Radiocarbon Dating Laboratory, Faculty of Science, University of Granada, of samples from Spain, Portugal, and the Sudan. Sample preparation techniques and benzene synthesis remain as described previously (R, 1982, v 24, p 217–221) and equipment and measurement of samples was also reported previously (R, 1985, v 27, p 610–615). Radiocarbon ages are calculated using the 14C half-life of 5570 years and 0.95 activity of NBS oxalic acid is used as modern standard. Sample descriptions are based on information provided by submitters. Age determinations were made with the help of Research Project 0925/81, CAICYT, Spain.

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 UCLA Radiocarbon Dates I

Radiocarbon ◽  
1962 ◽  
Vol 4 ◽  
pp. 109-114 ◽  
Author(s):  
G. J. Fergusson ◽  
W. F. Libby
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Radiocarbon Dates ◽  
Modern Standard

The measurements reported in this list have been made since the Radiocarbon Dating Laboratory at the Institute of Geophysics, UCLA became operational in August 1961. CO2proportional counting was used for all measurements in an 7 · 5-L counter at 1 atm pressure. Dates have been calculated on the basis of the C14half life of 5568 ± 30 yr, and 95% of NBS oxalic acid as modern standard. It is planned to discuss the half life in the light of the newer measurements at a conference in 1962. Prior to general agreement as to the new best figure we propose that all dates continue to be calculated on the old basis. Samples have been carefully inspected, cleaned, picked free of rootlets, and pretreated with HCl when necessary.

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