scholarly journals Gif Natural Radiocarbon Measurements X

Radiocarbon ◽  
1986 ◽  
Vol 28 (1) ◽  
pp. 9-68 ◽  
Author(s):  
Georgette Delibrias ◽  
M-T Guillier ◽  
Jacques Labeyrie
Keyword(s):  
Oxalic Acid ◽  
Standard Error ◽  
Proportional Counter ◽  
Half Life ◽  
Correction Curve ◽  
Geologic Samples ◽  
Made In

The following date list includes archaeologic and geologic samples dated by Gif Radiocarbon Laboratory mostly from 1973 to 1975. Volcanic samples reported here were dated up to 1981. Measurements were made in the same manner as previously reported (R, 1972, v 14, p 280). For undersized samples, a 0.1L CO2proportional counter was used with 5000-minute standard measurements. Ages listed are conventional14C ages based on the 5568-year Libby half-life; uncertainties are 1σ statistical standard error. Results are based on 95% of NBS oxalic acid activity. Some dates have been calibrated using the correction curve of Kleinet al(1982).

scholarly journals Gif Natural Radiocarbon Measurements VII

Radiocarbon ◽  
1972 ◽  
Vol 14 (2) ◽  
pp. 280-320 ◽  
Author(s):  
G. Delibrias ◽  
M. T. Guillier ◽  
J. Labeyrie
Keyword(s):  
Stainless Steel ◽  
Oxalic Acid ◽  
Proportional Counter ◽  
Half Life ◽  
Ofhc Copper ◽  
Geologic Samples ◽  
Modern Standard

C14 dates reported below were obtained mainly at the end of 1968 and during 1969 on archaeologic and geologic samples. Techniques of measurement used are unchanged. Since 1968, 4 complete routine sets have been running, each equipped with a 1 L CO2 proportional counter. One is made of stainless steel with a background of 2.70 cpm at pressure 1 atm and the others are of OFHC copper with a background of either 1.10 or 1.30 cpm for a corresponding pressure of, respectively, 1 or 2 atm. For age calculation, 95% activity of NBS oxalic acid is used as the modern standard and the value of 5570 ± 30 years is used for the half-life of C14. Dates are expressed in years b.p. (before a.d. 1950).

scholarly journals Nancy Natural Radiocarbon Measurements II

Radiocarbon ◽  
1969 ◽  
Vol 11 (2) ◽  
pp. 463-468 ◽  
Author(s):  
B. Hassko ◽  
B. Guillet ◽  
R. Coppens
Keyword(s):  
Oxalic Acid ◽  
Proportional Counter ◽  
Half Life ◽  
Counting Technique ◽  
Dating Method ◽  
Made In ◽  
Modern Standard

The following list includes a selected number of measurements made during 1967-1968 in the Natural Radiocarbon Laboratory of the Centre de Recherches Radiogéologiques de Nancy. This list is a continuation of Nancy Natural Radiocarbon Measurements I (Radiocarbon, 1968, v. 10, p. 119-123). The dating method, counting technique, and equipment are described in that list. All measurements were made in a proportional counter with a capacity of 1.16 L, normally filled with CO2 under a pressure of 736 mm Hg. Ages are calculated using a C14 half-life of 5568 yrs with 1950 as reference yr. Modern standard used following samples Ny-118 is 95% of NBS oxalic acid activity. The SC14 mentioned later in the date list are calculated according to Broecker and Olson (1959).

scholarly journals Stockholm Natural Radiocarbon Measurements IV

Radiocarbon ◽  
1962 ◽  
Vol 4 ◽  
pp. 115-136 ◽  
Author(s):  
Lars G. Engstrand ◽  
H. Göte Östlund
Keyword(s):  
Oxalic Acid ◽  
Proportional Counter ◽  
Half Life ◽  
The Third ◽  
Direct Continuation

This paper is a direct continuation of the third dating list (Stockholm III), and the entire technique is virtually unchanged, using one 0.5–1 and one 1.0.1 3 atm CO2proportional counter. Ages are calculated according to the recommendation given in the introduction of this book, and δC13has been measured for unknown samples and for the different CO2preparations of the NBS oxalic-acid standard. Since the numerical relationship between the C14activity of our old oak standard and that of NBS was valid for a δC13value of almost exactly −19 for the NBS preparation in question, it still holds true that all dates given in Stockholm I, II and III can be converted to the new scale by subtracting 55 yr. The NBS preparation St-532 measured by Craig (1961) having a δC13value of −17.2 is only one of several preparations with values between −17 and −20. Age figures are given in C14yr before A.D. 1950; the half life for C14is taken as 5568 ± 30 yr.

scholarly journals Tata Institute Radiocarbon Date List II

Radiocarbon ◽  
1964 ◽  
Vol 6 ◽  
pp. 226-232 ◽  
Author(s):  
D. P. Agrawal ◽  
S. Kusumgar ◽  
D. Lal ◽  
R. P. Sarna
Keyword(s):  
Oxalic Acid ◽  
Proportional Counter ◽  
Half Life ◽  
Radiocarbon Date ◽  
Naoh Pretreatment ◽  
Tata Institute ◽  
Gas Proportional Counter ◽  
Inorganic Fraction

The C14 dates presented here have been obtained by counting acetylene, synthesised from the sample, in an Oeschger-Houtermans’ gas proportional counter. The chemical and counting procedures have been described in some detail (Kusumgar et al., 1963a).Dates are based on the C14 half-life value of 5568 yr. For conversion of b.p. dates to a.d./b.c. scale, a.d. 1950 has been taken as the reference yr. Ninety-five % activity of NBS oxalic acid has been adopted as the value for the pre-1900 age-corrected wood.All samples were treated with dilute HCl. Whenever NaOH pretreatment was possible, it has been mentioned in the date list. In the case of bones, only the inorganic fraction has been dated.

scholarly journals Bratislava Radiocarbon Measurements II

Radiocarbon ◽  
1977 ◽  
Vol 19 (3) ◽  
pp. 389-391
Author(s):  
S Usačev ◽  
J Chrapan ◽  
J Oravec ◽  
B Sitár
Keyword(s):  
Oxalic Acid ◽  
Proportional Counter ◽  
Half Life ◽  
Nuclear Physics ◽  
Radiocarbon Dating ◽  
Initial Conditions ◽  
Sample Pretreatment ◽  
Active Volume ◽  
Statistical Errors ◽  
Sample Count

Radiocarbon dating facilities were built at the Department of Nuclear Physics, Comenius University in 1967 (Usačev et al, 1973). Initially, sample pretreatment and combustion systems for a proportional counter filled with CO2 were installed (Chrapan, 1966). One group adopted methods based on the use of methane (Usačev et al, 1973), a second group continued radiocarbon dating using an Oeschger-type proportional counter filled with CO2 (Chrapan, 1968). Later a modified Oeschger-type proportional counter with 1L active volume and with a background of approximately 8.10–2 bq was built (Schmidt and Chrapan, 1970). The pressure used in this counter is 105 Pa. 0.95 NBS oxalic acid is used as a standard of the present biosphere and the year 1950 refers to the zero year. Calculated radiocarbon ages are based on a 5568 ± 30 year half-life as recommended by the 8th International Radiocarbon Dating Conference. Statistical errors are calculated as a combination of the 3σ standard deviations of the sample count and the background. Samples were treated by HCl, NaOH or other chemicals according to their initial conditions.

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 Radiocarbon Dating at the University of Washington III

Radiocarbon ◽  
1966 ◽  
Vol 8 ◽  
pp. 498-506 ◽  
Author(s):  
A. W. Fairhall ◽  
W. R. Schell ◽  
J. A. Young
Keyword(s):  
Standard Deviation ◽  
Oxalic Acid ◽  
Lower Limit ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Isotope Fractionation ◽  
Statistical Error ◽  
Sample Count ◽  
The University ◽  
Made In

This date list consists of those measurements made since 1962. The counter is one described previously (Fairhall and Schell, 1963). The results are computed using NBS oxalic acid as the standard and 5568 for the half-life of C14. Standard deviations are computed for each measurement, including the statistical error in the sample count and uncertainties in background and standard. In general, each sample is counted at least twice. The quoted error on the date is the standard deviation. A 2σ criterion is used to establish a lower limit to the age of very old samples with no detectable trace of C14. No correction for isotope fractionation has been made in any of the measurements.

scholarly journals Louvain Natural Radiocarbon Measurements IV

Radiocarbon ◽  
1966 ◽  
Vol 8 ◽  
pp. 248-255 ◽  
Author(s):  
E. Gilot ◽  
N. Ancion ◽  
P. C. Capron
Keyword(s):  
Oxalic Acid ◽  
Tree Rings ◽  
Proportional Counter ◽  
Half Life ◽  
Experimental Error ◽  
The One ◽  
Contemporary Standard ◽  
Modern Standard

The following list covers most of the samples measured at the Louvain C14 laboratory since the last list (Louvain III).The method is essentially the same as the one used for the work described in the previous lists. A CH4 proportional counter, 0.6 L volume, operating at 3 atm pressure, is used. Equipment and counting techniques have been described in Louvain I. Dates are computed on the basis of the Libby half-life, 5570 yr, and the zero of the age scale is A.D. 1950. Ages are quoted with 1σ experimental error, which includes the counting variations of the sample as well as that of the background and the contemporary standard. As modern standard we now use NBS oxalic-acid standard or wood taken from A.D. 1870 to A.D. 1900 tree rings. No differences between the two standards have been observed.

scholarly journals Gif Natural Radiocarbon Measurements IX

Radiocarbon ◽  
1982 ◽  
Vol 24 (3) ◽  
pp. 291-343 ◽  
Author(s):  
Georgette Delibrias ◽  
Marie-Thérèse Guillier ◽  
Jacques Labeyrie
Keyword(s):  
Standard Deviation ◽  
South America ◽  
Oxalic Acid ◽  
West Africa ◽  
Sea Level ◽  
Half Life ◽  
Sea Level Variations ◽  
Geologic Samples ◽  
Modern Standard

The following list includes 14C measurements of geologic samples, the majority of which pertain to sea-level variations, and of archaeologic samples mainly from France, West Africa, and South America. Most of the dates were measured between 1972 and 1973 when installations were not modified. The technique used is described in Radiocarbon, 1972, v 14, p 280–320. Dates were calculated using the 14C half-life of 5568 years; modern standard is 0.95 of the NBS oxalic acid. Reported errors are one standard deviation for 2000 minutes measurements.

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