scholarly journals UCLA Radiocarbon Dates IX

Radiocarbon ◽  
1969 ◽  
Vol 11 (01) ◽  
pp. 194-209 ◽  
Author(s):  
Rainer Berger ◽  
W. F. Libby
Keyword(s):  
Oxalic Acid ◽  
Isotope Ratio ◽  
Individual Case ◽  
Radiocarbon Dates ◽  
Counting Error ◽  
Chemical Pretreatments ◽  
The Individual ◽  
Isotope Ratio Measurements ◽  
Energy Channels ◽  
Sixth International

The measurements reported have been carried out during the first half of 1968 in the Isotope Laboratory of the Institute of Geophysics and Planetary Physics as a continuation of the UCLA date lists I through VIII. Samples were analyzed as CO2-gas at close to one atm in a 7.5 L proportional counter with three energy channels described in earlier publication. Radiocarbon ages have been calculated for uniformity on the basis of a 5568 yr half-life in accord with a recommendation by the Sixth International C14and H3Dating 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 based on CO2obtained from marble. The error listed is always at least a one-sigma statistical counting error. In critical cases C13/C12isotope ratio measurements were made to correct the dates for fractionation. All samples were subjected to accepted NaOH, HCl or other special chemical pretreatments discussed below depending on the individual case to exclude contamination.

scholarly journals UCLA Radiocarbon Dates VIII

Radiocarbon ◽  
1968 ◽  
Vol 10 (2) ◽  
pp. 402-416 ◽  
Author(s):  
Rainer Berger ◽  
W. F. Libby
Keyword(s):  
Oxalic Acid ◽  
Proportional Counter ◽  
Isotope Ratio ◽  
Individual Case ◽  
Radiocarbon Dates ◽  
Counting Error ◽  
The Individual ◽  
Isotope Ratio Measurements ◽  
Energy Channels ◽  
Sixth International

The measurements reported were made during the 2nd half of 1967 in the Isotope Lab. of the Inst. of Geophysics and Planetary Physics as a continuation of the UCLA date lists I through VII. Samples were analyzed as CO2-gas at close to one atm in a 7.5 L proportional counter with 3 energy channels described earlier. Radiocarbon ages were calculated for uniformity on the basis of a 5568 yr half-life as was recommended by the Sixth International C14and H3Dating 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 labs. Background determinations have been based on CO2obtained from marble. The error listed is always at least a 1σ statistical counting error. In critical cases C13/C12isotope ratio measurements were made to correct the dates for fractionation. All samples were subjected to accepted NaOH and/or HCl pretreatments depending on the individual case as a minimum to exclude contamination.

scholarly journals UCLA Radiocarbon Dates VII

Radiocarbon ◽  
1968 ◽  
Vol 10 (1) ◽  
pp. 149-160 ◽  
Author(s):  
Rainer Berger ◽  
W. F. Libby
Keyword(s):  
Oxalic Acid ◽  
Proportional Counter ◽  
Isotope Ratio ◽  
Individual Case ◽  
Radiocarbon Dates ◽  
Counting Error ◽  
The Individual ◽  
Isotope Ratio Measurements ◽  
Energy Channels ◽  
Sixth International

The measurements reported have been carried out during the first half of 1967 in the Isotope Laboratory of the Institute of Geophysics and Planetary Physics as a continuation of the UCLA date lists I through VI. Samples were analyzed as CO2-gas at close to one atm in a 7.5 L proportional counter with 3 energy channels described earlier. Radiocarbon ages have been calculated for uniformity on the basis of a 5568-yr half-life as was recommended by the Sixth International C14 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 based on CO2 obtained from marble. The error listed is always at least a 1σ statistical counting error. In critical cases C13/C12 isotope ratio measurements were made to correct the dates for fractionation. All samples were subjected to accepted NaOH and/or HCl pretreatments depending on the individual case as a minimum to exclude contamination. The annual curve for the atmospheric C14 content at China Lake, California, will be published in the next date list.

scholarly journals UCLA Radiocarbon Dates VI

Radiocarbon ◽  
1967 ◽  
Vol 9 ◽  
pp. 477-504 ◽  
Author(s):  
Rainer Berger ◽  
W. F. Libby
Keyword(s):  
Solid State ◽  
Oxalic Acid ◽  
High Voltage ◽  
Isotope Ratio ◽  
Radiocarbon Dates ◽  
Counting Error ◽  
The Individual ◽  
Isotope Ratio Measurements ◽  
Energy Channels ◽  
Sixth International

The measurements reported have been carried out during 1966 in the Isotope Laboratory of the Institute of Geophysics and Planetary Physics as a continuation of the UCLA date lists I through V. Samples were analyzed as CO2-gas at one atm in a 7.5 L proportional counter with three energy channels. The all-solid-state unit is supplied with high voltage from a remarkably stable and interference-free battery source. Radiocarbon ages have been calculated on the basis of a 5568-yr half-life as was recommended by the Sixth International C14 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 based on CO2 obtained from marble. The error listed is always at least a one-sigma statistical counting error. In critical cases C13/C12 isotope ratio measurements were made to correct the dates. All samples were subjected to accepted pretreatments differing in the individual cases to exclude contamination.

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 UCLA Radiocarbon Dates III

Radiocarbon ◽  
1964 ◽  
Vol 6 ◽  
pp. 318-339 ◽  
Author(s):  
G. J. Fergusson ◽  
W. F. Libby
Keyword(s):  
Oxalic Acid ◽  
Barometric Pressure ◽  
Radiocarbon Dates ◽  
Counting Procedure ◽  
Carbonate Material ◽  
Barometric Effect ◽  
Energy Channels ◽  
Storey Building ◽  
Made In ◽  
Modern Standard

The measurements reported in this list have been made in the Isotope Laboratory of the Institute of Geophysics during 1963 and are a continuation of the work reported previously (UCLA I and UCLA II). The same counting procedure—CO2 proportional counting at 1 atm pressure in a 7.5 L counter with three energy channels—continues in use. No barometric effect on the background has been observed, presumably because of the combination of fairly constant barometric pressure in this area and the location of the equipment on the ground floor of a five storey building. Dates continue to be calculated on the basis of a C14 half life of 5568 yr according to the decision of the 1962 Cambridge Conference (Godwin, 1962). The modern standard has been taken as 95% of NBS oxalic acid for all organic samples, while for carbonate material such as shells and tufa, dates have been computed on the basis of estimates of the corresponding contemporary C14 activity (Broecker and Walton, 1959) as indicated in the description accompanying the results.

scholarly journals University of Georgia Radiocarbon Dates V

Radiocarbon ◽  
1976 ◽  
Vol 18 (3) ◽  
pp. 362-370 ◽  
Author(s):  
John E Noakes ◽  
Betty Lee Brandau
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dates ◽  
University Of Georgia ◽  
Counting Error ◽  
Statistical Variation ◽  
Sample Count ◽  
Counting Equipment

The following list of dates is compiled from samples prepared and catalogued since publication of our last date list (R, 1975, v 17, p 99-111). The counting equipment and operating procedures are the same. Ages are quoted with a 1σ counting error which includes statistical variation of the sample count as well as for background and standard, using ad 1950 as the reference year and 95% NBS oxalic acid for 14C dating as the standard. The half-life value used is 5570 years.

scholarly journals UCLA Radiocarbon Dates XI

Radiocarbon ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Rainer Berger ◽  
Reiner Protsch
Keyword(s):  
Oxalic Acid ◽  
Proportional Counter ◽  
Half Life ◽  
Count Rate ◽  
Radiocarbon Dates ◽  
Bone Material ◽  
Standard Manner ◽  
Counter Operation ◽  
Almost All ◽  
Energy Channels

The radiocarbon dates reported in this list are almost all based on collagen measurements from human archaeologic bone material. This collagen was isolated according to the methods developed by Berger, Horney and Libby (1964), Ho, Marcus and Berger (1969), Longin (1971) and Protsch (1973). All samples were counted as CO2 gas at close to 1 atm in a 7.5L proportional counter with three energy channels. The 14C dates reported are calculated with the Libby half-life of 5568 ± 30 years as required by convention. 13C measurements were used to normalize to −25‰ in the standard manner. The biospheric standard is 95% the count rate of NBS oxalic acid for radiocarbon laboratories. Background is based on CO2 obtained from marble. The accuracy of counter operation is checked against historically dated wood from the funerary boat of Sesostris III, 1872−8+4 bc (Hayes, 1962). The 14C ages are not tree-ring calibrated.

scholarly journals University of Georgia Radiocarbon Dates IV

Radiocarbon ◽  
1975 ◽  
Vol 17 (1) ◽  
pp. 99-111 ◽  
Author(s):  
Betty Lee Brandau ◽  
John E Noakes
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dates ◽  
University Of Georgia ◽  
Counting Error ◽  
Statistical Variation ◽  
Sample Count ◽  
Counting Equipment

The following list of dates is compiled from samples prepared since publication of our last date list (R, 1974, v 16, p 131–141). The counting equipment and operating procedures are the same. Ages are quoted with a 1σ counting error which includes statistical variation of the sample count as well as for background and standard, using ad 1950 as the reference year and 95% NBS oxalic acid for 14C dating as the standard. The half-life value used is 5570 years.

scholarly journals UCLA Radiocarbon Dates X

Radiocarbon ◽  
1983 ◽  
Vol 25 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Rainer Berger ◽  
Jonathon Ericson
Keyword(s):  
Oxalic Acid ◽  
Tree Ring ◽  
Proportional Counter ◽  
Half Life ◽  
Count Rate ◽  
Wood Sample ◽  
Radiocarbon Dates ◽  
Chemical Treatments ◽  
Counter Operation ◽  
Energy Channels

The measurements reported in this date list form the chronometric framework for obsidian hydration and trade studies in California (Ericson, 1975; 1977; 1978; 1981; Ericson et al, 1975; Singer and Ericson, 1977). All samples were analyzed as CO2 gas at close to 1 atm in a 7.5L proportional counter with three energy channels. Radiocarbon ages are based by convention on the 5568 ± 30 yr half-life. The biospheric standard is 95% the count rate of NBS oxalic acid for radiocarbon laboratories. Background is based on CO2 obtained from marble. Counter operation is checked against a historically dated wood sample from the funerary boat of Sesostris III, 1872 +4−8 BC (Hayes, 1962). All samples were subjected to accepted NaOH, HCl or other special chemical treatments to exclude contamination. No tree-ring calibration was applied to any of the samples listed.

scholarly journals UCLA Radiocarbon Dates IV

Radiocarbon ◽  
1965 ◽  
Vol 7 ◽  
pp. 336-371 ◽  
Author(s):  
Rainer Berger ◽  
G. J. Fergusson ◽  
W. F. Libby
Keyword(s):  
Sample Preparation ◽  
Oxalic Acid ◽  
Half Life ◽  
Count Rate ◽  
Radiocarbon Dates ◽  
New Methods ◽  
Counting Procedure ◽  
Energy Channels ◽  
Modern Standard

The measurements reported in this list have been carried out in the Isotope Laboratory of the Institute of Geophysics and Planetary Physics during 1964. They are a continuation of the previously reported date lists UCLA I, II and III. The same counting procedure has been continued: CO2 proportional counting at 1 atm of pressure in a 7.5 L counter with three energy channels. Dates have been calculated according to the recommendations of the Fifth Radiocarbon Conference, Cambridge, 1962, on the basis of a radiocarbon half-life of 5568 yr (Godwin, 1962). The modern standard for organic samples has been based on 95% of the count rate of NBS oxalic acid for radiocarbon laboratories. Background measurements are determined with CO2 derived from marble. The ages of carbonate-containing substances such as shells and tufa have been calculated on the basis of estimates for the corresponding contemporary C14 activity (Broecker and Walton, 1959), as discussed in the respective sample descriptions. New methods of sample preparation are described in context with the date listings.

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