scholarly journals Institut Royal du Patrimoine Artistique Radiocarbon Dates II

Radiocarbon ◽  
1971 ◽  
Vol 13 (1) ◽  
pp. 29-31 ◽  
Author(s):  
M. Dauchot-Dehon ◽  
J. Heylen
Keyword(s):  
Oxalic Acid ◽  
Atmospheric Pressure ◽  
Half Life ◽  
Isotopic Fractionation ◽  
Electronic Apparatus ◽  
Radiocarbon Dates ◽  
Unknown Sample ◽  
Preset Time ◽  
Standard Deviations

The method used was described in R., 1968, v. 10, p. 29–35. The counter is the same (M.B.L.E. Houtermans and Oeschger) but the electronic apparatus is new; all is transistorized and the installation operates in preset time. The counter is filled at a pressure of 600 to 1000 mm Hg; sample, modern reference, and background are counted at the same pressure and reduced to standard conditions: 760 mm Hg, 20°C. Atmospheric pressure and temperature are measured at each filling. Samples are counted for 20 hours at one month intervals and a third time if measurements do not agree within two standard deviations. Age calculations are based on a contemporary value equal to 0.95 of activity of NBS oxalic acid standard and 5570 yr for the half-life of C14, 1950 used as reference year. Errors quoted include the standard deviations of the count rates for unknown sample, modern and background; no corrections are made for isotopic fractionation.

scholarly journals Copenhagen Radiocarbon Dates IX

Radiocarbon ◽  
1968 ◽  
Vol 10 (2) ◽  
pp. 295-327 ◽  
Author(s):  
Henrik Tauber
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Isotopic Fractionation ◽  
Radiocarbon Dates ◽  
Unknown Sample ◽  
De Vries ◽  
Standard Deviations

The following list comprises a selected number of measurements made up to October, 1967. Age calculations are based on 95% of the activity of the NBS oxalic-acid standard, and on a half-life for C14 of 5570 yr. Results are reported in yr before 1950, and in the A.D./B.C. scale.Errors quoted include standard deviations of the count rates for the unknown sample, contemporary value, and background. Because possible errors arising from isotopic fractionation in the plants, or from the de Vries effect, have not been included, 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 Copenhagen Radiocarbon Dates VII

Radiocarbon ◽  
1966 ◽  
Vol 8 ◽  
pp. 213-234 ◽  
Author(s):  
Henrik Tauber
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Isotopic Fractionation ◽  
Radiocarbon Dates ◽  
Unknown Sample ◽  
De Vries ◽  
Standard Deviations

The following list comprises a selected number of measurements made up to November, 1965. 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 yr. Results are reported in years before 1950, and in the A.D./B.C. scale. Errors quoted include the standard deviations of the count rates for the unknown sample, the contemporary value, and the background. Because possible errors arising from isotopic fractionation in the plants, or from the de Vries effect, have not been included, calculated errors smaller than 100 yr have been increased by rounding to that figure as a minimum.

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 Łódź Radiocarbon Dates III

Radiocarbon ◽  
1991 ◽  
Vol 33 (1) ◽  
pp. 115-130 ◽  
Author(s):  
Andrzej Kanwiszer ◽  
Paweł Trzeciak
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dates ◽  
Unknown Sample ◽  
Standard Deviations ◽  
Contemporary Standard

The results presented in this list were obtained from 1986 to 1989. Equipment, measurement and treatment of samples are as reported previously (Kanwiszer & Trzeciak 1984: 111). Age calculations are based on a contemporary value equal to 95% of the activity of NBS oxalic acid standard and on the conventional half-life for 14C of 5568 ± 30 years. Results are reported in years before 1950 (years BP). Errors quoted (± 1σ) include standard deviations of count rates for the unknown sample, contemporary standard and background. The dates are not corrected for 13C fractionation. Descriptions and comments are based on information supplied by submitters of samples.

scholarly journals Gliwice Radiocarbon Dates V

Radiocarbon ◽  
1979 ◽  
Vol 21 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Anna Pazdur ◽  
Mieczyslaw F Pazdur ◽  
Andrzej Zastawny
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Counting Efficiency ◽  
Radiocarbon Dates ◽  
Unknown Sample ◽  
De Vries ◽  
Standard Value ◽  
Standard Deviations ◽  
Contemporary Standard

Most of the dates reported in this list were obtained between November 1975 and December 1976. All samples were subjected to standard de Vries pretreatment. Age calculations are based on a contemporary value equal to 0.95 of the activity of NBS oxalic acid standard and on the Libby value for the half-life of radiocarbon. Results are reported as conventional radiocarbon dates in years before ad 1950. All measurements were made with our L1 counter (Mościcki & Zastawny, 1976). Counting rates of all samples were normalized to the standard value of CO2 pressure and corrected for the counting efficiency (Pazdur et al, 1978). Errors quoted (±1σ) include estimated overall standard deviations of count rates for the unknown sample, contemporary standard and background (Pazdur, & Walanus, in press). No corrections for 13C/12C ratio were made for measurements reported in this list. The value of δ13C for our NBS oxalic acid standard is equal to — 19.41% relative to the PDB standard. The descriptions of the samples are based on information provided by the submitters.

scholarly journals Gliwice Radiocarbon Dates VI

Radiocarbon ◽  
1980 ◽  
Vol 22 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Mieczysław F Pazdur ◽  
Anna Pazdur ◽  
Andrzej Zastawny
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Radiocarbon Dates ◽  
Unknown Sample ◽  
Standard Deviations ◽  
Contemporary Standard ◽  
Counting Equipment

Results presented in this date list have been obtained from Jan 1977 to Dec 1977, but some earlier measurements are also included. All calculations are based on a contemporary value equal to 0.95 of the activity of NBS oxalic acid standard and on the Libby value for the half-life of radiocarbon. Ages are reported as conventional radiocarbon dates in years before AD 1950. No corrections for 13C/12C ratio were made for measurements reported in this list. Errors quoted (±1σ) included estimated overall standard deviations of count rates of the unknown sample, contemporary standard and background (Pazdur & Walanus, 1979). Counting equipment and experimental procedures have been described earlier (Mościcki & Zastawny, 1976, 1977; Pazdur et al, 1978; Pazdur & Pazdur, 1979a). Sample descriptions are based on information provided by the submitters.

scholarly journals Gliwice Radiocarbon Dates VII

Radiocarbon ◽  
1982 ◽  
Vol 24 (2) ◽  
pp. 171-181 ◽  
Author(s):  
Anna Pazdur ◽  
Romuald Awsiuk ◽  
Andrzej Bluszcz ◽  
Mieczysław F Pazdur ◽  
Adam Walanus ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Oxalic Acid ◽  
Integrated Circuit ◽  
Proportional Counter ◽  
Isotopic Fractionation ◽  
Radiocarbon Dates ◽  
Unknown Sample ◽  
Proportional Counters ◽  
Typical Measurement ◽  
Contemporary Standard

The following list contains the measurements of archaeologic samples made during 1978 and 1979 using carbon-dioxide-filled proportional counters. Most of the samples were dated with counter No. 3 (L3) filled to 1 or 2 atm pressure (Mościcki and Zastawny, 1977). Our counter No. 1 (L1) previously described (Mościcki and Zastawny, 1976) has been remounted and is now operating at 2 atm pressure of carbon dioxide. Samples measured with this counter have date numbers starting with Gd-1000. Parameters of proportional counters are listed in Table 1. Our transistorized electronics is being gradually replaced by more compact integrated-circuit electronics in CAMAC system (Bluszcz and Walanus, 1980). Counts from proportional counter and guard counters are recorded in 5 channels and punched every 100 minutes. Typical measurement of any sample, including background and oxalic acid samples, consists of a series of 20 to 25 partial measurements. Partial results obtained in such series are analyzed on ODRA 1325 computer at the Computing Centre of the Silesian Technical University according to code C14C written in ALGOL (Pazdur and Walanus, 1979). Age calculations are based on contemporary value equal to 0.95 of the activity of NBS oxalic acid standard and on the Libby value for the half-life of radiocarbon. Ages are reported as conventional radiocarbon dates in years before ad 1950. Corrections for isotopic fractionation in nature are made only for some samples with indicated values of δ13C Errors quoted (±1σ) include estimated overall standard deviations of count rates of the unknown sample, contemporary standard, and background (Pazdur and Walanus, 1979).

scholarly journals Arizona Radiocarbon Dates VIII

Radiocarbon ◽  
1971 ◽  
Vol 13 (1) ◽  
pp. 1-18 ◽  
Author(s):  
C. Vance Haynes ◽  
Donald C. Grey ◽  
Austin Long
Keyword(s):  
Sample Preparation ◽  
Oxalic Acid ◽  
Half Life ◽  
Isotopic Fractionation ◽  
Radiocarbon Dates ◽  
Carbon Isotopic ◽  
Isotopic Analyses

The carbon isotopic analyses reported here covers the period since the last list (Haynes et al., 1967) until summer 1969. All results relating to secular C14 fluctuations in atmospheric CO2 are now published separately (Damon et al., 1970). Sample preparation and counting procedures remain essentially unchanged since completion of our conversion to CO2 in 1960. All δC13 values are reported relative to PDB and all C14 dates, unless otherwise noted, are based on the 5568 year half-life, but are not corrected for C13 content. 0.95 NBS oxalic acid activity is our routine standard periodically monitored for isotopic fractionation.

scholarly journals Birbal Sahni Institute Radiocarbon Measurements II

Radiocarbon ◽  
1980 ◽  
Vol 22 (1) ◽  
pp. 54-60 ◽  
Author(s):  
G Rajagopalan ◽  
Vishnu Mittre ◽  
B Sekar
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Isotopic Fractionation ◽  
Counting System ◽  
Radiocarbon Dates ◽  
Counting Statistics

The radiocarbon dates covered in this list were measured during 1978. Chemical and counting procedures are as reported previously (R, 1978, v 20, p 398-404). Age calculations are based on the conventional 14C half-life (5570 yr) and on the contemporary value of 95% of the activity of NBS oxalic acid. Errors quoted correspond to 1σ value which takes into account the counting statistics, the uncertainty in the half-life, and the instability of the counting system. The ages are not corrected for isotopic fractionation in nature.

scholarly journals Birbal Sahni Institute Radiocarbon Measurements III

Radiocarbon ◽  
1982 ◽  
Vol 24 (1) ◽  
pp. 45-53 ◽  
Author(s):  
G Rajagopalan ◽  
B Sekar Vishnu-Mittre ◽  
T K Mandal
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Isotopic Fractionation ◽  
Counting System ◽  
Radiocarbon Dates ◽  
Counting Statistics

The radiocarbon dates reported in this date list cover the measurements carried out in 1979 to 1980. Chemical and counting procedures are the same as reported earlier (R, 1978, v 20, p 398–404). Age calculations are based on the conventional 14C half-life (5570 yr) and on the contemporary value of 95% of the activity of NBS oxalic acid. Errors quoted correspond to 1σ value which takes into account the counting statistics, the uncertainty in the half-life, and the instability of the counting system. The ages are not corrected for isotopic fractionation in nature.

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