scholarly journals University of Michigan Radiocarbon Dates IV

Radiocarbon ◽  
1959 ◽  
Vol 1 ◽  
pp. 173-198 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Isotope Fractionation ◽  
University Of Michigan ◽  
Reference Standard ◽  
Radiocarbon Dates ◽  
Carbonate Sample ◽  
Method Of Measurement

The following is a list of radiocarbon dates obtained since the time of the preparation of Michigan list III.∗ The description of the essential features of our method of measurement as given in the introduction to list III applies to this list. The modern standards used were obtained from hardwood logs, and were of various ages from 75 to 150 years by ring count. These standards were sufficiently old so that no correction for the recent dilution of the atmospheric C14is believed to be necessary in the dates reported here. The ages of carbonate sample are also calculated from modern wood as a reference standard, without any correction for isotope fractionation.

scholarly journals University of Michigan Radiocarbon Dates VII

Radiocarbon ◽  
1962 ◽  
Vol 4 ◽  
pp. 183-203 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Full Description ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Counting Technique ◽  
Method Of Measurement

The following is a list of C14dates obtained since the preparation of the manuscript for publication of Michigan Radiocarbon Dates VI in December 1960. The method of measurement and treatment of data are the same as described in the introduction to Michigan lists III and IV. Since the time of publication of list VI, a full description of the counting technique and equipment has been published (Crane, 1961a, b).

scholarly journals University of Michigan Radiocarbon Dates V

1960 ◽  
Vol 2 ◽  
pp. 31-48 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Method Of Measurement

The following is a list of radiocarbon dates obtained since the time of the preparation of Michigan list IV. The method of measurement and treatment of data are the same as those described in the introductions to lists III and IV.

scholarly journals University of Michigan Radiocarbon Dates VI

Radiocarbon ◽  
1961 ◽  
Vol 3 ◽  
pp. 105-125 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Method Of Measurement

The following is a list of radiocarbon dates obtained since the preparation of the manuscript for the publication of Michigan V, in December, 1959. The method of measurement and treatment of data are the same as those described in the introductions to Michigan lists III and IV. A full statement on the Michigan counter is referred to by Crane (p. 46) in this issue.

University of Michigan Radiocarbon Dates III

Science ◽  
1958 ◽  
Vol 128 (3332) ◽  
pp. 1117-1123 ◽  
Author(s):  
H. R Crane ◽  
J. B. Griffin
Keyword(s):  
University Of Michigan ◽  
Radiocarbon Dates

scholarly journals Tartu Radiocarbon Dates II

Radiocarbon ◽  
1968 ◽  
Vol 10 (1) ◽  
pp. 124-130 ◽  
Author(s):  
J. M. Punning ◽  
E. Ilves ◽  
A. Liiva
Keyword(s):  
Reference Standard ◽  
Radiocarbon Dates ◽  
Background Sample

The following list includes samples dated between 1956 and 1961. Wood dating from A.D. 1850 ± 10 yr is used as a contemporary reference standard. Background sample is synthesized from anthracite. All radiocarbon dates were calculated with the hall-life of C14 being equal to 5568 ± 30 yr. All dates are calculated from the year 1950.

scholarly journals Tallinn Radiocarbon Dates IV

Radiocarbon ◽  
1977 ◽  
Vol 19 (1) ◽  
pp. 111-117 ◽  
Author(s):  
J M Punning ◽  
R Rajamäe ◽  
M Ehrenpreis ◽  
L Sarv
Keyword(s):  
Half Life ◽  
Reference Standard ◽  
Radiocarbon Dates ◽  
Ca 50

The following list includes samples dated in 1975. The measurement of 14C activity was performed with 1-channel and 2-channel scintillation devices. Special attention was paid to the decrease of the background. The effectiveness of the measurement is ca 50% (Punning, Rajamäe, 1975). The “enriched standard” (Alekseejev et al, 1971) has been used as a contemporary reference standard of modern carbon. Age calculations are based on the 14C half-life of 5568 ± 30 yr, with 1950 as the standard year of reference. All samples are calculated to ± 1σ with respect to sample, standard and background after counting times of at least 2800 minutes. 13C/12C measurements and corrections have not been made for these samples.

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 University of Michigan Radiocarbon Dates XV

Radiocarbon ◽  
1972 ◽  
Vol 14 (1) ◽  
pp. 195-222 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Standard Deviations

The following is a list of dates obtained since the compilation of List XIV, and the method is essentially the same. Two CO2–CS2 Geiger counter systems were used. Equipment and counting techniques have been described elsewhere (Crane, 1961). Dates and estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conference of 1962 and 1965, in that (a) dates are computed on the basis of the Libby half-life, 5570 yr, (b) A.D. 1950 is used as the zero of the age scale, and (c) the errors quoted are the standard deviations obtained from the number of counts only. In Michigan date lists up to and including VII, we quoted errors at least twice as great as the statistical errors of counting, to take account of other errors in the over-all process.

scholarly journals University of Michigan Radiocarbon Dates XI

Radiocarbon ◽  
1966 ◽  
Vol 8 ◽  
pp. 256-285 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Standard Deviation ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Sources Of Error ◽  
The Many ◽  
Many Sources

The following is a list of dates obtained since the time of the compilation of List X in December 1964. The method is essentially the same as that used for the work described in the previous list. Two CO2-CS2Geiger counter systems are used. The equipment and counting techniques have been described elsewhere (Crane, 1961). The dates and estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conferences of 1962 and 1965, in that (a) dates are computed on the basis of the Libby half-life, 5570 yr, (b) A.D. 1950 is used as the zero of the age scale, and (c) the errors quoted are the standard deviations obtained from the numbers of counts only. In previous Michigan date lists up to and including VII we have quoted errors at least twice as great as the statistical errors of counting, in order to take account of other errors in the over-all process. If the reader wishes to obtain a standard deviation figure which will allow ample room for the many sources of error in the dating process, we suggest he double the figures that are given in this list.

scholarly journals University of Michigan Radiocarbon Dates VIII

Radiocarbon ◽  
1963 ◽  
Vol 5 ◽  
pp. 228-253 ◽  
Author(s):  
H. R. Crane ◽  
James B. Griffin
Keyword(s):  
Standard Deviation ◽  
Half Life ◽  
Radiocarbon Dating ◽  
Geiger Counter ◽  
University Of Michigan ◽  
Radiocarbon Dates ◽  
Statistical Errors ◽  
Counting Technique ◽  
Life Scale ◽  
The Many

The following is a list of dates obtained since the time of the compilation of List VII in December 1961. The method is essentially the same as that used for the work described in the previous list. Two CO2-CS2 Geiger counter systems are used. The equipment and counting technique have been described elsewhere (Crane, 1961a, 1961b). The dates and the estimates of error in this list follow the practice recommended by the International Radiocarbon Dating Conference of 1962, in that (a) dates are computed on the basis of a half life of 5568 years, (b) a.d. 1950 is used as the zero of the age scale and (c) the errors quoted are the standard deviations obtained from the numbers of counts only. In all previous Michigan date lists we have quoted errors at least twice as great as the statistical errors of counting, in order to take account of other errors in the over-all process. If the reader wishes to obtain a standard deviation figure which will allow ample room for the many other sources of error in the dating process, we suggest he double the figures that are given in this list. The procedures for converting the dates to the more recent half life scale and to a scale having its zero at any time other than 1950 need not be given here as they have been covered in this journal and elsewhere. Where there is no comment, it is because the submitter of the sample had none to make.

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