scholarly journals Riken Natural Radiocarbon Measurements VIII

Radiocarbon ◽  
1974 ◽  
Vol 16 (3) ◽  
pp. 331-357 ◽  
Author(s):  
Fumio Yamasaki ◽  
Chikako Hamada ◽  
Tatsu Ji Hamada
Keyword(s):  
Stainless Steel ◽  
Oxalic Acid ◽  
Half Life ◽  
Background Counting ◽  
Modern Standard

The 14C dates given below are continued from our previous list (R, 1972, v 14, p 223–238), and results obtained mainly during 1971–2 are described. A 2.7L stainless steel counter and a 3.3L copper counter are used as previously, yielding background counting rates of 6.9 and 6.0 cpm, respectively, when filled with dead CO2 at ca 1.8 atm. Dates have been calculated on the basis of the 14C half-life of 5568 yr and 95% of NBS oxalic acid is modern standard. No correction has been made for any of the samples in this list.

scholarly journals Riken Natural Radiocarbon Measurements VII

Radiocarbon ◽  
1972 ◽  
Vol 14 (1) ◽  
pp. 223-238 ◽  
Author(s):  
Fumio Yamasaki ◽  
Chikako Hamada ◽  
Tatsuji Hamada
Keyword(s):  
Stainless Steel ◽  
Oxalic Acid ◽  
Half Life ◽  
Background Counting ◽  
Modern Standard

The C14 dates given below are continued from our previous list (R., 1970, v. 12, p. 559–576), and results obtained mainly during 1970 are described. A 2.7 L stainless steel counter and a 3.3 L copper counter are used, yielding background counting rates of 5.5 and 8.5 cpm, respectively, when filled with dead CO2 at ca. 1.8 atm. Dates have been calculated on the basis of the C14 half-life of 5568 yr and 95% of NBS oxalic acid as modern standard.

scholarly journals Riken Natural Radiocarbon Measurements IX

Radiocarbon ◽  
1977 ◽  
Vol 19 (1) ◽  
pp. 62-95 ◽  
Author(s):  
Fumio Yamasaki ◽  
Chikako Hamada ◽  
Tatsuji Hamada
Keyword(s):  
Stainless Steel ◽  
Oxalic Acid ◽  
Half Life ◽  
Filling Pressure ◽  
Standard Errors ◽  
Standard Deviations ◽  
Background Counting ◽  
Modern Standard

The 14C dates given below are continued from our previous list (R, 1974, v 16, p 331-357), and results obtained mainly during 1972-73 are described. A 2.7L stainless steel counter and a 3.3L copper counter are used as previously, yielding background counting rates of 3.9 and 5.6cpm, respectively, when filled with dead CO2 at ca 1.7atm. Dates have been calculated on the basis of the 14C half-life of 5568 ± 30 yr and 95% of NBS oxalic acid is modern standard. Errors (± 1σ) include standard deviations for sample counts, background and modern standard, that of half-life, and, also, effective standard deviations for reading of filling pressure and temperature. No correction has been made for any of the samples in this list.

scholarly journals Riken Natural Radiocarbon Measurements IV

Radiocarbon ◽  
1968 ◽  
Vol 10 (2) ◽  
pp. 333-345 ◽  
Author(s):  
Fumio Yamasaki ◽  
Tatsuji Hamada ◽  
Chikako Fujiyama
Keyword(s):  
Stainless Steel ◽  
Oxalic Acid ◽  
Fresh Water ◽  
Half Life ◽  
Water Shell ◽  
Calcareous Deposits ◽  
Modern Standard

The C14 dates given below are a continuation of the work presented in our previous list (RIKEN III), and have been obtained by counting CO2 at ca. 2 atm pressure in a 2.7 L stainless steel counter. Results obtained mainly during 1967 are described.Shell samples were treated with 1% HCl to remove the outer 10%. Calcareous deposits on the surface, when observed, were removed by mechanical means.Dates were calculated on the basis of the C14 half-life of 5568 yr and 95% NBS oxalic acid as modern standard. No correction was applied even for fresh water shell samples.

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 Riken Natural Radiocarbon Measurements V

Radiocarbon ◽  
1969 ◽  
Vol 11 (2) ◽  
pp. 451-462 ◽  
Author(s):  
Fumio Yamasaki ◽  
Tatsuji Hamada ◽  
Chikako Hamada
Keyword(s):  
Stainless Steel ◽  
Oxalic Acid ◽  
Half Life ◽  
Modern Standard

The C14 dates given below are a continuation of the work presented in our previous list (Radiocarbon, 1968, v. 10, p. 333-345), and have been obtained by counting CO2 at ca. 2 atm pressure in a 2.7 L stainless steel counter. Results obtained mainly during 1968 are described.Dates have been calculated on the basis of the C14 half-life of 5568 yr and 95% of NBS oxalic acid as modern standard.

scholarly journals Rudjer Bošković Institute Radiocarbon Measurements VI

Radiocarbon ◽  
1981 ◽  
Vol 23 (3) ◽  
pp. 410-421 ◽  
Author(s):  
Dušan Srdoč ◽  
Adela Sliepčevic ◽  
Bogomil Obelic ◽  
Nada Horvatinčic
Keyword(s):  
Oxalic Acid ◽  
Soil Sample ◽  
Half Life ◽  
Sample Pretreatment ◽  
Radiocarbon Date ◽  
Sample Treatment ◽  
New Techniques ◽  
Counting Technique ◽  
Acid Sample ◽  
Modern Standard

The following radiocarbon date list contains dates of samples measured since our previous list (R, 1979, v 21, p 131-137). As before, age calculations are based on the Libby half-life 5570 ± 30 yr and reported in years before 1950. The modern standard is 0.95 of the activity of NBS oxalic acid. Sample pretreatment, combustion, and counting technique are essentially the same as described in R, 1971, v 13, p 135-140, supplemented by new techniques for groundwater processing (R, 1979, v 21, p 131-137) and for soil sample treatment (R, 1977, v 19, p 465-475).

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 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 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.

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