scholarly journals Florida State University Radiocarbon Dates III

Radiocarbon ◽  
1969 ◽  
Vol 11 (01) ◽  
pp. 15-21
Author(s):  
J. R. Martin ◽  
H. G. Goodell
Keyword(s):  
Oxalic Acid ◽  
Liquid Scintillation ◽  
Florida State University ◽  
State University ◽  
Liquid Scintillation Spectrometer ◽  
Radiocarbon Dates

Age calculations in this list include samples dated since January, 1967. Samples are converted to benzene and counted in a liquid scintillation spectrometer. Operations are essentially the same as those described in Radiocarbon, 1966, v. 8, p. 46–53 and Radiocarbon, 1967, v. 9, p. 38–42. Modern reference is 95% the activity of NBS oxalic acid standard, not age-corrected wood as reported in Radiocarbon, 1966, v. 8, p. 46–53.

scholarly journals Florida State University Radiocarbon Dates I

Radiocarbon ◽  
1966 ◽  
Vol 8 ◽  
pp. 46-53 ◽  
Author(s):  
J. J. Stipp ◽  
G. A. Knauer ◽  
H. G. Goodell
Keyword(s):  
Natural Radioactivity ◽  
Liquid Scintillation ◽  
Florida State University ◽  
State University ◽  
Liquid Scintillation Spectrometer ◽  
Radiocarbon Dates ◽  
Archaeological Chronologies

Laboratory construction was begun in December 1964 and routine dating was in progress by late February 1965. The primary purpose of this facility is to assist in marine geological studies and the archaeological chronologies of the region. Dating is carried out by utilizing the techniques of liquid scintillation described by Noakes et al. (1965), wherein the carbon of the sample to be dated is converted to benzene and the natural radioactivity detected in a liquid scintillation spectrometer.

scholarly journals Florida State University Radiocarbon Dates IV

Radiocarbon ◽  
1971 ◽  
Vol 13 (1) ◽  
pp. 19-25 ◽  
Author(s):  
S. J. Daugherty ◽  
J. R. Martin ◽  
D. S. Phelps
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Liquid Scintillation ◽  
Florida State University ◽  
State University ◽  
Liquid Scintillation Spectrometry ◽  
Radiocarbon Dates ◽  
Counting Error ◽  
The One

This list includes mainly the results of datings done from 1967 to 1969. Methods are essentially the same as those described in Radiocarbon, 1966, v. 8, p. 46–53, 1967, v. 9, p. 38–42, and 1969, v. 11, p. 15–21. Samples synthesized to benzene and counted by liquid scintillation spectrometry. Age calculations are based on 95% of the activity of the NBS oxalic acid standard and computed from the Libby half-life of 5570 yr and reference A.D. 1950. The error listed is the one-sigma statistical counting error. Most samples were counted for 2000 to 3000 min. HCL and NaOH pretreatments were applied to samples as required.

scholarly journals University of Miami Radiocarbon Dates II

Radiocarbon ◽  
1975 ◽  
Vol 17 (1) ◽  
pp. 112-120 ◽  
Author(s):  
J J Stipp ◽  
K L Eldridge
Keyword(s):  
Oxalic Acid ◽  
Half Life ◽  
Liquid Scintillation ◽  
Liquid Scintillation Spectrometer ◽  
Radiocarbon Dates ◽  
Laboratory Procedures ◽  
University Of Miami ◽  
Modern Standard

The following list of dates are selected from geologic and archaeologic samples measured in late 1973. The laboratory procedures and techniques are the same as indicated in R, 1974, v 16, p 402–408, where sample is synthesized to benzene and counted for 24 hours in either a Beckman LS-100-C or Packard 2311 liquid scintillation spectrometer. Ages are calculated relative to 0.95 x NBS oxalic acid using a 14C half-life of 5568 years. The quoted error is 1σ, which includes only the counting uncertainties of the background, modern standard, and sample. Sample descriptions and comments were written in collaboration with collectors and submitters.

scholarly journals University of Texas At Austin Radiocarbon Dates XIII

Radiocarbon ◽  
1979 ◽  
Vol 21 (2) ◽  
pp. 257-273 ◽  
Author(s):  
S Valastro ◽  
E Mott Davis ◽  
Alejandra G Varela
Keyword(s):  
Oxalic Acid ◽  
National Science Foundation ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
National Science ◽  
Sample Count ◽  
Counting Statistics ◽  
Modern Standard

This list reports certain 14C measurements completed by November 1978; other projects completed by this time will be reported later. Age calculations are based on 14C half-life of 5568yr and modern standard of 95% NBS oxalic acid, supplemented by tree rings of pre-industrial wood from a log cut in the 1850's (Tx-540; R, 1970, v 12, p 249). Deviations reported are based on counting statistics of sample, background and modern, and are ± 1σ, except that when sample count approaches either modern or background, 2σ limits are reported. Unless noted, 12C/13C measurements were not made and results are not corrected for 13C fractionation (assumed ratio = −25‰ WRT PDB). Our laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium-activated catalyst in preparation; chemical yields range between 95% and 99%. Three counters are employed; a Packard Tri-Carb Model 3002 and 2 Beckman LS320 spectrometers obtained through a grant from the National Science Foundation.

scholarly journals Instituto Venezolano de Investigaciones Cientificas Natural Radiocarbon Measurements III

Radiocarbon ◽  
1967 ◽  
Vol 9 ◽  
pp. 237-245 ◽  
Author(s):  
M. A. Tamers
Keyword(s):  
Oxalic Acid ◽  
Count Rate ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Liquid Scintillation Spectrometer ◽  
Modern Standard

The dates reported here represent a portion of those determined in 1966, The Radiocarbon Dating Laboratory of the Instituto Venezolano de Investigaciones Científicas carries out a synthesis of benzene for each sample and detects the activity with a liquid scintillation spectrometer. For routine measurements, 3 cc synthesized benzene and 1 cc commercial toluene, with PPO and dimethyl-POPOP scintillators, are used in a special small counting vial. The modern standard is 95% of the NBS oxalic acid, which gives a net modern count rate of 23.9 cpm. The background is now 8.5 cpm.

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 Illinois State Geological Survey Radiocarbon Dates I

Radiocarbon ◽  
1969 ◽  
Vol 11 (2) ◽  
pp. 394-395 ◽  
Author(s):  
Stephen M. Kim ◽  
R. R. Ruch
Keyword(s):  
Standard Deviation ◽  
Liquid Scintillation ◽  
Geological Survey ◽  
Counting Method ◽  
Alumina Catalyst ◽  
Liquid Scintillation Spectrometer ◽  
Radiocarbon Dates ◽  
Organic Sample ◽  
Chemical Procedure ◽  
Detailed Chemical

The radiocarbon dating laboratory of the Illinois State Geological Survey has been established to satisfy a growing need for radiocarbon dates for an active Pleistocene research program. Because of the age and type of material dated, the benzene liquid scintillation counting method is employed in this laboratory. The detailed chemical procedure for converting carbon to benzene has been published by Noakes, Kim, and Stipp (1965) and Noakes, Kim, and Akers (1967); however, the procedures for benzene synthesis and sample counting are briefly explained below to clarify this laboratory's procedure.An organic sample, such as peat, organic silt, or wood, is burned and the CO2 evolved is absorbed in NH4OH. SrCl2 solution is added to precipitate the carbonate, and the solution plus precipitate is boiled and cooled before filtration of SrCO3. The SrCO3 is acidified with dilute H3PO4 to liberate CO2 in a closed system, and the CO2 is converted to C2H2, as reported by Barker (1953). In this method, 2.4 gm of dry packed lithium, obtainable from the Lithium Corporation of America, is used for each liter of CO2 that is converted to C2H2. Trimerization of the C2H2 to form C6H6 is accomplished using a vanadium-alumina catalyst.To the C6H6 synthesized from the sample carbon, 2 cc of toluene containing 100 mg Butyl-PBD, 2-(4-tert-Butylphenyl)-5-(4-Biphenylyl)-1,3,4-Oxadiazole, are added, and this mixture is made to a total volume of 10 cc with spectrograde C6H6. A modified Packard Instrument Co. liquid scintillation spectrometer (Model 3375) is used for measurement of C14 activity.Ages are calculated from a C14 half-life of 5568 years, and the standard deviation (1σ) is based only on counting errors; however, if calculated error is less than 200 years, 200 years is chosen as one standard deviation (1σ).

scholarly journals University of Texas at Austin Radiocarbon Dates XII

Radiocarbon ◽  
1978 ◽  
Vol 20 (2) ◽  
pp. 245-273 ◽  
Author(s):  
S Valastro ◽  
E Mott Davis ◽  
Alejandra G Varela
Keyword(s):  
Oxalic Acid ◽  
National Science Foundation ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
National Science ◽  
Sample Count ◽  
Counting Statistics ◽  
Modern Standard

This list reports certain 14C measurements completed by November 1977; other projects completed by this time will be reported later. Age calculations are based on 14C half-life of 5568yr and modern standard of 95% NBS oxalic acid, supplemented by tree rings of pre-industrial wood from a log cut in the 1850's (Tx-540; R, 1970, v 12, p 249). Deviations reported are based on counting statistics of sample, background, and modern, and are ±1σ, except that when sample count approaches either modern or background, 2σ limits are reported. Unless noted, 12C/13C measurements were not made and results are not corrected for 13C fractionation. Our laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium-activated catalyst in preparation; chemical yields range between 95% and 99%. Three counters are employed: a Packard Tri-Carb Model 3002 and 2 Beckman LS320 spectrometers obtained through a grant from the National Science Foundation.

scholarly journals University of Granada Radiocarbon Dates V

Radiocarbon ◽  
1991 ◽  
Vol 33 (3) ◽  
pp. 367-373 ◽  
Author(s):  
Cecilio Gonzalez-Gomez ◽  
Purificacion Sanchez-Sanchez
Keyword(s):  
Liquid Scintillation Counting ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Boiling Temperature ◽  
Liquid Scintillation Spectrometer ◽  
Radiocarbon Dates ◽  
Standard Acid ◽  
Basic Procedure ◽  
The University

This paper includes some determinations of archaeological, art and palaeobotanical samples from Spain and Portugal, obtained at the University of Granada Radiocarbon Dating Laboratory, mostly from 1986 to 1988. Pretreatment of charcoal and wood samples is a standard acid-basic procedure using 8% HC1 and 2% NaOH at boiling temperature. The collagen of bone samples is obtained by the Longin (1971) method.The method of dating is benzene synthesis and liquid scintillation counting as previously reported (González-Gómez, López-González & Domingo-García 1982; González-Gómez, Sánchez-Sánchez and Domingo-García 1985; González-Gómez, Sánchez-Sánchez and Villafranca-Sánchez 1986, 1987).14C activity was measured in a Packard Tri-Carb Mod 4640 liquid scintillation spectrometer, using 20 ml low 40K counting vials with 5 ml benzene and 10 ml PPO-toluene as scintillator with a background of ca. 9 cpm. Efficiency was approximately 70% using the part of spectrum above the end point of tritium.

scholarly journals University of Texas at Austin Radiocarbon Dates XIV

Radiocarbon ◽  
1980 ◽  
Vol 22 (4) ◽  
pp. 1090-1115 ◽  
Author(s):  
S Valastro ◽  
E Mott Davis ◽  
Alejandra G Varela ◽  
Carolyn Ekland-Olson
Keyword(s):  
Oxalic Acid ◽  
National Science Foundation ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
National Science ◽  
Sample Count ◽  
Counting Statistics ◽  
Modern Standard

This list reports certain 14C measurements completed by December 1979; other projects completed by this time will be reported later. Age calculations are based on 14C half-life of 5568 yr and modern standard of 95% NBS oxalic acid, supplemented by tree rings of pre-industrial wood from a log cut in the 1850's (Tx-540; R, 1970, v 12, p 249). Deviations reported are based on counting statistics of sample, background and modern, and are ± 1σ, except that when sample count approaches either modern or background, 2σ limits are reported. Unless noted, 12C/13C measurements were not made and results are not corrected for 13C fractionation (assumed ratio = −25‰ WRT PDB). Our laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium-activated catalyst in preparation; chemical yields range between 95% and 99%. Three counters are employed; a Packard Tri-Carb Model 3002 and 2 Beckman LS230 spectrometers obtained through a grant from the National Science Foundation.

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