scholarly journals University of Texas At Austin Radiocarbon Dates IX

Radiocarbon ◽  
1972 ◽  
Vol 14 (2) ◽  
pp. 461-485 ◽  
Author(s):  
S. Valastro ◽  
E. Mott Davis ◽  
Alejandra G. Varela
Keyword(s):  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
Memorial Museum ◽  
Sample Count ◽  
Counting Statistics ◽  
The University ◽  
Made In ◽  
Modern Standard

This laboratory is now a branch of the Texas Memorial Museum of the University of Texas at Austin. This list reports C14 measurements made in projects completed between October 1969 and August 1971. A number of major projects are still in progress and are to be reported later. Age calculations are based on C14 half-life of 5568 yr and modern standard of 95% of NBS oxalic acid. 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. Except where noted, C12/C13 measurements have not been made, and results are not corrected for C13 fractionation. The laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium-activated catalyst in preparation; chemical yields average 88%. The counter is a Packard TriCarb Model 3002.

scholarly journals University of Texas at Austin Radiocarbon Dates VI

Radiocarbon ◽  
1968 ◽  
Vol 10 (2) ◽  
pp. 384-401 ◽  
Author(s):  
S. Valastro ◽  
E. Mott Davis ◽  
Craig T. Rightmire
Keyword(s):  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
Sample Count ◽  
Counting Statistics ◽  
The University ◽  
Administrative Responsibilities ◽  
Made In ◽  
Modern Standard

This laboratory is now a part of the Bureau of Economic Geology, The University of Texas at Austin. The present list reports C14 measurements made in dating projects completed in the year ending November, 1967, and some measurements for projects still in progress. Age calculations are based on C14 half-life of 5568 yr and a modern standard of 95% of NBS oxalic acid. The deviations reported are based on the counting statistics of the sample, background, and modern, and are ± 1σ except that when the sample count approaches either the modern or the background, 2σ limits are reported. The laboratory continues to use liquid scintillation counting of benzene, using Li2C2 and vanadium activated catalyst in preparation, as described in Texas IV and earlier lists. Chemical yields now average 85%.Rightmire's caliche dating (done for an M.A. thesis in the Dept. of Geol.) is the principal project reported in this list; in addition to the research he prepared the samples in our laboratory and wrote the statements which accompany the list. Valastro is in charge of all technical operations in the laboratory, and he and Davis share the administrative responsibilities. Davis, who handles sample screening (with the aid of an Advisory Committee) and archaeological appraisal, compiled the list.

scholarly journals University of Texas at Austin Radiocarbon Dates VII

Radiocarbon ◽  
1970 ◽  
Vol 12 (1) ◽  
pp. 249-280 ◽  
Author(s):  
S. Valastro ◽  
E. Mott Davis
Keyword(s):  
Oxalic Acid ◽  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
Sample Count ◽  
Counting Statistics ◽  
Made In ◽  
Modern Standard

This list reports C14measurements made in dating projects completed in the year ending December, 1968, and some measurements for projects still in progress. Age calculations are based on C14half-life of 5568 yr and a modern standard of 95% of NBS oxalic acid. 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. The laboratory uses liquid scintillation counting of benzene, with Li2C2and vanadium activated catalyst in preparation, as described in Texas IV (Radiocarbon, 1966, v. 8, p. 453–466) and earlier lists. Chemical yields average 85%.

scholarly journals University of Texas at Austin Radiocarbon Dates VIII

Radiocarbon ◽  
1970 ◽  
Vol 12 (2) ◽  
pp. 617-639 ◽  
Author(s):  
S. Valastro ◽  
E. Mott Davis
Keyword(s):  
Oxalic Acid ◽  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
Sample Count ◽  
Counting Statistics ◽  
Made In ◽  
Modern Standard

This list reports C14 measurements made in projects completed in the year ending October, 1969, and some measurements for projects still in progress. Age calculations are based on C14 half-life of 5568 years and a modern standard of 95% of NBS oxalic acid. 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. The laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium activated catalyst in preparation. Chemical yields average 88%.

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 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 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.

University of Texas at Austin Radiocarbon Dates X

Radiocarbon ◽  
1975 ◽  
Vol 17 (1) ◽  
pp. 52-98 ◽  
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 14C measurements completed between August 1971 and November 1973. Other projects completed in that period 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 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. The laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium-activated catalyst in preparation; chemical yields average 90%. Three counters are employed: a Packard Tri-Carb Model 3002, and 2 Beckman LS-230 spectrometers obtained through a grant from the National Science Foundation.

scholarly journals University of Texas At Austin Radiocarbon Dates XI

Radiocarbon ◽  
1977 ◽  
Vol 19 (2) ◽  
pp. 280-325 ◽  
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 reports14C measurements completed between August 1973 and November 1975. Other projects completed in that period will be reported later. Age calculations are based on14C 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 for13C fractionation. The laboratory uses liquid scintillation counting of benzene, with Li2C2and 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 LS-230 spectrometers obtained through a grant from the National Science Foundation.

scholarly journals University of Texas Radiocarbon Dates II

Radiocarbon ◽  
1964 ◽  
Vol 6 ◽  
pp. 138-159 ◽  
Author(s):  
M. A. Tamers ◽  
F. J. Pearson ◽  
E. Mott Davis
Keyword(s):  
Chemical Synthesis ◽  
Liquid Scintillation Counting ◽  
Radiocarbon Dating ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
The University

The Radiocarbon Dating Laboratory of the University of Texas was reorganized in late 1962. The dates reported in this list were obtained from February to November, 1963. The laboratory uses liquid scintillation counting with benzene solutions (Tamers, Stipp, and Collier, 1961; Noakeset al., 1963). The chemical synthesis has been modified and improved in several ways in order to permit one worker to produce a sample per day.

scholarly journals University of Texas Radiocarbon Dates I

Radiocarbon ◽  
1962 ◽  
Vol 4 ◽  
pp. 43-50 ◽  
Author(s):  
J. J. Stipp ◽  
E. Mott Davis ◽  
John E. Noakes ◽  
Tom E. Hoover
Keyword(s):  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Successful Development ◽  
Radiocarbon Dates ◽  
University Of Texas ◽  
Two Systems ◽  
The University

The C14Dating Laboratory of the University of Texas has been working on the development of two systems of counting: gas counting with methane, and liquid scintillation counting with benzene. Lack of adequate instrumentation has retarded the work on gas counting, but the liquid scintillation work, supported in part by the Department of Chemistry, finally led to the successful development of a system in which the benzene counting solvent was synthesized from acetylene by pyrolysis (Tamers, Stipp, and Collier, 1961).

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