scholarly journals University of Cambridge Natural Radiocarbon Measurements XI

Radiocarbon ◽  
1973 ◽  
Vol 15 (1) ◽  
pp. 156-164 ◽  
Author(s):  
V. R. Switsur ◽  
R. G. West
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Research Laboratory ◽  
Radiocarbon Dating ◽  
Organic Content ◽  
Wet Oxidation ◽  
High Carbon ◽  
High Carbon Content ◽  
University Of Cambridge ◽  
The University

The measurements presented in this paper were carried out at the University Radiocarbon Dating Research Laboratory during the second half of 1971 using carbon dioxide counting. The counting equipment used was substantially that described by Switsur, Hall, and West (1970). Oxidation of samples of sufficiently high carbon content was performed in a stainless steel high pressure combustion bomb, developed at this laboratory, otherwise by ‘wet’ oxidation using acidified permanganate solutions for lake mud and samples of low organic content.

scholarly journals University of Cambridge Natural Radiocarbon Measurements XIV

Radiocarbon ◽  
1975 ◽  
Vol 17 (3) ◽  
pp. 301-312 ◽  
Author(s):  
V R Switsur ◽  
R G West
Keyword(s):  
Research Laboratory ◽  
Radiocarbon Dating ◽  
Plastic Scintillator ◽  
Environmental Radiation ◽  
University Of Cambridge ◽  
Pure Carbon ◽  
Proportional Counters ◽  
Coincidence Mode ◽  
The University ◽  
Pure Carbon Dioxide

The dates presented in this paper comprise results of determinations made at the University Radiocarbon Dating Research Laboratory, mostly during the latter half of 1974. Radioactivity was measured with proportional counters using pure carbon dioxide at 2 atmospheres pressure as filling gas. Effects of cosmic and local environmental radiation on the counters were reduced by surrounding them completely with 1) a plastic scintillator anticoincidence shield, 7.5cm thick, viewed by 2 photomultiplier tubes operating in coincidence mode, the output pulses of which were in anticoincidence with the proportional counters signals, and 2) by a 17.5 ton lead castle.

Radiocarbon Dates and New World Chronology

Antiquity ◽  
1961 ◽  
Vol 35 (140) ◽  
pp. 286-291 ◽  
Author(s):  
Geoffrey Bushnell
Keyword(s):  
Radiocarbon Dating ◽  
New World ◽  
Radiocarbon Dates ◽  
The Past ◽  
University Of Cambridge ◽  
The University ◽  
The Impact

It is a commonplace of current archaeology that the publication of radiocarbon dates is revolutionizing our ideas of the past. Dr G. H. S. Bushnell, Curator of the Museum of Archaeology and Ethnology in the University of Cambridge, England, has already published in ANTIQUITY and elsewhere some of his views on the impact of radiocarbon dating on New World chronology. Here he studies the whole problem in detail. He adopts the useful convention of referring to a date already fully published in the Radiocarbon Supplement to the American Journal of Science simply by its laboratory designation and number {thus K-554 is reading no. 554 of the Copenhagen Laboratory), but in some cases, where the date is not fully published, he gives fuller information.

Sandscaping and C14: the Udal, N. Uist

Antiquity ◽  
1977 ◽  
Vol 51 (202) ◽  
pp. 124-136 ◽  
Author(s):  
Iain Crawford ◽  
Roy Switsur
Keyword(s):  
Eighteenth Century ◽  
Iron Age ◽  
Research Laboratory ◽  
Radiocarbon Dating ◽  
Radiocarbon Dates ◽  
Second Stage ◽  
Research Fellow ◽  
University Of Cambridge ◽  
Queen's University ◽  
European Standards

A research campaign into the scarcely known history and prehistoric origins of Scottish West Highland and Island settlement, has located an area of ‘fossil’ landscape at Coileagan an Udail (the Udal), N. Uist. The completion of a first stage of 14 years excavation (155 weeks) has provided detailed evidence of continuous occupation from the Iron Age to the eighteenth century AD. Sampling has shown positive indications of a similar picture back through much of prehistory at least as far as the Beaker period and is the basis for the proposed second stage of excavations. This remarkably long (by European standards) sequence of deposition has had its coherence confirmed by a first series of radiocarbon dates. The calibration of these dates and their relationship to crucial artifacts is considered. This article is by Iain Crawford, who has just completed two years as Senior Visiting Research Fellow at The Queen's University of Belfast, and Dr Roy Switsur, Head of the Radiocarbon Dating Research Laboratory University of Cambridge.

scholarly journals University of Cambridge Natural Radiocarbon Measurements IX

Radiocarbon ◽  
1970 ◽  
Vol 12 (2) ◽  
pp. 590-598 ◽  
Author(s):  
V. R. Switsur ◽  
M. A. Hall ◽  
R. G. West
Keyword(s):  
Solid State ◽  
High Voltage ◽  
Radiocarbon Dating ◽  
Cosmic Ray ◽  
New Techniques ◽  
Plastic Scintillation ◽  
University Of Cambridge ◽  
Solid State Devices ◽  
Proportional Counters ◽  
The University

The University of Cambridge Radiocarbon Dating Laboratory has been completely rebuilt and modernized, incorporating new techniques developed here for the various stages of measurements. Sample radioactivity is measured in gas proportional counters after conversion to highly purified CO2. Four counters are mounted within a single anticoincidence shield consisting of plastic scintillation material. This is surrounded by a graded cosmic ray shield of low radioactive steel, boron loaded wax, and finally, about 16 tons of ancient low radioactive lead blocks. The electronics are all solid state devices except for the stabilized high voltage supplies.

scholarly journals 14C Research at the Laboratory for the Analysis of Radiocarbon with AMS (LARA), University of Bern

2020 ◽  
Vol 74 (12) ◽  
pp. 1010-1014
Author(s):  
Sönke Szidat
Keyword(s):  
Mass Spectrometry ◽  
Carbon Dioxide ◽  
Quality Improvement ◽  
Particulate Matter ◽  
Radiocarbon Dating ◽  
Radioactive Carbon ◽  
Fossil Carbon ◽  
Air Quality Improvement ◽  
University Of Bern ◽  
The University

The Laboratory for the Analysis of Radiocarbon with AMS (LARA) at the University of Bern measures the radioactive carbon isotope 14C with accelerator mass spectrometry (AMS) in different applications. Besides radiocarbon dating of environmental and archaeological samples, the LARA focuses on source apportionment of air-borne particulate matter (i.e. aerosols) as well as greenhouse gases such as carbon dioxide and methane. This approach allows the identification and quantification of fossil carbon emissions in these air components, which is relevant for measures of air-quality improvement. The LARA furthermore develops instrumental setups for and at the AMS in order to analyze 14C samples in μg-amounts with low contamination and high throughput, preferably using online-hyphenated systems.

AMS radiocarbon dating of a Western Han period (3rd-1st century BC) lacquer-coated earthenware jar

2002 ◽  
Vol 712 ◽  
Author(s):  
G. W. L Hodgins ◽  
E. Farrell ◽  
R. D. Mowry
Keyword(s):  
Radiocarbon Dating ◽  
Organic Coating ◽  
Harvard University ◽  
Small Sample ◽  
Radiocarbon Date ◽  
High Carbon ◽  
High Carbon Content ◽  
Ams Radiocarbon Dating ◽  
Mineral Acids ◽  
Coating Mass

ABSTRACTThe chronometric dating of ceramic objects is normally achieved by thermoluminscence techniques (TL). Here we report both TL and a radiocarbon measurements on a Chinese earthenware hu jar (Harvard University Art Museums LTL1.2001.23 a,b). TL dates were obtained from earthenware core samples using established methods. The radiocarbon date was obtained from an organic coating present on the jar surface. The coating was preliminarily identified as urushi by a comparison of its FTIR absorption spectrum to absorption spectra obtained from modern and ancient lacquer standards. The material was found to be insoluble in a variety of solvents, mineral acids, and bases. Combustion and elemental analysis revealed that 64% of the coating mass was carbon. C measurement by AMS was carried out on a 3.9 mg sample of chemically cleaned lacquer. This measurement generated a date of 2191 ± 38 BP. Calibration of this measurement placed the age of the jar between 390BC and 160 BC at the 95% confidence interval. The calibrated radiocarbon date corroborated the TL measurement placing the jar at between 2400 and 1500 years old (400 BC to 500 AD). These findings also agreed with stylistic evidence that the jar was produced during the Western Han period (206 BC-AD 9). The literature on urushi composition, its pigment compatibility, its high carbon content, its apparent chemical stability, and the small sample required for C-accelerator mass spectrometry suggests that other lacquer-coated objects might be dated using a similar approach.

Sign in / Sign up

Export Citation Format

Share Document