HIGH SENSITIVITY DETECTION OF NATURALLY OCCURRING RADIOCARBON. I. CHEMISTRY OF THE COUNTING SAMPLE

Journal Article · Sat Jul 01 04:00:00 EDT 1961 · Geochim. et Cosmochim. Acta

DOI:https://doi.org/10.1016/0016-7037(61)90022-9· OSTI ID:4023220

Tamers, M A; Stipp, J J; Collier, J

The most promising method of increasing the sensitivity of radiocarbon dating is the use of radiation detection tech niques that are capable of counting large quantities of carbon. The liquid scintillation spectrometer is an instrument that is applied in several cases to increase the efficiency of C/sup 14/ dating. A means is presented by which the entire counting solution (not including the small amounts of phosphors) can be synthesized from the sample to be dated. The solvent used is benzene, which is one of the most suitable materials for liquid scintillation counting since it contains 92% carbon and shows no scintillation quenching properties. The chemistry involved in the complete synthesis of benzene is described in detail. The sample to be dated is burned and carbon dioxide collected in ammonium hydroxide solution. Strontium carbonate is precipitated upon the addition of strontium chloride. The dried carbonate is mixed with magnesium powder and strontium carbide is produced by ignition of the mixture in an evacuated stainless steel tube. Reaction of the carbide with water generates acetylene which is led into a circuit containing dry ice-cooled traps and a pyrolysis tube at 600 deg C. The acetylene polymerizes to benzene. This is collected in the cooled traps and then purified by distillation. The over-all yield in the synthesis is 30%. The chemical steps involve no special equipment or training. A 20-ml sample can be produced by two man-days of work and the entire procedure completed in less than a week. (auth)

• Research Organization: Univ. of Texas, Austin
• NSA Number: NSA-15-024829
• OSTI ID: 4023220
• Journal Information: Geochim. et Cosmochim. Acta, Journal Name: Geochim. et Cosmochim. Acta Vol. Vol: 24
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ACETYLENES
AGE ESTIMATION
AMMONIUM COMPOUNDS
BENZENE
CARBON 14
CARBON DIOXIDE
CARBON ISOTOPES
CHEMICAL REACTIONS
CHEMISTRY
CIRCUITS
COUNTERS
DETECTION
DISTILLATION
EFFICIENCY
HYDROXIDES
ICE
INSTRUMENTS
MAGNESIUM
PHOSPHORS
POWDERS
PREPARATION
SENSITIVITY
SOLVENTS
SPECTROMETERS
STAINLESS STEELS
STRONTIUM CARBIDES
STRONTIUM CARBONATES
TRAPS
TUBES
USES
WATER