SCINTILLATION COUNTER FOR SIMULTANEOUS ASSAY OF H$sup 3$ AND C$sup 14$ IN GAS-LIQUID CHROMATO-GRAPHIC VAPORS
An instrument for the assay of H/sup 3/ and C/sup 14/ in gas-liquid chromatographic effluents is described. An important change is the placing of a photomultiplier on each side of the counting chamber. Two fully transistorized counting channels were designed, each of which can be set independently for the detection of BETA rays of different energies. Radioactive analysis is practically simultaneous with the mass analysis. By the use of coincidence circuitry and pulse-height analysis with discriminators it is possible to measure simultaneously 2 radioactive isotopes contained in the same sample. Furthermore, the addition of a subtracting circuit to the electronic system permits the independent recording of C/sup 14/ and of H/sup 3/ counts. The instrument gives highly reproducible results; the maximum variation observed in counting a mixture of C/sup 14/-labeled fatty acid esters was 450 deg C in a 3%. Less than 0.1% of the H/sup 3/ counts appear in the C/sup 14/ channel, which (excepting specimens of very high H/sup 3/ and low C/sup 14/ content) may be neglected. On the other hand, about 16% of the C/sup 14/ counts are also recorded in the H/sup 3/ channel. The instrument is particularly suitable for the analysis of radioactive substances of high volatility. The electrical circuitry for subtraction of C/sup 14/ pulses from H/sup 3/ channel courts during simultaneous assay of the two isotopes with the aid of ratemeters is appended. (TCO)
- Research Organization:
- Hammersmith Hospital, London
- NSA Number:
- NSA-17-022026
- OSTI ID:
- 4727307
- Journal Information:
- Journal of Lipid Research (U.S.), Vol. Vol: 3; Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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