Scintillation spectrometer

Analytical Methods. Liquid scintillation counting (LSC) was done using Packard Models 3375 and 3380 Liquid Scintillation Spectrometers equipped with automatic external standards. Solid samples were combusted in a Packard model 306 Sample Oxidizer prior to LSC analysis. 

Horrocks, D. L., Low-Level Alpha Disintegration Rate Determinations with a One-Multiplier Phototube Liquid Scintillation Spectrometer,... 

Procedures for pretreatment of soil samples and synthesis of sample benzene for 14C analysis had been described in Chen et al. (2002b). Sample benzene was often left for 3-4 weeks to allow any radon with half-life of 3.82 days that may be present to decay. 14C activity of the CgFL was then determined using a 1220-QUANTULUS ultralow-level liquid scintillation spectrometer manufactured by WALLAC Company, Sweden. The 14C analyses were conducted at the Guangzhou Institute of Geochemistry, CAS. Results are reported as A14C, in parts per thousand of the 14C/12C ratio from that of the standard (oxalic acid decay corrected to 1950) (Stuiver and Po-lach 1977), and corrected for bomb 14C (Chen et al. 2002b), where ... 

Picer et al. [49] described a method for measuring the radioactivity of labelled DDT contaminated sediments in relatively large volumes of water, using a liquid scintillation spectrometer. Various marine sediments, limestone and quartz in sea water were investigated. External standard ratios and counting efficiencies of the systems investigated were obtained, as was the relation of efficiency factor to external standard ratios for each system studied. 

The washed-precipitate, containing antibody-bound morphine, is dissolved in NCS-solubilizer, and the radioactivity is counted with the help of a Packard-Iri-card Liquid Scintillation Spectrometer,... 

The mixture was then treated with 5 ml of alkaline hydroxyl-amine reagent ( 20 ml hydroxylamine hydrochloride titrated to pH 13 with 3.5M NaOH ) for 5 min and the protein precipitated with 5% trichloroacetic acid. After centrifuging ( 5000 g ) for 5 min the supernatant was carefully decanted and the precipitate washed twice with 10-ml aliquots of absolute ethanol. The material was then dissolved in 1 ml, of 0.2M NaOH, mixed with 10 ml of Insta-gel scintillator ( Packard Instrument (Pty) Ltd.), and the radioactivity counted in a Packard Tri Carb Liquid Scintillation Spectrometer. 

Bjomstad HE, Oughton DH, Salbu B. 1992. Determination of aluminum-26 using a low-level liquid scintillation spectrometer. Analyst 117 435-438. 

Quantitative determinations were reported by densitometry [63,72] or, in the case of Relabelled compounds, by scraping or cutting the chromatograms into strips and measuring the radioactivity in a liquid scintillation spectrometer [44,70]. 

Pullen, B.P. 1986. Cherenkov counting of 40K in KC1 using a liquid scintillation spectrometer../. Chem. Educ. 63 971-976. 

Hoogenboom, A. M. A New Method in Gamma-Ray Spectroscopy A Two Crystal Scintillation Spectrometer with Improved Resolution. Nucl. Instr. 3, 57 (1958). 

Greenwood, R. C., and J. Reed Scintillation Spectrometer Measurements of Capture Gamma-Rays from Natural Elements. Modem Trends in Activation Analysis—Proceedings of the 1961 International Conference in College Station, Texas, December, 1961. A and M College of Texas, College Station, Texas, pp. 166-171 (1961). 

The enzymatic radioassay method for the analysis of acetylcholine and choline in brain tissue has been reported by Reid et al. [210]. The method describes the determination of nanogram amounts of acetylcholine and choline in as little as 10 mg of brain tissue, involves isolation of acetylcholine by high-voltage paper electrophoresis, alkaline hydrolysis of acetylcholine to choline, and conversion of this into [32P]-phosphoryl choline in the presence of choline kinase and [y32P] ATP. The labeled derivative is isolated by column chromatography on Bio-Rad AG1-X8 resin, using Tris buffer solution as the eluent. Cerenkov radiation from 32P is counted (at 33% efficiency) in a liquid scintillation spectrometer. The amount of phosphorylcholine is proportional to the amount of choline over the range of 0.08-8.25 nmol. 

Simultaneously, the use of low-backgroimd laboratorial gamma-ray scintillation spectrometer in vessel conditions allowed determining Cs in bottom sediment samples at a level of 3 Bq/kg (according to the Russian Navy s standards [5], MAC for Cs in bottom sediments of the tidal zone makes up 2590 Bq/kg) and in fish - 2 Bq/kg raw weight (in keeping with the Russian Radiation Safety Standards (NRB-99) [1], MAC for Cs equals 11 Bq/kg, for °Sr - 5 Bq/kg). 

Figure 3-6. A refrigerated scintillation spectrometer. The large bottom cabinet is a deepfreeze unit that contains the sample holders and photomultiplier detection units. The typewriter is used for data print out. (Courtesy of Packard Instrument Company, Inc.)...

Figure 3-7. Block diagram of the basic electronic components of a scintillation spectrometer.

Figure 3-10. Operation of scintillation spectrometer discriminator circuits. The left graph represents the signals approaching the three discriminator circuits and the right panel depicts their output signals.

For precise quantitation the gels must be divided into small pieces and the amount of radioactivity per piece determined with a scintillation spectrometer. The most inexpensive apparatus used for this purpose is shown in Figure 6-18. It is simply a large number of razor blades with metal spacers between them usually only one spacer is placed between blades, yielding slices of 1 mm thickness. Gels to be analyzed are frozen... 

Figure 8-37. Schematic diagram describing the physical organization and operation of the y-ray sensing elements of a y-ray scintillation spectrometer. PMT indicates the photomultiplier tubes.

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