Detector liquid scintillation

It should be noted here that the variable temperature data presented for Np02 in Fig. 6 are close to those reported by Glebov et al. (43) but that the relaxivities presented in this figure for PuOl are different from those published by these authors (44) (the concentration of the PuO is uncertain in this reference). It has already been mentioned that special care must be taken in the preparation of solutions of plutonyl salts to avoid the presence of lower oxidation states. UV-visible spectroscopy (27) and liquid scintillation detectors (50) are particularly useful to assess the concentration and the nature of Pu species in solution. The purity of the PuO can also be tested by liquid liquid extraction with thenoyltrifluoroacetone, an agent known to be able to extract Pu" " from acidic aqueous phases but unable to extract PuO + (51). 

Calibration of a liquid scintillation detector for beta-particle counting is discussed in Experiment 9. 

In both scintillator and gas detectors, the absorption of radiation causes excitation and ionization however with the scintillation process, the absorbed energy produces a flash of light, rather than a pulse of current. The principal types of scintillation detectors found in the clinical chemistry laboratory are the sodium iodide crystal scintillation detector and the organic liquid scintillation detector. Because of the crystal detector s relative ease of operation and economy of sample preparation, most clinical laboratory procedures have been developed to measure nucfides, such as which can be counted efficiently in a crystal detector. A liquid scintillation detector is used to measure pure (3-emitters, such as tritium or C. 

Liquid Scintillation Detector, This detector measures radioactivity by recording scintillations occurring within a transparent vial that contains the unknown sample and liquid scintillator. Because the radionuclide is intimately mixed with, or actually dissolved in, the fiquid scintillator, the technique is ideal for the pure -emitters, such as H, and Typical efficiencies for liquid scintillation counting in the absence of significant quenching are 60% for tritium and 90% for... 

Other Components and Techniques. Other components of a liquid scintillator detector include (1) electronics, (2) a photomultiplier tube, (3) a preamplifier, and (4) a pulse-height analyzer. Description of these components and discussion of relevant topics such as (1) efficiency of scintillation counting, (2) quenching, (3) counting statistics, (4) assay optimization, and (5) radiation safety can be found in an earlier edition of this textbook. ... 

Liquid scintillation detectors operate on the principle of interaction of radiations with a special type of scintillating liquid that emits light upon interaction with radiation. The light is then processed in the same manner as in the case of a solid detector, as discussed below. 

E. Because of the weak beta radiation, tritium is NOT readily measured by the Geiger-Mueller counter used with most fielded radiac instruments and requires wipe testing swipes and a liquid scintillation detector to determine the level of contamination. 

Counting Alpha and Beta Particles with a Liquid Scintillation Detector... 

Figure 5 The KamLAND liquid scintillator detector. (Picture from reference 13.)... 

In summary, liquid scintillator detectors operating a few tens of meters below the Earth, with sizes and characteristics similar to existing detectors, could detect 1 kt explosions at a range of a few kilometers. 

Existing liquid scintillator detectors constructed about 50 m.w.e. (20 m of rock) below the surface could detect 1 kt tests a few kilometers from a source and therefore could be useful for the first two applications. The utility of such a detector ultimately depends on trade-offs between cost and the desire by states for a non-intrusive local nuclear monitoring system. 

C. Rothschild, M. Chen, F. Calaprice, Antineutrino Geophysics with Liquid Scintillator Detectors, http //xxx.lanl.gOv/abs/nucl-ex/9710001, Submitted to Geophysical Research Letters, 15 Oct. 1997. 

The length of the column used in the analysis was 7.1 cm, with a calculated volume of 0.25 ml. The time required to automatically pack the microcolumn was 4.5 min, including washing steps. After elution, online detection was carried out by a flow-through liquid scintillation detector, configured with a 0.5 ml flow cell. The detector integration time to accumulate counts for each data point reported... 

The above pilot experiment demonstrated that the SISAK system in combination with liquid scintillation detectors can be used for the investigation of chemical properties of superheavy elements. 

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