Plastic scintillation counters

Oatley and a succession of brilliant students, collaborating with others at the Cavendish Laboratory, by degrees developed an effective instrument a key component was an efficient plastic scintillation counter for the image-forming... 

The detector Engler et al. 1999 is an iron sampling calorimeter with the lateral dimensions 16 x 20 m2. It consists of 9 layers of ionization chambers and a layer of plastic scintillation counters to provide fast trigger signals interspaced... 

The remainder of this chapter is organized as follows. The next section describes some experimental and application investigations of in-beam Mossbauer spectroscopy using a Mn beam at the RIKEN RIBF. The system used for detecting Mossbauer 7-radiation in in-beam experiments is important. Nagatomo et al. [32] have recently developed a highly sensitive resonance counter based on parallel-plate avalanche and plastic scintillation counters. A new anticoincidence detection system is introduced. Finally, the experimental setup for online Mossbauer spectroscopy using the thermal neutron capture reaction, Fe (n, 7) Fe, and the results obtained are presented in the subsequent section. 

Radiometric analysis using a plastic scintillator connected to coincidence and anticoincidence circuits (e.g. a Picobeta counter) can be used to detect "Tc. The detection limit is estimated to be about 10 mBq. A slightly better detection limit (1-5 mBq) is reported for a gas flow counter with an anticoincidence shield [8],... 

Scintillation counters use materials that produce light when stimulated by radiation. Scintillation materials include sodium iodide crystals and special plastics. Radiation is measured by exposing the scintillation material to radiation and using a photomultiplier tube to count the number of resulting flashes. Photomultiplier tubes are photocells that convert light into electrical signals that can be amplifled and measured. 

Many examples of the application of radiotracers to environmental problems exist, and so we have selected only a few of the more interesting ones to discuss. Barry (1971) used 41 Ar, a short-lived gas found in reactor stack effluents, to trace the dispersion of stack effluent from the Chalk River nuclear reactor and relate it to conventional dispersion models. The 41Ar concentrations in the air at various distances from the emitting stack were measured by circulating the air through a counter consisting of layers of plastic scintillator. The (3 particles emitted in the decay of 41Ar were detected by the plastic scintillators. The detectors were... 

Figure 3-21. Plastic adapters for use of mini vials in a standard scintillation counter. (Courtesy of Packard Instrument Co., Inc.)...

Gamma-ray cylindrical sources The point source is mounted at the end of a plastic rod (diameter 9 mm). A disc can be fitted to this rod to facilitate its use in automatic samples changer. These sources are particularly suited for the calibration of well-type Nal(Tl) scintillation counters. 

Enzyme immunoassays (EIA) play an important role in clinical diagnostics, veterinary medicine, environmental control, and bioprocess analysis. Antibodies are coupled to enzymes like peroxidase or phosphatase, whose products can be measured after the degradation of a substrate. Because of its high selectivity and sensitivity, EIA enables the detection of a broad spectrum of analytes in complex samples. A solid phase EIA performed in a plastic microtitre plate is called an enzyme-linked immunosorbent assay (ELISA). The coloured products produced in the ELISA can be measured spectro-photometrically rather than in a scintillation counter as for the RIA. 

Use Polymerized with styrene to make a plastic phosphor. Single crystals used as scintillation counters. 

Figure 4. Schematic arrangement of the TRACER balloon instrument. The nuclear charge Z of traversing cosmic-ray nuclei is determined with plastic scintillators. An acrylic Cherenkov counter determines their Lorentz factor 7 at low energies, and arrays of single-wire proportional tubes measure 7 from the relativistic rise in specific ionization, and from transition radiation signals.

Anthracene and phenanthrene are stereoisomers that are crystals in pure form. Anthracene is a pale yellow crystal, while phenanthrene exhibits a yellow to brown hue. Besides its common name, anthracene is referred to as anthracin, green oil, or paranaphthalene. The compound is commercially produced by recovery from the coal tar distillation fraction known as anthracene oil or green oil. Anthracene is the key ingredient in the production of anthraquinone. However, it and phenanthrene are also used for the manufacture of dyes, fibers, plastics, and wood preservatives. ° Phenanthrene, also known as phenanthrin, can be produced by high-temperature fractional distillation of coal tar oil. It is additionally used for the oxidation of diphenic acid for use in polymers, as well as the production of chemical softeners, explosives, and some pharma-ceuticals. Recent research has extended the application of both isomers to scintillation counters, semiconductors, and photoconductors. ... 

Anthracene is used as an intermediate in dye production, in the manufacture of synthetic fibers, and as a diluent for wood preservatives. It is also used in smoke screens, as scintillation counter crystals, and in organic semiconductor research (Hawley 1987). Anthracene is used to synthesize the chemotherapeutic agent, Amsacrine (Wadler et al. 1986). Acenaphthene is used as a dye intermediate, in the manufacture of pharmaceuticals and plastics, and as an insecticide and fungicide (HSDB 1994 Windholz 1983). 

The fourth detector system is to use a resonance scintillation counter [57]. A standard type of plastic scintillator for /5-detection is doped with the resonant absorber. It is insensitive to the non-resonant background of primary... 

Scintillation counters for charged particles. The general subject of scintillation counters has been reviewed recently by Swank and luminescent materials have been reviewed by Garlick. The organic scintillators are used in all forms crystals, organic solutions (hereafter called Tiquid scintillators ) and solid solutions in plastics (referred to as plastic scintillators"). 

---