The evaluation of a gas mixture having an atomic composition similar to that of A-150 TE-plastic has been extended to a high energy neutron therapy beam. A-150 gas, air and methane-based TE gas were each flowed through A-150 plastic-walled ion chambers of different sizes ...

A series of dosimetric measurements was carried out at the Antoni van Leeuwenhoek Hospital, Amsterdam, using a Philips d+T generator, which produces neutrons with energies of approximately 14 MeV. A-150 plastic ionization chambers, an A-150 plastic calorimeter, and a GM dosimeter were used to ...

A series of dosimetric measurements was carried out at the Antoni van Leeuwenhoek Hospital, Amsterdam, using a Philips d + T generator, which produced neutrons with energies of approximately 14 MeV. A-150 plastic ionization chambers, an A-150 plastic calorimeter, and a GM dosimeter were used to ...

The interface effects arising in the measurement of absorbed dose by ionization chambers, owing to the inhomogeneity between the walls and the gas, have been evaluated by an analytical model. The geometrical situation considered here is appropriate for representing the behaviour of a plane-parallel ionization chamber exposed to a radiotherapeutic beam of ...

... PLASTICS, SILICONE PLASTICS, POLYVINYL CHLORIDE, NYLON, THERMOPLASTIC ... INSULATION, PACKAGING, COMPOSITE MATERIALS. ...

Measurements of central axis depth charge distributions (CADCD) in a p(66)Be(49) clinical neutron beam using A-150 TE plastic ionization chambers (IC) have shown that these distributions are dependent on the gas type filling the ICs. IC volumes from 0.1 to 8 cm/sup 3/ and nine different gases were investigated. Off ...

Effects of vacuums, ionization, electromagnetic radiation and meteoroids on plastics, elastomers and

This patent describes a method for sterilizing a transparent plastic article by ionizing radiation, the improvement which comprises utilizing as the transparent plastic article, an article which is made from a polymer composition.

New organic additions are described for the preparation of highly efficient plastic scintillators suitable for recording ionizing radiation. (auth)

The thermal defect, defined as the fraction of absorbed radiation energy which is not converted to heat energy in the calorimetric dosimetry absorber was investigated for A-150 tissue-equivalent plastic. Studies to measure the thermal defect as a function of proton energy and for various energies of alpha particles and the heavy recoil nuclei produced in tissue by neutrons are ...

A computer simulation of the interactions of 50 MeV d/sup +/ on Be and 42 MeV p/sup +/ on Be neutron spectra with ICRU muscle tissue and Shonka A-150 tissue equivalent plastic was performed to allow computation of the charged particle spectra that result. Nuclear data were obtained from the Evaluated Nuclear Data File (ENDF) whenever ...

Plastic scintillators are used for ionizing radiation detection and measurement. A brief review is given of the standard plastic base materials, typical classes of fluorescent compounds, and some processing methods for producing plastic scintillators. The available parameters that determine the resultant ...

The gamma-ray dose fraction from a moderated /sup 252/Cf source was determined by using three types of dosimetry systems. Measurements were carried out in air at a distance of 35 cm from the surface of the moderating sphere (50 cm from the source which is at the center of the sphere) to the geometrical center of each detector. The moderating sphere is 0.8-mm-thick stainless steel shell filled with ...

... The micro-laser plasma thruster (micro ... EXPANSION, *IONIZATION, *LASER APPLICATIONS, *PLUMES ... PLASTICS, DIODE LASERS, CELLULOSE ...

The actual and potential uses of high energy ionizing radiations in processing or modifying polymers, particularly plastics, are surveyed. Included are discussions of: those methods and end-products which have reached commercial status; advanced developme...

A plastic scintillator useful for detecting ionizing radiation comprising a matrix which comprises an optically transparent polysiloxane having incorporated therein at least one ionizing radiation-hard fluor capable of converting electromagnetic energy produced in the polysiloxane upon absorption of ionizing ...

A plastic scintillator useful for detecting ionizing radiation comprising a matrix which comprises an optically transparent polysiloxane having incorporated therein at least one ionizing radiation-hard fluor capable of converting electromagnetic energy produced in the polysiloxane upon absorption of ionizing ...

For measuring high radiation doses, plastics are promising great advantage. Consisting of elements with low atomic number, they meet the requirement of air equivalence. Undyed plastics are colored by ionizing radiation, i.e., the optical transmission is decreased. Colored cellophane, however, is discolored. The measuring ...

de- ionized water. The clean equipment will then be air-dried and stored inside double plastic bags. Sample bottles will be cleaned prior to use by rinsing twice with de-ionized...

de- ionized water. The clean equipment will then be air-dried and stored inside double plastic bags. Sample bottles will be cleaned prior to use by rinsing twice with de-ionized...

A precise evaluation of the dosimetric performance of epithermal neutron beams designed for boron neutron capture theory of brain tumours requires the use of a phantom material that closely matches brain tissue. The aim of this study was to investigate how well polyacrylamide gel (or PAG) and A-150 plastic performed as substitutes for brain tissue compared with standard ...

The interaction of ionizing radiation with organic substrates to produce useful physical and chemical changes is the basis of the radiation processing industry for plastics. Electron beam (EB) accelerators dominate the industry; however, there are a few s...

The actual and possible uses of essentially non-ionizing radiation in the fabrication of plastics are surveyed. Ultraviolet, infrared, induction, dielectric and microwave heating are explored. Included are discussions of those methods which have reached i...

SW Density (Compression and Rarefaction). - Ionization rates and probably several ... Convert normalized counts into flux using (time variable) efficiencies ...

The chamber medium is a mixture of solid dielectric bodies and gas, e.g. polythene plastic foam filled with gas. (Gmelin Inst)

S>The thermoluminescent properties of LiF (TLD-100) were investigated as a function of plastic deformation. Without exposure to ionizing radiation, plastic deformation up to fracture does not induce a thermoluminescent response. After subsequert exposure to ionizing radiation, the intensity of the ...

A rapid, high resolution liquid chromatography coupled with ElectroSpray Ionization Time-Of-Flight Mass Spectrometry (ESI/TOF/MS) method was developed for the determination of the toxin pattern in cultured cells of Ostreopsis cf. ovata from the Mediterranean Sea. The samples were separated on a Phenomenex Luna 3? HILIC 200A ...

The neutron exposure accelerator system for biological effect experiments (NASBEE) was developed to study biological effects of fast neutrons. We have characterized the NASBEE neutron beams with neutron energy spectrum, absorbed dose energy distributions, and space distributions. The neutron energy spectrum shows 2.3 MeV as mean energy and 3.0 MeV as kerma of ...

A detector for the direct measurement of the Linear Energy Transfer (LET) in cylindrical geometry was developed by Brandan and DeLuca. The detector successfully measured the LET of protons and a fraction of the heavy charged particles generated in cylindrical A150 plastic and graphite walls by 14.8 MeV neutrons. In this report, we ...

The operational procedure for using Shonka type air-ionization chambers for calibrating radiation fields at the Lawrence Livermore Laboratory Hazards Control Dosimetry Calibrations Laboratory is described. The Shonka chambers described are air ionization chambers made of air-equivalent plastic spherical outer walls and center ...

The construction of a direct reading, ionization chamber dosimeter is almost exclusively of thermoplastic material. Except for an electrometer frame and switch contacts, the dosimeter comprises components of injection molded thermoplastic material. The dosimeter barrel and most of the structural components are made from either electrically conducting polycarbonate or ...

In accordance with the foregoing principles and objects of the present invention, an improved optical fiber structure is provided which is hardened against the effects of ionizing nuclear radiation and comprises a conventional plastic, glass or silica optical fiber core and cladding, having an additional outer coating comprising phosphorescent or ...

Intravascular brachytherapy requires that the dose be specified within millimeters of the source. High dose gradients near brachytherapy sources require that the source-detector distance be accurately known for dosimetry purposes. Solid phantoms can be designed to accommodate these stringent requirements. This study reports dosimeter readings from 90Sr-90Y sources measured in water, ...

Luminescent and scintillation properties of polystyrene-based plastic scintillators with ?-diketone Eu complexes are investigated. A scintillator with dibenzoylmethane Eu complex containing two phenyl groups demonstrates the maximum scintillating efficiency. It is shown that plastic scintillators efficiency is dramatically decreased if ?-diketone ...

Three plastic scintillators based on polystyrene and four scintillators based on a copolymer of styrene with methyl methacrylate were tested under a pulsed electron beam for radiation-induced changes in their luminescence and absorption spectra. The purpose of the study was to assess the scintillators as candidate materials for plastic scintillation ...

At the NIU Institute for Neutron Therapy at Fermilab, the clinical tissue-equivalent ionization chamber response is measured every treatment day using a cesium source that was configured to match readings obtained at the National Bureau of Standards. Daily measurements are performed in air using the air-to-tissue dose conversion factors given in AAPM Report no. 7. The measured ...