ABSTRACT
Most of scintillators used for radiation detection exhibit afterglow, which is emission of light with longer decay times than that of main light pulse. High signal from afterglow has usually negative influence on detection parameters, e.g. for energy resolution in spectrometry measurements. The paper deals with long-term afterglow of some types of scintillators, which is more significant in the case of integral measurement when current in the photodetector is measured. The range of studied decay times was in the order of tens of seconds to days. Seven types of scintillators were measured: BGO, CaF2(Eu), CdWO4, CsI(Tl), LiI(Eu), NaI(Tl) and plastic scintillator. Excitation of scintillators was made using a UV lamp. After UV irradiation, a scintillator was inserted to scintillation detection unit and the anode current of photomultiplier tube was measured with a picoammeter. As results, CaF2(Eu) and plastic scintillator have relatively low long-term afterglow signal compared with other measured scintillators.
Subject(s)
Plastics , Scintillation Counting , Scintillation Counting/methods , Spectrum AnalysisABSTRACT
Neutron detection using nuclear emulsions can offer an alternative in personal dosimetry. The production of emulsions and their quality have to be well controlled with respect to their application in dosimetry. Nuclear emulsions consist mainly of gelatin and silver halide. Gelatin contains a significant amount of hydrogen, which can be used for fast neutron detection. The addition of B-10 in the emulsion is convenient for thermal neutron detection. In this paper, standard nuclear emulsions BR-2 and nuclear emulsions BR-2 enriched with boron produced at the Slavich Company, Russia, were applied for evaluation of fast and thermal neutron fluences. The results were obtained by calculation from the presumed emulsion composition without prior calibration. Evidence that nuclear emulsions used in the experiment are suitable for neutron dosimetry is provided.
Subject(s)
Emulsions , Fast Neutrons , Neutrons , Radiometry/instrumentation , Boron/chemistry , Bromides/chemistry , Calibration , Gelatin/chemistry , Helium/analysis , Hydrogen/chemistry , Image Processing, Computer-Assisted , Lithium/analysis , Phantoms, Imaging , Radiometry/methods , Silver Compounds/chemistryABSTRACT
Unique 3D tomography apparatus was built and successfully tested in Research Centre Rez. The apparatus allows three-dimensional view into the interior of low-dimension radioactive samples with a diameter up to several tens of millimeters with a betterresolution then 1 mm3 and is designed to detect domains with different levels of radioactivity. Structural inhomogeneities such as cavities, cracks or regions with different chemical composition can be detected using this equipment. The SPECT scanner has been successfully tested on several samples composed of a 3-mm radionuclide source located eccentrically within homogeneous steel bushings. To detect fine cracks inside a small sample, an ultrafine scan of the sample was carried out in the course of 24 hours with a 0.5-mm longitudinal and transverse step and 18° angular step. The exact location and orientation of a fine crack artificially formed inside a sample has been detected.
Subject(s)
Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional , Radiometry/instrumentation , Tomography, Emission-Computed, Single-Photon , Algorithms , Cobalt Radioisotopes , Diffusion , Gamma Rays , Geology , Models, Theoretical , Porosity , Radiometry/methods , Radon , Scintillation Counting , Silicon Dioxide , Software , TungstenABSTRACT
The paper describes a method of pulse height spectrum measurement in a wide energy range. The LVR15 research reactor building was chosen to demonstrate this method. Pulse height spectra were measured on the third floor of the reactor building. Two types of scintillation detectors, NaI (Tl) and a plastic scintillator, were used. The detectors were placed for about 25 m from the reactor core, thus, separated from the primary circuit water in the reactor pool, biological shielding, building wall and other constructional materials. Spectra were measured in a wide energy range from 30 keV to 1000 MeV, in which signals were recorded from natural and man-made radionuclides, prompt gamma radiation and cosmic radiation. Experimental data were collected both while the reactor was in operation and while it was out of operation. This study confirms that differences in these spectra can be detected remotely over relatively large distances from the reactor core by adequately simple detection means.
Subject(s)
Cosmic Radiation , Gamma Rays , Scintillation Counting/instrumentation , Scintillation Counting/methods , Construction Materials , Humans , Plastics , Radiation DosageABSTRACT
The VR-1 sparrow reactor is an experimental nuclear facility for training, student education and teaching purposes. The sparrow reactor is an educational platform for the basic experiments at the reactor physic and dosimetry. The aim of this article is to describe the new experimental equipment EMK310 features and possibilities for neutron detection by different gas filled detectors at VR-1 reactor. Among the EMK310 equipment typical attributes belong precise set-up, simple control, resistance to electromagnetic interference, high throughput (counting rate), versatility and remote controllability. The methods for non-linearity correction of pulse neutron detection system and reactimeter application are presented.