ABSTRACT
This article presents the evolution of the International Electrotechnical Commission (IEC) and the European standards for individual monitoring of ionising radiation issued, respectively, from the committees IEC/Sub Committee 45B and European Committee for Electro-technical Standardization/Technical Committee 45B 'Radiation protection instrumentation'. Standards for passive individual photon and beta dosimetry systems as well as those for active individual monitors are discussed. A neutron ambient dose equivalent (rate) meter standard and a technical report concerning the determination of uncertainty in measurement are also covered.
Subject(s)
Radiation Monitoring/standards , Radiation Protection/standards , Radiation, Ionizing , Beta Particles , Environmental Exposure/prevention & control , Environmental Exposure/standards , Europe , Humans , Neutrons , Occupational Exposure/prevention & control , Occupational Exposure/standards , Photons , Radiation Dosage , Radiation Monitoring/methods , Radiation Protection/methods , Reproducibility of Results , UncertaintyABSTRACT
This paper presents experience, found problems and lessons learnt during the evaluations of various TLD and CR-39 passive neutron dosemeters according to ISO 21909. Recommendations for the standard, being currently in revision, are also discussed.
Subject(s)
Neutrons , Radiation Protection/instrumentation , Radiation Protection/standards , Thermoluminescent Dosimetry/instrumentation , Thermoluminescent Dosimetry/standards , Calibration , Equipment Design , France , Humans , Occupational Exposure/analysis , Photons , Polyethylene Glycols/chemistryABSTRACT
This paper presents IEC/SC 45B 'Radiation protection instrumentation' and its standards for individual monitoring of ionising radiation: IEC 61526 Ed. 3 for active personal dosemeters and IEC 62387-1 for passive integrating dosimetry systems. The transposition of these standards as CENELEC (European) standards is also discussed together with the collaboration between IEC/SC 45B and ISO/TC 85/SC 2.
Subject(s)
Occupational Exposure/standards , Radiation Monitoring/standards , Radiation Protection/standards , Radiometry/standards , Guidelines as Topic , Humans , International Cooperation , Occupational Exposure/prevention & control , Radiation Monitoring/instrumentation , Radiation Protection/instrumentation , Radiation, Ionizing , Radiometry/instrumentationABSTRACT
Driven by the global concern about radon hazards, a wide variety of methods to measure radon and its decay products have been developed. Pin silicon photodiodes are increasingly applied in this field, their main advantages being high detection efficiency for alpha particles and low cost. In this paper, we present a system to determine the emanation factor for 222Rn from porous material based on a pin photodiode. This equipment is valid both for field and laboratory measurements, allowing to monitor the external emanation conditions by means of temperature, humidity and pressure sensors. To illustrate the capabilities of the system, we present two case studies of samples with high and low 226Ra content. The activity of this radionuclide in the samples had been previously determined by gamma-ray spectrometry.
Subject(s)
Radiometry/instrumentation , Radon/analysis , Silicon/radiation effects , Transducers , Electrochemistry/instrumentation , Electronics , Radiation Dosage , Radiometry/methods , Reproducibility of Results , Semiconductors , Sensitivity and Specificity , Soil Pollutants, Radioactive/analysis , Volcanic Eruptions/analysisABSTRACT
The photoncutron ambient dose around a 18 MV medical electron lineal accelerator has been measured with LiF:Mg,Ti chips of 3 x 3 x 1 mm inside moderating spheres. During the measurements a water phantom was irradiated in a field of 40 x 40 cm2. Two methods have been considered for comparison. In the first, a TLD-600/TLD-700 pair at the centre of a 25 cm diameter paraffine sphere was used, with the system behaving as a rem meter. In the second method, TLD-600/TLD-700 pairs, bare and at the centre of 7.6, 12.7, 20.3, 25.4, and 30.5 cm diameter polyethylene Bonner spheres were used to obtain the neutron spectrum. This was unfolded using the BUNKIUT code with the SPUNIT algorithm and the UTA4 and ARKI response functions. The neutron dose was followed by multiplying the unfolded neutron spectrum by the ambient dose equivalent to neutron fluence conversion factors. Both methods result in 0.5 mSv x Gy(-1) m away from the isocentre.
Subject(s)
Neutrons , Particle Accelerators , Radiotherapy Dosage/standards , Electrons , Europium , Indicators and Reagents , Lithium , Nuclear Medicine/standards , Quality Assurance, Health Care , Spain , Spectrum Analysis/methods , Thermoluminescent Dosimetry/methodsABSTRACT
The responses of TLD-1010, TLD-700 and TLD-600 thermoluminescence dosemeters to the radiation field inside a water tank enclosing an isotopic 241Am-Be neutron source are analysed. Separate contributions coming from thermal neutrons, neutrons with energies above thermal and gamma rays to the total response of the three types of TLD are obtained. This is accomplished by assuming that the gamma responses for materials with different 6Li enrichments are identical and that the neutron response of TLD-700 is negligible compared to TLD-100 and TLD-600. The last assumption is tested by Monte Carlo simulations of the neutron energy spectrum at the points where the TLDs are irradiated.
Subject(s)
Americium , Beryllium , Fluorides/radiation effects , Lithium Compounds/radiation effects , Magnesium/radiation effects , Neutrons , Radioisotopes , Thermoluminescent Dosimetry , Titanium/radiation effects , Cadmium/radiation effects , Computer Simulation , Fast Neutrons , Gamma Rays , Monte Carlo Method , Thermoluminescent Dosimetry/instrumentationABSTRACT
Reduced cost, high quantum efficiency and very good detection characteristics of PIN silicon photodiodes made possible their utilization for alpha particles detection. This paper presents different studies and applications of this type of detector for qualification and quantification of radon and its progeny in laboratory and in the field. Since photodiodes are sensitive to environmental electromagnetic fields, protecting cells were adapted for use around the detector. A small three-channel (2-5.5 MeV; 5.5-6.5 MeV; 6.5-8.2 MeV) portable alpha counter was developed that allows the determination of the radon concentration and the radon exhalation rate. Numerous field applications were conducted in different conditions (uranium waste storage, dwellings, etc.) where this simple and inexpensive instrumentation demonstrated very good performance, reliability, and easiness of operation while measuring radon concentrations from 50-100 Bq m(-3) to several MBq m(-3).
Subject(s)
Radiation Monitoring/instrumentation , Radon Daughters/analysis , Radon/analysis , Silicon , Equipment Design , Humidity , Radiometry , Temperature , Time FactorsABSTRACT
The use of silicon photodiodes for field radon measurements requires the utilization of measuring cells for protection against environmental electromagnetic fields. It is very important to study and optimize the impact of geometry conditions (dimensions of the measuring cell) on the photodiode detection efficiency that can be reduced more than 10-30 times. Two models (for volume-distributed nuclides around the detector and for radon progeny deposited on the diode surface radon progeny) were applied for simulation of the photodiode detection in measuring cells of different sizes. Their use allows an optimal choice of the most appropriate cell regarding the measurement conditions. Thus, for soil gas measurements cells we use a cell of 3.6 cm in diameter by 20 cm in height; for determination of the radon exhalation rate we use a cell of 16 cm in diameter by 14 cm in height; and for measurements in dwellings and large spaces we use cells larger than 20 cm and lower than 4 cm.
