bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of High Pressure Ionisation Chambers in Neutron and Photon Fields
Authors: Zoetelief J. , Golnik N. , Broerse J.J. 
Published: February 2017

Abstract
The responses from tissue-equivalent (TE) and Al high pressure ionisation chambers at various collecting potentials in dependence upon the pressure of several filling gases, including Ar, Ar with such hydrogen-rich gases as CH4, C2H4, and TE gas, are of practical and theoretical interest. The present investigations are aimed at developing a sensitive system for the determination of total dose and dose equivalent, the photon contribution, and obtaining information on cavity size effects. The use of CH4 in the TE chamber provides the most suitable system as regards sensitivity among the chamber/gas combinations investigated for total dose equivalent determination in the neutron energy region of 0.9 to 15 MeV. The Al/Ar high pressure chamber system is the most suitable as a photon dosemeter. Information on effects due to cavity size can be obtained from measurements with Ar and CH4 in both chambers.
Transfer of 226Ra and 210Pb to Forage and Milk in a Brazilian High Natural Radioactivity Region
Authors: Amaral E.C.S. , Carvalho Z.L. , Godoy J.M. 
Published: February 2017

Abstract
The Pocos de Caldas plateau, where the Brazilian uranium mine and mill facilities are located, is a natural high radioactivity region. A study has been carried out in order to assess the environmental transport of the natural radionuclides in the region. The present work is concerned with the transfer of 226Ra and 210Pb to forage and milk. Similar concentrations for both radionuclides were found in soil samples. In forage 210Pb concentrations are one order of magnitude higher than those of 226Ra, however, the milk samples presented higher values for 226Ra concentrations. The average forage to milk concentration factors are of the order of 10-4 d.l-1 for 226Ra and 10-5 d.l-1 for 210Pb. Regarding transfer mechanisms, the results suggest the foliar deposition as the main pathway for 210Pb uptake by the forage. In contrast, for 226Ra the root uptake appears as the main transfer pathway.
The Feasibility of Using Expert Systems to Cope with the Complexity and Extent of the Indoor Radon Problem
Authors: Raes F. , Poffijn A. , Eggermont (INVITED) G. 
Published: February 2017

Abstract
The main problems in predicting the average radon concentration in a single house are: (1) to obtain specific high resolution information about the house, and (2) to handle qualitative but relevant information. We introduce the idea of using an expert system to obtain high resolution data by interrogating the inhabitants about their house, as well as to interpret the qualitative information obtained in this way. To study the feasibility of this approach, a prototype expert system has been written which was given the obvious name Radon Expert System (RAES). RAES derives a radon index starting from information obtained from geological maps and other data bases. It subsequently refines this information and focusses on a single house by asking for information from the inhabitants. With the help of RAES, we interrogated the inhabitants of a number of houses where radon measurements had previously been performed. The correspondence between prediction and measurement is encouraging.
The Flow and Diffusion of Radon Isotopes in Fractured Porous Media: Part 2, Semi-infinite Media
Authors: Schery S.D. , Holford D.J. , Wilson J.L. , Phillips F.M. 
Published: February 2017

Abstract
The release of radon isotopes under conditions of combined diffusion and flow from a fractured, semi-infinite medium such as soil is analysed. Relations are developed to indicate when flow from fractures will dominate overall transport and when the radon released from fractures will have the concentration characteristic of great depths. The presence of pressure-driven flow from fractures can greatly enhance transport of radon, but narrow or shallow fractures are not necessarily important due to the strong diffusive exchange with the surrounding porous medium and a reduced vertical pressure gradient in the surrounding medium. Results should be of use in estimating whether fractures are important in transporting radon to air spaces where pollution from radon is a concern.
Uncertainties in Radon Daughter Measurement Arising from Fluctuations in Room Parameters
Authors: Vanmarcke H. , Berkvens P. , Poffijn A. , Raes (INVITED) F. 
Published: February 2017

Abstract
A Monte Carlo simulation model is described to evaluate the uncertainties induced, on the one hand, by assuming constant daughter concentrations and a constant flow rate during sampling and, on the other hand, in calculating the different physical parameters of the radon decay products, using the room model. It is found that, in general the uncertainties due to counting statistics and due to the fluctuations in the pump flow rate are small compared to the uncertainties induced by the fluctuations of the parameters of the room model. With the model a number of realistic situations, such as smoking cigarettes, opening or closing a window, etc. are simulated. Sampling half an hour after smoking a cigarette, for instance, under-estimates the steady state value of the 214Bi concentration by 35%. The uncertainties in the determination of the deposition rate of the unattached daughters are also evaluated. It is shown that, without special precautions to keep a steady state situation in the room, the error easily exceeds 50%.
Radon 222 Concentrations in the United States - Results of Sample Surveys in Five States
Authors: Ronca-Battista M. , Moon M. , Bergsten J. , White S.B. , Alexander B. , Holt N. 
Published: February 2017

Abstract
During the winter of 1986-1987, the United States Environmental Protection Agency (EPA) provided assistance to ten states to begin state-wide radon surveys. This paper presents survey results from the five states that completed a survey using a probability sample of housing units. Radon concentrations in six thousand homes in Alabama, Kentucky, Tennessee, Wisconsin, and Wyoming were measured. The data recorded from detectors placed in those houses have been compiled into the first multi-state survey of radon levels that allows valid extrapolation to the population at large. The target population was ground level, owner occupied residences with listed telephone numbers. Each state was partitioned into strata according to geologic characteristics relevant to radon levels. A systematic random sample of telephone numbers was selected within each stratum, and the telephone numbers together with associated names and addresses were supplied to each state. Charcoal canisters were deployed for a two-day period in each sample home, following the EPA screening measurement protocol. Strict procedures were followed to ensure randomness of the sample and the accuracy of the measurements. The results were analysed to produce estimates of the frequency distribution of radon concentrations throughout each state and for areas within states. A smaller sample of residences which were volunteered by their owners in each state also received detectors. The radon data from these houses were analysed separately. Estimates from the two northern states were significantly higher than those from the more southerly states and estimates for volunteers tended to be higher than the estimates from the random sample of homes. In the former case, the differences were influenced by the proportion of homes with basements.
Survey of the Natural Radiation of Belgium Territory as Determined by Different Methods
Authors: Deworm J.P. , Slegers W. , Gillard J. , Flemal J.M. , Culst J.P. 
Published: February 2017

Abstract
Measurement of the environmental exposure to natural radiation was performed by the Institute of Hygiene and Epidemiology and the Nuclear Research Centre in Mol. The aim of the study was the estimation of the external doses from natural radioactivity, received by the Belgian population and the setting up on a map of the territory of natural exposure rates measured using different methods.
House Characteristics Associated with Gamma Radiation and Radon Daughter Working Levels in Eastern Pennsylvania
Authors: Stebbings J.H. , Dignam J.J. , Reilly M.A. , Gerusky T.M. , Hartman T.T. , Anast G.A. 
Published: February 2017

Abstract
Working levels (WL) of radon daughters and ? measurements in basements are described for ~1200 houses near the Reading Prong. House variables included condition and construction materials of basement floors and walls, basement heights and areas, heating systems, air conditioning, water supply, and presence of drains and sump pumps. WLs were poorly predicted by house characteristics or ? measurements, while ? levels were well predicted by house characteristics and WL. Factors predicting high ? levels tended to be associated with low WLs and vice versa. Dirt basement floors and fieldstone basement walls were strongly associated with high ? levels, as were poor wall conditions in multivariate analyses. Gamma levels were low in electrically heated homes. High WLs were strongly associated with electric heat, low WLs with basement walls of fieldstone and/or in poor condition. Large house volumes and well water supply were also associated with higher WLs.
Reducing Radon Risks: The Approach in the United States
Authors: Guimond (INVITED) R.J. 
Published: February 2017

Abstract
Indoor radon levels in excess of 100,000 Bq.m-3 have been measured in homes in various areas in the United States. Thousands of homes have been identified with radon levels exceeding 1000 Bq.m-3. To respond to this serious public health problem, the United States has initiated a programme to assess the health risks posed by radon throughout the country and reduce unnecessary exposures from indoor radon. This paper provides an overview of the key elements that make up the strategy as implemented by the US Environmental Protection Agency. Some of the critical projects are described. These include national and regional surveys, health studies, geological mapping and characterisation studies, land evaluation activities, mitigation and prevention activities, and issuing health guidelines. The paper also reviews the recent legislation passed by the US Congress regarding indoor radon.
Reduction of Radon Progeny Concentration in Ordinary Room Due to a Mixing Fan
Authors: Abu-Jarad F. , Sextro R.G. 
Published: February 2017

Abstract
Three experiments were carried out at the Indoor Air Quality Research House (IAQRH) at Lawrence Berkeley Laboratory, University of California, to study the effect on the radon progeny of operating a mixing fan. At the beginning of every experiment, about 15 kBq.m-3 of radon was injected into a 36 m3 ordinary room. Measurements were conducted with three different aerosol particle concentrations of about 102, 104 and 105 per cm3. Real-time measurements of radon and progeny concentrations, particles and environmental parameters, were made throughout the experiments. Measurements of plated out activity on the surfaces of internal walls of the room and fan blades were measured directly by filter papers and CR-39 nuclear track detectors placed on the surfaces. The ratio of plated out activity to the total progeny activity in the room varied from 17% to 84%, in inverse relation to the particle concentrations. More than 99% of the plateout activity was found on walls and less than 1% on the fan blades.
Non-Homogeneous Kinetics in Irradiated Matter: An Appraisal of Computational Strategies
Authors: Klots C.E. , Hamm R.N. , Wright H.A. , Turner J.E. 
Published: February 2017

Abstract
The Monte Carlo method may be used to simulate chemical reactions occurring in the track of a charged particle. We compare these simulations with predictions of solutions to the diffusion equation. Conditions are delineated when the latter may be used.
Energy Migration in DNA Irradiated in the Solid State
Authors: Adams G.E. , Al-Kazwini A.T. , O'Neill P. , Fielden (INVITED) E.M. 
Published: February 2017

Abstract
Evidence for the role of energy migration in irradiated DNA is considered. In particular, data from fast time-resolved spectroscopy of DNA, in the solid state, irradiated with high energy pulsed electrons is discussed. The hydration layer in DNA has only a small effect on the intensity of the fluorescence emitted during pulse irradiation, but does influence post-irradiation changes as measured by diffuse reflectance spectroscopy. The short-lived fluorescence spectra from pulse-irradiated solid mixtures of DNA containing relatively low concentrations of the electron-affinic compound misonidazole, are reduced in intensity compared with the spectrum of pure DNA. These rapid quenching effects are interpreted in terms of the migration of energy liberated during irradiation.
On Possible Limitations of Experimental Nanodosimetry
Authors: Amols H.I. , Wuu C.S. , Zaider M. 
Published: February 2017

Abstract
Experimental microdosimetry is based on the assumption that energy deposited in a simulated volume can be approximated by the product of the number of ionisations detected and the W value. Energy deposited, however, is a stochastic variable representing the energy transfer expended in ionisation and excitation events. The proportionality between energy transfer and ionisation is only valid for large numbers of interactions per event, a condition usually satisfied in microdosimetry but not necessarily in nanodosimetry. Monte Carlo computer simulations of particle tracks in water vapour show that minimum ionising electrons traversing 1 nm spheres produce on average, 1.4 energy transfers per event. Simulated proportional chamber measurements of single event spectra are dominated by ion counting statistics rather than true energy deposition, with subsequent determination of average lineal energy being more than two times the true value. The interpretation of such data is discussed, as are conditions for which meaningful experimental data can be obtained.
Dose Mean Lineal Energy for Neutrons
Authors: Leuthold G. , Burger G. 
Published: February 2017

Abstract
Several proposals have been presented recently (ICRU 40, Zaider and Brenner, Kellerer) on the definition of the quality factor for charged particles on lineal energy density rather than on LET. The models of ICRU 40 and Kellerer result in a direct proportionality of the quality factor to y in the lower range of y up to about 100 keV.µm-1 with q(y) = 0.3 y. From this the neutron quality factor is derived to be Qn = 0.3 yD. The version of Zaider and Brenner results in a expression Qn = 0.03 + 0.24 yD. A similar expression was used by Bengtson in 1969. Without the knowledge of the f(y) distribution, yD can be calculated using the proximity function approach by Kellerer applied on calculated ion event tracks. Such calculations were performed for protons, a particles and heavy recoils in the energy range of 0.2 MeV.amu-1 up to 15 MeV.amu-1 in water vapour. From the charged particle data yD is then calculated as a function of neutron energy in soft tissue from thermal energy up to 14.1 MeV. The new proposals are related to the f(y) distribution in a sphere of 1 µm diameter. Smaller target sizes have, however, been proven to be relevant in quantitative radiation biology. The variation of yD with target size (1 nm up to 1 µm) is shown as a function of neutron energy and the deviation from the LET approximation is discussed, which is caused by straggling effects and d ray escape and is most pronounced at small target sizes. Results of the several new concepts are compared with each other and with old ones, based on q(L), and the impact on neutron radiation protection is discussed.
Implications of Radiobiological and Dosimetric Studies of DNA-Incorporated 123I: The Use of the Auger Effect as a Biological Probe at the Nanometre Level
Authors: Kassis A.I. , Makrigiorgos G.M. , Adelstein S.J. 
Published: February 2017

Abstract
A quantitative comparison of the radiotoxicity in V79 cells of the DNA-incorporated thymidine analogue, 5-iodo/bromo-2'-deoxyuridine labelled with 123I (123IUdR), 125I (125IUdR) and 77Br (77BrUdR) is presented. The total number of decays in the cell nucleus corresponding to a survival level of 37% (D37) is in the ratio of 2.2:1.0:3.0 for 123I, 125I and 77Br, respectively. The number of atoms that must be incorporated to produce a certain level of survival is radically different for the three nuclides because of their very different physical half-lives. However, the radiation dose to the nucleus (DN required to produce the D37 is approximately the same for all radionuclides (about 0.8 Gy) within the experimental uncertainty limits and, therefore, appears to be a good macroscopic parameter to describe radiotoxicity provided that the Auger electron emitters have identical intracellular localisation. The dose rate to the nucleus and its variation during the experiments is also about the same in the three cases. Dosimetric analysis at the microscopic level shows for the three isotopes that the number of decays needed to produce a certain level of survival is inversely proportional to the energy deposited per decay in 5 nm diameter volumes. This leads to considerations that preclude chemical identity, electron excitation energy, or nuclear recoil energy of the daughter atom as being important to the observed effects. In addition, it reveals that each of the two steps involved in the 125I decay is equally efficient in causing biological damage and that no saturation effects are present following the decay of 125IUdR in the DNA of V79 cells. Conclusions are reached regarding repair of sub-lethal damage caused by the Auger decay and the level of minimum energy required to be dissipated in 5 nm diameter sites in order to cause cell death (threshold for lethal radiation action).
Transient Dose Distribution in LiF Single Crystals Irradiated with High Energy Pulsed Electrons
Authors: Yamamoto T. , Oda K. 
Published: February 2017

Abstract
The build-up stage of short-lived excitons corresponds to the accumulating stage of the absorbed dose at the same region. Hence sequential observation of the former stage would make it possible to pursue the temporal variation of the accumulating absorbed dose. A pulse radiolysis system enables one to obtain the transient depth-dose profile in a sample irradiated with high energy electrons of 20 ps pulse duration by measuring the build-up process of the optical density through the sample. It has been observed that the electron energy is deposited to a certain depth in about 100 ps after the primary electrons have passed through that region. This means that the energy deposition is mainly attributed not to the primary electrons but to the slower secondary ones.
UV Induced Trapping in Powder and in Sintered CaSO4:Tm and CaSO4:Dy
Authors: Chakrabarti K. , Mathur V.K. , Abbundi R.J. , Hill M.D. 
Published: February 2017

Abstract
CaSO4:Tm and CaSO4:Dy are both known to possess a dosimetric peak at approximately 220 oC. A TL peak at a temperature higher than this dosimetric peak is observed on UV irradiation in powder CaSO4:Tm and CaSO4:Dy and on UV and ? irradiation in sintered CaSO4:Tm and CaSO4:Dy. This peak is at ~330 oC and ~280 oC in powder CaSO4:Dy and CaSO4:Tm respectively and at ~330 oC in the sintered pellets of both the materials. It is observed that UV light causes charge trapping as well as phototransfer involving this peak.
On the Thermoluminescence Mechanism of Non-Doped Corundum Monocrystals with Defect Structure
Authors: Gimadova T.I. , Bessonova T.S. , Tale I.A. , Avvakumova L.A. , Bodyachevsky S.V. 
Published: February 2017

Abstract
An investigation was carried out into the distribution of optical absorption, radioluminescence and thermostimulated luminescence (TSL) in large corundum crystals with defects. The dependence of energetic and stochastic parameters of the TSL process on stimulation temperature was analysed for detectors cut from fixed crystal points. TSL, proceeding by the mechanism of structural thermally initiated rearrangements and pure centre structures, was shown to provide for the occurrence of a unique set of operating parameters for ionising thermoluminescent detectors made of this material.
Dependence of Thermoluminescence Response of CaSO4:Dy and CaSO4:Tm on Grain Size and Activator Concentration
Authors: Kása I. 
Published: February 2017

Abstract
The influence of several factors on the thermoluminescence (TL) sensitivity and the shape of the glow curves of CaSO4:Dy and CaSO4:Tm phosphors have been investigated. The factors investigated are: quality of starting materials, activator concentration and grain size. The TL sensitivity and the height of low temperature peaks (LTP) are influenced by the impurity of the starting chemical (CaSO4.2H2O) and the concentration of activators (Dy and Tm). Sensitive CaSO4:Dy and CaSO4:Tm phosphors having small LTP were prepared by using purified starting chemical (CaSO4.2H2O). The measurement data from our samples were compared with the results of samples prepared in different laboratories.
Archaeological Dating by Infrared-Stimulated Luminescence Using a Diode Array
Authors: Spooner N.A. , Aitken M.J. , Smith B.W. , Franks M. , McElroy C. 
Published: February 2017

Abstract
An infrared diode array (emitting at 880 ± 80 nm) has been developed and tested on archaeologically-dated Romano-British sediment. There was good agreement with the latter and also with optical dating using 514 nm from a laser. The signal/background ratio for infrared stimulation was about 10 times that for laser stimulation. Twenty four diodes were used in the array giving a power at the sample of about 15 mW.cm-2. Intensity and wavelength drifts after switch-on necessitate a warming-up period, and a photodiode is used for monitoring/manual control; illumination of the sample is controlled by a shutter.
Indoor Radon Measurement in Some Regions of Algeria
Authors: Djeffal S. , Cherouati D.E. , Djouider F. 
Published: February 2017

Abstract
In order to estimate the population indoor exposure, a national radon monitoring programme is presently being carried out by the Radiation Protection Centre of the Haut Commissariat à la Recherche of Algeria. In this survey passive time-integrating dosemeters of the 'open' type, based on nuclear track detection, were used. So far, about 201 randomly selected houses have been monitored in some regions of Algeria, including Algiers, Ain Defla, Ain-Oussera, Batna, Bou-Saada and Ghardaia. The means of the concentrations in these cities were found to be respectively 32, 47, 33, 26, 31 Bq.m-3, leading to average effective dose equivalents of 0.98, 1.44, 1.01, 0.81, 0.96 and 0.95 mSv per year, respectively. The results obtained are presented and discussed.
Modifications Induced in the TLD-100 Trap Distribution During Exposures at Different Ambient Temperatures
Authors: Delgado A. , Gómez Ros J.M. 
Published: February 2017

Abstract
The evolution of the TLD-100 glow curve during long exposures at different temperatures (between 20 and 100 oC) has been studied using glow curve numerical analysis methods to follow the individual evolution of the different glow peaks. From this study it can be shown that even for the highest ambient temperatures that could be reached, the changes in the TLD-100 output during long exposures are due mainly to modifications in the trap population, in its number or even in its structure and not to leakage of trapped entities or Randall-Wilkins fading. The rather different behaviour of the main dosimetric peaks IV and V is also discussed. Some of the features of the peak IV variations do not help the peak IV traps to be converted into peak V traps despite the rather good compensation encountered between the variations experienced by both peaks during storage.