bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluxed and deposition rates of solutes in growing roots of Zea mays
Authors: Bret-Harte M. Syndonia , Silk Wendy K. 
Published: February 2017

Abstract
The equations and experimental methods are reviewed for calculating solute deposition rates and fluxes an growing parts of roots. Then the expression for the growth-sustaining sucrose flux in the meristem is presented and evaluated to show the sucrose flux required to produce the empirically observed biomass deposition rate in primary maize roots. Two independent methods (one based on dye transport measurements and the second based on Stokes radii) are used to estimate the symplasmic conductivity for diffusion. The concentration gradients required to drive a growth-sustaining symplasmic diffusion of sucrose are found to be physiologically unreasonable. Either our current understanding of plasmodesmatal ultrastructure is flawed, or alternative mechanisms must exist for sucrose transport to the meristem.
The Energy and Angle Dependence of Response to Photons of the NRPB Thermoluminescence Dosemeter in Terms of the New ICRU Quantities
Authors: Bartlett D.T. , Burgess P.H. , Francis T.M. , Dutt J.C. , Dimbylow P.J. 
Published: February 2017

Abstract
The ICRU has introduced the quantities ambient dose equivalent and directional dose equivalent for environmental monitoring; and individual dose equivalent, penetrating, and individual dose equivalent, superficial, for individual monitoring. The quantities are for use as secondary quantities within the framework of the system of dose limitation recommended by ICRP, which includes limits for effective dose equivalent for stochastic effects and for organ dose equivalent for non-stochastic effects. Measurements have been made of the energy dependence of the photon response of the NRPB thermoluminescence dosemeter mounted on a cuboid phantom, and of the energy and angle dependence of response of the dosemeter mounted on a 30 cm diameter spherical phantom. The phantom material was MS20, an epoxy resin based material designed to simulate muscle and found to be an acceptably close approximation to ICRU 4-element tissue. Values of exposures at the position of the dosemeter in the absence of dosemeter and phantom were converted to ICRU operational quantities using published conversion coefficients. Measurements were made for 137Cs and 60Co gamma radiation, the ISO narrow series of filtered X radiation (9 qualities, 33, 48, 65, 83, 100, 118, 161, 205 and 248 keV) and the ISO fluorescence series lower energy, 17.4 keV.
An Automated Laser Heated Thermoluminescence Dosimetry System
Authors: Braunlich P.F. , Tetzlaff W. 
Published: February 2017

Abstract
We describe a fully automated and computer controlled laser heated thermoluminescence dosimetry reader and a dosemeter which consists of eight thin-layer phosphor spots of thickness between 2 and 10 mg.cm-2. A CO2 laser delivers a heating beam of the same size as the dosemeter spots and has a uniform intensity profile. The heating power is 'time-shaped' by computer control to facilitate pre- and post-anneal treatment and to minimise background signals due to incandescence emission. The performance characteristics of this reader are demonstrated. Results obtained with beta exposures from 147Pm, 204Tl, and 90Sr sources, gamma radiation, and fast neutrons are presented.
Basic Data Necessary for Neutron Dosimetry
Authors: Caswell R.S. , Coyne J.J. , Gerstenberg H.M. , Axton (INVITED) E.J. 
Published: February 2017

Abstract
Among many developments in basic data for neutron dosimetry, four are highlighted: improvements in kerma factor data for carbon; the use of common data through unification of the European and American protocols for neutron radiation therapy dosimetry; the tabulation of a set of initial spectra of secondary particles produced in tissue and tissue-like materials; and proposed changes in the magnitude and definition of neutron quality factors, which, while not physical quantitites, are nevertheless basic to neutron dosimetry.
Implication of ICRU 39 for Radiation Protection Instrumentation
Authors: Portal (INVITED) G. 
Published: February 2017

Abstract
The implications for radiation protection instrumentation of the ICRU 39 proposals on new operational quantities for gamma and neutron ambient dose equivalent H* and individual dose equivalent, penetrating, Hp(10) measurements are considered. It is shown that the ICRU Working Committee has arranged for these quantities to be adaptable to existing instrumentation. The most important modification concerns the calibration procedure. It is essential to have at ones disposal transfer coefficients linking calibration and operational quantities.
Environmental Radiological Impact of Some Portuguese Uranium Mines
Authors: Galvão J.P. , de Bettencourt A.O. , Teixeira M.M.G.R. , Elias M.D.T. 
Published: February 2017

Abstract
An environmental radiological surveillance programme has been in progress around the most significant Portuguese uranium mines, from 1976 to 1983. A short description is given of the mines of Urgeirica (including uranium milling), Freixiosa, Pinhal de Souto and Bica. The results of the surveillance programme developed in the vicinity of these facilities are presented and the identified critical pathways are discussed. One of these pathways is the consumption of cabbage, which is an important component in the diet of the Portuguese population. The exposure of the critical groups, due to the intake of 226Ra through the diet, calculated from the results of this monitoring programme, range from 0.02 to 1.5 mSv.y-1, for the different mines under study.
Search for Buildings with High Radon Levels in Sweden: Measurements Carried out by Local Authorities in Both Older and Newly Built Homes
Authors: Swedjemark G.A. 
Published: February 2017

Abstract
Local authorities in Sweden have made about 58,000 radon daughter measurements with the following aims: (1) to search for houses with high radon daughter levels, (2) to determine the level above which the house would be regarded as an insanitary dwelling, and (3) to check that the radon daughter concentrations in newly built houses are below the established limit. The sampling of dwellings is therefore not representative for Swedish homes. 5300 homes were found to have levels above the limit 400 Bq.m-3 EER. The highest level found was 28,000 Bq.m-3. In about one third of the homes found to have levels exceeding the limit, measures had been carried out to decrease the radon daughter concentration. About half of the homes in which the levels were decreased had levels below the limit for rebuilding, e.g. 200 Bq.m-3. Measurements in order to ascertain levels in newly built houses were made in about 1100 homes out of 200,000 built since 1981 which was the year in which requirements for newly built houses came into force. Of those built with radon-safe or radon-protective foundations, 94% had concentrations below the 70 Bq.m-3 EER limit, compared to 80% for traditional building techniques.
LET Dependence of Linear and Quadratic Terms in Dose-Response Relationships for Cellular Damage: Correlations with the Dimensions and Structures of Biological Targets
Authors: Barendsen G.W. 
Published: February 2017

Abstract
Dose-effect relationships and the dependence of RBE on LET can be analysed to derive insights about the amounts of deposited radiation energy required in critical structures and about the dimensions of targets involved in the induction of various cellular responses. Amounts of energy of several hundreds of eV and dimensions of the order of 10 nm have been derived as critical values associated with the induction of cell reproductive death and chromosome aberrations, while effective cross sections are of the order of tens of square micrometres. To apply information from microdosimetric studies and from cellular responses to the development and testing of hypotheses about mechanisms of radiation action, it is necessary to correlate these data with insights concerning dimensions and structures of cellular constituents and macromolecules. This approach is illustrated by the correlation of cross sections for inactivation with dimensions of the cell nucleus in dependence on the culture conditions and by the comparison of the derived dimensions of critical targets with DNA packing and chromatin structure in cells. A model is suggested in which lethal and potentially lethal damage induced in mammalian cells by single ionising particles involves the induction of two DNA double strand breaks in close proximity in a chromatin fibre, while accumulation of damage causing the contribution, which increases with the square of the dose, might be associated with interaction of single DSBs produced at larger distances.
Inactivation Cross Sections of Yeast and Bacteria Exposed to Heavy Ions of Low Energy (less than 600 keV/u)
Authors: Schneider E. , Kost M. , Schafer M. 
Published: February 2017

Abstract
A haploid yeast mutant of Saccharomyces cerevisiae and spores of Bacillus subtilis were exposed to heavy ions with energies of maximal 600 keV.u-1 down to energies associated with ranges which are just high enough to penetrate yeast cells and bacteria. The experiments were performed at the UNILAC at GSI (Darmstadt, FRG). The primary energy of 1.4 MeV.u-1 was reduced by a titanium window and by Hostaphan foils of different thickness. Generally the inactivation cross section decreases when the velocity of the primary particle is reduced due to the shrinking dimensions of the d electron penumbra. The results of the experiments with Kr, Pb and U ions demonstrate that the inactivation cross sections for yeast as well as for bacterial spores do not change significantly when the energy is reduced stepwise below 600 keV.u-1. Close to the end of the range of the ions, however, in all cases an increase of 10 to 30% in total is observed. These results indicate that at the very end of the range of the particles, i.e. at particle energies of around 100 keV.u-1, other interactions than electronic stopping may play a more important role.
Interpretation of Damage to Mammalian Cells, E.Coli and Bacteriophages by Incorporated Radionuclides for Prolonged Irradiation
Authors: Younis A.-R.S. , Watt D.E. 
Published: February 2017

Abstract
Previous analysis of published survival data for Auger electron and beta emitting nuclides incorporated into mammalian cells have been extended to include E. coli and bacteriophages. A unified scheme for the expression of damage is explored in terms of the localised secondary charged particle fluence of electrons, their average mean free path for ionisation and the number of DNA segments at risk in the target.
Thermoluminescent and Exoemission Properties of New High-Sensitivity TLD a-Al2O3:C Crystals
Authors: Akselrod M.S. , Kortov V.S. 
Published: February 2017

Abstract
To determine the mechanisms of the electron-hole processes in a-Al2O3:C crystals, characteristics of their thermo- and photo-stimulated exoelectron emission (TSEE, PSEE) and luminescence have been studied. It is shown that the emission of F+ centres takes place with the temperature shift relative to the emission of F centres, and the hole-induced TSEE takes place synchronously with the emission of F centres. The electron energy distribution parameters at PSEE do not depend on the energy of stimulating light photons, which testifies to thermalisation of the released holes before their recombination. Parameters determined for doped anion-deficient corundum crystals are considered within the framework of the two-stage Auger process model.
On the Application of Silicon for Fast Neutron Dosimetry
Authors: Iwanowski R.J. , Sienkiewicz A. 
Published: February 2017

Abstract
The defect structure of a neutron-damaged silicon as a function of irradiation dose has been investigated. Two types of defects had been detected in the neutron-irradiated n-Si (FZ) crystals studied: divacancies (V2), from the IR absorption (1.8 µm band), and four-vacancy clusters (P3) from EPR spectrum, their concentration increasing linearly with fast neutron dose, FN. In a recent paper both V2 and P3 centres had been simultaneously observed in neutron-irradiated Si. The production efficiency of P3 clusters was found equal to 1 per 20 divacancies, independently of FN. From our estimate, approximately two P3 centres per primary cascade were produced (irrespective of FN). This suggests that both the above defects are mainly associated with the displacement spike which terminates the cascade. Excellent agreement of our results with partial literature data indicates that the concentrations NV2 and NP3 depend only on FN,irrespective of the shape of the neutron spectrum. Therefore, the divacancy-related 1.8 µm absorption band of silicon can be used for simple determination of fast neutron dose, up to FN = 1018 cm-2. Proper high temperature annealing of radiation defects enables multiple use of Si crystal as a fast neutron dosemeter.
Fast Neutron Dosimetry by Thermoluminescence Detection of Knock-on Protons
Authors: Braunlich P. , Tetzlaff W. 
Published: February 2017

Abstract
A thermoluminescence equivalent to the etched track technique for fast neutron dosimetry is described. It is based on 'reading' thin thermoluminescent (TL) layers with a tightly focused, scanning CO2 laser beam. With a spatial resolution of 30 µm, it detects and counts areas of high TL emission that result from individual knock-on-protons generated in a polyethylene foil.
Ultra High Level Dosimetry by ESR Spectroscopy of Crystalline Quartz and Fused Silicate
Authors: Wieser A. , Regulla D.F. 
Published: February 2017

Abstract
At present there is a great interest in ultra-high-level dosimetry exceeding the 0.5 MGy which can still be detected more conventionally by the ESR spectroscopy of alanine. Recently, the E1' defect in SiO2 was discovered for dosimetry. The defect generated in crystalline quartz by gamma irradiation was found to be an excellent candidate for ultra-high-level dosimetry at ambient temperatures up to 300 oC. The E1' centre is observed in all pure forms of quartz and silicate, but its dosimetric properties are specific for each material. This provides the precondition for a wide range of applications in dosimetry. Here, the properties of the E1' centre are compared for fused silicates and crystalline quartz. For the first time, supralinearity was observed for the E1' centre and that in silicate glass. The experiments are designed to be used at the HAW project in the Asse salt mine, Braunschweig, FRG.
PTFE in High Dose ESR-NMR Gamma Dosimetry
Authors: Milman I. , Putyrsky V. , Naimark M. , Popov V. 
Published: February 2017

Abstract
ESR and NMR of the broad line of polytetrafluoroethylene (PTFE) have been studied in connection with the use of material in industrial high dose measurement. Interaction between radiation and PTFE results in free radical formation and change in the condition of resonance observed for 19F nuclei, which can be detected by ESR-NMR spectroscopy methods. It has been found that the intensity and form of lines of the ESR signal are unambiguously related to the value of absorbed dose. Processing of NMR signals had indicated an increase of width and second moment of absorption in the spectrum and decrease of the line form factor with increasing dose. Fading of radiation-induced ESR and NMR signals is no more than 2% after a year of storage under standard conditions. The results presented show the possibility of using PTFE in high precision high dose dosimetry.
Study of GR200F LiF:Mg,Cu,P Detectors for Extremity Dosimetry
Authors: Yuen P.S. , Richter W.F. , Aikens M.S. 
Published: February 2017

Abstract
The dosimetric properties of GR200F LiF;Mg,Cu,P detectors with 5 mg.cm-2 sensitive layers have been studied for applications in extremity dosimetry. These properties included batch homogeneity, minimum detectable dose, reproducibility, residual signals, fading characteristics, linearity of response, effect of light exposure, photon energy and angular response, and beta energy and angular response. It was found that they are acceptable for extremity dosimetry. In particular, if used in conjunction with an extremity dosemeter holder with a window thickness of approximately 4 mg.cm-2, this detector can measure accurately the tissue dose at 7 mg.cm-2 delivered by low energy beta emitters such as 147Pm.
Ultraviolet Radiation Measurement with Neutron Pre-Irradiated Thermoluminescence Dosemeters
Authors: Yeh S.-H. , Weng P.-S. 
Published: February 2017

Abstract
The characteristics of TL 6LiF:Mg,Ti (TLD-600) to be used as an ultraviolet (UV) radiation dosemeter based on the phototransfer thermoluminescence (PTTL) method are considered. Thermoluminescence dosemeters were pre-irradiated with D2O moderated 252Cf neutrons instead of gamma rays in order to increase the growth efficiency of residual thermoluminescence to be transferred by UV radiation. The optimal pre-annealing condition before UV irradiation was investigated. It depends on the pre-irradiation neutron fluence. Area variation of the glow curve was studied in detail and it is concluded that no new charge carriers were created in the PTTL process. The lower limit of detection for UV is dependent on the pre-irradiation neutron fluence and is about 10 to 103 J.m-2 for neutron fluences of 1013-1011 m-2. The upper limit may be at least 106 J.m-2.
Energy Loss Function for Biological Material: Poly (CSP)
Authors: Fung A.Y.C. , Zaider M. 
Published: February 2017

Abstract
In this paper calculated cross sections are presented for the interaction of electrons with poly(CSP), a single-stranded chain that contains one cytosine sugar phosphate unit in the elementary cell. To model a single strand of helical DNA (e.g. the base stacking), the Watson-Crick model for the geometry of poly(CSP) has been used. The use, for computational simplicity, of a single, rather than a double stranded polynucleotide may be justified on the basis of previous calculations indicating that - to a good approximation - the electronic structure (other than excitation states) of complementary base pairs may be described as a superposition of the corresponding structures of the individual components. The cross sections are obtained from the dielectric response function of the system, _(q,?), which is calculated with the aid of a semi-empirical Hamiltonian, the parameters of which have been adjusted to fit available optical and electron scattering data on DNA and related systems.
A Comparison of Experimental and Calculated Survival Curves for V79 Cells Grown as Monolayers or in Suspension Exposed to Alpha Irradiation from 212Bi Distributed in the Growth Medium
Authors: Charlton D.E. , Kassis A.I. , Adelstein S.J. 
Published: February 2017

Abstract
It has been shown that a survival curve can be constructed from the distribution of doses to the nuclei of cells exposed to high LET irradiation using a variable D0 (specific lethal dose). D0 is a function of cell type and LET and exp(-Di/D0) is the fraction of cells which survive a dose Di. The variation of D0 with LET can be found from the literature on track segment irradiation. Using the variation of D0 with LET, the survival of V79 cells irradiated with 212Bi alpha sources was calculated by finding the probability of surviving individual passages through the nuclei where the dose and LET for each passage is different. The D0 obtained experimentally for V79 cells exposed to growth medium containing 212Bi is 141 kBq.ml-1 for suspended cells and 259 kBq.ml-1 for cell monolayers. Monte Carlo calculations give a D0 of 159 kBq.ml-1 for suspended cells and 266 kBq.ml-1 for cell monolayers.
Heating of Continuous Thermoluminescent Layers with Localised Laser Beams
Authors: Braunlich P. , Jones S.C. , Abtahi A. , deMurcia M. , Kelly P. 
Published: February 2017

Abstract
Thin uniform continuous layers of thermoluminescent materials are convenient dosemeter configurations for laser-heated thermoluminescence dosimetry. Rapid heating of a small circular spot determined by the Gaussian laser beam profile together with thermal diffusion yields characteristic glow curve shapes. The complex spatio-temporal behaviour of the thermoluminescence emission, which results from this particular situation of heat transfer and diffusion, was calculated as a function of time and compared with experimental data.
A Fast Automated Calibration System
Authors: Duftschmid K.E. 
Published: February 2017

Abstract
The design and application of an automated calibration device consisting of a pneumatic rabbit system with circular irradiation geometry is described. Four gamma radiation sources up to 3.7 TBq (100 Ci) 137Cs are stored in a revolving shielded container. The rabbits containing the sources travel through a bent lucite tubing down to an adjustable mechanical stop at the irradiation position. A flat circular segment is mounted at 1 m distance. The source position can be adjusted to the centre line of the dosemeters which are clamped behind lucite holders for fast and accurate positioning and secondary electron equilibrium. Up to 200 TLD cards can be exposed at once with the irradiation time controlled by an electronic clock. Frequent dose measurement with secondary standard ionisation chambers proved a reproducibility of exposure better than ±0.5% (2 sigma) for 5 minutes or more irradiation time. The automated calibration system has been routinely applied for fast, accurate and convenient calibration of over 50,000 TLD's used by our personnel monitoring service.
The Construction of a Diamond Detector for Ionising Radiation
Authors: Burgemeister E.A. , Schouten W. 
Published: February 2017

Abstract
Previously, diamond detectors used to be made in small quantities from selected natural diamonds; currently they are made from pure synthetic diamonds. At a few volts bias, the current is about 10-7 A when the diamond is irradiated with ß, ? or X rays having energies and dose rates used for radiotherapy in case of teletherapy. A diamond with linear dimensions of 0.8 mm and two opposite faces of granite is glued to the inside of an aluminium cap of 2 mm diameter and 0.1 mm wall thickness. An aluminium bar is glued to the other graphite face and fixed inside the cap. The cap and bar are connected to electrical leads, so that heavy metals are at some distance from the radiosensitive element. The response of 60Co shows rotational symmetry when the detector is irradiated perpendicularly to its axis. The effective measurement point lies nearly on the axis. The radiosensitivity of diamond is independent of the photon energy at effective values between 0.2 and 4 MeV and decreases gradually below 0.2 MeV. Because of their small size, diamond detectors prove very useful for accurate measurement of steep dose gradients. They are therefore applied in electron beams and in the penumbra and build-up regions of megavolt photon beams. The construction and electrical specifications of the detector also allow for dosimetry in vivo. As an example, the detectors are applied for rectal dosimetry.
Experience with a Track Etch Detector in Personnel and Environmental Dosimetry
Authors: Wernli C. , Duvoisin J. , Hauswirth G. , Janett A. 
Published: February 2017

Abstract
A neutron dosimetry system with a fission track detector and a spark counter has been used for more than 10 years in routine personnel and environmental dosimetry. For personnel dosimetry the badge consists of a 235U and a 232Th converter and a Makrofol KG detector. This badge is used at SIN (600 MeV proton accelerator) and for source handling (Am-Be) for a total of about 700 radiation workers. For environmental dosimetry (skyshine measurements around SIN and GSI Darmstadt) a 235U converter and a Makrofol KG detector are placed in the centre of a moderating sphere. For both systems data on sensitivity, energy dependence, reproducibility and fading, as well as a discussion of the long term experience and actual problems, are given.