bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Parameters of Low and High LET Radiation Dosimetry Using CaF2:Tm TLDs
Authors: Pradhan A.S. , Bhatt R.C. 
Published: February 2017

Abstract
The ratio of heights of two major glow peaks (150 oC and 240 oC) in CaF2:Tm varies significantly with the gamma ray dose above 10 Gy, with the energy of photons for doses below 10 Gy, and with the LET of charged particles. The change in peak height ratio can be used for high-level gamma ray dosimetry in the range from 10 Gy to 3 x 103 Gy, and beyond 3 x 103 Gy the change in colour itself becomes an indication of high-level irradiation. For dosimetry in the mixed fields of low and high LET radiations, extreme care has to be taken that the contribution due to the photons of energy below 200 keV is kept negligible. For high LET and fast neutron dosimetry the dose due to the gamma ray component should be a small fraction of the total dose.
Recent Advances in Thermoluminescence Dating
Authors: Aitken (INVITED) M.J. 
Published: February 2017

Abstract
Initially application was to ancient pottery and other baked clay, detection of forgeries in art ceramics having a particularly powerful impact. In recent years there has been a growing extension of TL into non-pottery materials. Heated flints from paleolithic fire-places is one application. Another is in the dating of igneous rocks from recent volcanic events; formerly this had been impossible on account of the malign phenomenon of non-thermal ('anomalous') fading exhibited by volcanic minerals but this is now being circumvented by utilising TL in the 600 oC region of the glow curve. TL dating has also been extended to unburnt calcite, one application being stalagmitic floors in paleolithic caves. Another recent development is the use of TL for dating aeolian sediment and some types of waterborne sediment. These developments give prospect of establishing a TL-based chronology, both for archaeology and quaternary research, extending back well beyond the range of radiocarbon, perhaps reaching a million years ago.
Dose Evaluation at Low Level with TL Dosimetry in the Linac Facility of Osaka University
Authors: Owaki S. , Hayashiuchi Y. , Ohkuma J. , Sawai T. , Okada T. , Kawanishi M. 
Published: February 2017

Abstract
Monthly environmental radiation doses in an accelerator facility were observed with a high sensitivity TLD system at 9 sites in a low background area. The average annual dose varied little from site to site, demonstrating the reliability of the system. However, a change in the environmental dose in the building, from month to month, was found to be large. Because the personnel dose due to accelerator operation is of the same order as the monthly environmental one, the environmental dose was evaluated by a statistical treatment, taking into account sensitivity level shifts of the TLD reader, uniformity and reproducibility of TL elements etc. The value obtained in this way is available to estimate the most probable personnel dose each month, as well as the exact environmental radiation dose.
Characteristics of a New Dosemeter Material: LiF(Mg,Cu,P)
Authors: DeWerd L.A. , Cameron J.R. , Da-Ke Wu , Papini T. , Das I.J. 
Published: February 2017

Abstract
Some of the dosimetric properties of a high sensitivity thermoluminescence dosemeter material, LiF(Mg,Cu,P), are described. This material, prepared at the Chinese Academy of Medical Sciences, has about 23 times higher sensitivity than that of LiF(Mg,Ti). It is stable and reusable without significant loss of sensitivity. The single peak has thermoluminescent emission in the blue region of the spectrum.
Alpha Energy Sensitive Devices for Dosimetric Purposes - Abstract only
Authors: Pai H.L. , Aitken J.H. , Duport P. , Story R.S. 
Published: February 2017

Abstract
This paper compares various approaches which may lead to simple means of obtaining the required energy resolution for dosimetry of alpha emitters occurring in the various stages of the nuclear fuel cycle. The report starts by considering the potential of high resolution etched track devices in view of the data obtained for Kodak pathe LR115 type II detector using alphas from a Van de Graaff accelerator and alpha particle spectroscopy data for CR39 obtained by Fews and Henshaw. Application to dosimetry is then discussed, including simple fast read-out methods such as use of an image analysis system (Artek #982). Three approaches are considered: (1) Absorber method. (2) Individual track light-intensity method. (3) Individual track-size measurement method.
Automatic Method for Evaluating Elapsed Time Between Irradiation and Readout in LiF-TLD
Authors: Moscovitch M. 
Published: February 2017

Abstract
It has been shown that by application of glow curve deconvolution when coupled with the fading properties of Peak 2 and Peak 3 integrals in LiF:Mg,Ti, it is possible to measure the time since irradiation to within 10%. An automatic peak search technique identifies the various glow peaks and provides the initial parameters required by the deconvolution program. Fading studies utilising this technique were made on LiF samples during a period of three months in which the time between irradiation and readout was systematically varied. These studies demonstrate that the ratio of the area of Peak 2 to that of Peak 5 can be used to estimate elapsed time up to 100 hours. The ratio of Peak 3 to Peak 5 integrals extends the elapsed time interval to at least three months. During this period of time, some gradual reduction in the relative intensity of the Peak 4 integral has been also observed.
ESR Dosimetry of A-Bomb Radiation Using Tooth Enamel and Granite Rocks
Authors: Ikeya M. , Miki T. , Kai A. , Hoshi M. 
Published: February 2017

Abstract
The A-bomb radiation dose of survivors at different distances from the centre of the A-bomb explosion has been determined using electron spin resonance (ESR) of their tooth enamel and compared with the tentative dose revised in 1985 considering shielding factors. A trial to determine A-bomb dose has been made using Ge and E' centre signals of quartz grains in the building wall and bridge pillar granite close to the hypocentre of the A-bomb at Hiroshima.
A TLD Reader System Upgrade Conversion to Microprocessor Technology
Authors: Bradley R.P. , Grogan D. 
Published: February 2017

Abstract
Since the conversion from film dosemeters to thermoluminescence dosemeters in 1976, the national monitoring programme operated by the Bureau of Radiation and Medical Devices, Department of National Health and Welfare, Canada, has used three readers of the type designed by the Chalk River Nuclear Laboratories. The question of replacing or updating this equipment was raised late in 1984 and a decision to upgrade by an electronic conversion method was made. This approach had already been used successfully in developing a fourth reader and dosemeter for the uranium mining and milling industry. Using the experience and confidence gained through this exercise, a more sophisticated microprocessor-based electronics package was designed. The microprocessor used was the model LC-3 manufactured by Cybernex of Ottawa, Canada and represented a significant increase in computational ability and speed over the previous choice of the LC-1. Once the conversion is completed, the readers, previously interfaced to and controlled by a Hewlett Packard HP-3000 minicomputer, will be stand-alone units. Full graphics capability, digitised glow curves and extensive monitoring of the system functions will be available. Details of the impact this will have on the operation and reliability aspects of the system are presented.
Review of the Principal Materials Available for Thermoluminescent Dosimetry
Authors: Portal (INVITED) G. 
Published: February 2017

Abstract
A chronological history of the thermoluminescent materials most commonly used for radiation dosimetry is presented. The evolution of their dosimetric and physical properties is analysed and compared. Conclusions are drawn on the way in which the characteristics of these products could be improved for the different fields of application envisaged.
Investigation of Phosphorescence Decay Using TL-like Presentation
Authors: Chen R. , Kristianpoller N. 
Published: February 2017

Abstract
The phosphorescence decay of radiation stimulated luminescent materials at a constant temperature reveals information on the processes involved. The shape of the decay curve depends on the kinetics. Inversely, a study of these curves yields information on the kinetic parameters. A way of presenting the phosphorescence decay which emphasises the features of the curve is to plot y=t(I(t) as a function of x=In t. This yields a peak shaped curve for a simple phosphorescence decay. This curve resembles the TL glow curve that one expects for the same kinetic law. In the present work, the shape of the curve is studied by checking the symmetry factor µg=d/? where d=x2-xm, ?=x2-x1 and where xm is the maximum point and x1, x2 are the two half-intensity points. The dependence of µg on the kinetic order b is determined. Inversely, the parameter b can be evaluated from the experimental results.
Predicting the Rate of 222Rn Entry from Soil into the Basement of a Dwelling Due to Pressure-Driven Air Flow
Authors: Nazaroff W.W. 
Published: February 2017

Abstract
A combination of analytical and numerical methods is applied to the problem of computing 222Rn transport from soil into a dwelling having a basement. Transport is assumed to occur solely by pressure-driven air flow, and the basement shell is assumed to have a single dominant leak that is uniformly distributed around the perimeter at the level of the floor. The results show that for small flow rates of air through the soil, the radon entry rate into the basement increases in proportion to ?Po, the outdoor-indoor pressure difference at the soil level. For large flow rates, the entry rate increases only in proportion to ?Po2/3, due to depletion of radon concentration in the soil. A sample calculation indicates that via this transport mode, soil having ordinary 226Ra content and moderately high permeability can be responsible for indoor radon concentrations of the order of 500 Bq.m-3, greater than recommended guidelines for new housing.
The Radial Dose Distribution as a Microdosimetric Tool
Authors: Varma M.N. , Zaider M. 
Published: February 2017

Abstract
We examine, as a function of a particle type and energy as well as the geometrical configuration of the sensitive site, the extent to which a description of the track in terms of itsradial dose distribution can be used as a substitute for a full microdosimetric description. The critical parameter appears to be the ratio between the site diameter and the maximum lateral extension of the track (penumbra): whenever this ratio is significantly larger than 1 the radial-distribution-derived microdosimetric spectrum is accurate. While in general, for ratios smaller than 1, the spectra thus calculated are not correct, one can obtain significant improvement by considering tracks of restricted radial extent (yet comprising most of the delivered dose). In terms of a microdosimetric-based quality factor the radial dose distributions generally lead to correct estimates.
Further Development of the Variance-Covariance Method
Authors: Chen J. , Brekow J. , Roos H. , Kellerer A.M. 
Published: February 2017

Abstract
Applications of the variance-covariance technique are presented that illustrate the potential of the method. The dose mean lineal energy, yD, can be determined in time-varying radiation fields where the fluctuations of the dose rate are substantially in excess of the stochastic fluctuations of the energy imparted. An added advantage is, that yD is little influenced by noise that affects both detectors simultaneously. The variance-covariance method is thus stable with respect to dose rate fluctuations and other temporal variations of a radiation field, and to various influences of noise and electronic artefacts. The dose mean lineal energy obtained at different simulated diameters agrees well with experimental data by other authors and can be determined for small simulated diameters (below 100 nm).
Studying Low Dose Effects Using Single Particle Microbeam Irradiation
Authors: Braby L.A. , Reece W.D. 
Published: February 2017

Abstract
Our current understanding of the effects of low doses of ionising radiation relies on extrapolation from doses which are orders of magnitude larger than those resulting from environmental or occupational exposure. This has been necessary, in part, because the stochastic nature of energy deposition by charged particle tracks makes it difficult to measure effects at low doses. At low doses test populations consist primarily of unirradiated cells, with a few cells which have been traversed by one track and a very small fraction which have been traversed by two or more tracks. Furthermore, the position of tracks relative to critical structures in the cells are random, resulting in large variations in the probability of an effect from one irradiated cell to another. These limitations on the study of the relationship between energy deposited in the cell and the biological effect can be largely eliminated by irradiating individual cells with a counted number of monoenergetic charged particles collimated so that they traverse specific target structures.
Current Status of Ultrasoft X Rays and Track Structure Analysis as Tools for Testing and Developing Biophysical Models of Radiation Action
Authors: Goodhead D.T. , Nikjoo H. 
Published: February 2017

Abstract
Ultrasoft X rays have provided a valuable tool to probe subcellular mechanisms of radiation action. Sufficient data have become available to allow meaningful comparisons between laboratories and between biological assays. A brief summary is given of these data. They show that there is generally good agreement between the results from different laboratories but that there are apparently major differences in RBE between cell types which do not conform to simple expectations or explanations. This raises an intriguing conundrum which awaits satisfactory solution. The solution should provide valuable additional insight into the subcellular mechanisms, including information on spatial distributions of critical subcellular target material and/or essential difference between the responses of different cell types. A variety of potential solutions to the conundrum are discussed and it is shown how Monte Carlo track structure analyses allow some of these to be studied in terms of properties of radiation tracks over nanometre dimensions.
The Role of Microdosimetry in the Understanding of Radiation Quality
Authors: Rossi (INVITED) H.H. 
Published: February 2017

Abstract
A recent report of the International Commission on Radiation Units and Measurements (ICRU) proposes various changes in the formulation of the quality factor (Q) in radiation protection. The recommendations are considered to be generally consistent with microdosimetric considerations and radiobiological findings. The principal inconsistency, which is based on technical limitations, relates Q to lineal energy in 1 micrometre sites rather than in more appropriate much smaller ones. However, the practical consequences seem acceptable in view of other, larger, uncertainties in radiation protection.
Dissolution Glow Curve in LLD
Authors: Haverkamp U. , Wiezorek C. , Pötter R. 
Published: February 2017

Abstract
Lyoluminescence dosimetry is based upon light emission during dissolution of previously irradiated dosimetric materials. The lyoluminescence signal is expressed in the dissolution glow curve. These curves begin, depending on the dissolution system, with a high peak followed by an exponentially decreasing intensity. System parameters that influence the graph of the dissolution glow curve, are, for example, injection speed, temperature and pH value of the solution and the design of the dissolution cell. The initial peak does not significantly correlate with the absorbed dose, it is mainly an effect of the injection. The decay of the curve consists of two exponential components: one fast and one slow. The components depend on the absorbed dose and the dosimetric materials used. In particular, the slow component correlates with the absorbed dose. In contrast to the fast component the argument of the exponential function of the slow component is independent of the dosimetric materials investigated: trehalose, glucose and mannitol. The maximum value, following the peak of the curve, and the integral light output are a measure of the absorbed dose. The reason for the different light outputs of various dosimetric materials after irradiation with the same dose is the differing solubility. The character of the dissolution glow curves is the same following irradiation with photons, electrons or neutrons.
Study of the Annealing Characteristics of LiF:Mg,Ti Using Computerised Glow Curve Deconvolution
Authors: Horowitz Y.S. 
Published: February 2017

Abstract
Computerised glow curve deconvolution (CGCD) based on first order TL kinetics has been used to study the dependence of the TL sensitivity, S, of glow peaks 2, 3 and (4+5) on choice of annealing temperature during the low and high temperature annealing procedures commonly applied to LiF:Mg,Ti (TLD-100, Harshaw/Filtrol). This was in order to determine optimal temperatures for these procedures as well as to investigate the role of annealing temperature reproducibility in the requirements of high precision TL dosimetry. The recommended optimum annealing procedure is: (i) 400 oC, for 1 h followed by an accelerated 'natural' cooling rate of approximately 150 oC. min-1. (ii) 75 ± 3 oC, 24 h pre-irradiation and/or 100 oC, 10 min post-irradiation.
Comparison of the Responses of Several TLDs to Various Radionuclides
Authors: Vekic B. , Ranogajec-Komor M. , Cukman M. 
Published: February 2017

Abstract
The TL responses of TLD-700, LiF:Mg,Ti, MgB4O7:Dy, CaF2:Mn and Al2O3:Mg,Y dosemeters were calibrated against the radiation of 99Tcm (140 keV) and 131I (80-723 keV) in addition to calibration with 226Ra (0.093-2.45 MeV) and 137Cs (0.66 MeV) sources. 99Tcm and 131I are the most commonly used radionuclides in nuclear medicine. According to our previous energy response studies involving X ray irradiations, the TL response of TLD-700, LiF:Mg,Ti and MgB4O7:Dy exhibit low energy dependence. The agreement between the calculated dose and the dose measured by these TLDs is satisfactory, especially in the case of the 131I source. CaF2:Mn and Al2O3:Mg,Y detectors require special encapsulation for use in the dosimetry of photons in the low energy region.
Modified Track Structure Calculation of Thermoluminescent Yields to Heavy Charged Particles
Authors: Chernov V.G. , Rogalev B.I. 
Published: February 2017

Abstract
Tracks of heavy charged particles are presented as a combination of uniform elementary excitation (so called spurs) with fixed volume and dose. An expression for the calculation of HCP track efficiency relative to gamma efficiency was derived. This expression was used to calculate the relative efficiency of an LiF:Mg, Ti detector to HCPs with energies from 0.01 to 1000 MeV per nucleon. The calculations were found to be in good agreement with the experimental data.
Ultrasound elicits behavioral responses through mechanical effects on neurons and ion channels in a simple nervous system
Authors: Kubanek Jan , Shukla Poojan , Das Alakananda , Baccus Stephen A. , Goodman Miriam B. 
Published: February 2017

AbstractFocused ultrasound has been shown to stimulate excitable cells, but the biophysical mechanisms behind this phenomenon remain poorly understood. To provide additional insight, we devised a behavioral-genetic assay applied to the well-characterized nervous system ofC. elegansnematodes. We found that pulsed ultrasound elicits robust reversal behavior in wild-type animals in a pressure-, duration-, and pulse protocol-dependent manner. Responses were preserved in mutants unable to sense thermal fluctuations and absent in mutants lacking neurons required for mechanosensation. Additionally, we found that the worm‘s response to ultrasound pulses rests on the expression of MEC-4, a DEG/ENaC/ASIC ion channel required for touch sensation. Consistent with prior studies of MEC-4-dependent currentsin vivo, the worm’s response was optimal for pulses repeated 300 to 1000 times per second. Based on these findings, we conclude that mechanical, rather than thermal stimulation accounts for behavioral responses. Further, we propose that acoustic radiation force governs the response to ultrasound in a manner that depends on the touch receptor neurons and MEC-4-dependent ion channels. Our findings illuminate a complete pathway of ultrasound action, from the forces generated by propagating ultrasound to an activation of a specific ion channel. The findings further highlight the importance of optimizing ultrasound pulsing protocols when stimulating neurons via ion channels with mechanosensitive properties.Significance StatementHow ultrasound influences neurons and other excitable cells has remained a mystery for decades. Although it is widely understood that ultrasound can heat tissues and induce mechanical strain, whether or not neuronal activation depends on heat, mechanical force, or both physical factors is not known. We harnessedC. elegansnematodes and their extraordinary sensitivity to thermal and mechanical stimuli to address this question. Whereas thermosensory mutants respond to ultrasound similar to wild-type animals, mechanosensory mutants were insensitive to ultrasound stimulation. Additionally, stimulus parameters that accentuate mechanical effects were more effective than those producing more heat. These findings highlight a mechanical nature of the effect of ultrasound on neurons and suggest specific ways to optimize stimulation protocols in specific tissues.
Bootstrap Distillation: Non-parametric Internal Validation of GWAS Results by Subgroup Resampling
Authors: Eccles David A. , Lea Rodney A. , Chambers Geoffrey K. 
Published: February 2017

AbstractGenome-wide Association Studies are carried out on a large number of genetic variants in a large number of people, allowing the detection of small genetic effects that are associated with a trait. Natural variation of genotypes within populations means that any particular sample from the population may not represent the true genotype frequencies within that population. This may lead to the observation of marker-disease associations when no such association exists.A bootstrap population sub-sampling technique can reduce the influence of allele frequency variation in producing false-positive results for particular samplings of the population. In order to utilise bioinformatics in the service of a serious disease, this sub-sampling method has been applied to the Type 1 Diabetes dataset from the Wellcome Trust Case Control Consortium in order to evaluate its effectiveness.While previous literature on Type 1 Diabetes has identified some DNA variants that are associated with the disease, these variants are not informative for distinguishing between disease cases and controls using genetic information alone (AUC=0.7284). Population sub-sampling filtered out noise from genome-wide association data, and increased the chance of finding useful associative signals. Subsequent filtering based on marker linkage and testing of marker sets of different sizes produced a 5-SNP signature set of markers for Type 1 Diabetes. The group-specific markers used in this set, primarily from the HLA region on chromosome 6, are considerably more informative than previously known associated variants for predicting T1D phenotype from genetic data (AUC=0.8395). Given this predictive quality, the signature set may be useful alone as a screening test, and would be particularly useful in combination with other clinical cofactors for Type 1 Diabetes risk.