bluuebunny/crossref_metadata_2025 huggingface dataset:
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

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

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

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.
ESR Accident Dosimetry Using Medicine Tablets Coated with Sugar
Authors: Kai A. , Ikeya amd T. Miki M.
Published: February 2017

Properties of radiation-induced radicals in medicine tablets were investigated using electron spin resonance (ESR). A sharp ESR signal sensitive to gamma ray irradiation was observed in the sugar coating part of the tablets. The signal has anisotropic g values of g1=2.0009, g2=2.0007 and g3=2.0002. The signal grows linearly with dose at least up to about 20 Gy. No fading was observed at room temperature even when exposed to sunlight. The dose to artificially irradiated tablets was estimated using the signal intensity and a previously determined calibration curve. The signal in sugar coated tablets can be utilised for dose measurements. In particular, the wide distribution of sugar coated tablets allows the use of the tablets as accident dosemeters.
Simultaneous Thermal Bleaching and TL Measurements on LiF:Mg,Ti
Authors: Peto Á.
Published: February 2017

The aim of this paper is to study the correlation of optical absorption bands and thermoluminescence peaks in LiF:Mg,Ti. Contrary to the numerous earlier publications related to this field, the present work uses a direct experimental approach. It reports on simultaneous thermal bleaching and thermoluminescence measurements on differently doped LiF:Mg,Ti single crystals in the 10-100 kGy dose range. The advantage of this technique is that the thermal bleaching curve of a given absorption band can be directly compared to the TL glow curve, since both were measured on the same sample, at the same time. This paper presents data on the 310, 350 and 380 nm absorption bands. The analysis reveals that all three bands strongly correlate with TL peaks 2 and 3, while they show no significant bleaching at the temperatures above peak 3. In addition the bleaching characteristics of the 350 nm band depend strongly on the Mg content of the sample.
Long-Term Fading of Peak 5 in TLD-100 Using Computerised Glow Curve Deconvolution (CGCD) and Thermal Peak Isolation Techniques
Authors: Shachar B.B. , Horowitz Y.S.
Published: February 2017

The long-term fading of peak 5 has been studied using four different annealing regimes. Following 400 oC for one hour annealing and 'natural cooling', peaks 4 and 5 (separated via (CGCD) appear to have an exquisitely complex time-dependent response, possibly due to clustering of dipole trapping centres associated with peaks 2 and 3. Peak 4 grows over the first nine months of storage and only then begins to decay: peak 5, on the other hand, decays rapidly in the first six months and then stabilises or even begins to glow. Peaks (4+5) together, however, fade in a montonically decreasing manner at a rate of approximately 8% per annum. Using thermal cleaning procedures to isolate the behaviour of peak 5 from its low temperature satellites, it has been established that the 20 oC mean-life of peak 5 is 5.5±1 year (1 SD). This mean-life is many orders of magnitude smaller than predicted by any of the kinetic measurements of s and E and suggests that precipitation of Mg2+ may be the major contributor to the decay of peak 5 over long storage intervals.
The Phenomenon of Heat Transferred Thermoluminescence in Zirconia Pre-Irradiated by Ultraviolet Radiation
Authors: Chang S.-C. , Su C.-S.
Published: February 2017

In previous work it was found that there were peaks around 70, 100 and 235 oC in the thermoluminescence (TL) glow curve of zirconia read out immediately after ultraviolet (UV) irradiation, but the 70 oC peak faded within approximately 30 min. Thus only 100 and 235 oC TL peaks usually appeared in the TL glow curve if the readout was not taken immediately after the UV irradiation. The discovery of the 70 oC peak in the TL glow curve of zirconia read-out the second time right after the first TL readout is reported. The ZrO2 still emitted TL to some extent in the second readout if no annealing was done after the first readout, but the 70 oC peak in the TL glow curve became the main peak. The recovery of the 70 oC peak can be explained as heat transferred TL of zirconia stimulated by heat energy from the heating planchet of the TL detector during the first readout. Detailed experimental work and discussion are presented.
Comparison of Main Thermoluminescent Properties of Some TL Dosemeters
Authors: Prokic M. , Bøtter-Jensen L.
Published: February 2017

Different types of TL dosemeters that are attractive for dosimetry practice were investigated and compared. The aim of this study was to evaluate the TL characteristics of different TL dosemeters using two basically different types of commercially available TL readers. The findings demonstrate that it is important that the TL dosemeter and TL reader used be compatible.
Comprehensive Study on LiF:Cu,Mg,P (GR-200 A)
Authors: Bacci C. , D'Angelo L. , Furetta C. , Giancola S.
Published: February 2017

The main properties of a new thermoluminescent (TL) material (LiF:Cu,Mg,P) produced in the People's Republic of China under the name of GR-200A have been already investigated by others. The purpose of this work is to establish a standardised procedure for use. Careful experiments were carried out with the aim of identifying the optimal annealing cycle and the dependence of TL sensitivity on the heating rate. Further more, reading procedure, fading, calibration and TL dependence on dose were studied along with other relevant physical features. The high sensitivity (20 to 30 times that of LiF TLD-100), the wide range of dose linearity (0-18 Gy), the short annealing procedure (10 min. at 513 k) together with a negligible fading at room temperature, quick readout cycle (35 s), good tissue-equivalence (Zeff=7-8) and TL signal reproducibility (SD <2.5%) make GR-200A TLDs particularly valuable for several dosimetry purposes. Their high sensitivity makes them especially eligible for environmental and radiological dosimetry, while the wide dose linearity range allows various radiotherapeutic applications in patient and machinery output dosimetry.
New BeO Ceramics for TL ESR Dosimetry
Authors: Kortov V.S. , Milman I.I. , Slesarev A.I. , Kijko V.S.
Published: February 2017

Several types of commercial BeO ceramics have been studied with a view to their possible application in TL and/or ESR dosimetry. The best results have been obtained with optically transparent high density ceramics with little tendency to sputtering, simultaneously doped with lithium and neodyminium ions and having no pyroelectrical effects during heating and cooling. TL and ESR signals associated with Li centres whose amplitude is proportional to the absorbed dose are observed. A complete anneal of the ESR signal takes place in the temperature range of the TL recordings.
A Gamma/Neutron Discriminating, Cooled, Optically Stimulated Luminescence (COSL) Dosemeter
Authors: Eschbach P.A. , Miller S.D.
Published: February 2017

The cooled optically stimulated luminescence (COSL) of CaF2:Mn (grain sizes from 0.1 to 100 µm) powder embedded in a hydrogenous matrix is reported as a function of fast neutron dose. When all the CaF2:Mn grains are interrogated at once, the COSL plastic dosemeters have a minimum detectable limit of 10 mSv fast neutrons; the gamma component from the bare 252Cf exposure was determined with a separate dosemeter. A proton recoil based dosemeter is described that generates pulse height spectra, much like the scintillator of Hornyak, to provide information on both the neutron and gamma dose. The plastic dosemeters were first submitted to an optical bleaching procedure using a high intensity ultraviolet laser and then exposed to fast neutrons using an unmoderated 252Cf source. The previously used COSL process relied on thermal contact of the cooled dosemeter with a room temperature slab of metal to promote electrons from the shallow traps. In this case, however, the standard COSL cooling and light-stimulation process was used to phototransfer electrons from deep to shallow traps, but with the use of a CO2 laser to warm the individual CaF2:Mn grains selectively within the plastic matrix. Grains within the plastic dosemeter that received large localised energy deposition produced larger-than-average COSL response when warmed by the CO2 laser. The data presented here demonstrate the concept of a neutron discriminating dosemeter. Future work will concentrate on the refinement of the individual grain readout process until individual grains receiving a single neutron-induced recoil proton can be distinguished.
High Energy Photon Response of Different Environmental TLDs
Authors: Sáez-Vergara J.C. , Gómez-Ros J.M. , Delgado A.
Published: February 2017

The presence of high energy photons (4-7 MeV) around nuclear power plants and high energy accelerators is important during operation. Environmental monitoring frequently uses passive TL measurements for the assessment of the radiological impact of these facilities. However, due to the presence of this energetic photon radiation component, the design of environmental TLDs must be reconsidered, in order to provide charged particle equilibrium. The energy dependence of phosphors (LiF:Mg,Ti, Li2B4O7:Cu, CaSO4:Tm) in different irradiation conditions has been measured in the range 0.6-6.5 MeV. Irradiations using 6 MeV photons were performed in the calibration facility recently established at PTB (Germany). These data also seem to indicate that it could be necessary to apply specific corrections to the TLD readouts to account for these high energies and the convenience of the use of a discriminant TL dosemeter with special dose calculation algorithms for this radiation. These algorithms are usually based on element ratios and can be impractical in field readouts. However, this is not a serious limitation since the maximum error should not exceed ±10%.
Measurement of Radial Dose Distributions Around Small Beta Particle Emitters Using High Resolution Radiochromic Foil Dosimetry
Authors: Soares C.G. , McLaughlin W.L.
Published: February 2017

A method is described for the direct measurement of the radial dose distributions around small (from several mm down to tens of µm in diameter) beta particle emitters. The method employs the high resolution readout of radiochromic dye foils. These foils form a blue image upon irradiation and require no processing to stabilise the image. The colour change (in units of absorbance) is nearly linear with absorbed dose over a range of 10Gy to 1000 Gy and the response to electrons is nearly identical to 60Co gamma radiation which makes the system easy to calibrate. Readout is performed with a laser scanning densitometer with a 100 µm spot size which can be stepped in increments of 40 µm in two dimensions. Examples of the results of measurements of 90Sr/90Y eye applicators as well as particle sources of 90Sr/90Y, 60Co, and 170Tm are given.
Personnel Neutron Dosimetry Improvements at Los Alamos National Laboratory
Authors: Harvey W.F. , Hoffman J.M. , Bliss J.L. , Brake R.J.
Published: February 2017

Methods are being investigated to improve neutron dosimety at Los Alamos National Laboratory (LANL) using the etched track dosemeter CR-39. Specifically, use of CR-39 for dynamic environments, typically encountered at the LANL Plutonium Facility, is shown to be a superior method for personnel neutron dosimetry when compared to the currently used TLD system. The results of glovebox experiments simulating hydrogenous shielding used at LANL, temporal variations of neutron correction factors used at the Plutonium Facility, trial implementation at this facility and preliminary neutron spectroscopy measurements are presented and compared to reference dosimetry measurements. The results confirm that use of a TLD system in a facility implementing hydrogenous shielding requires frequent field recalibration. When such correction factors are not re-evaluated frequently, or are maintained at pre-shielding levels, significant (i.e. 2- to 3-fold) overestimation of the neutron dose equivalent can occur.
Diamond Detector Dosimetry for Medical Applications
Authors: Vatnitsky S.M. , Khrunov V.S. , Fominych V.I. , Schuele E.
Published: February 2017

The use of the diamond detector and air filled ionisation chamber calibrated in terms of the absorbed dose to water to measure absorbed dose in high energy photon, electron and proton beams is discussed and the results of the measurements are presented. The suitability of the diamond detector for dose measurements in special radiotherapy applications was studied.
A Remote Fibre Optic Laser TLD System
Authors: Jones S.C. , Sweet J.A. , Braunlich P. , Hoffman J.M. , Hegland J.E.
Published: February 2017

A fibre optic laser heated TLD system has been developed for use in remote in vivo, in situ dosimetry. A high power, near infrared CW semiconductor laser is used to heat TL elements at the distal end of standard optical fibres. Lengths of up to 200 m are feasible, with overall diameter as small as 1 mm. The system is multiplexed, with current capability of evaluating up to five dosemeter probes in under 30 s. with extension to larger numbers a trivial matter. The system is inherently immune to electromagnetic interference. The small mass of the TLD element ("100 µg) provides for highly localised dose measurement capability. A wide variety of TLD phosphors are used for various applications requiring high sensitivity, low fading, or a combination of both, providing a useful dose range of 1 mGy to greater than 100 Gy. Such applications include radiotherapy dosimetry (external and internal when constructed with a sterile catheter), hazardous and remote environments, such as monitoring ground water or soils for radioactive contamination.
Theory of Intertrack Pairwise Lesion Interaction
Authors: Harder D. , Virsik-Peuckert R.P. , Bartels E.R.
Published: February 2017

Experimentally observed heavy ion inactivation cross sections of mammalian cells exhibit the superposition of three effects, namely the 'hooks' due to delta ray range, the 'plateau' due to the multiplicity of lethal products per incident particle, and the underlying restricted LET dependence of the yield µ of lethal products per particle traversal. After elimination of the first two effects, the latter has been observed to follow the fitting function µ = uL? + v2L2 ?, which means that yield µ does not show saturation characteristics as a function of L?. Based on this formula it is shown that the RBE maximum for mammalian cell inactivation is always obtained at that position of the LET scale where a particle traversal through the cell nucleus produces about one lethal product. The quadratic term is derived from first principles under consideration of the reaction kinetics holding for pairwise lesion interaction in molecular 'interaction r egions' and of the proper statistical averaging procedures.
Radiosensitivity Parameters for Lethal Mutagenesis in Caenorhabditis Elegans
Authors: Cucinotta F.A. , Wilson J.W. , Katz R.
Published: February 2017

For the first time track structure theory has been applied to radiobiological effects in a living organism. Data for lethal mutagenesis in Caenorhabditis elegans, obtained after irradiation with nine different types of ions of atomic number 1-57 and gamma rays have yielded radiosensitivity parameters (E0, s0, ? , m = 68 Gy, 2.5 x 10-9 cm2, 750, 2) comparable with those found for the transformation of C3HT10 1/2 cells (180 Gy, 1.15 x 10-10 cm2, 750, 2) but remote from those (E0 and s0 = (2 Gy, (5 x 10-7 cm2) for mammalian cell survival.
Performance of TEPCs at Low Pressures: Some Attempts to Improve their Dose Equivalent Response in the Neutron Energy Range from 10 keV to 1 MeV
Authors: Gerdung S. , Grillmaier R.E. , Lim T. , Pihet P. , Schuhmacher H. , Ségur P.
Published: February 2017

A TEPC, from its operation principle, fulfils reasonably well the requirements of an area monitor with dose equivalent response nearly independent of neutron energy to be used for radiation protection dosimetry at various work places. However, between neutron energies from 10 keV to 1 MeV, which are of relevance for environments with strongly moderated neutron fields, the response of TEPCs with thin walls is too low. Attempts to increase the response in this energy region by modifying gas pressure, gas composition and wall thickness show that significant improvement first requires operation of the TEPC at lower simulated diameters compared with the 2 µm diameter commonly used. Preliminary investigations to improve the operational properties of TEPCs at low pressures are presented.
New Analytical Representation of W Values for Protons in Methane-Based Tissue-Equivalent Gas
Authors: Siebert B.R.L. , Grindborg J.E. , Grosswendt B. , Schuhmacher H.
Published: February 2017

The interpretation of ion yields measured with ion chambers or proportional counters in terms of energy deposited depends on a precise knowledge of the W values, i.e. the mean energy expended to form an ion pair. Methane-base tissue-equivalent (TE) gas is widely used in neutron dosimetry. Neutrons ionise indirectly by induced charged particles. In tissue and TE material, recoil or reaction protons account for a major fraction of the energy deposited. This report presents a new analytical representation of proton-W values. New experimental results are included which strongly influence the analytical fit, as they have small measurement uncertainties and include W values for proton energies as low as 1 keV and as high as 3.46 MeV. The differences between the present and older evaluations as found in the literature are discussed. The new analytical fit includes a 'bump' in W values for proton energies at about 300 keV. The covariance matrix of the new model is studied and the influence of the new fit on Wn values and on microdosimetric spectra for neutrons is discussed.
Aloof Trajectory Interactions of Low Energy Electrons with Condensed Matter
Authors: Ritchie R.H. , Bolch W.E.
Published: February 2017

An exploratory study has been made of the energy loss of a low energy electron incident on a thin dielectric film while it is travelling outside of the dielectric. Quantal theory is used to represent the electron while the polarisation propagator of the dielectric is constructed from local theory for water. Numerical results using this theory have been compared with experimental data from thin, solid, amorphous H2O films. Although not strictly comparable, since the media considered are not identical, it is believed that under some circumstances such aloof losses could represent a significant part of the measured loss distributions, particularly at the lower energies employed.
On the Linear Extrapolation to Low Doses
Authors: Katz R. , Waligorski M.P.R.
Published: February 2017

While radiobiological data are conveniently fitted by a linear quadratic formula to data of limited dynamic range at doses typically exceeding 1 Gy, they are extrapolated linearly to doses below a milligray for the evaluation of low dose RBEs. However a single relativistic electron passing through a cell nucleus deposits a 'dose' there in the neighbourhood of a milligray. The validity of the linear extrapolation then rests on the demonstration that a single electron transit through a cell nucleus can cause inactivation or mutation or can lead to cancer induction. The extrapolation made is a huge one, of some three orders of magnitude, from thousands of electrons traversing a cell to a single cell traversal, and with only qualitative and rhetorical foundation (one track-two tracks), and ignoring the statistical fluctuations of track intersections with targets. Existing data obtained with beams of electrons, protons, X ray photons, incorporated tritium and 125I, demonstrate that hundreds of electrons may traverse a cell for inactivation and millions may be required for cancer induction. If linear extrapolation were valid these numbers would be reduced to one. These contradictions suggest serious reconsideration of accepted radiation protection standards.
Formation of Track Entities by Photons in Water
Authors: Grosswendt B.
Published: February 2017

To study the photon-induced formation of track entities in water, the photon attenuation in, and the penetration through, an infinitely extended water medium was simulated using the Monte Carlo method. Four interaction processes were involved: the photoelectric effect, coherent and incoherent scattering, both taking electron binding into account, and electron-positron pair creation followed by the annihilation process of positrons. Conventional sampling techniques were used to calculate the spectral distribution of secondary electrons produced by photons of energies between 10 keV and 10 MeV as a function of the number of photon interactions along the photons' paths. After this, to look into the photons' track structure, the electron distributions produced were classified according to the well known 'track entity' concept of Mozumder and Magee. In the course of this it turned out that the photon-induced formation of track entities is quite different from that of primary electrons. Whereas the number of track entities induced by primary electrons is nearly proportional to the primary particles' energy, the photon-induced number of track entities is practically independent of the photon energy.
Chemical Consequences of Non-Homogeneous Energy Deposition by Ionising Radiation
Authors: Jonah  (INVITED) C.D.
Published: February 2017

The use of radiation chemical measurements to address the initial energy deposition events of water radiolysis is discussed. Experiments that probe both the number of ionisations in a spur and the average size of the spur in radiolysis are detailed. The experimental results are compared with present knowledge. The number of ions in a spur is consistent with the (large) range of calculated values. The spatial distribution of an electron relative to the point of the initial ionisation is determined by the loss of electron kinetic energy to vibrational modes of the solvent and not due to the energy loss to electronic states of the solvent. It is suggested that the use of a radiation chemical variable, such as spur number distribution and spatial distributions from track structure calculations might facilitate the understanding of radiation damage mechanisms in biological systems.
The Effectiveness of High Energy Neon Ions in Producing Chromosomal Aberrations in Human Lymphocytes
Authors: Edwards A.A. , Finnon P. , Moquet J.E. , Lloyd D.C. , Darroudi F. , Natarajan A.T.
Published: February 2017

This paper presents the results of the observation of chromosomal aberrations in human lymphocytes following irradiation by 189 MeV 20Ne ions. Dicentrics were observed at the first metaphase and chromosomal breaks at early interphase using the premature chromosome condensation technique (PCC). Comparison of these measurements with previous work with low LET radiation, produced RBEm values of 0.3 and 0.6 for dicentrics at metaphase and for breaks in early interphase, respectively. Recently published work on the repair of double strand breaks using the PCC technique shows that following X irradiation, the dicentric yield does not alter with repair time but the breaks decrease with repair time with a time constant in the region of 1 or 2 h. More recently published data in which cultures of mixed irradiated and unirradiated cells were scored for both dicentrics at metaphase and breaks at early interphase show that interphase death affects the dicentric yield at metaphase but not the break yield at early interphase. These observations place restrictions on the acceptability of models of radiation action.
Incorporating Chromatin Dynamics in Radiation Carcinogenesis Modelling: Advantages and Uncertainties
Authors: Andreev S.G.
Published: February 2017

Existing experimental evidence supports the hypothesis that initiation of radiation-induced carcinogenesis is a highly frequent epigenetic event and does not require the impairment of specific genes directly by radiation. An attempt to formulate a model of radiation neoplastic transformation including an epigenetic mechanism is undertaken which is based on the close relationships between gene expression and chromatin structure. The model simulates some data on morphological transformation and allows the prediction of dose-response curves but still with insufficient accuracy. On the basis of modelling possible relationships between the damage of chromatin domains and carcinogenic initial lesions are discussed.
The Influence of Dust on the 210Po Signal in Retrospective Radon Measurements
Authors: Johansson L. , Wolff M. , Samuelsson C.
Published: February 2017

In retrospective radon measurements, the signal from implanted 210Po is to be correlated with the long-term radon concentration of the indoor environment. The magnitude of the surface activity of 210Po is affected by external factors such as plateout rate. In our evaluation of the retrospective method, using sheets of glass as samples, an obstacle for implantation of 210Po in glass might be the thin layer of dust covering every authentic sample. Dust is present in every 'normal' indoor aerosol environment and tends to cover openly exposed surfaces like pictures and photographs. Since the range of the recoiling nuclides from the alpha decay is short, approximately 50 nm, the dust particles may prevent radon daughters from implantation in the glass. In this study, 20 authentically dusty glass samples were exposed to high radon concentrations in a radon room facility. The 210Po signal was then evaluated and compared with a clean reference glass, exposed under the same circumstances. The aerosol conditions were kept at an appropriate level typical for the indoor dwelling environment. To quantify the area of the dust particles on the glass, extinction measurements were performed on the dust layer of the glass samples.
Mapping the Proportion of the Housing Stock Exceeding a Radon Reference Level
Authors: Miles J.C.H.
Published: February 2017

In order to identify homes with high radon levels as efficiently as possible, it is necessary to have accurate numerical information on radon-prone areas. Maps based on geological indicators are generally qualitative and sometimes contain significant errors. Maps based on radon measurement in homes are definitive if sufficient results are available. Often there are small numbers of measurements, making it difficult to map the fraction of the housing stock which exceeds the reference level. However, distributions of radon levels are usually lognormal, so modelling of the distribution allows the fraction of the housing stock exceeding any level to be calculated. A database of 62,555 radon results in southwest England is used to show that the data within 5 km grid squares are consistent with lognormal distributions and to develop techniques for estimating for fraction of homes exceeding a radon reference level in each grid square, even where data are sparse.
Calibration of a Polycarbonate Etched Track Detector
Authors: Vanmarcke H. , Toye A. , Oberstedt S.
Published: February 2017

The efficiency of the Karlsruhe etched track detector was determined over a wide range of radon exposures. Sixty four detectors were placed in an airtight chamber. The radon concentration was kept at about 80 kBq.m-3 by circulating air over a solid radium source. At predetermined times, a group of four detectors was taken out of the chamber. The exposure period varied from a few hours up to several months in order to determine the efficiency curve for low exposure as well as for the region of saturation. The functional form y=a(1-e-bx) was fitted to the data. The low exposure range was fitted with only first six data points. The slope is 0.546 tracks.cm-2.kBq-1.m3.h-1, which is comparable to the earlier value of 0.55 tracks.cm-2.kBq-1.m3.h-1. The high exposure range was fitted with the whole data set. The two curves intersect at 2700 tracks.cm-2. At higher track densities the curve based on the whole data set has to be used to convert the number of tracks into an exposure.
Radon Programme in the Netherlands: Risk Assessment and Risk Management
Authors: Jung D.W.G.
Published: February 2017

The Dutch policy on the control of the risk of radon is predominantly based on the results of the Radon Research Programme. Important topics of the Radon Research Programme are described. Furthermore, the Dutch policy on indoor radiation is reviewed in view of the national environmental policy and radiation risk management. The policy on the control of radon in domestic and other buildings is related to other policies, both national and international, e.g. economic, environmental and housing policy. A short review of these relations in the Netherlands is given. In brief a description will be given of the attention paid by the government to the communication strategies used in order to enforce, for instance, remedial actions and the implementation of risk reduction technology.
The Effect of Temperatures up to 130 oC on the Responses of TLD 700
Authors: Douglas J.A. , Binns P.J.
Published: February 2017

The need to measure doses at temperatures up to 130 oC led to an investigation into the effect of exposure and storage at these temperatures on the response of TLD 700 before and after UV photo-transfer. As a preliminary, the delays required during the UV re-estimation process were optimised. The effects of storage and exposure were compared. This was followed by a detailed examination of the effects of storage at temperatures up to 130 oC. Glow curves were analysed to investigate the rates of growth and decay of the different peaks. The findings for peaks 6 and 7 are compatible with previously reported effects at lower temperatures on peaks 3, 4 and 5. Storage at temperatures of 130 oC or below for periods up to 28 days does not affect the UV photo-transfer response.
The Use of the Pre-Dose Technique for Environmental Dosimetry
Authors: Bailiff I.K. , Haskell E.H.
Published: February 2017

The pre-dose effect associated with the 100 oC TL peak of quartz is the basis of a dating technique developed at the Oxford Laboratory, and now in use to date pottery and brick at the Durham Laboratory. Recently its use for the measurement of fallout gamma dose has been initiated at the University of Utah. Using quartz extracted from fired brick, the technique has been shown to be sufficiently sensitive to measure doses in the region of 10 mGy. The complexities of the technique encountered during dating in its upper range (~5 Gy) are equally apparent in its lower range (10 mGy). With a common interest in the pre-dose technique, we discuss the research that is being performed to apply the technique through its full range in environmental dosimetry.
Calibration of Thermoluminescence Skin Dosemeter Response to Beta Emitters Found in Ontario Hydro Nuclear Power Stations
Authors: Walsh M.L. , Agnew D.A. , Donnelly K.E.
Published: February 2017

In this study the response of the Ontario Hydro Thermoluminescence Dosimetry System to beta radiation in nuclear power station environments was evaluated. Synthetic beta spectra were constructed, based on activity samples from heat transport systems and fuelling machine contamination smears at nuclear power stations. Using these spectra and dosemeter energy response functions, an overall response factor for the skin dosemeter relative to skin dose at 7 mg.cm-2 was calculated. This calculation was done assuming three specific geometries; (1) an infinte uniformly contaminated plane source at a distance of 33 cm (50 mg.cm-2 total shielding) from the receptor; (2) an infinite cloud surrounding the receptor; (3) a point source at 33 cm. Based on these calculations, a conservative response factor of 0.7 has been chosen. This provides an equation for skin dose assignment: Skin Dose = 1.4 x Skin Dosemeter Reading, when the skin dosemeter is directly calibrated in mGy (gamma).
Temperature Dependence of the Fluorescence Spectra of Single Crystal CaF2:Mn
Authors: Abbundi R.J. , Cooke D.W. , Mathur V.K , Royce G.A. , Brown M.D.
Published: February 2017

The temperature dependence of the fluorescence under X ray excitation of single crystal CaF2:Mn (3%) was examined from 13-519 K. The fluorescence spectra consisted of a broad band centred near 500 nm. The full width at half maximum steadily increased from 0.191 eV at 13 K to 0.295 eV at 519 K. A fit of these data to the usual expression for the full width of an emission band W(T) = W(0) [coth (h?/2kT)]1/2 yielded W(0) = 0.206 eV and ? = 7.0 x 1013 sec-1. The shape of the distribution was found to be non-Gaussian at all temperatures with a skewness to the high wavelength side. The peak position was observed to shift, as a result of the reduction in the crystal field, about 5 nm toward lower wavelength between 13-300 K and then remain stationary with further increase in temperature. The area under the fluorescence peak increased, between 13-400 K, by a factor of 2 and then gradually decreased at higher temperature.
Dose Independent Use of LiF Detectors in Mixed Neutron-Gamma Radiation Fields
Authors: Uray I.
Published: February 2017

The glow curve characteristics of TLD-100, -600 and -700 ribbons were investigated after irradiation by various mixed neutron-gamma fields. It was stated, that the supralinearity of the detectors shows a clear dose dependence, which can be handled mathematically. By this method the neutron and gamma responses of the detectors can be separately determined over a wide range of dose and mixing ratios. The accuracy of the separation of the response components is characterised mostly by the statistical error. The response to dose conversion for the gamma component is simple, while for the neutron component it depends on the neutron spectra and on the type of the detector. Simultaneous use of different types of LiF detectors may therefore give us some information about the energy spectra of the neutrons also. By this means a response to dose conversion is already achievable, also when the neutron spectra are unknown.
A Solid Basis for Individual Monitoring Systems. Silver Iodide, Lithium Fluoride or Silicon?
Authors: Dennis (INVITED) J.A.
Published: February 2017

Technical experts have a tendency to believe that the selection of an appropriate system for personal dosimetry, i.e. photographic film, thermoluminescence, exoelectron emission, etc., will be determined by technical merit. There is in particular a tendency to believe that the accuracy and precision of the dosemeter is an overriding factor in selection. In fact, within the concepts and accuracies required and possible for personal monitoring, there is very little difference between the various systems. The perception of a need for innovation, the institutional image, accounting methods, and system reliability, are often decisive factors and ultimately in the modern world the economic factors of capital investment and running costs. System reliability is one of the most important and possibly neglected aspects of running costs, and a factor which has so far prevented the replacement of photographic film in many individual monitoring systems.
Thermoluminescence Dating of Sediments
Authors: Mejdahl (INVITED) V.
Published: February 2017

Thermoluminescence (TL) dating of sediments is based on the observation that exposure of quartz and feldspar to sunlight rapidly reduces the TL level to a small residual value. Therefore, sediments transported by air or water will usually be deposited with a very small TL level. When the sediment has been covered as a result of subsequent sedimentation, the TL level again increases with time as a result of exposure of the minerals to the natural background radiation. The TL level is thus a measure of the accumulated radiation dose (the palaeodose), and the time elapsed since sedimentation is given by the ratio of the palaeodose to the annual dose. Techniques for determining the palaeodose are described including the regeneration, additive dose and R-T methods. Insufficient bleaching during transport, instability of the latent TL signal and non-linear dose response for older samples pose particular problems which are discussed. In several respects, TL dating of sediments is still at the experimental stage, but the method has a great potential for dating sediments within the last 500,000 years, a period for which there are few other absolute dating methods.
Properties of Radiophotoluminescent Glass Dosemeter Systems Using Pulsed Laser UV Excitation
Authors: Piesch E. , Burgkhardt B. , Fischer M. , Röber H.G. , Ugi S.
Published: February 2017

The UV pulsed laser excitation of PL glasses has been investigated using the new Toshiba reader FGD-8 and flat FD-7 glasses of size 16x16x1.5 mm3. In comparison with the conventional UV excitation with mercury lamps, the nitrogen laser excitation decreases the pre-dose Ho by a factor of 100 to about 10 µSv. Glass cleaning is no longer necessary. The main parameters studied were the empirical standard deviation s(H) relative to dose, the total random uncertainty sR(H) with dose, and the lowest detectable dose HLDL has been found to be 30 µSv and 7 µSv for 10 laser pulses and 200 laser pulses per readout. For a dose equivalent >1 mSv the relative s-value is <1%. The photon energy dependence of flat glass dosemeters for the indication of Hp(10) is ±13% in the energy range 15 keV - 1.2 MeV. In combination with an automatic readout still in development at Toshiba the RPL system will in future be attractive for a large scale use in personal and environmental monitoring.
Mixed Field Multi-Element Beta/Gamma Dosemeter Design
Authors: Rayes I.M. , Stoebe T.G.
Published: February 2017

A multi-element TLD badge system has been designed for use with a Teledyne Isotopes TLD system. The badge contains four areas, each with its unique filtration, to allow discrimination between beta and gamma contributions at the various energies present in a mixed radiation field. The active TL element in the badge consists of CaSO4:Dy embedded in Teflon. Filtration from three filter elements allows energy and radiation discrimination in the badge. These filters are designed as follows: (a) a beta shield to filter out 97% of the incident betas; (b) a gamma energy compensation filter to allow dose determination for photon radiation of all energies; and (c) a bias filter to record all high energy photons. Doses recorded by the TL element under each filter are compared with the total dose recorded under an open window. Intercomparisons of recorded doses from these four areas then allow both beta-gamma discrimination and gamma energy discrimination.
The Reconstruction Problem in Microdosimetry
Authors: Breckow J. , Friede H. , Hahn K. , Roos H. , Kellerer A.M.
Published: February 2017

A generalised formulation of microdosimetry clarifies the linkages between the spatial distribution of energy deposits, their proximity function, and the specific energy. The role of the proximity function suggest that it may replace, for various purposes, the inchoate distribution. The Fourier transform of the proximity function is the product of the Fourier transform of the inchoate distribution with its conjugate. This operation causes the loss of phase information, and the reconstruction problem - the reconstruction of the inchoate distribution from its proximity function - can, therefore, not be resolved by a mere deconvolution. For any finite point pattern one can, however, show that its proximity function permits, in principle, the reconstruction. Numerical examples with 2-dimensional patterns of up to 30 points have consistently led to unique solutions, apart from reflections. While there is a finite algorithm, it is readily seen that the number of steps becomes excessive when the number of points in the pattern increases. The reconstruction problem can, thus, be solved in principle but not necessarily in practice. A more general approach must thus be based on numerical optimisation. The algorithm starts with an assumed initial point pattern and utilises a suitable measure for the difference between its proximity function and that of the original pattern. Minimising this difference can lead to the original or to a similar pattern. With simple algorithms one obtains convergence only for patterns of few points; but improved optimisation methods are likely to provide more general solutions.
Biological Action of Single Heavy Ions on Individual Yeast Cells
Authors: Kost M. , Schneider E. , Kiefer J.
Published: February 2017

Diploid yeast cells placed on nuclear track detector foils were exposed to heavy ions of different atomic number and energy. To assess the action of one single heavy ion on an individual yeast cell, track parameters and the respective colony forming capabilities were determined with the help of computer aided image analysis. The results show that the biological action depends on atomic number and specific energy of the impinging heavy ions.
Highly Sensitive Thermoluminescent Anion-Defect Alpha-Al2O3:C Single Crystal Detectors
Authors: Akselrod M.S. , Kortov V.S. , Kravetsky D.J. , Gotlib V.I.
Published: February 2017

New highly sensitive thermoluminescence detectors of universal application on the basis of anion-defect a-Al2O3:C single crystals have been developed. The decisive role of non-stoichiometry in forming luminescence properties of crystals has been ascertained by methods of optical, luminescent and exoemission spectroscopy. Detectors possess the sum total of unique dosimetric properties: sensitivity to gamma radiation 50 times higher than that of LiF:Mg,Ti: low background; dose threshold about 10-6 Gy; a single glow peak at 460 K; blue luminescence band at 420 nm; negligible fading and possibility of re-use without annealing procedures.
Thermoluminescence and Thermally Stimulated Exoelectron Emission in Ca3(PO4)2:Ce
Authors: Fukuda Y.
Published: February 2017

Ca3(PO4)2, an essential constituent of bones and teeth, was doped with CeO2 and X irradiated to study its thermoluminescence (TL) and thermally exoelectron emission (TSEE). The intensity of the TL response against irradiation dose was increased remarkably by the addition of Ce ions, the TL peaks being found at (1) 90-100 oC, (2) 125-130 oC, (3) 225-235 oC, (4) 315-320 oC, and (5) 340-350 oC. These peaks appeared in a-Ca3(PO4)2 doped with CeO2 obtained by heating the ß phase. In the TSEE glow spectra of a-Ca3(PO4)2 doped with CeO2 the TSEE peaks were found at (A) 115-120 oC, (B) 245-250 oC, and (C) 340-345 oC. Peaks (A), (B), and (C) seem to correspond to the TL peaks (2), (3), and (5), respectively. The TL emission spectra for Ca3(PO4)2 doped with CeO2 showed a maximum at 350 nm for all temperatures during TL measurements. The emission is possibly due to the recombination reaction: Ce4+ + e ® Ce3+* ® Ce3+ + hv (350 nm).
Thermoluminescent Response of 6LiF (Mg,Cu,P) and 7LiF (Mg,Cu,P) TL Chips in Neutron and Gamma Ray Mixed Radiation Fields
Authors: Wang S.S. , Cai G.G. , Zhou K.Q. , Zhou R.X.
Published: February 2017

The newly developed 6LiF (Mg,Cu,P) and 7LiF (Mg,Cu,P) TL chips have been investigated for their relative TL sensitivity, glow curve structure, photon energy dependence, gamma ray and neutron dose response linearity. The experimental results given in this paper establish that: (1) the TL sensitivities of 6LiF (Mg,Cu,P) and 7LiF (Mg,Cu,P) were nearly the same as that of LiF (Mg,Cu,P) for gamma rays; (2) the TL response (reading) of 6LiF (Mg,Cu,P) was nine times larger than that of 6LiF (Mg,Ti) for thermal neutrons, but normalised to gamma ray response this ratio was 0.33; and (3) normalised to gamma ray response the sensitivity for thermal neutrons was much lower for 7LiF (Mg,Cu,P) than for TLD-700.
TSEE and TL Beta Dosimetry
Authors: Hobzová L. , Novotný J.
Published: February 2017

Thermoluminescence (TL) and thermally stimulated exoelectron emission (TSEE) responses of various detectors to beta emitters of different maximum energy have been studied for the purposes of beta dosimetry. Theoretically calculated values of relative dose distribution in tissue and plastics were compared with experimentally observed responses. The improvement in beta detection efficiency of newly prepared TL materials with or without graphite was also investigated.
Triboluminescence of Sodium Chloride
Authors: Copty-Wergles K. , Nowotny R. , Hille P.
Published: February 2017

The triboluminescence of sodium chloride was measured by shaking the grain material in a flat pan in an axial direction. The glow curves were measured over periods longer than 270 min. The influence of radiation dose was investigated in a dose range of 0.1 Gy and 3 kGy. Saturation occurs at 1.5 kGy. The total light output measured for triboluminescence is more than a factor of 192 of that observed for lyoluminescence depending on the integration interval. Triboluminescence was also measured for other alkali halides such as LiF (TLD-100), NaBr and LiCl using the same apparatus and glow curve patterns different from that of NaCl were observed.
On the Physical Properties of Metallic Colloids in Ionic Crystal Applicable to a Dosemeter
Authors: Inabe K. , Owaki S.
Published: February 2017

Thermal stability of Na colloids formed in NaC1 after intense electron irradiation was investigated by using photoacoustic spectroscopy (PAS). It was found that both isothermal and isochronal bleaching of the colloidal band (C-band) consists of two stages: initial slow and subsequently rapid decay, which shows an exponential decrease associated with a thermal activation energy more than 2.0 eV. The rapid decay of the C-band was also found to accompany a TL glow peak indicating the recombination between the colloids and the hole centres.