bluuebunny/crossref_metadata_2025 huggingface dataset:
Field Calibration Technique for Albedo Neutron Dosemeters
Authors: Burgkhardt B. , Piesch E.
Published: February 2017

For field calibrations of a two-component albedo dosemeter, a polyethylene sphere of 30 cm diameter with the same type of TL detector in the centre serves as a reference dosemeter and as a phantom for the albedo dosemeter. With respect to angular dependence, the reference dosemeter indicates the ambient dose equivalent H*(10) and the personnel dosemeter the individual dose equivalent H'(10). The problem of calibration in nearly isotropic radiation fields has been overcome by (a) the assumption that personal dosemeters should preferably indicate H'(10) for irradiations from the front half space only and, (b) the field calibration technique which adds the reading of two albedo dosemeters irradiated in diametrically opposed positions on the surface of the sphere. Thus, the albedo response has sufficient angular independence and a conservative characteristic for the indication of H'(10) in personnel dosimetry. The results of field calibrations here show that the variety of neutron fields can be classified into four typical application areas. Within one of these types of neutron fields, the albedo response does not vary by more than a factor of two. For reactors, linacs and the fuel element cycle, a constant calibration factor is used. For radionuclide sources and particle accelerators the albedo response relative to the actual reading ratio of the thermal neutron and the albedo detector in the personal dosemeter is used to correct for local or workplace dependent changes of the albedo response. The calibration data are applicable to other TLD systems and to stray neutron fields.
Numerical Study of the Influence of Phantom Material and Shape on the Calibration of Individual Dosemeters for Neutrons
Authors: Bauer B.W. , Hollnagel R. , Siebert B.R.L.
Published: February 2017

The use of appropriate phantoms for the calibration of individual neutron monitors is necessary, as the shape and the material of the phantom significantly influence the reading of such monitors. The International Commission on Radiation Units and Measurements (ICRU) considers the ICRU sphere to be suitable. This in practice may be questionable. A systematic numerical study of the influence of various phantoms on the readings of thermoluminescent detectors (TLDs) and etched track detectors (TEDs) has been performed. Elliptical cylinders consisting of ICRU soft tissue or polyethylene and resembling the trunk of an exposed person, with or without a cavity simulating the lung volume, have been compared with the ICRU sphere. In certain irradiation situations the readings of dosemeters exposed on elliptical cylindrical phantoms can be appreciably higher than on the ICRU sphere. If fast neutrons cannot be neglected, it may be necessary to use an anthropomorphic calibration phantom for both albedo dosemeters and etched track detectors.
Calibration Procedures for Determining the Radiation Response Characteristics of Neutron Measuring Devices Used for Radiation Protection
Authors: Schraube H. , Chartier J.L. , Cosack M. , Delafield H.J. , Hunt J.B. , Schwartz R.B.
Published: February 2017

The proposals of an ISO working group (ISO-TC85/SC2/WG2) for standardising the procedures to be used for the calibration of neutron measuring devices are summarised. Definitions and techniques are given both for type testing and routine calibration. The aim of the standard is to obtain calibration factors independent of the particular calibration facility or experimental technique employed.
CIRCEG, A Portable Device for Photon-Neutron Dosimetry
Authors: Marchetto A. , Leroux J.B. , Herbaut Y. , Latu M. , Tinelli P.
Published: February 2017

A portable photon-neutron dosemeter has been developed for working area and environmental monitoring. The electronic device called CIRCEG consists of a 256-channel pulse height analyser and a microprocessor system. Associated with a tissue equivalent proportional counter it gives the absorbed dose and the dose equivalent for photons and neutrons in a single measurement. Moreover, it computes the quality factor and displays the microdosimetric distributions in lineal energy (y). The materials, methods and experimental results are described. The range of dose equivalent rates due to neutrons is from 1 µSv.h-1 to 0.1 Sv.h-1.
Measurement of Neutrons from High Energy Electron Linear Accelerators
Authors: Sherwin A.G. , Pearson A.J. , Richards D.J. , O'Hagan J.B.
Published: February 2017

Electron linear accelerators (linacs) above 10 MeV are capable of generating significant neutron fluxes, particularly when operating in the X ray mode. This paper describes a prototype passive, integrating system for neutron measurements, based on the plastic etch-pit technique, and the methodology used to determine neutron leakage from linacs. Results are presented from measurements on several machines, and are compared with those obtained using an established gold activation technique. Close agreement was observed. The results also indicate that neutron leakage may be a function of machine age and state of adjustment.
Clinical Dosimetry of High Energy Neutron Beams: Future Developments
Authors: Mijnheer (INVITED) B.J.
Published: February 2017

Accuracy requirements for the assessment of absorbed dose in a patient irradiated by high energy neutron beams will be formulated by analysing dose-effect curves for local tumour control and for normal tissue complications. Uncertainties in the various steps in the delivery of the prescribed absorbed dose in a patient will then be estimated for both fast neutron and megavoltage X ray beams. At present, even for simple treatment conditions, the proposed accuracy in absorbed dose delivery cannot be fully achieved in photon therapy while fast neutron therapy is even less accurate. Reduction of type A uncertainties can be obtained by an extensive quality control programme, including dosimetry intercomparisons under actual treatment conditions applying dose calculations using the computer planning system. Reduction of type B uncertainties can be obtained by performing dosemeter calibrations directly in neutron beams and by better knowledge of the physical parameters employed in ionisation chamber dosimetry. Recommendations given in the new ICRU Report on Clinical Neutron Dosimetry, and accepted by both US and European groups, will be discussed. With the increasing clinical interest in three dimensional dose distributions, methods for dose calculations have to be refined. Some recent developments for photon beams will be discussed and possible application of these procedures in neutron dosimetry will be indicated.
Dosimetry Research Using Low Pressure Proportional Counters for Neutrons with Energies up to 60 MeV
Authors: Menzel H.G. , Pihet P. , Folkerts K.H. , Dahmen P. , Grillmaier R.E.
Published: February 2017

Low pressure proportional counters (PC) with walls made of A-150 plastic and graphite were used to measure ionisation yield spectra and kerma in radiation fields designed to produce monoenergetic neutrons in the energy range of 20-70 MeV at the Swiss Institute for Nuclear Research (SIN). The investigation at nominal energies of 27.8, 39.7 and 60.3 MeV has shown that the PC is a suitable instrument for dosimetry research in this energy range also. The spectrum information can be used to study absorbed dose build-up in detail. The combined graphite and A-150 measurements were used to evaluate gas-to-wall absorbed dose conversion factors. The kerma ratio of carbon to A-150 follows the shape of curves for theoretical values but is systematically lower. This is explained by a contamination of the beam with low energy neutrons.
Microdosimetric Investigations for Neutron Therapy
Authors: Schmidt R. , Hess A.
Published: February 2017

Microdosimetric investigations are commonly performed to determine the radiation quality of neutron sources applied in radiotherapy. At the DT neutron therapy unit of the University Hospital at Hamburg-Eppendorf, microdosimetric spectra were measured with spherical proportional counters at different positions in a solid tissue-equivalent phantom. Counters with different types of wall materials were used to analyse the spectra with respect to the relative contribution of the different types of charged particles to the total absorbed dose. An iterative procedure usually applied for activation analysis was modified to evaluate RBEs relative to lineal energy functions from radiobiological and microdosimetric data. A set of RBE values obtained with the Withers system at various neutron sources was used together with the corresponding microdosimetric spectra. A second set of data resulting from an earlier biological and microdosimetric intercomparison is used to show the sensitivity of the unfolding procedure to changes in the data base.
Experimental Verification of the Accuracy of A 2-D Dose Calculation Algorithm for A d(8)D2(8) Neutron Beam Incident on Curved Surfaces
Authors: Kuchnir F.T. , Pelizzari C.A. , Reft C.S.
Published: February 2017

The computerised treatment planning algorithm used at the University of Chicago Neutron Therapy Facility is based on linear interpolation of experimental beam data. These were obtained by relative ionisation measurements with a TE chamber in TE solution contained in a large square phantom with the beam incident normally onto a flat surface. Under these conditions, the d(50%) for a beam 12 x 12 cm2 at 105 cm from the target is 10.2 g.cm-2. In the dose calculation algorithm, surface curvature is taken into account by using the ratio of TPRs for the density weighted path lengths for the oblique and central rays. The purpose of this work is to test this calculation approximation by comparing measurements and calculations in a cylindrical, water-filled phantom with variable curvature cross section. Results of measurements and calculations are presented for two beam geometries.
Treatment Planning Comparison of Low and High Energy Neutron Therapy
Authors: Chen G.T.Y. , Reft C. , Spelbring D , Kuchnir F.T. , Rosenberg I. , Sutton H.
Published: February 2017

A treatment planning comparison between rival plans using low and high energy neutron beams in a mixed photon/neutron treatment plan for carcinoma of the prostate has been analysed. Dose volume histograms of critical structures and the target are presented. It is concluded that differences in the composite dose distribution are small when mixed beams are used.
Electrical Charge in Radon Daughter Deposition: A Critical Review
Authors: Marlow (INVITED) W.H.
Published: February 2017

The roles that electric charges play in the various deposition processes of radon daughter atoms has been a matter of conjecture for many years. In this review, several possible effects of charge are described. The sources of cluster ions in indoor air and their attachment to aerosol particles are then considered. Since the 'background' aerosol is central to the questions of deposition, its physical behaviour is discussed in the context of charge attachment and other properties. Data from experiments on decay product neutralisation during the first few seconds after birth, room air interactions from several different types of experiments, and deposition following inhalation are then reviewed. The interpretation of these experiments is given and directions for research needed better to identify critical issues are isolated.
Human Population Exposure to Cosmic Radiation
Authors: Bouville A. , Lowder (INVITED) W.M.
Published: February 2017

Critical evaluations of existing data on cosmic radiation in the atmosphere and in interplanetary space have been carried out in order to estimate the exposure of the world's population to this important component of natural background radiation. Data on population distribution and mean terrain heights on a 1 x 1 degree grid have been folded in to estimate regional and global dose distributions. The per caput annual dose equivalent at ground altitudes is estimated to be 270 µSv from charged particles and 50 µSv from neutrons. More than 100 million people receive more than 1 mSv in a year, and two million in excess of 5 mSv. Aircraft flight crews and frequent flyers receive an additional annual dose equivalent on the order of 1 mSv, though the global per caput annual dose equivalent from airplane flights is only about 1 µSv. Future space travellers on extended missions are likely to receive dose equivalents in the range 0.1-1 Sv, with the possibility of higher doses at relatively high dose rates from unusually large solar flares. These results indicate a critical need for a better understanding of the biological significance of chronic neutron and heavy charged particle exposure.
Contribution to the Study of Portuguese Population Exposure to Gamma Radiation
Authors: Vaz Carreiro J. , Mateus do Amaral E. , Severo A.
Published: February 2017

The initiation and development of a programme of surveying gamma radiation in Portugal is reported. Outdoor measurements of gamma radiation levels were carried out all over the country, contributing first estimates towards the establishment of a radiological map. Three specific regions were studied in more detail. One of them is well known as a high background area where uranium mines are in operation and the other two are related to sites selected for the installation of nuclear power plants. Indoor measurements in dwellings were made in two specific areas, Distrito de Viseu and Distrito de Braganca, respectively, of high and medium radiation levels. These values are insufficient to give a complete picture of the population exposure but they give an overview of the average dose rates in the country and an estimate of the average population doses for two particular regions.
Radon Inhalation Studies in Animals
Authors: Cross F.T.
Published: February 2017

A summary of updated biological effects data resulting from chronic radon inhalation exposures of animals is presented. Emphasis is placed on the carcinogenic effects of radon and radon decay products, including the influences of radon progeny exposure rate, unattached fraction and disequilibrium, and co-exposures to other pollutants. Plausible values are provided for the radon (radon progeny) lifetime lung cancer risk coefficients.
A Generalised Formulation of Microdosimetric Quantities
Authors: Kellerer (INVITED) A.M.
Published: February 2017

The microdosimetric quantities energy imparted, lineal energy, and specific energy are defined with reference to certain volumes but are quantified in terms of frequency distributions of possible values without regard to spatial interrelations. Computer simulations of the patterns of energy deposits seem, therefore, only loosely related to the microdosimetric distributions. In a more general formulation one treats the specific energy and the related microdosimetric quantities as point functions; one deals then with the spatial distribution of their random values and not merely with the frequency of different values. A further extension of the formalism admits reference regions of vanishing size; the inchoate distribution of energy deposits is then the limit case of specific energy. The definitions are related to Matheron's concept of the regularisation of a spatial variable; this is a convolution process that permits a flexible mathematical treatment. One resulting possibility is the definition of specific energy with reference not to the conventional geometry of a sphere or a cylinder but to a disperse region of support. This extension provides distributions of specific energy that are relevant to diffusion or transport processes and it can help to free biophysical models from a one-sided fixation on the concept of geometric targets. The formalism is applied also to the definition of the proximity functions and the related spatial autocorrelation functions.
Modelling of Alpha Particle Induced Soft Errors in Dynamic Random Access Memories (DRAM)
Authors: Haque A.K.M.M. , Stevens D.S. , Al-Affan I.A.M.
Published: February 2017

In order to model the alpha-particle-induced soft error phenomenon in Dynamic Random Access Memories (DRAM), analytical methods of Bradford, and Pickel and Blandford have been used to calculate the chord length distribution in rectangular sensitive volumes, which are then compared with those for cylindrical volumes given by Charlton et al (Monte Carlo). Soft error rates (SER) for an alpha flux density of 10-4 particles µm-2.s-1 incident on a 256K DRAM have been calculated for a set of funnelling lengths in the range of 1.5 - 4.5 µm, and compared. The experimental values are well within the range of the computed SERs, the methods for which need further development.
Simulation of Space and Time Evolution of Radiolytic Species Induced by Electrons in Water
Authors: Terrissol M. , Beaudré A.
Published: February 2017

We present results obtained with Monte Carlo type codes able to calculate the space and time distributions of the radicals and the molecular products resulting from the water radiolysis between 10-15 and 1 s: e-aq, OH, H, H3O+, H2O2, OH-, H2, HO2. These basic data may then be used to carry out radiophysical, radiotherapic, microdosimetric or radiobiological applications or investigations.
Comparison of Particle Tracks Calculated by Monte Carlo Computer Codes with Experimental Tracks Observed with the Harwell Low Pressure Cloud Chamber
Authors: Briden P.E. , Holt P.D.
Published: February 2017

Photographs of the droplets associated with the ionisations caused by charged particle tracks in the Harwell low pressure cloud chamber have been analysed. The radiation types these represent are alpha particles, protons and low energy X rays (carbon and aluminium) in either tissue-equivalent gas or water vapour. The tracks were used to test the validity of two Monte Carlo codes developed by Wilson and Paretzke, namely MOCA14 for the generation of proton and alpha particle tracks, and MOCA8 for the generation of electron tracks. The comparisons showed that the code MOCA14 would appear to be valid for protons with energies greater than about 390 keV, and for alpha particles with energies greater than 1.6 MeV. No disagreement was found between the low energy X ray tracks from the cloud chamber and the tracks calculated from MOCA8, although this comparison was severely limited by droplet diffusion.
Radiosensitivity Parameters for Cancer-like Biological Endpoints in Some Mammalian Cell Cultures
Authors: Waligorski M.P.R.
Published: February 2017

Radiosensitivity parameters of Katz's cellular track structure model have been evaluated for oncogenic transformations and survival in C3H 10T1/2 cells from the data of Hei et al (1988), and for chromatid exchanges, abnormal metaphases and survival in CH2B2 cells, from the data of Skarsgard et al (1967). Model predictions for transformations and survival in the C3H 10T1/2 mammalian cell line after neutron irradiations are compared with the experimental data of Miller et al (1988, 1989).
Measurements of Quality Factors and Dose Equivalents with CIRCE Inside the Soviet Space Station MIR
Authors: Nguyen V.D. , Bouisset P. , Akatov Y.A. , Petrov V.M. , Kozlova S.B. , Siegrist M. , Zwilling J.F.
Published: February 2017

During the French-Soviet space mission 'Aragatz', the experiment CIRCE (Computer Intégrateur de Rayonnement Complexe dans l'Espace) recorded the dose rate and quality factor values inside the MIR station. This paper presents results obtained with a new active dose equivalent meter based on microdosimetric techniques and using a low pressure tissue-equivalent proportional counter. In terms of lineal energy the CIRCE device works in the 0.2 - 1200 keV.µm-1 range in tissue. Preliminary studies were performed in photon, neutron and heavy ion beams, and in the real stratosphere cosmic radiation field. Long-term measurements on board the MIR station from December 1988 to April 1989 gave an average quality factor value equal to 1.9 ± 0.3. Through the South Atlantic Anomaly (SAA), the quality factor was equal to 1.4. The temporal orbital variations of the dose rates and quality factors have been established in space dosimetry for the first time.
Microdosimetry of Radon and Radon Daughters
Authors: Caswell R.S. , Coyne J.J.
Published: February 2017

We have developed an analytical method for calculations of slowing down spectra (fluence rate spectra) and lineal energy spectra for radon and its important alpha emitting daughters, 218Po and 214Po. We have also made calculations of microdosimetric parameters and quality factors for radon-related alpha particles. The y spectra show some increase in average values of y with cell depth.
Point Defects and the Pre-Dose Effect in Quartz
Authors: Yang X.H. , McKeever S.W.S.
Published: February 2017

The thermal annealing properties of (H3O4)0 centres in single crystal SiO2 were studies by means of electron spin resonance (ESR). The data indicate that these centres take part in the TL process at 110 oC in this material. The mechanism suggested for this TL signal is the thermal release of electrons from (GeO4)- centres and their recombination with holes trapped at (A104)0 and (H3O4)0 centres. We have also monitored the radiation-induced infra-red absorption bands in order to examine the thermal stability of A10H centres. Correlations between the A10H annealing curves and the pre-dose thermal activation curves indicate that hydrogen impurities are mobile in the quartz lattice during the pre-dose activation sequence.
Self Optical Attenuation Coefficient of TL Glow in BeO Detectors
Authors: Lembo L. , Pimpinella M. , Mukherjee B.
Published: February 2017

Thin ceramic pellets of BeO are now being used in many institutions as cheap, reliable, personnel monitoring dosemeters. Morphologically, in contrast to LiF TLDs, the BeO detectors have an opaque microporous, and hard ceramic constitution. It is evident that during the readout of BeO chips, exposed to gamma rays, where the TL emission centres are uniformly distributed throughout the bulk of the detector, a substantial amount of TL output is absorbed inside the chip. The present paper describes the experimental procedure for the determination of the self-absorption coefficient of TL light in the Be0 Thermalox 995 detectors. The results show that the self absorption effect should be considered when comparing the TL readouts measured with BeO detectors of different thickness.
MOS Structure for Emergency Gamma and Proton Dosimetry
Authors: Litovchenko P.G. , Barabash L.I. , Rosenfeld A.B. , Khivrich V.I. , Zinets O.S. , Kuts V.I. , Marusan I.A. , Petrov V.I. , Sluchenkov G.F. , Koval G.N. , Fominych V.I. , Belovodskiy L.F. , Dumik A.I. , Kiblik V.Ya.
Published: February 2017

Effect of gamma and proton irradiation on threshold voltage shift ? VT for n-channel MOSFET has been studied. For MOSFET with zero gate bias during gamma irradiation the shift ? VT is linear with dose D? (up to doses of 10 Gy) and the sensitivity ? VT/D? is approximately 120 mV.Gy-1. The sensitivity of MOSFETs with positive gate bias Vg during irradiation varies as Vg  2/3 and no saturation is observed up to breakdown voltage. n-MOSFETs with bias of 100 V have the sensitivity of approximately 5 V.Gy-1. When n-MOSFETs are irradiated with 50 MeV protons the shift ? VT varies as Dp  0.67 (for proton doses Dp ranged from 0.2 to 900 Gy). The positive charge storage in oxide is shown to contribute mainly to the radiation sensitivity of n-MOSFETs investigated.
Lyoluminescence in a Non-Aqueous Medium
Authors: Dixon S.M. , Ettinger K.V.
Published: February 2017

Lyoluminescence of mannose in water has been compared with that in water-methanol mixtures and in pure methanol. The light yield is larger in methanol by a factor, dependent upon the dose, which can reach 20 times. The yield in methanol increases with the temperature of the solvent. The nature of the dose response curve and the onset of saturation are the same. The fading on storage is faster for readout in methanol.
Optimisation of LiF:Cu,Mg,P for Radiation Protection Dosimetry
Authors: Horowitz A. , Horowitz Y.S.
Published: February 2017

The results of our investigations of various parameters of the preparation procedure of thermoluminescent LiF:Cu,Mg,P are reported. The parameters under investigation are: (i) the relative concentration of the incorporated Mg, Cu and (PO4)-3 dopants; (ii) the influence of incorporation of oxygen; (iii) particle size distribution of the prepared powder samples; (iv) emission wavelength; (v) high temperature '300 oC, 10 min' pre-irradiation annealing. Incorporation of oxygen in the molten stage plays an essential role in the creation of thermoluminescence: 0.5 mol.% oxygen leads to a TL material with approximately twenty times the intensity of TLD-100. We also find that the relative intensity of the undesirable high-temperature TL (270 oC) shows no apparent correlation with oxygen or other dopant concentrations. The loss in TL sensitivity following 300 oC, 10 min annealing shows similar behaviour.
Relative Thermoluminescent Efficiency of LiF:Cu,Mg,P to Alpha Particles: Theory and Experiment
Authors: Horowitz Y.S. , Stern N.
Published: February 2017

The relative thermoluminescent response of LiF:Cu,Mg,P to 4 MeV alpha particles has been calculated theoretically using the convolution of the radial dose around the alpha particle track with the gamma generated TL dose response function, with the result ?a? = 0.04 ± 0.01. Experimentally, the alpha particle generated TL signal was measured with the irradiated side both facing and away from the photomultiplier in order to measure TL light self-absorption with the result µd = 1.32 ± 0.03 (1 SD), and ?a? = 0.065 ± 0.01 in reasonable agreement with theory and previous measurements of the fast neutron relative TL response. The very low sensitivity of LiF:Cu,Mg,P to high LET particles is a microdosimetric effect arising from the very rapid saturation of the TL signal at high ionisation density.
LiF(Mg,Cu.P) Thin Dosemeter for Skin Dose Measurement
Authors: Fang W. , Ziying Z. , Jian L. , Zhongmei Z.
Published: February 2017

The thin dosemeter is composed of 5 mg.cm-2 of LiF(Mg,Cu,P) powder bonded to a base tape of polyimide with organosilicon adhesive and covered by a 5-7 mg.cm-2 black film of polyethylene. The elements can be annealed at 240 oC and re-used more than 10 times with an uncertainty of 3-4%(1 SD). Its detection threshold is 30 µGy which remains unchanged after irradiation by a large dose of up to several Gy. The TL material utilised has good gamma energy response, whilst experiments indicate a relative response to beta rays from 147Pm, 204Tl and 90Sr-90Y of 0.38, 1.01 and 1.00 respectively. The background signal from the elements is equivalent to less than 150 µGy. The variation of the TL signal of the detector for exposure to 60Co ? rays at different angles of incidence of the radiation is within 4%. The dosemeters show satisfactory environmental stability and the elements can be used with general TL readers without need of any special design and operated manually.
Use of Solid State Nuclear Track Detectors in National Radiation Protection Monitoring Programmes
Authors: Guhr A. , Kraus W. , Rimpler A. , Sarenio O. , Lehmann R.
Published: February 2017

In the National Board of Nuclear Safety and Radiation Protection of the GDR solid state nuclear track detectors (SSNTD) have been used routinely both for individual neutron dosimetry and for long-term measurements of radon and radon daughter products in flats and in the environment. For neutron monitoring a fission track dosemeter is used for the simultaneous response to fast and intermediate neutrons, using Makrofol KG as a detector. The long-term dosemeter for registering radon and radon daughter products is based on the diffusion chamber principle. Makrofol DE 1-4 of 300 µm thickness is used as the detector. Detector evaluation and calibration methods are described in detail and detection limits are stated. In addition, a screening measuring method based on CR-39 is presented, allowing the rational performance of long-term measurements by radon diffusion chambers.
Relationship of Anomalous Fading to Feldspar Inclusions in Quartz
Authors: Fragoulis D. , Stoebe T.G.
Published: February 2017

The potential relationship between feldspar inclusions and anomalous fading in quartz is examined. Using scanning electron microscopy and electron microprobe observations, feldspar inclusions are observed to occur in natural quartz grains taken from a variety of locations. Anomalous fading in these samples is compared with the fraction of feldspar inclusions. The results indicate that the feldspar inclusions probably account only for a portion of the observed fading. The results also indicate than an HF etch is not necessarily reliable for the removal of feldspars from quartz samples.
The IAEA Intercomparison for Individual Monitoring
Authors: Griffith R.V. , Böhm J. , Herrman D. , Strachotinsky C. , Thompson I.M.G.
Published: February 2017

In 1985 the International Commission on Radiation Units and Measurements introduced a new set of operational quantities for radiation protection purposes through Report 39. A significant amount of additional information about these quantities was presented at the end of 1988 in ICRU Report 43. The International Atomic Energy Agency has been concerned with the impact of possible adoption of these quantities by its 113 Member States. In an effort to assess the potential degree of impact, and to begin defining recommendations for calibration procedures using the new quantities, the Agency implemented a Coordinated Research Programme on Intercomparison for Individual Monitoring in 1987. The first phase completed with a Research Coordination meeting of the participants in April, 1989. Photon exposures were provided at 11 energies over a range from 18 KeV to 1.25 MeV at three standards laboratories in Austria, the GDR and the UK. Technical coordination was provided by the PTB, Braunschweig. Twenty one laboratories from 19 countries participated with film, TLD of various types, and combination dosemeters. Irradiations were performed on the IAEA 30 cm cubic, water-filled phantom that is in use throughout its network of 61 Secondary Standard Dosimetry Laboratories. Conversion coefficients for the IAEA phantom were calculated by the PTB and confirmed through measurements at ASMW in the GDR. Preliminary results indicated that the type of dosemeter (film or TLD) had little effect on the quality of results. The most important factor appears to be the specific techniques used for data interpretation.
Analysis of Beta Radiation Fields in the Fuel Cycle
Authors: Burgkhardt B. , Piesch E. , Vilgis M.
Published: February 2017

Depth-dose distributions have been measured in typical beta-photon radiation fields of the fuel element cycle using TL detectors and shielding layers of varying thickness in source-to-detector distances between 5 cm and 80 cm. Five representative beta contaminants namely 58CO, 60Co, 124Sb, 106Ru/106Rh, 234Th/234Pa have been found. An analytical approach takes into account the absorption of low beta radiation within the detector thickness and in the air in order to assess the dose equivalent distribution as a function of tissue depth for any source-to-detector distance. Typical data are presented for the dose quantities (H'(0.07), H'(10) and for the relevant dose equivalents in the gonads and the lens of the eye.
Some Characteristics of the AEOI Neutriran Albedo Neutron Personnel Dosemeter
Authors: Sohrabi M. , Katouzi M.
Published: February 2017

The Neutriran Albedo Personnel Neutron Dosemeter (NAPND) is based on the combination of a sensitive polymer such as polycarbonate (PC) in contact with 6LiF or 10B pellets in a cadmium cover. By adding a 10B pellet in front, the design of the dosemeter can be such that when worn on the body, direct thermal neutron induced alpha tracks (TNIAT), albedo neutron induced alpha tracks (ANIAT) and fast neutron induced recoil tracks (FNIRT) can be simultaneously detected in a single electrochemically etched PC foil. To establish a national personnel neutron dosimetry service in Iran, different parameters such as the effect of 10B(n,a)7Li convertor thickness. Cd thickness and its diameter, dosemeter distance from the phantom, dosemeter angle with phantom and directional response were studied using different phantoms. Under optimised conditions, a sensitivity of 1500 tracks.cm-2.mSv-1 for 252Cf neutrons with a lowest value of 0.05 mSv was measured. The results of these studies are reported and discussed.
The Active Personnel Dosemeter - Apfel Enterprises Superheated Drop Detector
Authors: Ipe N.E. , Donahue R.J. , Busick D.D.
Published: February 2017

The Active Personnel Dosemeter (APD) provides a digital readout of events caused by neutrons interacting with superheated liquid droplets. The droplets are suspended in a gel held in a replaceable cartridge. Upon neutron interaction, the superheated droplet vaporises, forming a bubble. The sound produced in this process is recorded by transducers that sense the accompanying pressure pulse. The APD electronically discrimates against spurious noise and vibration. Studies with the production prototype APDs indicate that the detector response is linear up to about 0.40 mSv, with large variations sometimes from predicted values and between cartridges at higher dose equivalents. The response to standard neutron sources (bare 252Cf, Pu-Be, Pu-B, Pu-F, Pu-Li) is reported and compared with the expected response. Unirradiated cartridges self-nucleate when heated to temperatures of 46 oC. The APD is insensitive to low energy photons but responds to high energy photons and electrons.
Environmental Alpha and Gamma Survey
Authors: Segovia N. , Gaso M.I. , Chavez A. , Tejera A. , Gutierrez A. , Azorin J. , Balcazar M. , Lopez A. , Tamez E. , Cervantes L. , Monnin M.
Published: February 2017

Radon data in soil and gamma and radon levels in air have been obtained for several years at the site of a Nuclear Research Centre and at a Radioactive Waste Storage Facility. Radon detection was carried out with SSNTD while for gamma levels TLD was used. Cross checking of gamma levels in air using gamma scintillation counting was also performed. The results obtained at the site of the Nuclear Research Centre showed a stability over time in the local average radioactive environment except for seasonal fluctuations essentially due to meteorological parameters which were continuously recorded. Results obtained at the Radioactive Waste Storage Facility indicate average gamma levels in air of 0.2 µGy.h-1 for most of the monitoring stations. One station with a higher radioactivity level was systematically observed. Measurements of radon in air up to 150 cm indicate a rapid dilution in the atmosphere.
Determination of the Dose Distribution of an Ophthalmic 106Ru Irradiator with TLDs and an Eye Phantom
Authors: Binder W. , Chiari A. , Aiginger H.
Published: February 2017

Two 106Ru applicators of the type CCB as manufactured by the Zentralinstitut für Isotopen- und Strahlenforschung (Berlin, GDR) were investigated. The homogeneity of the relative dose distribution at the surface of the applicators was determined. For the evaluation of the data extremely small TLD crystals (2x1x1 mm3) had to be manufactured as well as an almost tissue-equivalent acrylic eye phantom. In order to ensure reproducibility of the applicator positioning, the plaque suture eyelets had to be placed on locating pins. 120 measurement points located within the active plaque area of 20 mm diameter were evaluated. The results show that the area to be used in tumour treatment is about 20 to 25% less than expected. One plaque shows a considerable inhomogeneity with respect to dose distribution (up to 40%). A modified eye phantom was used for the determination of the central axis depth dose distribution.
Uncertainties in Dose Estimation Under Emergency Conditions and ESR Dosimetry with Human Teeth
Authors: Nishiwaki Y. , Shimano T.
Published: February 2017

There are uncertainties in estimating dose-effect relationships under emergency conditions. There may be a number of other noxious effects such as infection, various toxic substances and non-ionising radiations, in addition to radiological uncertainties, and also mental aspects. Therefore, the possibility of the combined effects of all direct factors and the indirect factors must be considered in interpreting the effects of a radiation accident, instead of ascribing all the effects solely to ionising radiation. The exact dose to a particular person is difficult to estimate, but is is also necessary to have some direct measurement of individual dose in order to confirm dose-effect relationships due to radiation. As a method of confirming the individual dose under emergency conditions, ESR dosimetry of tooth enamel has been carried out, not only to estimate the dose, but also to estimate the incident angle of radiation.
Thermoluminescent Dust for Identification of Irradiated Spices
Authors: Göksu H.Y. , Regulla D.F. , Hietel B. , Popp G.
Published: February 2017

It is shown that most of the natural products contain minute amounts of wind blown or intruding dust which can be separated and used to identify irradiated spices by measuring its thermoluminescence (TL). The method has several advantages over the use of the whole grains of spices. There is no spurious signal due to oxidation of the organic components, therefore the samples can be heated to higher temperatures at which more stable TL peaks are accessible. As a consequence, the method provides (1) high reliability in indentification, (2) an access to a quantitative assessment of the administered dose even after some years, (3) determination of the time elapsed between the food irradiation and the TL readout. Thermoluminescent dust obtained from cumin, green pepper, sage, rosemary, mugwort, lovage, thyme, dill weed, oregano, savory, marjoram and basil is investigated.
Use of Thermoluminescence Detectors in National Radiation Protection Monitoring Programmes
Authors: Kraus W. , Will W. , Buchröder H. , Edelmann B. , Schwedt J.
Published: February 2017

Thermoluminescence detectors have been used in national radiation surveillance programmes in the GDR for more than 15 years. The detectors and dosemeters used for individual monitoring (whole body or hand exposures), for selected workplace studies, for environmental monitoring and for monitoring of radon daughter product concentrations are described. Experience with the routine application of the dosimetric systems and prospects for further development, particularly of a microcomputer controlled automatic TL reader, are discussed.
Optical Absorption and Thermoluminescence in Natural Beryl
Authors: Blak A.R. , McKeever S.W.S.
Published: February 2017

Ultraviolet (UV) illumination of colourless beryl (goshenite) produces a single photo-induced TL peak centred at 150 oC which becomes prominent for illumination wavelengths between 230 and 240 nm. Optical absorption (OA) spectra have been measured from 350 to 190 nm. The effect of thermal treatments in the range 600 to 900 oC was monitored for both thermoluminescence (TL) and OA. In the OA spectra a general decrease in the absorption at all wavelengths was observed at the beginning of the treatments, with no further changes occurring for longer periods of time. Similar behaviour was observed for the TL curves. The sensitvity of the 150 oC goshenite glow peak is strongly enhanced when the sample, which was previously heated to 900 oC for less than 30 min, is exposed to UV light. For periods of time of more than one hour, the TL signal, for all the thermal treatments performed before UV illumination, becomes equally low. It is known from electron paramagnetic resonance (EPR) measurements that atomic hydrogen in interstitial sites is produced in UV-illuminated goshenite from the dissociation of OH- ions. The free hydrogen diffuses through the lattice, being stabilised by traps. When the material is heated the trapped hydrogen atoms become free to move and are captured by oxygen atoms, which act as recombination centres. In this work an attempt is made to correlate the Ho EPR line and the TL peak. OA and TL measurements have also been carried out on pink beryl (morganite). Different TL and OA spectra from the goshenites are observed since these samples contain different amounts and types of impurities.
Ultra-Low Dose (100 nGy - 100 µGy) Response of Alpha-Al2O3:C
Authors: Moscovitch M. , Kaufman M.M. , Rodgers J.E. , Niroomand-Rad A.
Published: February 2017

The thermoluminescence dose response of a-Al2O3:C at ultra-low dose levels (100 nGy - 100 µGy) has been measured. It has been shown that computerised glow curve deconvolution (CGCD) can be applied to the glow curve of a-Al2O3:C using two Gaussian peak shape functions, to fit the main peak, superimposed on a linear background term. The CGCD analysis interpolates the background signal under the main peaks, eliminating the need for second readout. It has been demonstrated that with the background subtraction and by eliminating any possibility of the material being exposed to light, dose measurements down to 300 nGy are possible.
TL Peak Structure of MgB4O7:Dy
Authors: Souza J.H. , Ferrari V.A. , de Freitas L.C.
Published: February 2017

MgB4O7:Dy is usually reported as having one dosimetric peak. Two sets of experimental studies followed by computer analysis of more than 200 glow curves indicate that a combination of at least 11 peaks of first order kinetics is necessary to describe the glow behaviour of MgB4O7:Dy. For a heating rate of 1 oC.s-1 the maximum intensity of the individual peaks are situated at the following temperatures: 101, 110, 126, 142, 155, 160, 173, 192, 224, 231 and 304 oC.
ESR Dosimetry
Authors: McLaughlin (INVITED) W.L.
Published: February 2017

The demonstration 30 years ago that the amino acid, alanine, could serve as a solid dosemeter by electron spin resonance (ESR) spectrometry, has led to a fascinating success story. Radiation-induced paramagnetic centres, the de-aminated free radicals associated with unpaired electrons, are stable during and after irradiation. The free radical concentration proportional to the absorbed dose can be measured as the main peak-to-peak amplitude of the first derivative of the ESR absorption spectrum. In addition to alanine, other solids (e.g. certain sugars and polymers, quartz, bone) may be used to cover a broad range of absorbed dose, 10-108 Gy. Indeed, efforts proceed to improve the sensitivity, accuracy, and precision of ESR dosimetry. Advantages include the ability to simulate biological tissues in terms of radiation absorption properties, small size (e.g. thin films and small pellets), the possibility of in vivo dosimetry, ruggedness, stability, and resistance to environmental and dose rate effects.
Application of Thermoluminescence Dosimetry in the Exploration for Oil and Gas Using Chinese GR-200 LiF (MG,Cu.P) TLD
Authors: Wang Z. , Qin D. , Zhuang G. , Zha Z. , Wang S. , Shen W. , Cai G.
Published: February 2017

Radiometric methods have been used in exploration for oil and gas by the Institute of Geophysical and Geochemical Exploration (IGGE) since 1984. More than 20,000 km2 of regional survey and 2,000 km2of detailed survey on the surface have been covered successively by this method. As a result, the distribution pattern of abnormal radiometric fields over oil and gas fields is confirmed by cavity gamma thermoluminescence dosimetry, which is an ideal radiometric accumulation measurement technique in searching for oil and gas. GR-200 LiF(Mg,Cu,P) dosemeters made in China are suitable detection elements. A thermoluminescence anomaly delineated survey over an oil field in comparison with drilling results, shows the advantages of this method in that 91% of dry holes or wells with water are outside the anomaly, and 61% of oil wells are inside the anomaly.
An Algorithm for Supralinearity Correction Applied to Radiation Therapy Thermoluminescence Dosimetry
Authors: Moscovitch M. , Taylor P.L. , Rodgers J.E. , McRae D.A.
Published: February 2017

A dose calculation algorithm for correcting the supralinear response of LiF:Mg,Ti (TLD-100) at radiation fields and dose levels typical to radiation therapy applications was developed. The TL dose response of TLD-100 was measured at various tissue depths up to 100 Gy using both photons and electrons in the energy range 6 to 18 MeV. It has been shown that the supralinearity correction factor can be applied in all cases using a single parameter B as follows: D = D0/(1 + D0B); D0 is the uncorrected reported dose and D is the dose following supralinearity correction. The 'best-fit' values of B for the data at various radiation fields and depth are reported. The accuracy of the method has been demonstrated to be within 1.5-4.0%.
Thermoluminescence Dosimetry at High Temperature and High Doses
Authors: Barthe J. , Hickman C. , Heindl R. , Portal G.
Published: February 2017

The increasingly wide spread use of electronuclear energy has led to the need for an improved knowledge of the radiation doses received by various structural materials. Dose rates are particularly high in regions in the vicinity of the core of a reactor, steam generators and the pool in which spent fuel elements are stored; high dose rates will also be encountered at high-level waste disposal sites. In most, involving gamma radiations resulting from the de-activation of fission products, thermal conditions can be problematic: temperatures as high as 300 oC can be reached inside the core or steam generators. Preliminary tests performed in high-level waste disposal environments suggest that similar temperatures are likely to be reached. Thermoluminescence (TL) dosimetry can be employed if certain conditions are satisfied: the TL products must possess at least one deep trap and must also be sensitive over a sufficiently wide dynamic range. The following materials have been investigated for this purpose: dysprosium doped calcium sulphate powder, alumina and cerium doped ceramic glasses. The maximum dose measurable depends on the material employed and ranges from a fraction of a kilogray for alumina, to a few kilograys for calcium sulphate and cerium doped glasses. A comparative study of the various available products has been performed in order to define the limits and to optimise their use.
Study of TL Response in Heavily Irradiated Rock Salt
Authors: Ortega X. , Dies X. , de las Cuevas C.
Published: February 2017

Within the framework of the CEC R&D Programme 'Management and Storage of Radioactive Waste', the study of the generation of radiation damage in heavily irradiated rock salt is being carried out. This work describes the experiments carried out for the validation of the TL techniqus, in the assessment of the phenomena related to the energy absorbed by the rock salt, due to the high levels of irradiation. The samples analysed are natural rock salt coming from the Sallent mine (Spain). The chemical composition of the rocks is, in all cases, higher than 90% NaCl, having small amounts of SO4, Mg, K, Br and Sr as major impurities. A first set of irradiations was performed at the laboratory with a source of 137Cs. The doses reached were lower than 20Gy. A second set of irradiations was performed at an industrial facility with a source of 60Co, achieving doses up to 2.5 MGy. Afterwards the irradiated samples were analysed with TL and optical absorption techniques. The results have facilitated a study of the glow curves, their evolution in time and the influence of the chemical composition, the absorbed dose, and the absorbed dose rate. These experiments have increased knowledge of the behaviour of heavily irradiated rock salt.