Radiation Measurements

In this work the Full-Energy Peak Efficiency (FEPE) o f NaI(Tl) -scintillation detectors (5.08x5.08 cm 2 and 7.62x7.62 cm 2 ) values are calculated for coaxial cylindrical sources with radii greater than the detectors faces rad ii. Th is was calculated by the effect ive solid angle method, taking into account the source self-attenuation effect. In the experiments the gamma sources that contain several radionuclides covering the energy range from 59.52 to 1408.01 keV were used. By comparison, it was found that the theoretical and the experimental FEPE values are in a good agreement.

Thermal stability as well as recuperation stands among the crucial general characteristics of different OSL components in quartz. Through a series of thermal stability and recuperation experiments, in conjunction with curve fitting studies, a component resolved analysis is carried out, studying these two aspects for the OSL components identified in quartz samples collected from sites around Istanbul. A thermally unstable ultra-fast component is reported, which is almost totally removed by heating up to 250.280 • C. Most slow and medium components show a stability temperature region between 200 and 350 • C, whereas the thermal stability of the final slow component is limited up to almost 300 • C. No detectable recuperation occurs for the first five components reported. The greatest recuperation occurred in the sixth component, despite the fact that it was less than 1%.

The high-temperature ratio (HTR) is a parameter quantifying changes of the shape of the high-temperature part of the LiF:Mg,Ti glow-curve after exposure to densely ionizing radiation. It was introduced in order to estimate the 'effective LET' of an unknown radiation field and to correct the decreased relative TL efficiency for high-Linear Energy Transfer (LET) radiation. In the present work the dependence of HTR on proton energy (14.5 -58 MeV) and dose (0.5 -30 Gy) was investigated. All measured HTR values were at the level of 1.2 or higher, therefore significantly different from the respective value for gamma-rays (HTR=1), but HTR was found to be insensitive to changes of proton energy above 20 MeV. As a result the relationship between HTR and relative TL efficiency is not unequivocal. The HTR was found to be dependent on absorbed dose even for the lowest studied doses.

The thermal to epithermal neutron flux ratio ƒ, epithermal neutron flux shape factor α, thermal neutron flux th  , and epithermal neutron flux epi  in the irradiation channels of the Malaysian Nuclear Agency research reactor were re-determined after a core reconfiguration to guarantee accuracy in applications the of k0-neutron activation analysis (k 0 -NAA) method. The ƒ and α parameters were determined using bare biisotopic monitor and bare triple-monitor methods, respectively, and Au and Zr monitors were used in 30 rotary rack (RR) irradiation channels. It was found that ƒ was between 14.82 and 24.67 and that α ranged from 0.0011 to 0.0672. Average values of th  and epi  were determined to be (2.15 ± 0.25) × 10 12 and (1.20 ± 0.20) × 10 11 cm -2 s -1 , respectively. The results were compared to those of previous studies at the MNA reactor and those of similar reactors in other countries. The accuracy of the method was evaluated by analysing ERM-DB001 human hair reference materials. The results showed an adequate level of consistency.

Applicability of two-dimensional thermoluminescence slab dosimeter based on Al2O3:Cr for the quality assurance of robotic 1 radiosurgery 2 ○Yanagisawa Shin (1), Shinsho Kiyomitsu (1), Inoue Mitsuhiro (2), Koba Yusuke (3), Matsumoto Kazuki (4), Ushiba Hiroaki (4), 3 Andoh Takayuki (5) 4

Spatial radionuclides distribution was studied in recent estuarine sediments in the Krka River Estuary. Sediment samples were analyzed for 40 K and 232 Th by gamma-spectrometry. Activities of 40 K were found in the range of 18-457 Bq kg -1 and activities of 232 Th in range of 1.9-29.4 Bq kg -1 . Distribution of 232 Th activities follows that of 40 K, with correlation coefficients higher than 0.97 in all analyzed samples from the Krka River estuary. Spatial distribution of natural radionuclides ( 40 K and 232 Th) in recent estuarine and marine sedimentation area can be a useful tool for recognizing the possible input of terrigenous material, as well as for fast locating of the area where such material is predominantly settled. Krka River Estuary sediments radionuclide distribution gamma-spectrometry 40 K 232 Th * Dedicated to the memory of the late Professor Marko Branica.

In this paper we report the results of comparative EPR studies on free radicals generated in γ-irradiated powder samples of feather keratin powder and human fingernails. In degassed samples of both materials irradiated at 77 K the major component of EPR spectrum represents sulphur-centred radicals in cysteine residues. It quickly decays after air admission at room temperature while a singlet assigned to semiquinone melanin radicals remains the only one seen. The singlet recorded with fingernails decays slowly at room temperature and might be potentially useful for dose assessment by EPR. The advantages and limitations of fingernails EPR dosimetry are discussed.

At the Dalat Nuclear Research Reactor (DNRR) in Vietnam, some calculations and experiments of the Boron Neutron Capture Therapy (BNCT) method have been performed at horizontal channel No. 2 of the DNRR using a phantom. This research used the Monte Carlo N-Particle version 5 (MCNP5) code to simulate and calculate the distribution of absorbed dose components of the BNCT method. The collimator of horizontal neutron channel No. 2 of the DNRR was changed from cylindrical to conical to increase the flux of the neutron beam. Simultaneously, neutron crystal filters corresponding to 20 cm Si and 3 cm Bi are also employed to produce high-purity thermal neutron beams. The thermal neutron flux and absorbed dose components have been computed in a water phantom. The gamma dose from the reactor core of the DNRR can be omitted when calculating the total absorbed dose in the BNCT method.

An international intercomparison of whole-body counters with the partici pation of 7 laboratories from 5 member countries was organized in 1976 by the Consultative Scientific and Technical Council for Radiation Protection of the CMEA. The Health Physics Department of the Central Research Institute for Physics also, participated in this intercomparison. The main aim of the par ticipation was to check our calibration method, measuring and evaluation procedures to determine their suitability for routine measurements and to investigate the advantages and drawbacks of applying different measuring geometries and evaluation methods. The final results of the intercomparison including our data in more detail are shown in the paper. The results ob tained for different measuring geometries, evaluation methods and phantom sizes applying a simple calibration procedure are also given. The results show that a simplified calibration method using point sources embedded in an elliptic cylinder shaped scattering medium and a computerized least square fitting procedure in the evaluation of measurements combine to yield a final accuracy of ±15% in the gamma energy range of 250-1500 keV assuming uniformly distributed sources, a wide range of body sizes, and the choice of a particu lar measuring geometry. В соответствии с рабочим планом координационного научно-технического совета по радиационной безопасности /Рабочей группы по радиационной безопас ности/ СЭВ в 1976 году было организовано международное сличение спектромет ров излучения человека с участием 7-и лабораторий из 5-и стран-участниц СЭВ. При проведении сличения принял участие и Главотдел радиационной безопасности ИЛЭ ЦИФИ с той целью, чтобы, с одной стороны, проверить методы калибровки, измерения и оценки, которые считались пригодными для проведения рутинных из мерений, а, с другой стороны, рассмотреть преимущества и недостатки различных геометрических условий измерения и методов оценки. В работе описываются ре зультаты сличения и подробно излагаются результаты наших измерений. Даются также и результаты, полученные в различных геометрических условиях и методов контроля путем простой калибровки для всех фантомов различного размера, под вергнутых измерению. На основе результатов можно установить, что если комбиниро вать мэтоц калибровки с точечным источником -применяя рассеиватель эллиптически-цилиндрической формы -с приближением по методу наименьших квадратов при разложении спектров на ЭВМ, то в случае равномерного распределения точечных источников могут быть получены результаты с точностью + 15% в области энергии гамма-излучения 250-1500 кэв и в широком диапазоне размера тела, независимо от выбранной геометрии измерения. A KGST Sugárbiztonsági Tudományos-műszaki Koordinációs Tanács munkater vében foglaltaknak megfelelően 1976-ban 5 ország 7 laboratóriumának részvé telével egésztestszámlálós összemérést szerveztek. A KFKI Sugárvédelmi Főosz tálya is részt vett az összemérésben azzal a céllal, hogy egyrészt letesztel jük a rutin mérésekre alkalmasnak tartott kalibrációs eljárásunkat, mérési és kiértékelési módszerünket, másrészt megvizsgáljuk különböző mérési geometriák és kiértékelési módszerek előnyeit és hátrányait. A dolgozatban bemutatjuk az összemérés végeredményét, ezen belül részletesen tárgyaljuk a saját mérési eredményeinket. Megadjuk a különböző mérési geometriák, kiértékelési módsze rek által szolgáltatott eredményeket, melyeket egy egyszerű kalibrációs eljá rással az összemérésben szereplő különböző méretű fantomokra nyertünk. Az eredményekből megállapítható, hogy egy elliptikus henger alakú szóróközeget alkalmazó pontforrásos kalibrálás párositva egy legkisebb négyzetes illesztés elvén alapuló számitógépes spektrumdekomponáló eljárással, egyenletes forrás eloszlás esetén megfelelő, mintegy +15%-ra pontos eredményt tud szolgáltatni a 250-1500 keV gamma energia és széles testméret tartományban, függetlenül a mérési geometria megválasztásától.

Searching for gas exhalation around major tectonic contacts raises important methodological issues such as the role of the superficial soil and the possible long distance transport. These effects have been studied on the Xidatan segment of the Kunlun Fault, Qinghai Province, China, using measurement of the radon-222 and carbon dioxide exhalation flux. A significant radon flux, reaching up to 538 ± 33 mBq m -2 s -1 was observed in a 2-3 m deep trench excavated across the fault. On the soil surface, the radon flux varied from 7 to 38 mBq m -2 s -1 , including on the fault trace, with an average value of 14.1 ± 1.0 mBq m -2 s -1 , similar to the world average. The carbon dioxide flux on the soil surface, with an average value of 12.9 ± 3.3 g m -2 day -1 , also remained similar to regular background values. It showed no systematic spatial variation up to a distance of 1 km from the fault, and no clear enhancement in the trench. However, a high carbon dioxide flux of 421 ± 130 g m -2 day -1 was observed near subvertical fractured phyllite outcrops on a hill located about 3 km north of the fault, at the boundary of the large-scale pull-apart basin associated with the fault. This high carbon dioxide flux was associated with a high radon flux of 607 ± 35 mBq m -2 s -1 . These preliminary results indicate that, at the fault trace, it can be important to measure gas flux at the bottom of a trench to remove superficial soil layers. In addition, gas discharges need to be investigated also at some distance from the main fault, in zones where morphotectonics features support associated secondary fractures.

< We demonstrate a new diagnosis method for high energy ions using CR-39. < Ions with energies greater than the detection threshold limit of CR-39 can be detected. < Application to laser-driven ion acceleration experiments identified 50-MeV/u ions.

In the Foundations of Natural Right, Fichte attempts to deduce the reality of the concept of right by beginning with the act of self-positing. He understands right as a transcendental condition for the possibility of self-consciousness. According to Fichte, the concept of right should not be grounded in moral obligation but should instead be based on the relation between rational beings through mutual recognition. However, this deduction has often been criticized as unconvincing. This thesis seeks to defend Fichte’s position by reconstructing the steps of his argument. It argues that the concept of right, understood as a condition for self-consciousness, can be plausibly justified. To support this claim, the thesis analyzes a central concept in the deduction of right, namely the concept of summons. Through the summons, the subject becomes aware of itself. The thesis argues that the summons must possess both normative and causal dimensions in order to support the justification of the concept of right.

Contamination of food and water with radioactive substances is a serious health problem. There are several methods to detect and measure radioactive materials, some of which have been developed in recent years. This paper aims to discuss the methods of detecting and measuring radioactive substances in food and water. The principles and the advantages and disadvantages of each method have been discussed. The results showed that some of these methods, such as spectrometry γ-ray high-purity germanium, portable radon gas surveyor SILENA, RAD7, and inductively coupled plasma mass spectrometry, have a higher sensitivity for detection and measurement. The spectrometry γ-ray high-purity germanium method has attracted more attention than other methods because it can measure a wide range of radionuclides with high resolution.

Post-irradiation stability of high-dose dosimeters has traditionally been an important measurement influence quantity. Though the exceptional stability of the alanine dosimeter response with time has rendered this factor a non-issue for routine work, the archival quality of the alanine dosimeter has not been characterized. Here the alanine pellet dosimeter response is measured up to seven years post-irradiation for a range of absorbed doses. This long-term study is accompanied by an examination of the environmental influence quantities (e.g., ambient light) on the relatively short-term (3-4 month) stability of both pellet and film commercial dosimeters. Both dosimeter types demonstrated exceptional stability in the short term and proved to be relatively insensitive to common influence quantities. The long-term data revealed a complex dose-dependent response trend.

Research and development on alternative thermal neutron detection technologies and methods are nowadays needed as a possible replacement of 3 He-based ones. Commercial solid state silicon detectors, coupled with neutron converter layers containing 6 Li, have been proved to represent a viable solution for several applications as present in literature. In order to better understand the detailed operation and the response and efficiency of such detectors, a series of dedicated GEANT4 simulations were performed and compared with real data collected in a few different configurations. The results show a remarkable agreement between data and simulations, indicating that the behavior of the detector is fully understood.

We present new developments for an ab-initio model of the neutron relative biological effectiveness (RBE) in inducing specific classes of DNA damage. RBE is evaluated as a function of the incident neutron energy and of the depth inside a human-sized phantom. The adopted mechanistic approach traces neutron RBE back to its origin, i.e. neutron physical interactions with biological tissues. To this aim, we combined the simulation of radiation transport through biological matter, performed with the Monte Carlo code PHITS, and the prediction of DNA damage using analytical formulas, which ground on a large database of biophysical radiation track structure simulations performed with the code PARTRAC. In particular, two classes of DNA damage were considered: sites and clusters of double strand breaks (DSBs), which are known to be correlated with cell fate following radiation exposure. Within a coherent modelling framework, this approach tackles the variation of neutron RBE in a wide energy ...

This contribution presents experimental data concerning the inuence of fast heavy ions on magnetic susceptibility of VITROVAC R 6025 and VITROPERM R 800 metallic glasses. Samples of magnetic ribbons were irradiated with Au, and Ta ions at 11.1 MeV/A (energy per nucleon), and U ions at 5.9 MeV/A. The irradiation uences varied from 5 × 10 10 up to 1.2 × 10 13 ions/cm 2 . Relative change of the samples' magnetic susceptibility after and before irradiation was measured and evaluated as a function of the irradiation uence. Measurements were done with a commercial Kappa-bridge device. We observed that VITROPERM R showed less change of magnetic susceptibility in comparison with VITROVAC R and this change occurred at higher uences. This indicates higher radiation hardness of VITROPERM R compared with VITROVAC R against high-energy heavy ions. In addition, heavier ions caused larger change of magnetic susceptibility than the lighter ones and the eect could be roughly scaled with the level of electronic stopping.

Astronauts are exposed to high-energy cosmic radiation which may have harmful health effects. At the altitude of the International Space Station (ISS), the main radiation sources are Galactic Cosmic Rays (GCRs), Solar Particle Events (SPEs) and trapped protons of the Van Allen Belts. The radiation field mainly consists of protons, helium nuclei and heavy ions with energies up to hundreds of GeV/n. A powerful approach to determine the effect of space radiation on astronauts is microdosimetry. The Centre for Medical Radiation Physics is active in the development of Silicon-On-Insulator (SOI) microdosimeters, as an alternative to Tissue Equivalent Proportional Counters (TEPCs) for radiation protection purposes. SOI microdosimeters are portable and do not require a high-voltage power supply. They consist of a matrix of silicon Sensitive Volumes (SV), which mimic the dimensions of biological cells. In this study, we investigated for the first time the response of the 3D "Mushroom" microdosimeter, a type of SOI microdosimeter in the Columbus module of the ISS. Tissue-equivalent microdosimetric spectra of GCRs, SPEs, and trapped protons were obtained to estimate the dose equivalent delivered to the astronauts. Results demonstrate a non-negligible production of secondary particles due to the propagation of space radiation through the wall of the Columbus and the microdosimeter. A number of heavy ions were detected with high lineal energies, these events pose a significant hazard in terms of radiation protection. Moreover, the dose evaluation shows a good agreement with experimental data found in the literature, confirming the suitability of our Geant4 model and the feasibility of using the SOI microdosimeter for ISS astronauts' personal dosimetry.

We describe the procedure developed for the electrolytic concentration of 3H in water, together with systematically applied checks to guarantee the reproducibility of the process and to minimize the variability between water samples concentrated simultaneously in the different electrolytic ceils. Starting from initial volume of 250 ml water, we obtained enrichment parameters normally greater than 70%, with a dispersion always less than 5%. Measuring the concentrated and the unelectrolyzed samples under the same conditions, we found that the lowest detectable activities had been improved from around 1.5 to 0.3 Bq/l. This allowed us to quantify the 3H activity levels of 100% of the rainwater samples collected in Cficeres from 1994 to 1996. The resulting average value for this period was (0.79+0.38) Bq/l.

The radioisotopes and nuclear explosions in upper layers of the atmosphere have vigorously polluted the earth. These radionuclides can be transferred to humans through the food chain. Rice is important and a major source of carbohydrates for humans. Soil contains the natural radionuclide such as Uranium, Thorium and Potassium. A study was conducted to determine the radionuclide content and their level of radioactivity in various types of rice eaten by the Malaysian. Six varieties of rice, Faiza Basmati, white glutinous, black glutinous, Siam, Kurnia and Utara were taken under consideration. Hyper Pure Germanium Detector (HYPe) was used to measure the radioactivity level. The average concentration of Uranium, Thorium and Potassium was found to be in the range of ( .33-25.10)±0.01 BqKg -1 , (35.49-64.97)±0.01 BqKg -1 and (64.802-109.929) ± 0.001 BqKg -1 respectively. Effective dose per annum was resided in the range of 0.02 μSv year -1 to 0.03 μSv year -1 .

The TOP-IMPLART project consists of the design and implementation of a linear proton accelerator, its control and monitoring systems for the treatment of superficial and semideep tumors. The energy of 150 MeV (corresponding to a penetration in tissue of about 15 cm) is a milestone in design being useful for the proton therapy treatment of almost 50% of tumors based on their position and depth (including ocular melanoma, head-neck tumors, pediatric tumors, and more superficial tumors). The capability to vary the intensity on a pulse-to-pulse basis combined with an electronic feedback system allows to get the required dose uniformity (±2.5%) reducing the number of re-paintings. In this paper the state of the art and the objectives of the TOP-IMPLART project are described within the framework of the progress of Protontherapy.

A radiography technique which makes use of -particles as penetrating radiation has been developed. The images were registered in the solid-state nuclear track detector CR-39 and the conditions to obtain the best radiography image were 2.2 h of irradiation and 25 min of etching in a KOH (30%) aqueous solution at 70 • C. For such conditions the resolution in the image was 23 m. Some radiographs are shown and demonstrate the potential of the technique to inspect samples with thickness in the m range.

The samples of CR-39(DOP) and SR-90 polymer track detectors have been exposed to -particles from 241 Am source in an exposure unit. The temperature of the detectors during irradiation has been varied from ∼ -30 • C to 70 • C. These exposed samples have been etched in 6:25 N NaOH solution at 60 • C for various etching times. The variation of sensitivity of these detectors as a function of registration temperature has been studied. It has been observed that at the ÿxed registration temperature, the sensitivity of SR-90 is more than CR-39(DOP) polymer track detector. However, the enhancement in sensitivity with the decrease in registration temperature is more pronounced in case of CR-39(DOP) than SR-90.

We search for the flavor-changing neutral current decays D 0 → µ + µ -and D 0 → e + e -, and for the lepton-flavor violating decays D 0 → e ± µ ∓ using 660 fb -1 of data collected with the Belle detector at the KEKB asymmetric-energy e + e -collider. We find no evidence for any of these decays. We obtain significantly improved upper limits on the branching fractions: B D 0 → µ + µ -< 1.4 × 10 -7 , B D 0 → e + e -< 7.9 × 10 -8 and B D 0 → e + µ -+ B D 0 → µ + e -< 2.6 × 10 -7 at 90% confidence level.

We present results from a proton accelerator beam test to measure radiation damage and activation in advanced scintillator materials. Samples of LaBr3:Ce and LaCl3:Ce were exposed to protons from 40-250 MeV at the Proton Irradiation Facility of the Paul Scherrer Institute in Switzerland. Twelve energy bands were used to simulate the spectrum of the South Atlantic Anomaly (SAA), with different samples exposed to the equivalent of 4 months, 1 year, and 5 years of SAA passage. No significant decrease in light output was found due to radiation damage, indicating that these new scintillator materials are radiation tolerant. High-resolution spectra of the samples were obtained before and after irradiation with a Germanium spectrometer to study activation. We present a detailed analysis of these spectra and a discussion of the suitability of these scintillator materials for detectors in future space missions.

A&met-The analysis of the effect of soaking in alcohol and/or water in track development was evaluated in Makrofol E using electron microscopy. Alcohol seems to be the main cause of track development when no other chemical reagent is used. No .track development is achieved when water is used as an etching agent.

The submicroscopic track kinetic theory (STKT) is able to deal with a broad range of cases. We derive here its behaviour for very short etching times (new born tracks) and also for long etching times, where the classical track kinetic theory is a particular case of the STKT. Experimental data obtained previously by Bean et al. using the electroconductivity method are then analyzed by the STKT method. We show that good agreement is obtained between Bean and STKT theoretical results for the track diameter evolution.

time in Makrofol E is evaluated applying the nuclear track replica method and electron microscopy with 10 A resolution. The induction time is observed in foils with and without pre-etching. The track diameter vs etching time curves do not follow a linear relation for small track diameters.

An attempt is made to determine the response of CR-39 and cellulose nitrate plastic track detectors subjected to thermal neutrons. The a-particles are produced from (n, a) reactions in lithium tetraborate convertor placed in contact with different plastics and are recorded in the detectors. The corrected track density gives a fluence sensitivity and dose sensitivity of the order of 10-* tracks per neutron and 102 tracks/cm s mrem respectively. A linear relationship is observed between track density and neutron fluence.

The aim of this work is to present a reproducible methodology for the evaluation of total equivalent doses in organs during proton therapy facilities. The methodology is based on measuring the dose equivalent in representative locations inside an anthropomorphic phantom where photon and neutron dosimeters were inserted. The Monte Carlo simulation was needed for obtaining neutron energy distribution inside the phantom. The methodology was implemented for a head irradiation case in the passive proton beam of iThemba Labs (South Africa). Thermoluminescent dosimeter (TLD)-600 and TLD-700 pairs were used as dosimeters inside the phantom and GEANT code for simulations. In addition, Bonner sphere spectrometry was performed inside the treatment room to obtain the neutron spectra, some relevant neutron dosimetric quantities per treatment Gy, and a percentual distribution of neutron fluence and ambient dose equivalent in four energy groups, at two locations. The neutron spectrum at one of tho...

Mass Attenuation Coefficient of X-rays have been determined for the ayurvedic Nano-medicine (Kasisa bhasma) of three brands in the X-ray energy range from 17.781 to 44.216 keV by employing good beam transmission geometry using the NaI(Tl) scintillation X-ray detector. The variation in X-ray mass attenuation coefficient (decreasing) with incident photon energy (increasing) was noted. And the XRD analysis confirms the crystalline nature of the nanomedicine with particle size ranging from 38.31 nm (for DKB) and 49.86 nm (for VKB) to 52.75 nm (PKB). Also we observed that, as the sample particle size is increased there is increase in value of mass attenuation coefficient of X-ray, this clearly reflects the mass attenuation coefficient values strongly depends on size of particles of the sample.

The B2 meson mass is measured to be mBS : ( 5374 ;l; I6 ;l; 2 ) MeV/C2 D; aY(I260) and J/1/2 ¢ decay modes, with identified kaons in the final state. candidates have been selected over a negligible background using the D; 7r+ , ing and of the hadron identification capabilities of DELPHI. Three B2 decay the LEP collider. The analvsis relies on the combined use of accurate track final states, using the data collected in 1992 by the DELPHI experiment at Strange beauty mesons BS have been reconstructed through exclusive hadronic

Elevated levels of radon and thoron in the indoor atmosphere may cause the deleterious effects on the mankind. Mining sites and their environs attract a special interest in radon studies as higher levels are frequently reported in the habitats. In the present study, radon and thoron levels were measured in the dwellings of Buddonithanda, a village in the environs of proposed uranium mining site, with pin-hole (SSNTDs) dosimeters for the period of a year. The measured radon and thoron levels were found to vary widely from 14 to 675 Bq m -3 (geometric mean = 94 Bq m -3 ) and from 21 to 704 Bq m -3 (geometric mean = 121 Bq m -3 ), respectively. An attempt was made to understand the large spatial variation of these levels. The seasonal and diurnal variation studies were used in unraveling the behavior of the radioactive isotopes in indoor environment and the same was explained with the help of a simplified mathematical model. Quantification of inhalation dose due to radon and thoron was done with suitable occupancy factors. Radon, being inert gas and radioactive in all of its isotopes, attracts much importance from radiological pollution point of view. The investigations across the globe indicate that half of the average annual natural background radiation dose comes from radon and its isotopes. Out of the various isotopes, the isotopes which are practically significant to the inhalation radiation dose are 222 Rn and 220 Rn, called as radon and thoron. The first one is more abundant, has half-life of 3.8 days and comes from the decay of 226 Ra. The latter has a very short half-life of 55.6 s and comes from the decay of 224 Ra 1 . Radon and thoron can enter human body by inhalation and most of the inhaled will be exhaled. However, a small fraction of the concentration of the gases might stuck in the lungs/ respiratory tract and these trapped radioactive elements on successive disintegration emit alpha particles that possibly ionize the lung tissues and results in the lung damage 2,3 . Epidemiological studies have confirmed that the exposure to radon in work places and dwellings increase the risk of developing lung cancer. Exposure to indoor radon and its isotopes have been determined to be the second leading cause of lung cancer after tobacco smoking 3 . The studies on uranium miners proved to be a positive risk coefficient on health and the measurements of radon and thoron levels are made inevitable in the indoor environment. This attention has been picked up the pace during last few decades and has become a global observable fact. The concentration of radon and thoron gases in the indoors is largely influenced by the materials used for construction, life style of dwellers, geology and meteorological conditions of the study area 4 . Generally, the exposure to 222 Rn and its daughter products contribute more to radiation dose than that of 220 Rn 5 . However this perception has been changed, due to many systematic investigations across the world during the last few decades suggesting that, the 220 Rn is also significantly contributes to the inhalation dose if the thorium content is rich in materials used for construction and local geology .

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This work explores the potentials and di culties in thermoluminescence (TL) dating of marble objects, which have never been exposed to sunlight since their ÿrst burial, by applying a new procedure similar in approach to sediment dating. The idea is based on the observation that exposure to sunlight reduces the TL peaks of marble to a residual level. When the marble is buried after bleaching, radiation from the sample and soil, as well as cosmic radiation, reÿll the electron traps that have been emptied by the sunlight. Using the additive dose method, an attempt has been made to date a sample of known age (2nd century BC) buried since antiquity. The peak at 290 • C was selected as the most suitable for dating (activation energy 1.7-2:0 eV, minimum spurious e ects, high intensity, linear response up to 50 Gy, bleachable down to the residual level in 1 h). This peak is well deÿned in most types of marble, common in antiquity (marble from Penteli, Paros, Naxos and Thassos). The age calculation gave 2570 ± 410 years, which is quite close to the archaeological age. Possible error sources, such as surface impurities and regenerated thermoluminescence, and ways to minimise them are discussed.

We report a spurious thermoluminescence (TL) present in three types of calcite powders which also show regenerated TL (RTL). The amount of RTL was found to depend on storage time and on the heating rate used during TL readout. Different heating rates during TL readout caused profound changes in the measured TL spectra in the range 400--650 nm. These changes can be explained by manganese ions moving into and out of clusters during the heating process.

The band structure of Ca 3 Ga 2 Ge 3 О 12 with the garnet structure has been determined for the first time by X-ray emission and photoelectron spectroscopy. It has been established that the bottom of the valence band is formed by Ge d states, which are not dominant in the chemical bonding. Strong hybridization of oxygen 2s states with 4p states of Ga and Ge revealed by the presence of an extra structure in the X-ray emission spectra has been found. The middle of the valence band has been demonstrated to be occupied by d states of Ga, while Ga and Ge 4рstates with a considerable admixture of oxygen 2p states form the top of the valence band.

The purpose of this analysis was to investigate dose distribution of Three Dimensional Conformal Radiation Therapy (3DCRT), Intensity Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) for Head and Neck cancer using 3-dimensional PRESAGE® dosimeter. Method: Computer Tomography (CT) scans of Radiological Physics Center (RPC) Head and Neck anthropomorphic phantom with both RPC standard insert and PRESAGE® insert were acquired separated with Philipp's CT scanner and both CT scans were exported via DICOM to the pinnacle treatment planning system (TPS). Each plan was delivered twice to the RPC phantom first containing the RPC standard insert having Thermoluminescent detectors (TLD) and film dosimeters and then again containing the PRESAGE® insert having three dimensional dosimeter (PRESAGE®) by using a Varian True beam linear accelerator. After irradiation, the standard insert including point dose measurement (TLD) and planner GafChromic® EBT film measurement was read using RPC standard procedure. The 3D dose distribution from PRESAGE® was read out with the Duke Midsized optical scanner dedicated to RPC (DMOS-RPC). Dose volume histogram (DVH), mean and maximal doses for organ-at-risk (OARs) were calculated and compared among each Head and Neck technique. The prescription dose was same for all Head and Neck radiotherapy techniques which was 6.60 Gy per friction. Beam profile comparison and gamma analysis were used to quantify agreement among film measurement, PRESAGE® measurement and calculated dose distribution. Quality assurances of all plans were performed by using ArcCHECK method. Results: VMAT delivered the lowest mean and maximal doses to organ at risk (spinal cord and parotid) than IMRT and 3DCRT. Such dose distribution was verified by absolute dose distribution using TLD system. 2D gamma 5%/3 mm criteria of Pinnacle vs. EBT2 film 3DCRT (92.34%), IMRT (92.3%) and VMAT (96.63%) in axial plan respectively. It was also found that agreement between PRESAGE® and pinnacle along the axial, sagittal and coronal plans VMAT agreement was better than IMRT and 3DCRTplan excludes a 7 mm rim at the edge of the dosimeter using 2D gamma map criteria (±5%/3 mm) with 5% threshold dose. Profile showed good agreement for all plans between film, PRESAGE® and pinnacle. 3D gamma was performed for planning target volume (PTV) and organ at risks (OARs) VMAT and 3DCRT endow with better agreement than IMRT. Conclusion: VMAT delivered lowered mean and maximal doses to organ at risk and better PTV coverage. TLD, EBT film and PRESAGE® dosimeter has suggested that VMAT would be superior modality for the treatment of Head and Neck cancer than IMRT and 3DCRT.

An analytical study, corroborated by Monte Carlo simulations, is presented which describes the interaction of a 300  keV–830 mA proton beam with a Cu and Al dumping system. The analytical calculations rely on the theoretical framework of the Particle Induced X-ray Emission, while the Monte Carlo simulations are performed by means of the GEANT4 toolkit. The case study is related to the project SORGENTINA-RF fusion neutron source and in particular to the tests devoted to assess the performance of the ion source of the plant. The results provide a detailed physical insight of the main processes occurring in the beam dump material, and are also important to give some realistic figures of the radiation emission expected during operation.

Magnesium tetraborate doped with dysprosium (MgB 4 O 7 :Dy) is known as a good thermoluminophor for personal dosimetry of gamma ray and X-ray radiation because of its high sensitivity and close tissue equivalence. This material can be produced by different routes. The sintered pastilles of magnesium tetraborate mixed with Tefl on (40%) used in this work were manufactured at the Federal University of Sergipe, Department of Physics by the solid-state synthesis. Magnesium tetraborate was already used for high-dose dosimetry, exhibiting linearity for a wide range of doses. In this work, the authors examined its main characteristics prior to potential use of detectors in everyday dosimetry, comparing this material to a widely used LiF:Mg,Ti phosphor. The following tests infl uencing dosimetric peaks of MgB 4 O 7 :Dy were presented: (1) the shape of the glow curves, (2) annealing conditions and post-irradiation annealing and its infl uence for background of the detectors, (3) the choice of the heating rates at the read-out and (4) the threshold dose, that is, the lowest possible dose to be measured. Simil ar tests were performed with LiF:Mg,Ti detectors, produced and widely used in Poland. The results were compared and discussed.

International studies of radon indoors and in workplaces have shown significant radiation dose burden of the general population due to inhalation of radon ( Rn) and its short-lived progeny ( 218 Po, 214 Pb, 214 Bi, 214 Po). As far as atmospheric radon concerns, 222 Rn, is not necessarily in equilibrium with its short-lived progeny. For this reason, radon's equilibrium factor F was solved graphically as a function of the track density ratio R=T B /T R , namely of the ratio between the recordings of cup-type and bare CR-39 detectors. T B was computed through special Monte-Carlo codes which were implemented for the calculation of the efficiency of bare CR-39 polymers, regarding their ability in sensing the alpha particles emitted by the decay of radon and its short-lived progeny. For a realistic approach, Monte-Carlo inputs were adjusted according to actual experimental concentration measurements of radon, decay products and F of Greek apartment dwellings. Concentration measurements were further utilized for the calculation of the unattached fraction, f p , in terms of Potential Alpha Energy Concentration (PAEC, defined as the sum of the initial -per volume -energies of all alpha particles emitted due to the decay of radon and its short-lived progeny that are present within a certain amount of air). This was employed for the calculation of F in terms of ratio (A 4 /A 0 ), where A i represents the activity concentration of radon (i=0) and 214 Po (i=4) respectively. Measured and calculated values of F were plotted versus R. The results were fitted and checked with model's predictions.

The primary objective with radiation sources and facilities is the protection of both radiation workers and the general public. The biological shields of the Secondary Standard Dosimetry Laboratory of the Radiation Protection Institute (RPI) Ghana had been evaluated for a collimated isotropic cesium-137 source for calibration purpose using MCNP5 code. The dose rate at supervised areas ranged from 0.57 to 8.35 :Sv/h and 0.26 to 10.22 :Sv/h at control areas when the source was panoramic. When the source was collimated, the dose rate ranged from 0.05 to 0.30 :Sv/h at supervised areas and 0.23 to 8.88 :Sv/h at control areas for 22.2 GBq of the cesium-137 source. The scatter contribution from the surfaces of the walls and roofs were also accounted for. The scatter radiation in the room decreased to 400 :Sv/h when the source was first collimated and to 3.5 :Sv/h when the source was further collimated. These results agreed quite well with experimental measurement. To effectively protect the staff, a narrow beam of 1.2 cm diameter which was defined at 1.0 m by the total surface of the ISO slab phantom was recommended to reduce the dose rate to less than 1.5 :Sv/h outside the calibration bunker even when the current activity is doubled. It was concluded that the 4.7 cm diameter of the existing narrow beam should be decreased to 1.2 cm by further collimation of the beam.

Thermoluminescent MCP-N detectors based on LiF:Mg,Cu,P are by about 2 orders of magnitude more sensitive than TLD-100 detectors based on conventional LiF:Mg,Ti, which makes it possible to use them in short-term monitoring of ionizing radiation in the environment (e. g., over a two-week period, rather than over 3-12 months). We describe the properties of MCP-N detectors and methods of their application in environmental monitoring. The system was tested in short and long-term exposure periods at 100 sites around Krakow region. MCP-N detectors were then applied to measure variation of radiation dose rate at four selected villages in Serbia, where depleted uranium ammunition was deployed in 1999. Together with short-term thermoluminescent dosimetry, in situ measurements using proportional counters were per formed in order to assess the range of variation of natural radiation background in these villages. The mean terrestrial kerma dose rate in these villages was found to vary between 85...

Time-resolved infra-red stimulated luminescence (TR-IRSL) technique enables an understanding of the dynamics of trapped electrons after IR excitation in the band-tail states of feldspar. This work intends to study the underlying physical mechanism of IRSL production. TR-IRSL studies were carried out on four feldspar mineral specimens of variable chemical composition and structural state. Assuming the IR excited trapped electrons make random walks in the band-tail states and recombine by tunnelling dynamically, hopping time is derived from the OFF time data of TR-IRSL. This analysis indicates that the hopping time decreases with stimulation temperature. Using Einstein diffusion equation, hopping probability is computed and is shown to obey the equation describing variable range hopping mechanism of Mott kind. Mott's parameters (hopping length and hopping energy) are then derived. Hopping length decreases with stimulation temperature whereas hopping energy increases with temperature. The average hopping length and energy are in the range of 11e18 Å and 45e55 meV respectively and the diffusion constant is estimated to be in the range of 10 À10 e10 À9 cm 2 s À1 for all the feldspar samples.