Papers by Djamel Imatoukene
Radiation Measurements, 2013
ABSTRACT The damaged produced by proton beam slowed down in CR-39 polymer results in highest degr... more ABSTRACT The damaged produced by proton beam slowed down in CR-39 polymer results in highest degree of disorder with change of free volume proprieties. Positron annihilation lifetime spectroscopy (PALS) is nowadays well recognized as powerful tool of microstructure investigations. PALS is used in order to get more information at an atomic scale of modifications induced by irradiation of polymers particularly the variation of free volume in the irradiated region. In this paper, the mean free volume hole radii and average free volume of the micro-voids in CR-39 polymer irradiated with 200 MeV therapy proton beam at different positions in spread out Bragg Peak region (SOBP) at Ithemba proton therapy facility have been determined using PALS. © 2006 Elsevier Ltd. All rights reserved.
In Algeria, the individual monitoring of workers occupationally exposed to external radiation
(e... more In Algeria, the individual monitoring of workers occupationally exposed to external radiation
(estimated at 10.000 workers) is carried out mainly by photographic dosimetry. This dosimetry, based on the use
of traditional empirical formulas, for the measurement of individual dose equivalent, introduced unacceptable
uncertainties in accordance with the new international recommendations (ICRP, ICRU, IAEA). However, many
works undertaken recently, particularly the implementation of numerical methods suitable for the measurement
of individual dose equivalent, allowed us to reach real progress in the field of photographic dosimetry. A
sophistical algorithm enabling the evaluation of doses, for mixed radiation fields (X, γ), from the measurement
of apparent doses under the various filter elements, is explained in the present paper.. In this study, a dosimeter
standard PS1 which consists of an Eastman Kodak Type 2 film sandwiched within a film holder, was used. The
energy response beneath each filter was determined over a photon energy range of 20 keV – 1.3 MeV, selected
from series of reference radiations recommended by the International Standards Organisation (ISO) reference
4037-1. Two procedures allowing the evaluation of the individual dose equivalent have been tested, one
developed by the Nuclear Research Center of Algiers (CRNA) based on an empirical formula, the second based
on the Simplex algorithm method, stemmed from a software of linear programming developed by Frontline
Systems Inc. The results obtained showed that the Simplex method, applied to the film dosimeter, gives better
accuracy on the nature and the quantity of exposure in an unknown mixed radiation field.
Journal of Luminescence, Jan 1, 2009
The behaviour of trap centres and luminescence centres has been investigated for fired and unfire... more The behaviour of trap centres and luminescence centres has been investigated for fired and unfired natural quartz from bricks and sediments irradiated at 100 Gy and annealed at different temperatures in the range 350–700 °C. The annealing treatment affects thermoluminescence (TL) glow curve as various changes were observed. The higher sensitization occurred for an annealing in the region 550–600 °C. At this annealing temperature, it has been observed the emergence of two peaks arising at 96 and 180 °C. At lower annealing temperatures, these peaks are overlapped by the peaks localized at 90 and 195 °C, respectively. Concerning the fired quartz, the higher sensitization occurred for an annealing in the region 500–550 °C for peak temperature around 200 °C and an unusual desensitization for the peak temperature around 100 °C. The behaviour of the two types of quartz is analyzed regarding to their kinetic parameters and luminescence emission and compared to literature data.
Radiation Measurements, Jan 1, 2008
The thermoluminescence detectors (TLD) have been widely used for environmental radiation monitori... more The thermoluminescence detectors (TLD) have been widely used for environmental radiation monitoring around nuclear facilities. In this study, a new environmental dosimeter based on Al2O3:CAl2O3:C detectors placed in black Perspex holder with appropriate filtrations (0.2 mm Aluminium, 0.2 mm Copper and 0.4 mm Lead) has been proposed. The energy response beneath each filter was determined over a photon energy ranging from 20 keV to 1.3 MeV according to the recommendations of the International Standards Organisation (ISO). An algorithm has been elaborated in order to evaluate the ambient dose equivalent from linear combination of the TL-reading of each detector. The results obtained in terms of energy and angle responses are analysed regarding the environmental monitoring standard performance.
Radiation Measurements, Jan 1, 2008
In this study, the effect of gamma pre-treatment on etching rates has been investigated on CR-39 ... more In this study, the effect of gamma pre-treatment on etching rates has been investigated on CR-39 detectors manufactured by Pershore Mouldings (PM) as standard grade and (PM355) as dosimetry grade. The detectors have been exposed to 60Co gamma rays at absorbed dose ranging from 0 to 105Gy. The chemical etching was carried out in four PEW solutions (potassium ethanol in water) with various concentrations (KOH 6.25 N with 0%, 20%, 40% and 60% of ethanol). The results show that the effect of gamma rays on CR-39 etching characteristics is more pronounced when the ethanol concentration increases in the etching solution especially in the region ranging from 103103 to 104Gy. In this range, VBVB etching rate decreases till values less than those observed for virgin material. The structural alterations (cross linking or main chain scissions) produced by gamma rays in this plastic detector have been determined using UV–visible and FTIR spectroscopy and compared to those induced by proton irradiation.
Radiation Measurements, Jan 1, 2008
The radial size of the damaged region induced by the proton beams in the CR-39 has been determine... more The radial size of the damaged region induced by the proton beams in the CR-39 has been determined by small angle neutron scattering (SANS).The radii of the track core have been estimated by SANS technique using Guinier-plots and have been found to be about 0.7±0.20.7±0.2, 0.9±0.40.9±0.4 and 1.5±0.4nm at the fluences of 10111011, 10121012 and 5×1012cm-2, respectively.These results are compared with those calculated using Waligorski radial dose distribution and those obtained by Yamauchi et al. using atomic force microscopy (AFM) and UV spectrophotometer.Finally, a correlation between the present results and those obtained in the previous work permits to propose a chemical structure of the proton latent track in CR-39.
Radiation Measurements, Jan 1, 2006
Dating and retrospective dosimetry are the main applications related to the properties of thermol... more Dating and retrospective dosimetry are the main applications related to the properties of thermoluminescence of fired quartz. The performance of these techniques can be improved by understanding and characterisation of the traps and luminescence centers responsible for the thermoluminescence emission. In this study, a fired quartz powder sample, extracted from local bricks, is used. Seven overlapping TL peaks are identified by the Tm-TstopTm-Tstop method. The best peak separation procedure is carried out using the appropriate dose level and pre-heating temperature. For isolated TL peaks located at 100, 202 and 350∘C (as measured with a heating rate of 5∘Cs-1), the associated kinetic parameters (activation energy and kinetic order) are determined by three methods: peak shape, whole glow curve and computerised glow curve deconvolution. The results are presented, discussed and compared with those reported in the literature.
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Papers by Djamel Imatoukene
(estimated at 10.000 workers) is carried out mainly by photographic dosimetry. This dosimetry, based on the use
of traditional empirical formulas, for the measurement of individual dose equivalent, introduced unacceptable
uncertainties in accordance with the new international recommendations (ICRP, ICRU, IAEA). However, many
works undertaken recently, particularly the implementation of numerical methods suitable for the measurement
of individual dose equivalent, allowed us to reach real progress in the field of photographic dosimetry. A
sophistical algorithm enabling the evaluation of doses, for mixed radiation fields (X, γ), from the measurement
of apparent doses under the various filter elements, is explained in the present paper.. In this study, a dosimeter
standard PS1 which consists of an Eastman Kodak Type 2 film sandwiched within a film holder, was used. The
energy response beneath each filter was determined over a photon energy range of 20 keV – 1.3 MeV, selected
from series of reference radiations recommended by the International Standards Organisation (ISO) reference
4037-1. Two procedures allowing the evaluation of the individual dose equivalent have been tested, one
developed by the Nuclear Research Center of Algiers (CRNA) based on an empirical formula, the second based
on the Simplex algorithm method, stemmed from a software of linear programming developed by Frontline
Systems Inc. The results obtained showed that the Simplex method, applied to the film dosimeter, gives better
accuracy on the nature and the quantity of exposure in an unknown mixed radiation field.
(estimated at 10.000 workers) is carried out mainly by photographic dosimetry. This dosimetry, based on the use
of traditional empirical formulas, for the measurement of individual dose equivalent, introduced unacceptable
uncertainties in accordance with the new international recommendations (ICRP, ICRU, IAEA). However, many
works undertaken recently, particularly the implementation of numerical methods suitable for the measurement
of individual dose equivalent, allowed us to reach real progress in the field of photographic dosimetry. A
sophistical algorithm enabling the evaluation of doses, for mixed radiation fields (X, γ), from the measurement
of apparent doses under the various filter elements, is explained in the present paper.. In this study, a dosimeter
standard PS1 which consists of an Eastman Kodak Type 2 film sandwiched within a film holder, was used. The
energy response beneath each filter was determined over a photon energy range of 20 keV – 1.3 MeV, selected
from series of reference radiations recommended by the International Standards Organisation (ISO) reference
4037-1. Two procedures allowing the evaluation of the individual dose equivalent have been tested, one
developed by the Nuclear Research Center of Algiers (CRNA) based on an empirical formula, the second based
on the Simplex algorithm method, stemmed from a software of linear programming developed by Frontline
Systems Inc. The results obtained showed that the Simplex method, applied to the film dosimeter, gives better
accuracy on the nature and the quantity of exposure in an unknown mixed radiation field.