الفهرس 
Theoretical BackgroundOnly 14 pages are availabe for public view
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Abstract
With the ever increasing use of nuclear energy, particularly for power production,
there is more and more need for radiation detection and dose assessment for a variety
of purposes. In the present work, some new aluminum based nanophosphor
absorbers, with chemical formulas of Ca9Al (PO4)7: x, y (symbolized as CAP: x, y),
Na5Ca2AlP4O16: x and Al2O3: x series, [where x, y (mol%) represent the dopants
with their concentrations], were prepared using sol-gel method. All mentioned series
were subjected to 5 Gy γ-dose for their sensitivity study. Samples of highest TLsensitivity were selected for further studies including nanostructures testing using
XRD and TEM images analysis, SEM-EDX mapping, and subjected to different
60Co γ-doses for their dosimetric properties. The selected samples from CAP: x, y,
Na5Ca2AlP4O16: x and Al2O3: x series were symbolized as, CAP: Si0.3, CAP: Si0.3,
La0.7, CAP: Si0.7, La0.3, CAP: Ce0.01, CAP: Cr0.1, CAP: Mg0.5, CAP: Mg0.5, La0.3, CAP:
Cr2, Si8, Na5Ca2AlP4O16: Si and Al2O3: 0.005 (Ca, P, Cr, Si).
The phase purity and the crystal structures of the as-prepared samples were identified
and verified using XRD and TEM data analysis. Average size values of
nanoparticles obtained from XRD and TEM are very closely related and confirmed
the successful synthetic method in preparing the present nanophosphors.
Elemental mapping by SEM-EDX revealed the localization of constituent elements
and indicates the homogeneous distribution of co-dopants confirming the feasibility
of doping in each of the selected samples.
The TL-response was 1.22, 1.16, 1.05, 2.24, 0.53, 0.89, 0.77 times that of MTS-700
commercial detector for CAP: Si0.3, CAP: Si0.3, La0.7, CAP: Si0.7, La0.3, CAP: Ce0.01,
CAP: Cr0.1, CAP: Mg0.5, CAP: Mg0.5, La0.3 samples, respectively.
The relative standard deviations (RSDs) of peak areas for the reproducibility (using
6 chips of each selected samples) and repeatability study (using 1 chips 6 times for
each selected samples) were performed when samples were exposed to 5 Gy γ-doseand the RSDs found to be <10% (acceptable internationally) for all exposures which
reflected good homogeneity and confirmed the good reusing of the selected
nanophosphors.
TL-glow curves for chips of the selected nanophosphors at different γ-doses (0.167-
20 Gy) using 60Co gamma source were recorded by PCL3 TL reader at 10ºC/s
heating rate. The dose response curve vs. the ROI was given and confirmed a good
linearity dependence up to 20 Gy for CAP: Si0.3, CAP: Si0.3, La0.7, CAP: Si0.7, La0.3,
CAP: Ce0.01, CAP: Mg0.5 and Al2O3: 0.005 (Ca, P, Cr, Si) samples. On the other
hand, in sequence, samples CAP: Cr2, Si8, CAP: Mg0.5, La0.3, CAP: Cr0.1 and
Na5Ca2AlP4O16: Si had good linearity dependence up to 15, 13.59, 10 and 40 Gy,
respectively.
Chips from the selected nanophosphors were delivered to 5 Gy γ-doses to study the
fading effect for storage period from 0.25 up to 480 hrs. The loss of TL-signals after
24 hrs were 33, 20, 24, 10, 15 and 15% from the irradiation process for CAP: Si0.3,
CAP: Ce0.01, CAP: Cr0.1, CAP: Mg0.5, La0.3, Na5Ca2AlP4O16: Si and Al2O3: 0.005 (Ca,
P, Cr, Si) samples, respectively. After 48 hrs, samples CAP: Si0.7, La0.3, CAP: Mg0.5
and CAP: Cr2, Si8 showed 20, 56 and 35% TL-signal loss. CAP: Si0.3, La0.7 sample
has 35% TL-signal loss after 240 hrs. Thenceforth no significant loss beyond the
above mentioned interval of times for each selected samples.
Samples CAP: Si0.3, CAP: Si0.3, La0.7, CAP: Si0.7, La0.3, CAP: Ce0.01, CAP: Cr0.1,
CAP: Mg0.5, CAP: Mg0.5, La0.3, CAP: Cr2, Si8, Na5Ca2AlP4O16: Si and Al2O3: 0.005
(Ca, P, Cr, Si) had minimum detectable dose of 11, 13, 26, 10.71, 51, 21, 23,
115×103, 50 and 77×103 μGy, respectively.
Glow curve of each selected samples was deconvoluted using PeakFit program
(PFP) and the trap parameters, E (eV) and s (s-1), of the deconvoluted peaks were
identified using different methods.Data of the variation of energy dependece (ED) with energy for each selected
sample showed an independece behavior within the photon energy range of 0.10 to
20 MeV (ROI) for each selectd nanophophors.
Calculation of µm for the selected nanophosphors revealed that Compton incoherent
scattering cross section is the predominant one. Results of the present work are
discussed within the frame work of γ-interaction with the selected samples using
WinXcom program.
Zeff value of each selected sample varied in the range ⁓10 -11.62 which are close that
of natural bone.
The resultant response curve reflected great evidence of γ-dosimetric potential of the
studied new selected nanophosphors and indeed they can highly recommended as γ-
dosimeters within the linear part of their respective response curves.
Moreover, the low detection limit (≈ μGy) of our prepared nanophosphors makes
them useable in X- and γ- rays detection as tissue and bone equivalent of human to
study the doses received by patients and workers who submitted to ionizing
radiation.