Speaker
Mr
Seif EBRAHEEM
(National center for Radiation Research and Technology, Egypt)
Description
During the last two decades, a team of NCRRT researchers developed and
assisted many dosimetry systems depending on the electron paramagnetic
resonance (EPR) analyzing method. EPR dosimetry is characterized by
its non-destructive read-out and the possibility of dose archival.
Recently, monosodium glutamate powder and prepared rods containing
different concentration of it ($3\times 10$ mm) were studied to be a
radiation sensitive dosimeter measured by ESR method of analysis. The
dose range from $10$–$90$ kGy tested for powder, whereas, rods are
useful in the dose range from $10$–$120$ kGy.
NCRRT researchers studied different substances evaluated as; taurine,
strontium carbonate, riboflavin, strontium carbonate, anhydrous
strontium sulfate, 2-methylalanine, magnesium lactate, ammonium
oxalate, and arginine mono-hydrochloride.
The response of taurine to $\gamma$-radiation doses in the range from $0.1$
to $50$ kGy was investigated, as well as that in the range from $1.0$ to
$20.0$ Gy using numerically enhanced EPR taurine spectra. The
radiation-induced defects in strontium carbonate (SrCO$_3$) rod dosimeter
in the dose range of $2.5$ Gy–$25$ kGy was investigated using EPR
resonance technique. The un-irradiated riboflavin (RF) exhibits a
very weak EPR signal ($g = 2.00950$) and upon $\gamma$-ray exposure the
signal increases up to an absorbed dose of $50$ kGy. Anhydrous
strontium sulfate (SrSO$_4$) has shown a promise candidate as a dosimeter
for low dose applications producing unique EPR signals with
$\gamma$-rays which it has a linear response relationship ($r_2 \approx 0.999$)
in the range of $1$–$100$ Gy. The dosimetric characteristics of
$\gamma$-radiation induced free radicals in 2-methylalanine (2MA)
pellet dosimeter are investigated using EPR in the high-dose range of
$1$–$100$ kGy. The EPR spectrum of irradiated magnesium lactate (ML) rods
was characterized by a quartet signal with the spectroscopic splitting
$g$-factor of $2.0048700003$ at $0.4$ mT. The useful dose range of the rod
dosimeter was $100$ Gy to $80$ kGy. The dosimetric properties of the of
ammonium oxalate (COONH$_4$)$_2$H$_2$O studied under low and high radiation
doses. The EPR spectra of ammonium oxalate have the spectroscopic
splitting $g$-factor of $2.00095$ for C$_2$O$_4^-$ radical detected as EPR
signal. The dose-response curves have very good linearity in the
range $10$–$1000$ Gy for low doses and show slight sub-linearity in high
dose region up to $25$ kGy. Arginine mono-hydrochloride rods ($3$–$10$ mm)
were irradiated with $^{60}$Co $\gamma$-rays to study radicals for
dosimetric materials with EPR. The rods have significant signal which
develops upon irradiation and the intensity of signal increases upon
the increase in irradiation dose, in the dose range from $5$ to $120$ KGy.
More and more articles ware published by the NCRRT researchers group
dialing with this issue represents the unique analyzing method of
using EPR in the field of dosimetry.
| Country/Organization invited to participate | Egypt |
|---|
Primary author
Mr
Seif EBRAHEEM
(National center for Radiation Research and Technology, Egypt)
