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ST 1.2 –
Dosimetría externa
HIGH-DOSE DOSIMETRY USING NATURAL SILICATE MINERALS
Watanabe, Shigueo; Rao, T. K. Gundu; Gennari, Roseli F.;
Carmo, Lucas S.; Lucas, Natasha N.; Sato, Karina M.;
Cano, N.F; Barbosa; R. F
Universidad de Federal de São Paulo. Brasil.
* Autor Responsable, email: etoledo@dfn.if.usp.br
Radiation dosimetry is basic for Radiation Protection. The ionic crystals in Radiation Dosimetry
since long became widely used due to several advantages such as, high sensitivity,
reproducibility, low cost, easy to handle, etc. Silicate minerals abundantly found in Brazil are
ionic crystals and exhibit a good TL response to the radiation, therefore, quite appropriate for
radiation dosimetry. In this work we used green quartz, three varieties of beryl (goshenite-
uncoloured, aquamarine-blue/green and emerald-green), jadeite and pink tourmaline.
Fragments of these minerals have been crushed and sieved retaining grains with 0,080 to
0.180mm in size. They were annealed at 6000C for 30 minutes to eliminate previous radiation
effect. Then they were divided into portions to be irradiated with gamma doses varying from
tens of kGy up to 2000 kGy. The irradiated green quartz samples were measured by EPR and
TL, all other samples by TL. The EPR and TL intensities were then plotted as function of dose.
The resulting calibration curves indicate that these silicate minerals can be used in high to very
high dose dosimetry. In practice there are many situations where high or very high doses are
involved and these dosimeters would be valuable. High doses are present in high energy
particles accelerator laboratories, in sterilization of medical objects facilities, in food and
agricultural products preservation by irradiation center, in industry that use radioactive isotopes,
etc.