Defects induced in bioglass by gamma radiation for dosimetric purposes

Abstract

Some dosimetric properties of the glass system 50P 2 O 5 •30-40CaO•20-10Na 2 O mol% were studied applying the thermoluminescence technique.. The glass samples were powdered, and were pressed with Teflon™ in the proportion 1:2 to produce pellets. The glow curves of the pellets presented three peaks at 130 °C, 215 °C and 270 °C, respectively. The TL response reproducibility presented a maximum coefficient of variation lower than 10%. The calibration curve is linear between 1.0 Gy and 1 kGy. Minimum detection limits were also determined. The gamma radiation dose response and the thermal stability of the materials were studied with the purpose to establish the best conditions of the present bioglass system for use in gamma ray TL dosimetry.

Thermoluminescence Properties of Bioglass for Radiation Dosimetry

“…Figure (3) shows the glass transition temperature values, T g , of the glass samples, which increase slowly as the alkali and alkali earth elements oxide mixture content increases, i.e. the structural connectivity increases.…”

“…In bioglass exposed to ionizing radiation, electron-hole and recombination processes are rich in interesting mechanisms involving charge and energy transfer between populations of speci c impurities and defects (3) . Thermoluminescence (TL) is a massive technique for investigating the origin of defects in solid materials (4).…”

“…The development of amorphous systems is therefore critical for this particular application (5; 6). New silicate materials with improved sensitivity and linearity of TL performance over a wide range of dosages are currently being developed (1)(2)(3)(4).…”

Caracterização de silicatos e carbonatos de cálcio aplicados à dosimetria de doses altas

“…Da Costa et al (2007). Melo (2007) verificou que amostras de jade (nefrita), proveniente de três países diferentes, actinolita, tremolíta, diopsídio e rodoníta apresentam propriedades dosimétricas satisfatórias para serem utilizados como dosímetros de doses altas em feixes de radiação gama e X.…”

Caracterização do jade e dos silicatos da família do jade para aplicação em dosimetria das radiações

“…No Laboratório de Calibração de Instrumentos do IPEN já foram estudadas amostras de vidros nacionais e importadas, quanto à possibilidade de sua utilização em dosimetria da radiação gama (Caldas, 1989;Teixeira, 2004), e de vidro nacional, para dosimetria de radiação de elétrons (Caldas e Souza, 1991), utilizando a técnica da termoluminescência. Recentemente Costa et al (2007) estudaram algumas propriedades dosimétricas de biovidros e os seus defeitos induzidos pela radiação gama ( 60 Co).…”