N. Šeperienė “The development of polymer structures with the enhanced sensitivity to low dose irratiation” doctoral thesis defence

Author, Institution: Neringa Šeperienė, Kaunas University of Technology

Science area, field of science: Technological Sciences, Materials Engineering, 08T

Scientific Supervisor: Prof. Dr. Diana Adlienė (Kaunas University of Technology, Technological
Sciences, Materials engineering–08T).

Dissertation Defence Board of Materials Engineering Field:
Prof. Dr. Jolita Ostrauskaitė (Kaunas University of Technology, Technological Sciences, Materials engineering–08T) – pirmininkė,
Prof. Dr. Saulutė Budrienė (Vilnius University, Physical Sciences, Chemistry – 03P),
Prof. Dr. Habil. Arvaidas Galdikas (Kaunas University of Technology, Technological Sciences, Materials engineering–08T),
Dr. Viktoras Grigaliūnas (Kaunas University of Technology, Technological Sciences, Materials engineering–08T),
Dr. Gunta Kizane (Latvia University, Physical Sciences, Chemistry – 03P),
Prof. Dr. Liutauras Marcinauskas (Kaunas University of Technology, Technological Sciences, Materials engineering–08T).

 The doctoral dissertation is available at the library of Kaunas University of Technology (K. Donelaičio St. 20, Kaunas).

Annotation:

The research presented in this dissertation is focused on the investigations of <10 Gy irradiated polymer gels and composites. Performed investigations are addressed to two objectives: development of dose gels with enhanced sensitivity to low dose irradiation for dosimetry in radiotherapy and development of lead free optically transparent polymer composites as filling material in radiation protection screens. Dose gels were irradiated from 0.5 to 10 Gy photon and particle irradiation. Samples were investigated by Raman and UV-VIS spectroscopy. By varying concentrations of the nMAG gel components, the dose gel of advanced composition was developed. Dose sensitivity was improved by 30 % to high-energy photons. The composition of the advanced nMAG gel was as follows: 8 % w/w of methacrylic acid, 6 % w/w of gelatin, 86 % w/w of purified water, and 15 mM of hydroxymethyl phosphonium chloride. A new photo scanning dosimetry instrumentation for dose evaluation in the irradiated gels was developed. The constructed system allowed the scanning of irradiated polymer gel samples with a spatial resolution of 0.20 mm. The development of different lead-free polymeric composites, recording X-ray attenuation properties that are similar to lead, revealed that (NH₄)₆H₂W₁₂O₄₀xH₂O concentration of 60 % in the composite was sufficient enough for its application in the radiation protection equipment, since the estimated lead equivalent of the composite was 0.63 mmPb, and UV-VIS transparency – 89 %.