| Summary: | 碩士 === 國立清華大學 === 輻射生物研究所 === 85 === Thermoluminescent material has long been used to determine the
radiation dose. The proton research and therapy are becoming
more important, now. In our study the response of CaF2:Tm and
CaF2:Dy to protons will provide the dose data for proton therapy
in future.
The source of proton beam was from by a Van de Graaff
accelerator with an energy range between 0.7 to 3.0 MeV. We
have analyzed the influences of various proton energies, proton
number and fluence on the response of CaF2:Tm and CaF2:Dy. The
results show that CaF2:Tm with well defined peak 2 and peak 5 is
an optimum dosimeter for the determination of proton energy by
means of peak height ratio of peak 2 and peak 5. The more
sensitive CaF2:Dy is an optimum dosimeter for measuring low-
level proton radiation
Foe the photon experiment, the new material MgB4O7:Dy,Na was
investigated with reference to annealing procedure. This new
material can approximately determine the absorbed dose of human
body since its effective atomic number is close to that of
tissue. Its glow curve is rather simple, with only one well
defined peak about 210o C. The proper annealing procedure for
this material will insure its applications. The method used was
to analyze the reproducibility while exposed to gamma. After
proper annealingost residual TL of MgB4O7:Dy,Na can be
eliminated. The results show that at 550o C for 2 h, the
annealing procedure can retain the least TL residual, provide
high reproducibility and good linearity of a large dose range.
|
|---|
