Study of track formation mechanism in CR-39 plastics by heavy ion irradiation

The CR-39 plastic is widely accepted as a detector in the radiation monitoring field and better explanations are needed for its characteristic nature. Mass spectrometry(MS), electron spin resonance(ESR), and other methods provide us to help elucidation of chemical and physical processes taking place in CR-39. In this study, we applied ESR measurements for the detection of radiation-induced radicals and found that the ESR spectra of CR-39 were composed of several radicals and by the time-scan analysis each radicals had different life times. We will present irradiation effects of the heavy ions and the relation between ion species and radical types detected

Complementary approach for heavy ion dosimetry with Ag+-doped phosphate glasses

The Ag+-doped phosphate glass is well-known as a personal dosimeter based on theradio-photo-luminescence (RPL) detection. The intense luminescence due to the ionizing radiation is emitted by the excitation with ultraviolet light, which is proportional to the amount of the irradiated dose. Recently, we have found out this glass can be operated as a nuclear track etch detector [1]. The glass is etchable in the alkaline solutions and able to form etch pit for heavy ion irradiation. It means that we can observe not only RPL but also nuclear etched tracks in the same glass. The luminescence efficiency strongly depends on the LET (linear energy transfer) of heavy ions, which drastically decreases at the high LET region of > 10 keV/μm. For Xe ion beam irradiation, very high LET particles of several thousand keV/μm, the absorbed dose obtained from RPL underestimates ~70% for calibrated ionization chamber output. Meanwhile, the dose obtained from LET spectrum of nuclear etched tracks is good agreement with ionization chamber’s. The physical quantities due to the different physical processes of excitation and ionization were successfully observed in the same glass plate, which shows good correlation between RPL and nuclear etched tracks for several LET data points. We found a complementary approach of radiation dose evaluation by combining both information of RPL and nuclear etched tracks. The nuclear track detection would supply the alternative signals in the glass dosimeter.The 26th International Conference on Nuclear Tracks in Solid

Application of Ag+-doped phosphate glasses as nuclear track etch detectors

The Ag+-doped phosphate glass which is commonly employed as the radiophotoluminscence (RPL) dosimeter has been applied as a nuclear track etch detector. The glass is etchable in the NaOH solutions and forms clear nuclear etch pit. The etching performances and track parameters vary as a function of the concentration of NaOH solution. The most sensitive normality was confirmed to be 7 N. The track response is controllable with NaOH concentration at the range of Z∗/β ≥ 80 (Z∗: effective charge, β: velocity). The charge spectroscopic resolution for Xe (Z∗/β = 107) was found to be 0.23 cu (charge unit), which would allow to identify individual nuclear charge of ultra heavy nuclei around Actinides in the cosmic rays. The Ag+-doped phosphate glass would be a promising detector for high Z spectroscopy for cosmic ray and nuclear physics fields and has the potential to operate not only RPL dosimeter but also nuclear track etch detector