Influence of crystalline surface quality on TlBr radiation detector performance
In this study, TlBr detectors were fabricated from crystals purified by the multipass zone refining and grown by the Bridgman method. Detectors were prepared using TlBr 0.3-mm-thick wafers, with surface submitted to different mechanical and chemical treatments. Optical microscopy and scanning electron microscopy evaluated the TlBr wafers surface quality. To analyze the surface quality influence in the detector response, systematic measurements of the pulse height spectra and energy resolution were carried out for each prepared radiation detector. The radiation response for these detectors was performed under /sup 241/Am gamma radiation excitation at room temperature. The influence of the surface quality of the TlBr wafer on its performance as a radiation detector was observed.
Multi-elemental segregation analysis of thallium bromide impurities purified by the repeated Bridgman technique
TlBr crystals were purified and grown by the repeated Bridgman method from commercial TlBr salt and characterized to be used as radiation detectors. To evaluate the purification efficiency, measurements of the impurity concentration were made after each growth, analyzing the trace impurities by inductively coupled plasma mass spectroscopy (ICP-MS). A significant decrease of the impurity concentration resulting from the purification number was observed. To evaluate the crystal as a radiation semiconductor detector, measurements of its resistivity and gamma-ray spectroscopy were carried out. The radiation response depended on the crystal purity. The repeated Bridgman technique improved the TIBr crystal quality used as a radiation detector. An exponential model was used to fit the impurity concentration as a function of the repetition number of the Bridgman growth.
Symptomatic Trans-sexualism
A 24-year-old male schizophrenic had a delusion that he was female and had lived his life as a woman for almost two years. Unlike the only other reported case, his ‘symptomatic transsexualism’ responded to the effective treatment of his schizophrenia.