[Luminescence Characteristics of Scintillator Y2SiO5∶Ce].

Cerium doped Y2SiO5 (YSO) is an important scintillator material due to its high density, non-hygroscopic, excellent light output and fast decay time nature. in the paper, Y2SiO5∶Ce3+0.2%(YSO∶Ce) was grown with high-temperature solid-phase method. The time-resolved excitation and emission spectra and fluorescent decay curves at low temperature and room temperature (RT) were measured and discussed. There were two types of luminescence, one was the crystal defect emission, the center at 320 nm; the other one was doped Ce3+ ions 5d→4f emission, the center at 440 nm. Only when the excitation energy (Ex) was greater than the band gap width (Eg), the crystal defect emission can be observed corresponding to slow process, and the emission intensity was higher at low temperature. The crystals defect emission was hardly observed in the time-resolved emission spectra when the temperature rose to room temperature because of temperature quenching. Regions from 60~300 nm corresponding to emission due to 5d→4f transitions in the activator Ce3+ ions peaks at 440 nm, a plurality of excitation peaks were observed. Among them, the excitation with energy less than 6.1 eV(Ex

[Nonlalocalized interference in multiple-beam interferometer].

The authors studied the nonlocalized interference in multiple-beam interferometer. The light intensity distribution function was obtained. The result shows that the function in the circle center has the same form with localized interference. Numerical simulation method was used to analyse the light intensity distribution function. As the reflection coefficient increases, the stripe becomes sharp, Resolution ratio was improved, while the noise occured around the lower interference index. The noise becomes obviously as the reflection coefficient increases. While changing the receiving screen distance, the simulation result shows that linear relationship exists between inteference index and cosine value of interference stripe dip angle. The mirror spacing can be obtained through the straight line slope. With changing the mirror spacing, the numerical simulation result shows that linear relationship exists between interference index and stripe radii square. The straight slope shows a linear relationship with the mirror spacing.