Microwave emission by nonlinear crystals irradiated with a high-intensity, mode-locked laser

We report on the experimental investigation of the efficiency of some nonlinear crystals to generate microwave (RF) radiation as a result of optical rectification (OR) when irradiated with intense pulse trains delivered by a mode-locked laser at $1064\,$nm. We have investigated lithium triborate (LBO), lithium niobate (LiNbO$_3$), zinc selenide (ZnSe), and also potassium titanyl orthophosphate (KTP) for comparison with previous measurements. The results are in good agreement with the theoretical predictions based on the form of the second-order nonlinear susceptibility tensor. For some crystals we investigated also the second harmonic generation (SHG) to cross check the theoretical model. We confirm the theoretical prediction that OR leads to the production of higher order RF harmonics that are overtones of the laser repetition rate.Comment: accepted for publication in Journal of Optics, in pres

Particle detection in rare gas solid crystals: a feasibility experimental study—exploring new ways for dark matter searches: Exploring new ways for dark matter searches

This article reviews the experimental activity that has been carried out within the INFN DEMIURGOS research and development (R&D) project. This R&D concerns the study of possible innovative experimental approaches for the detection of low-energy-releases of feeble interacting particles within the matter. Possible applications could be the direct investigation of Dark Matter candidates. The idea behind the proposed scheme is to exploit rare gas solid crystals both pure and doped, combined with the in-vacuum single electron detection technology. In pure materials, the signal can be the charge produced directly during the ionization. Laser-assisted processes can instead be used to probe low-energy-releases in doped materials. Both these mechanisms should lead to a detectable electronic signal triggered by the incoming particle. In such a way, energy threshold ranging from meV to tens of eV could in principle be reached, opening-up the possibility to probe theoretically, well-motivated regions of unexplored electroweak parameter-space and thus test the existence of light Dark Matter candidates. The activity presented here has been performed to understand the mechanisms at the basis of the proposed detection scheme and possible showstopper. The experimental investigations refer to the research and development phases about: the crystal growing techniques and the corresponding set-up, the electrons’ extraction from rare gas crystals to the vacuum environment, and finally the spectroscopic studies on atomic species embedded into rare gas matrices

Cathodo- and radioluminescence of Tm3+^{3+}:YAG and Nd3+^{3+}:YAG in an extended wavelength range

We have studied the cathodo- and radioluminescence of Nd:YAG and of Tm:YAG single crystals in an extended wavelength range up to $\approx 5\,\mu$m in view of developing a new kind of detector for low-energy, low-rate energy deposition events. Whereas the light yield in the visible range is as large as $\approx 10^{4}\,$photons/MeV, in good agreement with literature results, in the infrared range we have found a light yield $\approx 5\times 10^{4}\,$photons/MeV, thereby proving that ionizing radiation is particularly efficient in populating the low lying levels of rare earth doped crystals.Comment: submitted for publication in Journal of Luminescenc

A new technique for infrared scintillation measurements

We propose a new technique to measure the infrared scintillation light yield of rare earth (RE) doped crystals by comparing it to near UV-visible scintillation of a calibrated Pr:(Lu$_{0.75}$Y$_{0.25}$)$_{3}$Al$_5$O$_{12}$ sample. As an example, we apply this technique to provide the light yield in visible and infrared range up to \SI{1700}{nm} of this crystal.Comment: submitted to NIM

PERFIL DOCENTE E O DESEMPENHO NO ENADE 2015 DOS CURSOS DE ADMINISTRAÇÃO E CIÊNCIAS CONTÁBEIS DE SANTA CATARINA

O objetivo deste estudo foi analisar a relação entre o perfil docente e a nota contínua do ENADE dos cursos de Administração e Ciências Contábeis das IES Catarinenses. O método utilizado para atingir o objetivo proposto pode ser classificado como uma pesquisa quantitativa de natureza descritiva, utilizando-se de dados secundários provindos do censo da educação superior. Foram coletados dados de 148 cursos que participaram do ENADE de Administração e Ciências Contábeis no ano de 2015 e obtiveram a nota contínua do ENADE. Os dados foram analisados utilizando-se de regressão linear múltipla com utilização do software SPSS 22. Os resultados indicam que as variáveis escolhidas relativas ao perfil docente como, Número de Docentes, Nota Bruta de Mestres, Nota Bruta de Doutores e Nota Bruta do Regime de Trabalho, explica 24% e 22% na Nota Continua do ENADE dos alunos dos cursos de Administração e Ciências Contábeis respectivamente. Analisando os dois cursos juntos, o perfil docente explica 22% na Nota Continua do ENADE. Nas análises individuais e conjunta a Nota Bruta do Regime de Trabalho influencia negativamente o desempenho dos alunos. Conclui-se que apesar dessas variáveis do perfil docente terem uma grande relevância para o cálculo do CPC, eles pouco influenciaram o desempenho dos alunos na Nota Contínua do ENADE