Spectral modeling of scintillator for the NEMO-3 and SuperNEMO detectors

We have constructed a GEANT4-based detailed software model of photon transport in plastic scintillator blocks and have used it to study the NEMO-3 and SuperNEMO calorimeters employed in experiments designed to search for neutrinoless double beta decay. We compare our simulations to measurements using conversion electrons from a calibration source of $\rm ^{207}Bi$ and show that the agreement is improved if wavelength-dependent properties of the calorimeter are taken into account. In this article, we briefly describe our modeling approach and results of our studies.Comment: 16 pages, 10 figure

Scanning Angle Plasmon Waveguide Resonance Raman Spectroscopy for the Analysis of Thin Polystyrene Films

Scanning angle (SA) Raman spectroscopy was used to characterize thin polymer films at a sapphire/50 nm gold film/polystyrene/air interface. When the polymer thickness is greater than ∼260 nm, this interface behaves as a plasmon waveguide; Raman scatter is greatly enhanced with both p- and s-polarized excitation compared to an interface without the gold film. In this study, the reflected light intensities from the interface and Raman spectra were collected as a function of incident angle for three samples with different polystyrene thicknesses. The Raman peak areas were well modeled with the calculated mean-square electric field (MSEF) integrated over the polymer film at varying incident angles. A 412 nm polystyrene plasmon waveguide generated 3.34× the Raman signal at 40.52° (the plasmon waveguide resonance angle) compared to the signal measured at 70.4° (the surface plasmon resonance angle). None of the studied polystyrene plasmon waveguides produced detectable Raman scatter using a 180° backscatter collection geometry, demonstrating the sensitivity of the SA Raman technique. The data highlight the ability to measure polymer thickness, chemical content, and, when combined with calculations of MSEF as a function of distance from the interface, details of polymer structure and order. The SA Raman spectroscopy thickness measurements agreed with those obtained from optical interferometery with an average difference of 2.6%. This technique has the potential to impact the rapidly developing technologies utilizing metal/polymer films for energy storage and electronic devices

NIKOLOV I., Dispersion properties of optical polymers

In this report dispersion properties of different types of optical polymers are discussed on the base of measured refractive indices and the Cauchy-Schott approximation. A number of dispersion curves are presented in the visible and near infrared spectral regions between 400 and 1060 nm. A comparison with some optical glasses with similar refraction is performed. The nonlinear dependence of dn/ dλ of polymer materials and test glasses on the wavelength is calculated and analyzed. Normalized dispersion curves at 550 nm and 880 nm are presented to illustrate better the dispersion of the polymers in the considered spectral regions, separately. Abbe numbers are calculated to exhibit the mean and partial dispersion

Dispersion Properties of Optical Polymers

In this report dispersion properties of different types of optical polymers are discussed on the base of measured refractive indices and the Cauchy-Schott approximation. A number of dispersion curves are presented in the visible and near infrared spectral regions between 400 and 1060 nm. A comparison with some optical glasses with similar refraction is performed. The nonlinear dependence of dn/dλ of polymer materials and test glasses on the wavelength is calculated and analyzed. Normalized dispersion curves at 550 nm and 880 nm are presented to illustrate better the dispersion of the polymers in the considered spectral regions, separately. Abbe numbers are calculated to exhibit the mean and partial dispersion