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New methods for efficient and unambiguous interconnection between electronic position sensitive detectors and target units based on nuclear photographic emulsion films have been developed. The application to the OPERA experiment, that aims at detecting ν µ ⇋ ν τ oscillations in the CNGS neutrino beam, is reported in this paper. In order to reduce background due to latent tracks collected before installation in the detector, on-site large-scale treatments of the emulsions ("refreshing") have been applied. Changeable Sheet (CSd) packages, each made of a doublet of emulsion films, have been designed, assembled and coupled to the OPERA target units ("ECC bricks"). A device has been built to print X-ray spots for accurate interconnection both within the CSd and between the CSd and the related ECC brick. Sample emulsion films have been extensively scanned with state-of-the-art automated optical microscopes. Efficient track-matching and powerful background rejection have been achieved in tests with electronically tagged penetrating muons. Further improvement of in-doublet film alignment was obtained by matching the pattern of low-energy electron tracks. The commissioning of the overall OPERA alignment procedure is in progress.

Results of the second stage of the RAMBAS (RAdiation Mechanism of Biomolecular ASymmetry) experiment on investigation of the radiation mechanism of the influence on chiral molecules are presented. Optical activity of samples of racemic mixtures of amino acids with heavy metals was compared prior to and after irradiation by electron flux from a radioactive source. It is found that the irradiation results in asymmetric degradation of both complexes and amino acids and in production of chiral asymmetry of the samples under study. These results confirm the conclusions inferred from the first stage of the RAMBAS experiment and could be important for the solution of the origin-of-life and biological homochirality problems.

The OPERA neutrino oscillation experiment is based on the use of the Emulsion Cloud Chamber (ECC). In the OPERA ECC, nuclear emulsion films acting as very high precision tracking detectors are interleaved with lead plates providing a massive target for neutrino interactions. We report on studies related to the effects occurring from the contact between emulsion and lead. A low radioactivity lead is required in order to minimize the number of background tracks in emulsions and to achieve the required performance in the reconstruction of neutrino events. It was observed that adding other chemical elements to the lead, in order to improve the mechanical properties, may significantly increase the level of radioactivity on the emulsions. A detailed study was made in order to choose a lead alloy with good mechanical properties and an appropriate packing technique so as to have a low enough effective radioactivity.

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