100 m Nuclear emulsions are made of micro- crystals of silver halides (AgBr) dispersed in a gelatin layer. The energy released by ionizing particles to the crystals, produces a latent image which is almost stable in time. A chemical development process reduces the irradiated grains to metallic Ag. After fixing and washing to remove undeveloped crystals the gelatin is transparent; the paths of an ionizing particle is visible as sequence of black silver grains about 0.5 m size. Provide: Three-dimensional spatial information. Excellent Resolution < 1 m. High hit density ~ 300 hits/mm. Ideal to detect short-lived particles ( decay) OPERA target: ~ ECC Bricks 8 m Real time analysis: ~ 30 neutrino selected interactions per day; ~ 6000 cm per day have to be analyzed with a sub- micrometric precision during 5 years data taking. Emulsion sheet (10 x 12 cm 2 ): 2 emulsion layers (44 m ) on both sides of a plastic base (205 m) Move Focal Plane Camera gs camera optical tube objective emulsion transparent slide with vacuum system motorized stage motorized axis condenser lamp auxiliary monitor for real-time display Computer with: frame grabber and vision processor motors and lamp controllers 1. Nuclear Emulsion References:N. Armenise et al., Nucl. Instrum. Meth. A551 (2005) 261; L. Arrabito et al., ArXiv:physics/ , Nucl. Instrum. Meth. A (in press). Presented at the 10th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD06) 1-5 October 2006 Siena, Italy G.Sirri (INFN Bologna) on behalf of the OPERA Collaboration beam beam 2. OPERA experiment Fast automated scanning of emulsion films for the OPERA (CNGS1) experiment 3. OPERA Lead-Emulsion Target 4. Automatic Emulsion Scanning System 5. Emulsion Readout New automatic fast automatic scanning systems have been developed: the European Scanning System (ESS) and the S-UTS in Japan. emulsion plastic base tracks 44 m 205 m base tracks cluster microtracks 44 m Top emulsion layer Bottom emulsion layer 3m3m By adjusting the focal plane of the objective, the whole 44 m emulsion thickness is spanned and a sequence of 15 tomographic images of each field of view, taken at equally spaced depth levels ( m), is obtained. Emulsion images are digitized, converted into a grey scale of 256 levels, sent to a vision processor board, hosted in the control workstation, and analyzed to recognize sequences of aligned grains (clusters of dark pixels of given shape and size). OPERA is a long baseline experiment (located in the INFN Gran Sasso Underground Laboratories) which will investigate for oscillations in the parameter range suggested by atmospheric neutrino experiments. The goal is to observe the appearance of leptons in a pure beam produced at the CERN-SPS (the CNGS neutrino beam). The leptons are identified through the direct detection of their decays that, at the CNGS energies, are at distances of 1 mm from the production point. Therefore, a high precision detector is needed. Lead 1 mm ECC Brick (10x13x8 cm) sequence of 56 Lead and Emulsion sheets The OPERA detector is a hybrid system consisting of electronic detectors and a massive lead-emulsion target segmented into ECC bricks The Emulsion Cloud Chamber (ECC), a sequence of dense material (Lead) sheets, acting as target, interleaved with emulsion sheets, acting as high precision trackers, satisfies the need of both a large mass and a high precision tracking capability. Industrially mass production of films by Fuji Co in 2 years. OPERA detector at Gran Sasso 20 cm/h [44 m emulsion layer] European Scanning System. Several test exposures at pions beams were performed for estimating the scanning performances. The scanning systems are successfully running with high efficiency (>90%), good signal/background ratio (~2 tracks/cm /[angle 20 mrad ~ Emulsion scanning system layout. The three-dimensional structure of a track in an emulsion layer is reconstructed by combining clusters belonging to images at different levels and searching for geometrical alignments. A linear fit to these clusters allows the determination of the track position and angle. After emulsion sheets alignment, tracks are reconstructed in the entire brick. Plastic base ! Emulsion Sheet Reconstruction of a neutrino interaction in a ECC Brick position = 1 m angle = 2 mrad The position and angular resolutions at small incident angles are position = 1 m and angle = 2 mrad. By adjusting the focal plane of the objective, the whole 44 m emulsion thickness is spanned at equally spaced depth levels ( m), and a sequence of 15 tomographic images of each field of view is obtained. Emulsion images are digitized, converted into a grey scale of 256 levels, sent to a vision processor board, hosted in the control workstation, and analyzed to recognize sequences of aligned grains (clusters of dark pixels of given shape and size).