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SPIDER (Source for the Production of Ions of Deuterium Extracted from RF plasma) is the 100keV Ion Source Test facility (presently under construction in the Neutral Beam Test Facility at Consorzio RFX premises, in Padua, Italy) representing the full scale prototype of the Ion Source (IS) for the ITER 1 MeV Neutral Beam Injector (NBI). SPIDER Ion Source, polarized at -100kVdc Power Supply, is meant to produce Deuterium or Hydrogen negative ions which, after being extracted by the extraction grid, are accelerated up to ground potential. The required Ion Source and the Extraction Grid Power Supplies (ISEPS) system and the associated diagnostics need to be hosted inside a -100kVdc air-insulated Faraday cage, called High Voltage Deck (HVD), while a High Voltage Transmission Line (TL) transmits the power and signal conductors from the ISEPS to the Ion Source. An air insulated design of the TL, duly screened against Electromagnetic Interferences (EMI) produced by the frequent IS grids breakdowns was preferred to a more complex and costly Gas Insulated Line design because of the large diameter required by the TL inner conductor to host all ISEPS power and signal conductors, fibres optic and cables. The TL is procured (together with the HVD) by COELME SpA, via a procurement contract with Fusion for Energy (F4E) started mid 2013. The paper describes the construction solutions developed by the Manufacturer to meet the design indications and technical specification requirements for such unconventional device. Moreover, the results of factory type tests, carried out on a first section of the TL mid-2015 to validate the design and release the manufacturing of the overall TL, are also described. Finally, the paper reports on the on-site installation and commissioning activities, presently ongoing, up to the final acceptance foreseen within the current year.

The linear and nonlinear optical properties of the heteroaromatic push-pull-push two-photon absorbing dye N-methyl-2,5-bis[1-(N-methylpyrid-4-yl) ethen-2-yl]-pyrrole ditriflate (PEPEP) are reported. The determination of the two-photon absorption (TPA) cross-section spectrum has been performed with different techniques: femtosecond TPA-white light continuum probe experiments, two-photon-induced fluorescence, and open aperture Z-scan measurements using both nanosecond and femtosecond laser pulses. The measured TPA cross sections and their wavelength dispersion show a marked dependence on the parameters of the laser pulses and on the measurement technique employed. These properties are discussed in terms of the different microscopic mechanisms that can contribute to the multiphoton absorption processes, with different weight depending on the measurement conditions and on the photophysical parameters of the dye. © 2008 American Chemical Society.

We have investigated the photoinduced optical properties of a new class of chiral methacrylic polymers characterised by the presence in the side chain of an optically active pyrrolidinyl ring linked to a trans-azoaromatic system. The homopolymers are enantiomerically pure and their strong optical activity indicates that the macromolecules assume, both in solution and in solid thin films, highly homogeneous conformations with a prevailing chirality. As expected, the studied polymers exhibit reversible linear dichroism and birefringence when irradiated with linearly polarised light. By irradiating with circularly polarised light, we have discovered that it is possible to photomodulate the chiroptical properties of the polymer films. After irradiation with L-polarised light, the CD spectra of the films show a net inversion of their relative sign. The effect is reversible and the original shape of the CD spectra can be restored by pumping with R-polarised radiation. This unexpected new phenomenon can be explained in terms of the ability of the L-polarised radiation to invert the prevailing helicity of the polymeric chains. The observed effect seems to open new possibilities for the use of azobenzene-containing materials as chiroptical switches.

Tazzoliite, ideally Ba2CaSr0.5Na0.5Ti2Nb3SiO17[PO2(OH)(2)](0.5), is a new mineral (IMA 2011-018) from Monte delle Basse, Euganei Hills, Galzignano Terme, Padova, Italy. It occurs as lamellar pale orange crystals, which are typically a few mu m thick and up to 0.4 mm long, closely associated with a diopsidic pyroxene and titanite. Tazzoliite is transparent. It has a white streak, a pearly lustre, is not fluorescent and has a hardness of 6 (Mohs' scale). The tenacity is brittle and the crystals have a perfect cleavage along {010}. The calculated density is 4.517 g cm(-3). Tazzoliite is biaxial (-) with 2V(meas) of similar to 50 degrees, it is not pleochroic and the average refractive index is 2.04. No twinning was observed. Electron-microprobe analyses gave the following chemical formula: (Ba1.93Ca1.20Sr0.52Na0.25Fe0.102+)(Sigma 4) (Nb2.88Ti2.05Ta0.07Zr0.01V0.015+)(Sigma 5.02)SiO17[(P0.13Si0.12S0.07)(Sigma 0.32)O-0.66(OH)(0.66)][F-0.09(OH)(0.23)](Sigma 0.32). Tazzoliite is orthorhombic, space group Fmmm, with unit-cell parameters a = 7.4116(3), b = 20.0632(8), c = 21.4402(8) angstrom, V = 3188.2(2) angstrom(3) and Z = 8. The crystal structure, obtained from single-crystal X-ray diffraction data, was refined to R-1(F-2) = 0.063. It consists of a framework of Nb(Ti) octahedra and BaO7 polyhedra sharing apexes or edges, and Si tetrahedra sharing apexes with Nb(Ti) octahedra and BaO7 polyhedra. The structure, which is related to the pyrochlore structure, contains three Nb(Ti) octahedra: two are Nb dominant and one is Ti dominant. Chains of A2O(8) polyhedra [A2 being occupied by Sr(Ca,Fe)] extend along [100] and are surrounded by Nb octahedra. Channels formed by six Nb(Ti) octahedra and two tetrahedra, or four A2O(8)(OH) polyhedra (A1 being occupied by Ba), alternate along [100]. The channels are partially occupied by [PO2(OH)(2)] in two possible mutually exclusive positions, alternating with fully occupied A3O(7) polyhedral pairs [A3 being occupied by Ca(Na)]. The seven strongest X-ray powder diffraction lines [d in angstrom (I/I-0) (hkl)] are: 3.66 (60) (044), 3.16 (30) (153), 3.05 (100) (204), 2.98 (25) (240), 2.84 (50) (064), 1.85 (25) (400) and 1.82 (25) (268). Raman spectra of tazzoliite were collected in the range 150-3700 cm(-1) and confirm the presence of OH groups. Tazzoliite is named in honour of Vittorio Tazzoli in recognition of his contributions to the fields of mineralogy and crystallography.

We report the first example of a heterocycle-based multi-branched two-photon absorption (TPA) dye. We show that the new pyridinium chromophore presents a very large TPA cross-section in the femtosecond regime. Comparison of the TPA cross-sections between the branched system and the corresponding \"monomeric unit\" shows a strong cooperative enhancement. A value of 22.6:1, corresponding to a 750% enhancement, was obsd.

An original and convenient three steps (swelling-poling-deswelling) process of poling a cross-linked polymer/NLO-phore composite to produce a stable second harmonic generation is described, using as a model system a cross-linked poly-amido amine network carrying covalently attached a modified Disperse Red One, a well known NLO-phore. This procedure is expected to be of wide applicability to produce composite polymeric materials with a rather stable second harmonic generation and of particular interest for NLO-phores sensitive to temperature. (c) 2007 Elsevier B.V. All rights reserved.

The amplification of Raman signals of the heteroaromatic cation 1-(N-methylpyrid-4-yl)-2-(N-methylpyrrol-2-yl)ethylene (PEP+)) bound to Au nanorods (NRs) was investigated at different excitation wavelengths to study the effect of the laser resonance with the absorption band of the PEP+ moiety and with the two plasmon oscillation modes of the NR. Two different PEP+ derivatives, differing in the length of the alkyl chain bearing the anchoring group, were used as target molecules. Raman spectra obtained exciting at 514 or at 785 nm (i.e., exciting the transverse or the longitudinal plasmon band) present a higher intensity than that at 488 nm suggesting a higher Raman amplification when the laser excitation wavelength is resonant with one of the two plasmon modes. Moreover, considering results of Discrete Dipole Approximation (DDA) calculations of the local field generated at the NR surface when either the transverse or the longitudinal plasmon modes are excited, we deduced that the resonance condition of the 514-nm laser excitation with the absorption band of the dye strongly contributes to the amplification of the Raman signal. © 2014 The Author(s).

In this work we present an investigation of the non-linear optical (NLO) properties of two octupolar chromophores: [Zn(4,4'-bis(dibutylaminostyryl)-[2,2']-bipyridine)(3)](2+) and [Zn(4,4'-bis((E)-2-(N-(TEG)pyrrol-2-yl)vinyl)-[2,2']-bipyridine)(3)](2+) with Zn(ii) as the coordination center, using two-photon emission technique (TPE) in fs-pulse temporal regime. Compared to the free ligands, our results do not show a net increase in the two-photon absorption (TPA) cross-section for the octupolar complexes, once normalized to the ligand unit. This is in partial disagreement with a previous theoretical study investigating the first molecule where a significant increase of the TPA cross-section was predicted (X. J. Liu, et al., J. Chem. Phys., 2004, 120, 11 493).

A novel scheme for implementing the joint exploitation of different, somehow complementary mechanisms of nonlinear transmission in an optical limiting device is proposed. As active materials we have chosen the fullerene derivative FULP, as a reverse saturable absorber, and a new heterocyclic quadrupolar dye, PEPEP, with highly efficient multiphoton absorption for nanosecond pulses. The nonlinear absorption properties of PEPEP in solution are extensively investigated for both femtosecond and nanosecond pulses. When Z-scan experiments are performed with nanosecond pulses, much larger effective cross sections are measured than with femtosecond pulses and with remarkably different wavelength dispersion. This is interpreted as due to two-photon absorption followed by one-photon absorption from the excited state. Chemically modified nonlinear molecules are incorporated in a hybrid organic-inorganic sol-gel matrix. Sufficiently high concentrations are achieved to allow the assembling of thin sol-gel disks into a "tandem" limiter with a total thickness smaller than the Rayleigh range of the focused laser beam. Preliminary testing of our limiter is reported and shows encouraging results. The resistance of the FULP-doped sol-gel glass to laser damage is substantially improved and the nonlinear attenuation at high pulse energies is enhanced.

The first examples of heterocycle-based multi-branched dyes with efficient two-photon absorption (TPA) activity are reported; the novel chromophores exhibit large TPA cross sections ( as high as 1600 x 10(-50) cm(4) s photon(-1) molecule(-1), measured with 150 fs laser pulses at 800 nm); a strong cooperative enhancement in the branched systems with respect to the one-dimensional sub-units is found

The multiphoton absorption properties of an organic push-molecule are investigate with nano- (ns) and femto-second (fs) laser sources. The active molecule is a new quadrupolar dye, named PEPEP, where heterocyclic units act as strong donor-acceptor moieties. Z-scan and pump-probe experiments (both single-color and with white light pulses) allow us to measure the value and the wavelength dispersion of the cross section for instantaneous two photon absorption (TPA). When Z-scan experiments are performed with nanosecond pulses, much larger effective cross sections are measured than with femtosecond pulses and with remarkably different wavelength dispersion. This is interpreted as due to two-photon absorption followed by one-photon absorption from the excited state (TPA-ESA). The TPA (or TPA-ESA) spectrum is measured, through pump-probe and z-scan measurements in a large visible range, in order to find the peak wavelength for multiphoton absorption.