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ITER envisages the use of two heating neutral beam injectors plus an optional one as part of the auxiliary heating and current drive system, to reach the desired performances during its various phases of operation. The 16.5 MW expected neutral beam power per injector is several notches higher than worldwide existing facilities.In order to enable such development, a Neutral Beam Test Facility (NBTF) was established at Consorzio RFX, exploiting the synergy of two test beds, called SPIDER and MITICA. SPIDER is dedicated developing and char-acterizing large efficient negative ion sources at relevant parameters in ITER-like conditions: source and accel-erator located in the same vacuum where the beam propagates, immunity to electromagnetic interferences of multiple radio-frequency (RF) antennas, avoidance of RF-induced discharges on the outside of the source. Three years of experiments on SPIDER have addressed to the necessary design modifications to enable full perfor-mances. The source is presently under a long shut-down phase to incorporate learnings from the experimental campaign, in particular events/issues occurred during operation, which led to the identification of improvement opportunities/necessities (e.g. RF discharges, local burns, water leaks, other damages, configuration/design upgrades to maximize chances/margin to quest target parameters).Parallelly, developments on MITICA, the full-scale prototype of the ITER Neutral Beam Injector (NBI) featuring a 1 MV accelerator and ion neutralization, are underway including manufacturing of the beam source, accel-erator and the beam line components, while power supplies and auxiliary plants, already installed, are under final testing and commissioning.Integration, commissioning and tests of the 1 MV power supplies are essential for this first-of-kind system, unparalleled both in research and industry field. 1.2 MV dc insulating tests of high voltage components were successfully completed. The integrated test to confirm 1 MV output by combining invertor systems, DC gener-ators and transmission lines extracted errors/accidents in some components. To realize a concrete system for ITER, said events have been addressed and solutions for the repair and the improvement of the system were developed.Hence, NBTF is emerging as a necessary facility, due to the large gap with existing injectors, effectively dedicated to identify issues and find solutions to enable successful ITER NBI operations in a time bound fashion. The lessons learned during the implementation on NBTF and future perspectives are here discussed.

An investigation of the gamma background was carried out in the VESUVIO spectrometer at the ISIS spallation neutron source. This study, performed with a yttrium-aluminum-perovskite (YAP) scintillator, follows high resolution pulse height measurements of the gamma background carried out on the same instrument with the use of a high-purity germanium detector. In this experimental work, a mapping of the gamma background was attempted. trying to find the spatial distribution and degree of directionality of the different contributions identified in the previous study. It is found that the gamma background at low times is highly directional and mostly due to the gamma rays generated in the moderator-decoupler system. The other contributions, consistently to the findings of a previous experiment, are identified as a nearly isotropic one due to neutron absorption in the walls of the experimental hall, and a directional one coming from the beam dump. (c) 2009 Elsevier B.V. All rights reserved.

The absorption and luminescence spectra of Er3+-doped Ba2NaNb5O15 single crystals have been measured at 10 and 298 K. The lifetimes of the lower lying excited states, emitting in the visible and NIR regions, have been measured as a function of the temperature. From the oscillator strengths of the absorption transitions, the Judd-Ofelt intensity parameters have been evaluated. The spontaneous transition probabilities, the branching ratios and the radiative lifetimes have been determined for the most important emitting states using the calculated intensity parameters and the results have been compared with the experimental data. The stimulated emission cross section have been estimated for the 1.5 mu m transition. These experimental results are discussed in order to evaluate the potentialities of this material as active medium in solid state laser devices. (c) 2005 Elsevier B.V. All rights reserved.

In this work we present the first direct observation of a 220 cm −1 progression in the absorption spectrum of trans -azobenzene in the vapour phase. The mode at 220 cm −1 is essential to explain both the electronic absorption spectrum and the Raman excitation profiles of the most intense Raman bands of trans -azobenzene in the 1000–1600 cm −1 shift range. Our data in the vapour phase assure that this frequency pertains to an internal molecular mode.

A review of the electrical and optical beam parameters is given. We describe our computer controlled, four slit beam characterization technique called computer controlled beam diagnostic CCBD system. The CCBD system can be operated in beam profile and emittance modes. The data collection is finished with appearance on the screen of the corresponding three-dimensional diagram: the current density map of x ; x ′ and y ; y ′ emittance maps. As a result of software manipulation further beam characteristics like current contours, emittance patterns, emittance as a function of beam fraction etc. can be deduced. The setup consists of four motorized, water cooled slits with variable slit width allowing to handle beams from μA up to hundreds of μA.

Polarized Raman spectra at 77 K of all- trans -β-carotene stretch-oriented in polyethylene films are reported for the first time. The measurements were carried out either in the 90° and back-scattering geometries at excitation wavelengths in resonance with the lowest allowed 1 B u « 1 A g electronic transition, and indicate a rather good orientation of the polyenic chains along the stretching direction. By changing the excitation wavelength, a significant dispersion of the Raman shift relative to the CC stretching mode is observed. One interpretation of this effect, based on the existence of two (or more) species (rotational conformers, aggregates, etc.) whose resolved absorption structures are displaced by one half the CC vibrational frequency, is presented and discussed.

Resonant Raman spectra of highly oriented trans polyacetylene have been obtained for different scattering configurations at various exciting wavelengths. The polarization properties of the Raman active phonons have been determined for the first time. The changes in the Raman bandshapes observed upon changing the scattering configuration seem to imply that the dispersion of the Raman bands originates from a distribution of conjugation lengths.

The Cs 8S level hfs splitting δ 8 has been measured. The experimental value δ 8 = (900 ± 60) MHz is in good agreement with both other experimental results and theoretical predictions.

Novel data on the polarization properties of the two resonantly enhanced Raman bands of trans polyacetylene have been obtained using the 609.6 nm line of a dye laser. Approximate corrections to take into account the optical anisotropy of the sample have been worked out. The changes of the observed band shapes and of the corrected intensities with the scattering configuration are consistent with a distribution of conjugation lengths. For short conjugated segments the electronic transition moment does not appear to be strictly aligned along the chain direction.

We have developed a manufacturing process for arrays of high resistance lead glass tubing of various diameters, ranging from 500 μm to several mm, for the detection of γ-rays. We describe the applications of this type of device to positron emission tomography and high energy physics.

Results of an experiment to measure the 2P 3/2 −2S 1/2 energy difference δ 1 in the muonic (μ −4 H e) + ion are presented; we found δ 1 exp = 1.5274 ± 0.0009 eV. Comparison with QED predictions shows that there is agreement between theory and experiment within 0.0087 eV; this limitation is mainly due to the uncertainty with which the r.m.s. charge radius of the 4 He nucleus is known.

Raman excitation profiles for the chromate 863 cm−1 totally symmetric mode and for its first two overtones, measured in rigorous resonance with the absorption band at 372 nm, are reported. Data were taken on a lyophilised mixture of K2CrO4 in K2SO4, and the 981 cm−1 sulphate fundamental was used as an internal standard for intensity measurements. Results are analysed in terms of a model based on the Franck-Condon scattering mechanism assuming either a singlet F2 resonant state or three non-degenerate states resulting from the Cs symmetry of the CrO2−4 ion in our medium. Comparisons are made with the results obtained by other authors for the isoelectronic MnO−4 ion.

The results of a new measurement of the 2 S 1 2 -2 P 3 2 splitting S 1 in the muonic ion (μ −4 He) + are presented. We found S e xp 1 = 1527.5 ± 0.3 meV. Using the new, recently determined, value of the rms charge radius for 4 He we obtain for the difference D , between S exp 1 and the corresponding theoretical prediction, the value D = 0.2 ± 4.2 meV: this value directly confirms, assuming μ-e universality, the QED vacuum polarization prediction to 0.25 %.

Pionic X-rays have been observed when negative pions are stopped in a hydrogen gas target. The intensity of the K lines has been found to be about 0.12 X-ray/pion stopped; moreover we found K α /K = 0.53 ± 0.04.

We descril'e here an assembly target-X-ray detector that is particularly suitable for detecting muonic and pionic X-rays in the range 1.3–10 keV. Some of the main features of the system are described.

The measurement of the 2S 1 2 → 2P 1 2 energy transition in muonic helium is presented. The energy difference S1 is found to be Sexp1 = 1381.3±0.5 meV. This result agrees with the expected value S 1 = 1381.2±0.3 meV obtained assuming the previously measured value for the 2S 1 2 → 2P 3 2 energy difference.

The Cs 8S-level lifetime has been measured. The experimental value τ exp (8S) = 73 ± 5 ns is smaller than the theoretical prediction. Evidence for cooperative effects in the e.m. cascade has been found.

Spectra have been measured of protons, deutrons and tritons emitted following the capture of negative pions in 4 He. The proton spectrum agrees with existing calculations but the deuteron spectrum does not.