Description of a PLACET-compatible ground motion generator

Goals of ATF2 will be to provide nanometer size beams and sub-nanometer stability. To achieve it, simulations of feedback systems should be done based on realistic ground motion generators. A generator which produces output compatible with the PLACET simulations was developed with Matlab to reproduce the vibration spectra measured on the ATF floor at KEK. Spatial coherence between elements was also introduced in an approximate way. This generator is described here

Study of supports for the final doublets of ATF2

We investigated supports for the final doublets of ATF2 with vertical relative motion to the floor of final doublets below 10nm. Our calculations of relative motion were done by using data of ATF ground motion. We studied the vibratory behaviour of a steel lightweight honeycomb table as a base for fixing magnets. First, the table was fixed to the floor by four steel feet at its corners. Its first vertical resonance was at 41Hz, which induces a non negligible relative motion (5.7nm) compared to ATF2 tolerances. Modal shape measurements show that the six first resonances of the table (below 150Hz) are rigid body modes in the six degrees of freedom. The conclusion of these measurements is that the table is very rigid and well adapted for ATF2 project but the rigidity of the four steel feet is not sufficient compared to the rigidity of the table. Consequently, the table was fixed to the floor on one entire face to break these six rigid body modes by three large steel plates. The first vertical resonance was then at higher frequencies (92Hz), which show that good boundary conditions were chosen for the table. The relative motion was then low (3.5nm above 0.1Hz) compared to ATF2 tolerances. To finish, we studied the vibratory behaviour of one ATF2 FD sextupole and one ATF2 FD quadrupole with their intermediary supports made at LAPP and used to fix these magnets to the honeycomb table. The measurements showed that the final doublets with their intermediary supports were well designed because the first resonance of sextupoles and quadrupoles was at high frequency (above 100 Hz and at 76Hz respectively), which induced a small relative motion of final doublets to the floor compared to ATF2 tolerances

Simulation of Multiknobs Correction at ATF2

THPD096International audienceThe ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. During initial commissioning, we started with larger than nominal ?-functions at the IP, to reduce the effects from higher-order optical aberrations and thereby simplify the optical corrections needed. We report on simulation studies at two different IP locations developed based on waist scan, dispersion, coupling and ? function multiknobs correction in the large ? optics of ATF2, in the presence of two kinds of magnet inaccuracies (quadrupole gradient and roll errors) to generate all possible linear optics distortions at the IP. A vertical beam size which is very close to the nominal beam size is obtained based on the simulation study

Linear Collider Test Facility: Twiss Parameter Analysis at the IP/Post-IP location of the ATF2 beam line

THPD077International audienceAt the first stage of the ATF2 beam tuning, vertical beam size is usually bigger than 3um at the IP. Beam waist measurements using wire scanners and a laser wire are usually performed to check the initial matching of the beam through to the IP. These measurements are described in this paper for the optics currently used (?x=4cm and ?y=1mm). Software implemented in the control room to automate these measurements with integrated analysis is also described. Measurements showed that beta functions and emittances were within errors of measurements when no rematching and coupling corrections were done. However, it was observed that the waist in the horizontal (X) and vertical (Y) plane was abnormally shifted and simulations were performed to try to understand these shifts. They also showed that multiknobs are needed in the current optics to correct simultaneously ?x, ?y and the horizontal dispersion (Dx). Such multiknobs were found and their linearity and orthogonality were successfully checked using MAD optics code. The software for these multiknobs was implemented in the control room and waist scan measurements using the ?y knob were successfully performed

Linear collider test facility: ATF2 final focus active stabilisation pertinence

International audienceBeam motion at the Interaction Point (IP) of ATF2 has to be less than 10nm relative to the instrumentation used for measurements. Due to ground motion (GM), the beam can pass off-axis through the quadrupoles of the beam line and hence be deflected. It was shown in previous studies that good spatial coherence of the GM over a few meters makes the relative motion of the Final Doublets (FD) small enough for the tolerance not to be exceeded. However, since the coherence drops rapidly with distance, other quadrupoles further upstream can be expected to induce significant effects. In this paper, an evaluation taking into account all ATF2 quadrupoles is presented, using a GM generator with parameters tuned to dedicated measurements done recently along the ATF2 beam line and propagating to the IP with the optical transfer matrices. It was shown that although large IP beam motion can indeed be induced by some specific upstream quadrupoles, the combined effect of all is small because of compensations. The tolerance can thus be achieved without specially stabilising these quadrupoles

Nitrogen DBD plasma treatment to enhance adhesion of wood flooring.

Tratamento por plasma caracteriza-se como eficiente e como uma alternativa econômica e limpa para modificar a superfície da madeira. O presente estudo objetivou aumentar a adesão de peças de piso de madeira por plasma a frio. Para o tratamento dos pisos de madeira, utilizou-se um reator a plasma admitindo-se uma mistura de argônio e nitrogênio entre os eletrodos durante 10 minutos em baixa pressão. Configurou-se o reator para três níveis de potência ? 50, 100 e 150 W e uma frequência de 13.5 MHz. O fluxo de gás de argônio e nitrogênio foi estipulado em 10 e 100 sccm, respectivamente. As modificações na adesão foram investigados por meio de um goniômetro para a mensuração do ângulo de contato e a energia livre superficial. Para cada amostra, três gotículas (9.6 μl) foram dispensadas na superfície da madeira. Os principais resultados encontrados mostraram que o ângulo de contato das amostras modificadas por plasma foram ~2 vezes menor em relação ao ângulo de contato mensurado nas amostras não tratadas. A energia livre superficial da madeira modificada por plasma aumentou significativamente. O ângulo de contato e a energia livre superficial das amostras tratadas em diferentes potências foram estatisticamente iguais. Portanto, os tratamentos de plasma modificou significativamente a superfície da madeira em diferentes níveis de potência, o que resultou no aumento da adesão.EBRAMEM

Preliminary deployment of Grid-assisted oceanographic applications

Abstract. Grid integration of OGS oceanographic remote instruments and coupled physical-biogeochemical model has been explored in the framework of the EC-FP7 DORII project. We discuss here the first preliminary results achieved, describing the different tools developed with the support of the project consortium. A general background of the Grid technology for the e-Science is also provided.</p