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The increase of luminosity demanded by the High Luminosity LHC (HL-LHC) requires an increase of beam intensity, which might result in instabilities appearing at injection energy in the CERN PS. Transverse head-tail instabilities have already been observed on operational LHC beams and a stabilizing mechanism as an alternative to linear coupling is currently being studied. It consists of reducing the mode number of the transverse oscillation by changing linear chromaticity and in succession completely suppressing the instability by a transverse damper system with appropriate bandwidth. Therefore, a chromaticity correction scheme at low energy exploiting the intrinsic possibilities offered by special circuits mounted on top of the main magnet poles, the Pole Face Windings (PFW), has been examined. The presence of destructive betatron resonances, which restrict the choice of the injection working point and the maximum acceptable tune spread, forms an additional limitation for high-brightness and high-intensity beams in the CERN PS. To improve the current working point control scheme, the influence of the PFW on the machine resonances is presented in this paper.

Some of the upgrade scenarios of the high-luminosity LHC require large intensity per bunch from the injector chain. Single bunch beams with intensities of up to 3.5 to 4e11 p/b and nominal emittances were successfully produced in the PS Complex and delivered to the SPS in 2010. This contribution presents results of studies with this new intense beam in the SPS to probe single bunch intensity limitations with nominal gamma transition. In particular, the vertical Transverse Mode Coupling Instability (TMCI) threshold with low chromaticity was observed at 1.6e11 p/b for single nominal LHC bunches in the SPS. With increased vertical chromaticity, larger intensities could be injected, stored along the flat bottom and accelerated up to 450 GeV/c. However, significant losses and/or transverse emittance blow up were then observed. Longitudinal and transverse optimization efforts in the PSB, PS and SPS were put in place to minimize this beam degradation and succeeded to obtain single 2.5e11 p/b LHC type bunches with satisfying parameters at extraction of the SPS.

The current 1.4 GeV CERN PS injection energy limits the maximum intensity required by the future High- Luminosity LHC. The bare-machine large chromaticity combined with the non-linear space charge forces make high-brightness and high-intensity beams cross betatron resonances along the injection flat bottom, inducing transverse emittance blow-up and beam losses. A scan of the working point plane (Qx,Qy) was done in order to identify beam destructive resonances, in the framework of a possible 2 GeV injection energy upgrade which would reduce the space charge effect on the tune. Experiments were carried out in order to review the maximum space charge tune shift for which no transverse emittance blow-up is observed. The results of measurements and simulations will be presented in this paper.

The CERN Proton Synchrotron has been continuously improving its beam performances since 1959. The working point parameters of the accelerator are mainly controlled by dedicated windings installed on the poles of the main combined function magnets. In 2007, the power supplies of these windings were renovated and extended from three to five independent groups, allowing exploration of new working point settings. This configuration offers the flexibility of several adjustment strategies such as leaving one current free or to control an additional physical parameter, like Q′′ h. A non-linear chromaticity measurement campaign, at different beam momenta, resulted in matrices defining the relationship between the five pole face winding currents and the four beam parameters Qh, Qv, h, and v. Each cell of these matrices was fitted against momentum. The final result is a single matrix as a function of beam momentum, which is now used by the operational software to trim the working point. This paper summarises this measurement campaign by presenting the resulting matrix with a brief overview of the adjustment tools and strategy. Furthermore a few future possible benefits of this control enhancement will be discussed.

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The commissioning of CERN's ion injector complex [1] to allow 1.1 PeV collisions of ions in LHC is well under way. After the Low Energy Ion Ring (LEIR) in 2005 [2] and the Proton Synchrotron (PS) in 2006 [3], the Super Proton Synchrotron (SPS) has now been commissioned with the 'Early' ion beam, which should give a luminosity of $5×10^{25}cm^{-2}s^{-1}$ in the LHC. This paper summarizes the operation in 2007 of all the machines involved in the ion injection chain.

The working point of the CERN Proton Synchrotron, which is equipped with combined function magnets, is controlled using pole-face-windings. Each main magnet consists of one focusing and one de-focusing half-unit on which four pole-face-winding plates are mounted containing two separate coils each, called narrow and wide. At present they are connected in series, but can be powered independently. In addition, a winding called the figure-of-eight loop, contours the pole faces and crosses between the two half units, generating opposite fields in each half-unit. The four optical parameters, horizontal and vertical tune and chromaticity, are adjusted by acting on the pole-face-winding currents in both half units and in the figure-of-eight loop, leaving one physical quantity free. The power supply consolidation project opened the opportunity to use five independent power supplies, to adjust the four parameters plus an additional degree of freedom. This paper presents the results of the measurements that have been made in the five-current mode together with the influence of the magnetic nonlinearities, due to the unbalance in the narrow and wide winding currents, on the beam dynamics.

In the Lead Ion Facility at CERN [1] Pb53+ ion beams are accelerated up to a kinetic energy of 4.2 GeV/u in the CERN PS, extracted and stripped to Pb82+ in the transfer line from PS to SPS where they are injected and accelerated up to 157 GeV/u. The stripping efficiency, emittance growth and energy loss in Al strippers of different thicknesses have been measured and they are in good agreement with the theoretical values. The results of these measurements and considerations on the PS-SPS transmission efficiency are presented. [1] D. Warner, ed., ŒCERN Heavy-Ion Facility Design Report¹, CERN 93-01.

The LHC will, in addition to proton runs, be operated with Pb ions and provide collisions at energies of 5.5 TeV per nucleon pair, i.e. more than 1.1 PeV per event, to experiments. The transformation of CERN's ion injector complex (Linac3-LEIR-PS-SPS) to allow collision of ions in LHC in 2008 is well under way. The status of these modifications and the latest results of commissioning will be presented. The remaining challenges are reviewed.

The first LHC Pb ion run took place at 1.38 A TeV/c per beam in autumn 2010. After a short period of runningin, the injector chain was able to fill the collider with up to 137 bunches per ring, with an intensity of 108 Pb82+ ions/bunch, about 50% higher than the design value. This yielded a luminosity of 3×1025 Hz/cm2, allowing the experiments to accumulate just under 10 b-1 each during the four week run. We review the performance of the individual links of the injector chain, and address the main issues limiting the LHC luminosity, in view of reaching 1026 Hz/cm2 in 2011, and substantially beyond when the LHC energy increases after the long shutdown in 2013-14.

Objective. The purpose of this study was to investigate differences in gross motor coordination in healthy-weight, overweight, and obese children of different ages. Methods. Using a cross-sectional design, data were collected in 954 Flemish primary school children (500 girls, 454 boys) stratifi ed in consecutive age groups (5 - 7 years, 8 - 9 years, 10 - 12 years). Weight status (healthy-weight, overweight, obese) was defined according to the International Obesity Task Force body mass index (BMI) cut-off points for children. Gross motor coordination was assessed by means of the K ö rperkoordinationstest f ü r Kinder (KTK). Results. Childhood overweight and particularly obesity were found to result in poorer KTK performances (p