Q0 Status

The Q0 scheme of the LHC insertion region is based on the introduction of a doublet of quadrupoles at 13 meters from IP. In this scenario the value of can be reduced to 0.25 m with a moderate increase of the function inside the inner triplet. We present here an optical layout, with the requiredmagnets parameters such as gradients, lengths, positions and apertures. We also discuss in some details the tolerance on alignment and the energy deposition

Are Large-Aperture NbTi Magnets Compatible with 1e35?

To protect magnets in the insertion region, we have some degrees of freedom to use for optimal performance. Aperture, distance from the IP, the length of the magnets and the design of absorption systems are important parameters for the optimization. We look exclusively here at the effects of the collision debris, which give the major contribution to the heat deposition in the insertion magnets. To answer the challenging question in the title of this contribution, the approach was to use the baseline upgrade scenario for phase 1 and simply imagine higher particle fluxes from the higher luminosity (no change in optics). From this, a simple approach of magnet shielding using a liner in the cold bore tube gave us the answer: NbTi technology may be compatible with a luminosity of 1035. This gives also the interesting possibility to extract heat from this liner at a higher cryogenic temperature. However the final demonstration needs a detailed model. We have also made some parameter variations (crossing angle, TAS aperture) and checked the Q0 upgrade scenario concerning deposited heat. The effect of a D0 magnet on heat deposition in the IR has also been evaluated

Investigations on a Q0 Doublet Optics for the LHC Luminosity Upgrade

The Q0 scheme of the LHC insertion region is based on the introduction of a doublet of quadrupoles at 13 m from the IP. We present here the doublet optics and the magnets layout such as gradients, lengths, positions and apertures. In this scheme we show the gain in luminosity and chromaticity, with respect to a nominal layout with $\beta^{*}$ = 0.25 m (i.e. LHC phase 1 upgrade) and $\beta^{*} = 0.15 m, due to a smaller beta-max. We show the alignment tolerance and the energy deposition issues, in Q0A-Q0B. We also consider shielding the magnets with liners. The capability of Q0 optics to limit the b function could be exploited after the LHC Phase 1 upgrade in order to reduce the$\beta^{*}$ below 0.25 m, leaving the upgraded triplet unchange

The UA9 Experiment at the CERN-SPS

The UA9 experiment intends to assess the possibility of using bent silicon crystals as primary collimators to direct coherently the beam halo onto the secondary absorber, thus reducing out-scattering, beam losses in critical regions and radiation load. The experiment will be performed in the CERN-SPS in storage mode with a 120 or 270 GeV/c proton beam. The otherwise stable beam will be perturbed to create a diffusive halo. The setup consists of four stations: the crystal station with two goniometers for crystals, two tracking stations at about 90 degrees phase advance with detectors for single particle tracking and the collimation (TAL) station with a 600 mm long tungsten absorber. The observables are the localization of the losses in the collimation area, the collimation efficiency and the shape of the deflected beam phase space. We discuss the experimental layout and the way we expect to collect data in 2009

Simulation results for crystal collimation experiment in SPS UA9

The UA9 experiment will first take place in 2009 at the CERN-SPS and will evaluate the feasibility of silicon crystals as primary collimators for a storage ring. A crystal placed at 6 σ from the beam core will deviate protons towards two Roman Pots and a tungsten absorber (TAL). In this paper the authors show simulations of the expected beam dynamics and of the capture efficiency into the secondary collimator. The result of these simulations will guide us in interpreting the experimental data expected in UA9

Crystals Application in the TOTEM Experiment to Increase the Acceptance of a Roman Pot

Bent crystal may enhance the physics reach of a near-beam physics detector in the CERN-LHC, by increasing the acceptance of scattered protons in low transverse momentum reactions. As an example we present simulations demonstrating the increase of the Roman Pot acceptance in the TOTEM apparatus. Starting from the MadX v6.5 collision optics, a crystal is placed at different longitudinal and transversal positions: for each scheme a gaussian beam of protons with different kinematic variables is created and tracked along the optical line with crystal. The number of protons with transversal coordinates greater than 10 s + 0:5 mm, that is inside the Roman Pot, is compared with the total number of protons. The possible gain in acceptance is around 15-20%

Interaction Region with Slim Quadrupoles

An optical performance's improvement of the interaction region can be obtained with the addition of new quadrupoles in the forward detectors area. Such scenario would allow decreasing the ß* below the nominal value.The basic concept consists in using quadrupoles to break the quadratic behavior of ß in the free space between the IP and the IR triplets.I In this new configuration we present the performance improvements and the hardware requirements