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

Random Errors in Superconducting Dipoles

The magnetic field in a superconducting magnet is mainly determined by the position of the conductors. Hence, the main contribution to the random field errors comes from random displacement of the coil with respect to its nominal position. Using a Monte-Carlo method, we analyze the measured random field errors of the main dipoles of the LHC, Tevatron, RHIC and HERA projects in order to estimate the precision of the conductor positioning reached during the production. The method can be used to obtain more refined estimates of the random components for future projects

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

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%

Dependence of Magnetic Field Quality on Collar Supplier and Dimensions in the Main LHC Dipole

C. Santoni, coll. Atlas, to be published in the proceeding of the conferenceIn order to keep the electro-magnetic forces and to minimize conductor movements, the superconducting coils of the main Large Hadron Collider dipoles are held in place by means of austenitic steel collars. Two suppliers provide the collars necessary for the whole LHC production, which has now reached more than 800 collared coils. In this paper we first assess if the different collar suppliers origin a noticeable difference in the magnetic field quality measured at room temperature. We then analyze the measurements of the collar dimensions carried out at the manufacturers, comparing them to the geometrical tolerances. Finally we use a magneto-static model to evaluate the expected spread in the field components induced by the actual collar dimensions. These spreads are compared to the magnetic measurements at room temperature over the magnet production in order to identify if the collars, rather than other components or assembly process, can account for the measured magnetic field effects. It has been found that in one over the three Cold Mass Assemblers the driving mechanism of the magnetic field harmonics b2 and a3 is the collar shape

Effective Field Theory for the perturbations of a slowly rotating black hole

We develop the effective theory for perturbations around black holes with scalar hair, in two directions. First, we show that the scalar-Gauss-Bonnet theory, often used as an example exhibiting scalar black hole hair, can be deformed by galileon operators leading to order unity changes to its predictions. The effective theory for perturbations thus provides an efficient framework for describing and constraining broad classes of scalar-tensor theories, of which the addition of galileon operators is an example. Second, we extend the effective theory to perturbations around an axisymmetric, slowly rotating black hole, at linear order in the black hole spin. We also discuss the inclusion of parity-breaking operators in the effective theory.We develop the effective theory for perturbations around black holes with scalar hair, in two directions. First, we show that the scalar-Gauss-Bonnet theory, often used as an example exhibiting scalar black hole hair, can be deformed by galileon operators leading to order unity changes to its predictions. The effective theory for perturbations thus provides an efficient framework for describing and constraining broad classes of scalar-tensor theories, of which the addition of galileon operators is an example. Second, we extend the effective theory to perturbations around an axisymmetric, slowly rotating black hole, at linear order in the black hole spin. We also discuss the inclusion of parity-breaking operators in the effective theory

Estimating field quality in low-beta superconducting quadrupoles and its impact on bBeam stability

Random components of field harmonics in superconducting quadrupoles are usually estimated by computing the effect of a random positioning of the coil blocks with an r.m.s. of 0.05 mm. Here, we review the experience acquired in the construction of 7 superconducting quadrupoles in the RHIC and in the LHC projects to estimate the reproducibility in the coil positioning. Post-processed data show that the reproducibility is around 0.020 mm r.m.s., and independent of the aperture. Using this result, we work out a scaling law for the random components as a function of the magnet aperture. As an application, we analyse the impact on geometrical aberrations of the expected field errors in presence of large beta functions in the triplet

CXC and CC chemokines as angiogenic modulators in nonhaematological tumors.

Chemokines are a superfamily of structurally homologous heparin-binding proteins that includes potent inducers and inhibitors of angiogenesis. The imbalance between angiogenic and angiostatic chemokine activities can lead to abnormalities, such as chronic inflammation, dysplastic transformation, and even tumor development and spreading. In this review, we summarize the current literature regarding the role of chemokines as modulators of tumor angiogenesis and their potential role as therapeutic targets in patients with nonhaematological tumors

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

Short Circuit Localization in the LHC Main Dipole Coils by means of Room Temperature Magnetic Measurements

During the construction of the LHC main dipoles, 12 cases of short circuits between the cables of the superconducting coils have been detected. Some of them appeared only under the press, making impossible their localization after disassembly. In this paper we describe a method to locate electrical shorts through the use of room temperature magnetic measurements. An example case is discussed in detail to illustrate the features of the approach, and a statistic of the cases met during the production of more that 70% of the dipole total quantity is presented