Normal Form Analysis of the LHC Dynamic Aperture

Normal form is a well developed tool to study the nonlinear dynamics of even the most complicated structures. This can become particularly useful in the design of large nonlinear hadron colliders like the LHC. In this study the correlation of various quality factors derived through normal forms with the dynamic aperture are used to investigate a machine that is dominated by octupolar errors

Scaling Laws for Magnetic Energy in Superconducting Quadrupoles

The stored energy in superconducting magnets is one of the main ingredients needed for the quench calculation and for designing quench protections. Here we propose an analytical formula based on the Fourier transformation of the current density flowing within the winding to determine the magnetic energy stored in superconducting quadrupoles made of sector coils. Two corrective coefficients allowing to estimate the energy enhancement produced either by current grading or by the presence of an unsaturated iron yoke are respectively derived from a numerical and an analytical study. This approach is applied to a set of real quadrupoles to test the validity limits of the scaling law, which are shown to be of ~10%

130 mm Aperture Quadrupoles for the LHC Luminosity Upgrade

Several studies for the LHC luminosity upgrade pointed out the need for low-beta quadrupoles with apertures larger than the present baseline (70 mm). In this paper we focus on the design issues of a 130 mm aperture quadrupole. We first consider the Nb-Ti option, presenting a magnetic design with the LHC dipole and quadrupole cables. We study the electromagnetic forces and we discuss the field quality constraints. For the Nb$_{3}$Sn option, we sketch three designs, two based on the LARP 10 mm width cable, and one on a larger cable with the same strand. The issue of the stress induced by the e.m. forces, which is critical for the Nb$_{3}$Sn, is discussed using both scaling laws and finite element models

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

Parametric Study of Energy Deposition in the LHC Inner Triplet for the Phase 1 Upgrade

To be able to make a global parametric analysis and to have some basic understanding of the influence of critical parameters, scaling laws may be of help. For the design of the LHC insertion regions triplets, among the critical parameters the energy deposited in the superconducting triplet plays a fundamental role in avoiding magnet quench, too heavy load on the cryogenic system, and degradation of the materials due to radiation. The influence on energy deposition of the lay-out key parameters, such as the magnet apertures, the magnet lengths and positions, has been studied for beta* = 0.25

Energy Deposition Patterns in the LHC Inner Triplet and Their Impact on the Phase II Luminosity Upgrade

Recent studies show that the energy deposition for the LHC Phase I luminosity upgrade, aiming at a peak luminosity 2.5×10**34 cm**-2s**-1, can be handled by appropriate shielding. The Phase II upgrade aims at a further increase of peak luminosity by a factor 4, possibly using Nb$_{3}$Sn quadrupoles. This paper describes how the main features of the triplet layout, such as quadrupole lengths, gaps between magnets, and aperture, affect the energy deposition in the insertion. We demonstrate how the energy deposition patterns depend on the triplet lay-out. An additional variable which is taken into account is the choice of conductor, i.e. solutions with Nb-Ti and Nb$_{3}$Sn are compared. Nb$_{3}$Sn technology gives possibilities for increasing the magnet apertures and space for new shielding solutions. Our studies give an indication on the possibility of managing energy deposition for the Phase II upgrade

MonitorNet: studio italiano osservazionale multicentrico per la valutazione del profilo rischio-beneficio dei farmaci biologici nella pratica clinica reumatologica

Over the last decade, several new biologic agents have become available for the treatment of patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis (AS) and psoriasis (Ps). In contrast to conventional disease modifying anti-rheumatic drugs (DMARDs), these biological agents have rapid onset of action and pronounced disease reducing activity when administered as monotherapy or in combination with MTX. Pre-registration randomised clinical trials have compared biological agents against placebo over a limited time span (1-3). Wider use of biologics has resulted in reports of a wide range of adverse events (4), including evidence of reactivation of latent tuberculosis, increased incidence..

Mimicry technology : a versatile tool for small RNA suppression

A decade ago the discovery of the target mimicry regulatory process on the activity of a mature microRNA (miRNA) enabled for the first time the customized attenuation of miRNA activity in plants. That powerful technology was named MIMIC and was based on engineering the IPS1 long noncoding transcript to become complementary to the miRNA under study. In order to avoid IPS1 degradation, the predicted miRNA-mediated cleavage site was interrupted by three additional nucleotides giving rise to the so-called MIMIC decoy. Since then, MIMIC technology has been used in several plant species and in basic and translational research. We here provide a detailed guide to produce custom-designed MIMIC decoys to facilitate the study of sRNA functions in plants

Optimization of the Even Normal Multipole Components in the Main Dipole of the Large Hadron Collider

In this paper we discuss even multipolar components of the Large Hadron Collider dipole in relation to the manufacturing features and target values required by beam dynamics. Due to the two-in-one collar geometry, systematic components are induced by the mutual influence of the two apertures and are strongly affected by the shape of the magnetic iron yoke. In order to optimize the normal quadrupole and octupole harmonics, a new design was chosen for the ferromagnetic insert between the iron yoke and the collars. Three different insert shapes were selected and installed in a full scale prototype. The measured dependence of the even multipoles on the insert shape shows a good agreement with simulations based on a magnetostatic code. A final design of the insert has been worked out and implemented in pre-series magnets. Data relative to even multipoles in pre-series magnets are presented, both at room temperature and at the operational temperature of 1.9 K. Comparison with target values required by beam dynamics is discussed