Industrial Learning Curves: Series Production of the LHC Main Superconduting Dipoles

By mid August 2006, 1160 of the 1232 of LHC main dipoles have been delivered to CERN by the three suppliers in charge of the production. The training of the staff, mostly hired just for this manufacture, and the improvement of the procedures with the acquired experience, naturally decrease the time necessary for the assembly of a unit. The aim of this paper is to apply methodologies like the cost-based learning curves and the time-based learning curves to the LHC Main Dipole production comparing the estimated learning percentage to the ones experienced in other industries. This type of analysis, already presented on 500 units is here extended to more than 1000 completed units. The work also tries to identify which type of industry presents the learning percentages that are the most similar to our case and to investigate the impact of the production strategy on the process efficiency

Parametric Analysis of Forces and Stresses in Superconducting Quadrupole Sector Windings

This paper presents a review of the existing analytical approximations of the magnetic field of a sector winding quadrupole, evaluating to which extent these formulae are usable as a first estimation of the resultants of the electromagnetic forces and related mechanical stresses produced. The distribution of the forces has been investigated to better understand the stress provided to the structure containing the windings and the compression effect induced on the coil mid plane. Therefore, the study has been carried out setting the magnet current at its critical value, analyzing forces and stresses as functions of the geometrical layout and of the magnetic gradient as well. In the last part the effect of an iron yoke on the magnetic field and forces is presented

A 120 mm Bore Quadrupole for the Phase I LHC Upgrade

The phase I LHC upgrade foresees the installation of a new final focusing for the high luminosity experiences in order to be able to focus the beams in the interaction points to ß* 0.25 cm. Key element of this upgrade is a large bore (120 mm) superconducting quadrupole. This article proposes a magnet design that will make use of the LHC main dipole superconducting cable. Due to the schedule constraints and to the budget restrictions, it is mandatory to integrate in the design the maximum number of features successfully used during the LHC construction. This paper presents this design option and the rationales behind the several technical choices

Comparison of 2-D Magnetic Designs of Selected Coil Configurations for the Next European Dipole (NED)

The Next European Dipole (NED) activity is developing a high-performance Nb$_{3}$Sn wire (aiming at a non-copper critical current density of 1500 A/mm2 at 4.2 K and 15 T), within the framework of the Coordinated Accelerator Research in Europe (CARE) project. This activity is expected to lead to the fabrication of a large aperture, high field dipole magnet. In preparation for this phase, a Working Group on Magnet Design and Optimization (MDO) has been established to propose an optimal design. Other parallel Work Packages are concentrating on relevant topics, such as quench propagation simulation, innovative insulation techniques, and heat transfer measurements. In a first stage, the MDO Working Group has selected a number of coil configurations to be studied, together with salient parameters and features to be considered during the evaluation: the field quality, the superconductor efficiency, the conductor peak field, the stored magnetic energy, the Lorentz Forces and the fabrication difficulties. 2-D magnetic calculations have been performed, and the results of this comparison between the different topologies are presented in this paper. The 2-D mechanical computations are ongoing and the final stage will be 3-D magnetic and mechanical studies

Performance of LHC Main Dipoles for Beam Operation

At present about 90% of the main dipoles for the LHC have been manufactured and one of the three cold mass assemblers has already completed the production. 85% of the 1232 dipoles needed for the tunnel have been tested and accepted. In this paper we mainly deal with the performance results: the quench behaviour, the magnetic field quality, the electrical integrity quality and the geometry features will be summarized

Chapter 15: Integration, (de-)installation and alignment

The HL-LHC will require modifying the machine and infrastructure installations of the LHC in several points along the Accelerator Ring, in particular: P1, P2, P4, P5, P6, P7 and P8. Part of the modifications and improvement in P2, P4, P7 and P8 shall be completed during Long Shutdown 2 (LS2) and be operational for LHC Run 3, while the largest part of the interventions will take place in Long Shutdown 3 (LS3) and they will affect primarily P1, P4, P5, P6 and P7. The activities required point by point will be therefore listed and analysed here below

Research and Application on Clustering Algorithms for Genetic Data

摘要 作为数据分析中的两个重要工具，聚类分析（Clustering）和形式概念分析（FCA）在数学、计算机科学和生物学等各个科学领域得到广泛的应用。在生物学研究领域，基因芯片因其研究对象的复杂，产生了大量的基因表达数据；人们希望能够了解这些数据里面包含的重要信息，因此如何高效地使用这两个数据分析工具，成了目前研究的热点。 目前虽然提出了一些经典的聚类分析和建立概念格的算法，包括层次聚类分析、K-means算法和SOMs等。但是这些算法或多或少存在着时间复杂度大、对初始聚类中心敏感和聚类结果不稳定等缺点，且层次聚类和K-means算法需要预输入合适的类数值，这对未知数据集结构的研究人员是难以...Abstract As two of the most important tools of the data analysis, Clustering and Formal Concept Analysis (FCA) have been widely used in the area of Mathematics, Computer Science, Biology and so on. For the biological research area, gene chips have produced a considerable amount of gene expression data. Additionally, these data carry much important information. Therefore, the problems of how to us...学位：理学硕士院系专业：信息科学与技术学院智能科学与技术系_人工智能基础学号：3152008115332

Magnetic and Mechanical Design of the Nested Orbit Correctors for HL-LHC

In order to further enhance its discovery potential, LHC will be upgraded in the framework of the High-Luminosity LHC (HL-LHC) project. Among other equipment, the HL-LHC requires the MCBXF orbit correctors, with an aperture diameter of 150 mm. In order to save space, MCBXF consists of two nested dipoles acting on the horizontal and vertical planes. Each dipole shall provide up to 2.1-T central field. The HL-LHC layout needs long (2.5 m) and short (1.5 m) orbit correctors, which will share the same cross section to decrease the cost. This paper is focused on the short version, although some calculations are needed to be extended to the long one due to the fabrication compatibility required between them. First of all, cosine-theta coils are chosen as the most adequate configuration. The main design challenge is the mechanical structure necessary to hold the large torque arising when both dipoles are powered. Magnetic calculations are cumbersome as well. Main difficulties arise from the large aperture, the short straight section, the noticeable iron saturation, and the variable field orientation. Several solutions are evaluated in this paper, and the final conceptual design is presented