engBallarino, AHigh Temperature Superconducting Current Leads for the Large Hadron ColliderAccelerators and Storage RingsLHC-Project-Report-337CERN-LHC-Project-Report-337The Large Hadron Collider (LHC) will be equipped with about 8000 superconducting magnets. Some 3380 leads will feed the currents ranging from 60 to 13000 A. To reduce the heat inleak into the liquid helium, CERN aims to use High Temperature Superconducting material for leads having current ratings between 600 and 13000 A. Specifications have been written for 13000 A current leads, incorporating a High Temperature Superconducting section, for the main magnets of the LHC, and contracts have been placed with several firms for the supply of prototypes for comparative testing. The leads used for feeding locally the 60 and 120 A dipole orbit correctors will be conventional conduction cooled resistive leads. An optimized lead of variable cross section has been tested, and an integral design has been initiated. This report describes the design status of the current leads for the LHC, emphasizing, for the different solutions, the principle of optimization and the choice of the cooling methods.1999-12-01http://cds.cern.ch/record/410572http://cds.cern.ch/record/410572oai:cds.cern.ch:410572 engHaverkamp, MBottura, LSchneider, MStudies of Decay and Snapback Effects on LHC Dipole MagnetsAccelerators and Storage RingsLHC-Project-Report-336CERN-LHC-Project-Report-336LHC model magnets have dynamic field imperfections of various nature. Two effects of particular importance are field component decay during injection and ''snapback'' during the first few seconds of acceleration, which happens over typically 15 to 20 mT. The dynamic behaviour of the model magnets was measured as a function of several parameters in the operation cycle and powering history. We demonstrate how the systematic variation of only one single operation cycle parameter can affect the behaviour of the sextupole component.1999-12-01http://cds.cern.ch/record/410571http://cds.cern.ch/record/410571oai:cds.cern.ch:410571 engAnashin, V VBaglin, VCimino, RCollins, I RDostovalov, R VFedorov, N VGómez-Goñi, JGröbner, OswaldHenrist, BernardHilleret, NoëlKrasnov, A ALaurent, Jean MichelMalyshev, O BPyata, E EPivi, MExperimental Investigations of the Electron Cloud Key ParametersAccelerators and Storage RingsLHC-Project-Report-313CERN-LHC-Project-Report-313Motivated by a potential electron cloud instability and the possible existence of electron mulitpacting in the LHC vacuum system, that may result in additional gas desorption and unmanageable heat loads on the cryogenic system, an extensive experimental research program is underway at CERN to quantify the key parameters driving these phenomena. Parameters, such as: photoelectron yield, photon reflectivity, secondary electron yield etc. from industrially prepared surfaces have been quantified. In addition to their dependence on photon dose the effect of temperature and presence of external fields has also been studied.1999-10-18http://cds.cern.ch/record/404144http://cds.cern.ch/record/404144oai:cds.cern.ch:404144 engCollins, I RGröbner, OswaldMalyshev, O BRossi, AStrubin, Pierre MVeness, R J MVacuum Stability for Ion Induced Gas DesorptionAccelerators and Storage RingsLHC-Project-Report-312CERN-LHC-Project-Report-312Ion induced vacuum instability was first observed in the Intersecting Proton Storage Rings (ISR) at CERN and in spite of substantial vacuum improvements, it remained a limitation of the maximum beam current throughout the operation of the machine. Extensive laboratory studies and dedicated machine experiments were made during this period to understand the details of this effect and to identify ways of increasing the limit to higher beam currents. Stimulated by the recent design work for the LHC vacuum system, the interest in this problem has been revived with a new critical review of the parameters which determine the pressure run-away in a given vacuum system with high intensity beams.1999-10-18http://cds.cern.ch/record/404143http://cds.cern.ch/record/404143oai:cds.cern.ch:404143