A LOW GRADIENT TRIPLET QUADRUPOLE LAYOUT COMPATIBLE WITH NbTi MAGNET TECHNOLOGY AND β * = 0.25m *
The paper presents a triplet layout option with long (about 100m total triplet length), low gradient (45T/m to 70T/m) quadrupole magnets. Assuming a maximum magnet diameter of 200mm, the peak coil field at the magnet coils still remains below 7T which is still compatible with conventional NbTi magnet technology. The peak beta function inside the triplet magnets reaches 22km and the configuration therefore requires an additional chromaticity correction scheme similar to a dipole first layout option. However, at the same time, the presented solution provides an interesting alternative to a high gradient triplet layout which requires the new Nb3Sn magnet technology.
LHC Luminosity and energy upgrade : A Feasibility Study
We discuss a possible staged upgrade of the LHC and of its injectors, with a view to increasing the luminosity from the nominal 1034 cm 2 s 1 to 1035 cm 2 s 1 in each of the two high-luminosity experiments. We also consider possible scenarios for an upgrade to a proton beam energy of about 14TeV. Starting from beam dynamics considerations and fundamental limitations of the hardware subsystems, we derive realistic requirements for the major components, such as superconducting magnets, cryogenic and RF systems, beam dump and vacuum. We also discuss a novel approach to the optimization of the collider performance, compatible with the beam-beam limit for high intensity proton bunches or long `super-bunches', and sketch a new design of the interaction regions, including an alternative beam crossing scheme. Finally we identify further studies required for an LHC performance upgrade and propose an R&D programme. CERN{EST Division yCERN{LHC Division zCERN{PS Division x CERN{SL Division {CERN{TIS Division Administrative Secretariat LHC Division CERN CH-1211 Geneva 23 Switzerland Geneva, December 2002
Influence of electric fields on friction electrification between metals and borosilicate glass
Abstract In a cylindrical geometry, electric fields were applied through the entire contact area between the sliding metal and the glass surface. The maximum electric charges developed on the metal were measured and plotted against the applied voltage producing the field. The metals were high-purity nickel and gold. The borosilicate glass was Pyrex, brand 7740. The experiments with nickel, which has a work function greater than that of the glass, were performed in 10 −7 mm Hg vacuum. The experiments with gold, with a work function smaller than that of glass, were carried out in air at atmospheric pressure. The results show that: 1. 1) There is both asymmetry and a reversed slope portion in the charge vs. voltage plot. 2. 2) For a certain range of reversing fields, the electric charge developed on the nickel is always negative and the charge on gold is always positive.