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.
EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH European Laboratory for Particle Physics A Solution for Phase-one Upgrade of the LHC Low-beta Quadrupoles Based on Nb-Ti
We discuss the possibilities of upgrading the LHC triplet quadrupoles by significantly increasing their aperture (and length), using the Nb-Ti cable of the main dipoles. The goal of this first phase in upgrading the triplet is to allow a rapid improvement of the luminosity mostly by removing limitations related to the triplet aperture. Neither the experimental area, including the TAS, nor the basic optics are modified. By the same token, steps are made to allow a moderate increase of the luminosity within the capabilities of the existing detectors. The triplet aperture is sized to decrease the collimator impedance below significance, allow a potential increase of the luminosity by some 50% or up to a factor of 2 with an external ancillary system acting on the geometrical loss factor. Some extra aperture is foreseen to lower the power deposition, to improve field quality and/or to allow a stronger focusing in the event some baseline beam parameters would not be reached. In this way, the proposed phase-one upgrade is versatile and should allow improved performance in a large range of situations.
Towards fast-pulsed superconducting synchrotron magnets
The concept for the new GSI accelerator facilities is based on a large synchrotron designed for operation at BR=200 Tm and with the short cycle-time of about one second to achieve high average beam intensities. Superconducting magnets may reduce considerably investment and operating costs in comparison with conventional magnets. A R&D program was initiated to develop these magnets for a maximum field of 2-4 Tesla and a ramp rate of 4 T/s. In collaboration with JINR (Dubna), the window-frame type Nuclotron dipole, which has been operated with 4 T/s at a maximum field of 2 Tesla, shall be developed to reduce heat losses and to improve the magnetic field quality. Another collaboration with BNL (Brookhaven) was established to develop the one-layer-coil cos/spl theta/-type RHIC arc dipole designed for operation at 3.5 Tesla with a rather slow ramp-rate of 0.07 T/s towards the design ramp-rate of 4 T/s. The design concepts for both R&D programs are reported.