Investigations on a Q0 Doublet Optics for the LHC Luminosity Upgrade (original) (raw)
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Beta functions at two interaction points (IP) in the high luminosity LHC upgrade lattice (HL-LHC) at collision energy will be significantly reduced compared to the nominal LHC lattice. This will result in much higher beta functions in the inner triplet (IT) quadrupoles adjacent to these IPs. The consequences are a larger beam size in these quadrupoles, higher IT chromaticity, and stronger effects of the IT field errors on dynamic aperture (DA). The IT chromaticity will be compensated using the Achromatic Telescopic Squeezing scheme [1]. The increased IT beam size will be accommodated by installing large aperture Nb3Sn superconducting quadrupoles with 150 mm coil diameter. The stronger effects of the IT field errors can be remedied by optimizing the IT field error specifications. The latter must satisfy two conditions: provide an acceptable DA and be compatible with realistically achievable field quality. Optimization of the IT field errors was performed for the LHC upgrade layout version SLHCV3.01 with IT gradient of 123 T/m and IP beta functions of 15 cm. Dynamic aperture calculations were performed using SixTrack. Details of the optimization are presented along with recommendation for improving the field error correction.
Low-β Quadrupole Designs for the LHC Luminosity Upgrade
Proceedings of the 2005 Particle Accelerator Conference, 2005
Several scenarios are considered for the upgrade of the LHC insertions in view of increasing the luminosity beyond 10 34 cm -2 s -1 . In the case of "quadrupole first" option, superconducting low-β quadrupoles with apertures in the range of 90-110 mm are required in view of increased heat loads and beam crossing angles. We present possible low-β quadrupole designs based on existing Nb3Sn and LHC NbTi superconductors, present scaling laws for the magnet parameters and discuss relative advantages of the underlying triplet layouts.
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 Nb3Sn 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 Nb3Sn are compared. Nb3Sn 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.
Low Gradient, Large Aperture IR Upgrade Options for the LHC compatible with Nb-Ti Magnet Technology
The paper presents three different layout and optics solutions for the upgrade of LHC insertions using Nb-Ti superconducting quadrupoles. Each solution is the outcome of different driving design criteria: a) a compact triplet using low gradient quadrupoles; b) a triplet using low gradient quadrupoles of modular design, and c) a layout minimizing the B-max while using modular magnets. The paper discusses the different strategies and design criteria for the three solutions. It also discusses their relative advantages and disadvantages and identifies outstanding studies that need to be addressed in order to develop the solutions further. All cases assume that the first quadrupole magnet requires a smaller minimum aperture and therefore, can feature a slightly larger gradient than the remaining final focus quadrupole magnets.
IEEE Transactions on Applied Superconductivity, 2000
The design and construction of a 120 mm wide-aperture, Nb-Ti superconducting quadrupole magnet for the LHC insertion region is part of a study towards a luminosity upgrade of the LHC at CERN, envisaged for 2020-22. The main challenges for this accelerator quality magnet are to operate reliably with the high heat and radiation loads that are predicted in the insertion magnet regions. Calculations give approximately 500 Watts over the 30-m-long string of insertion magnets, while today LHC is operating for a nominal heat load of 12 Watts. To extract this heat, the model magnets incorporate new features: Open cable insulation, open ground insulation, open magnet structure, and a quench
Magnetic design of a high gradient quadrupole for the LHC low-β insertions
Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167), 1998
Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory have formed a consortium to provide components for the Large Hadron Collider (LHC) to be built at CERN. The U.S. contribution includes half of the high gradient quadrupoles (HGQ) for the inner focusing triplets. In this paper a description of the HGQ magnetic design is given, including short sample limit for field gradient, sources and expected values of systematic and random field errors, and possible strategies for field quality correction. 3398 0-7803-4376-X/98/$10.00
Test results of Fermilab-built quadrupoles for the LHC interaction regions
As part of the US LHC Accelerator Project, Fermilab is nearing the completion of the Q2 optical elements for the LHC interaction region final focus. Each Q2 element (LQXB) consists of two identical high gradient quadrupoles (MQXB) with a dipole orbit corrector (MCBX). This paper summarizes the test results for the LQXB/MQXB program including quench performance, magnetic measurements and alignment, and gives the status of production and delivery of the LQXB magnets to the LHC.
Performance of the 1-meter models of the 70 mm aperture quadrupole for the LHC low-beta insertions
1998
Following the successful testing of the first 1-metre model of the 70 mm aperture quadrupole for the LHC low-beta insertions, two further 1-metre magnets have been built. All magnets feature a four-layer coil wound from two 8.2 mm wide graded NbTi cables and a four-way split yoke supporting structure. In this paper we review the training history of the three magnets performed at 4.3 K and 1.9 K in several tests. All magnets surpassed the operating gradient required for the LHC, with the third magnet reaching 260 T/m, its short-sample gradient at 1.9 K. The peak temperatures in the superconductor at various operating conditions are reported and a summary of magnetic field measurements is given.
IEEE Transactions on Appiled Superconductivity, 1997
Within the LHC magnet development program Oxford Instruments has built a one metre model of the 70 mm aperture low-quadrupole. The magnet features a four layer coil wound from two 8.2 mm wide graded NbTi cables, and is designed for 250 T/m at 1.9 K. The magnet has previously been tested between 4.5 K and 2.3 K. In this paper we review the magnet rebuild and the subsequent tests. Results on magnet training at 4.3 K and 1.9 K are presented along with the results related to quench protection studies.
STUDY OF IR DESIGN FOR THE LHC UPGRADE EuCARD-Del-D11-2-2-v12
A conceptual novel optics was developed for a future upgrade of the LHC interaction regions (IR). Applying the collision scheme with a large Piwinski angle and crab waist, originating from e+e- colliders, to an existing pp collider requires fairly unequal IP beta functions, while the transverse proton emittances are naturally equal. The extremely small vertical IP beta function calls for a novel final magnetic focusing element, a so-called double half quadrupole. At least a partial local chromatic correction is mandatory. Similar, simpler optics designs were explored for the LHeC electron beam. Possible benefits were also studied for higher-energy proton collisions at the HE-LHC, for which the proposed scheme appears quite attractive. Pertinent beam experiments were performed, analysed and prepared at DAFNE and LHC.