Abstract-The Large Hadron Collider (LHC) needs more than 6000 superconducting corrector magnets. These must be sufficiently powerful, have enough margin, be compact and of low cost. The development of the 11 types of magnets was spread over several years and included the magnetic and mechanical design as well as prototype building and testing. It gradually led to the systematic application of a number of interesting construction principles that allow to realize the above mentioned goals. The paper describes the techniques developed and presently used in practically all the LHC corrector magnets ranging from dipoles to dodecapoles.
Abstract-The Large Hadron Collider (LHC) will be equipped with a large number (6400) of superconducting corrector magnets. These magnets are powerful, with typical peak fields of 3-4 T on the coils, but at the same time compact and of low cost. There are many types: sextupoles, octupoles and decapoles to correct the main dipole field, dipoles, quadrupoles, sextupoles and octupoles to condition the proton beams and several nested correctors from dipole to dodecapole in the inner triplets. The sizes vary from 6 kg, 110 mm long, nested decapole-octupole spool pieces to 1800 kg, 1.4 m long, trim quadrupoles. THE fabrication of the 11 different types of magnets is assured by 10 contracts placed at 6 firms, two of which are in India. A number of magnets are now in series production, others in their pre-series production. The paper describes the present state of the fabrication and the testing of these magnets.Index Terms-Correctors, LHC, magnets, superconducting.
I. LHC CORRECTOR MAGNET OVERVIEWT HE Large Hadron Collider (LHC) will be equipped with more than 6400 corrector magnets ( Fig. 1 shows two examples). About 3800 single aperture and 1000 twin aperture corrector magnets will be used. The 194 mm beam separation gives sufficient lateral space to build all correctors as single bore modules, with a nominal working point between 40-60% along the load line. Twin aperture units are assembled by keying corresponding modules into laminated support structures. The assembly by keying insures mechanical precision and allows flexibility during mounting, since the same type of module is used for a normal or for a skew magnet. To optimize the cost of the corrector magnets, common design and fabrication principles
II. CORRECTOR TYPES AND CIRCUITSWe distinguish several types of correctors for LHC.
Abstract-The main quadrupoles of the Large Hadron Collider (LHC) are connected in families of focusing and defocusing magnets. In order to make tuning corrections in the machine a number of quadrupole corrector magnets (designated MQT) are necessary. These 56 mm diameter aperture magnets have to be compact, with a maximum length of 395 mm and a coil radial thickness of 5 to 7.5 mm, while generating a minimum field gradient of 110 T/m. Two design options have been explored, both using the "counter-winding" system developed at CERN for the fabrication of low cost corrector coils. The first design, with the poles composed of two double-pancake coils, each counter-wound using a single wire, superposed to create 4-layer coils, was developed and built by ACCEL Instruments GmbH. A second design where single coils were counter-wound using a 3-wire ribbon to obtain 6-layer coils was developed at CERN. This paper describes the two designs and reports on the performance of the prototypes during testing.
-In the Large Hadron Cnllfder (LHC) the mafn dipoles will hc equipped with scxtupole (MCS) and decrpolc (MCD) spool corrcctors to meet the very high demands of field quality required for the satisfactory operation nf the rmcliinc, Each decnpole corrector will in addition have nn octupolc invert (MCO)
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