operation of a "string" test facility simulating the basic machine half-cell. EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH than specified. Some lm long model quadrupoles were occurred instead because of a too fast down-ramp rate during OCR Output retraining after thermal cycling. Their field quality was better cells) by heat transported through helium. Propagation they exhibited training from 6.6+7.2 kA to 8 kA and some adjacent quarter cells (the string was subdivided into quarter length prototype quadrupoles were built at LBL. TypicallyThere was no evidence of quench propagation between component at injection needed to be better controlled. Full mentioned:within requirements, only the drift of the skew quadrupole Among the results of general interest the following should be excellent with little training. Their field quality was generally using superconducting magnets and in particular the LHC.performance at the operation temperature of 4.35 K was gathered with this test will help any future accelerator project prototype dipoles were built at BNL and FNAL. Their quench and three spool pieces [6]. The very valuable experience design, materials and fabrication techniques [5]. Most of the cell of the machine, comprising ten dipoles, two quadrupoles progress and has led to many advancements in understanding, decision to terminate the project, was the power test of a full during a decade the main stimulation of accelerator magnetThe last important activity on the SSC magnets, after the due to the unfortunate termination of the project, has been starting at about 7.5 kA.The SSC magnet development programme, presently ended conductor short sample limit, 8.4 kA, after a few quenches manufactured by a US/German consortium. They reached the Design parameters of superconducting main magnets in accelerator/colliders Table I reduction of costs and space occupancy. cost and space occupancy. Superconducting magnets have be the two-in-one configuration leading to a considerable cavities, identified as the means to reach higha energy saving of the traditional NbTi supuconductor, and by the adopdon of prime promoter of applied superconducdvity, magnets and r.f. superfluid helium technique, thus enhancing the performance High Energy Physics has been for almost three decades the gradient. A bold step is being made with the LHC using the I. INTRODUCTION reinements in manufactiuing have permitted to raise Eeld and better insuladon systems and face containment structures and facility simulating the basic machine ha1f·ce11.Improvement in performance of superconductors [3,4], aperture dipoles and the successful operation of a "s¤ing" test main magnets for accelerators is recalled in Table I
