The ATLAS magnet test facility at CERN

Abstract

--The magnet system for ihc ATLAS delcctor at CERN cnnsists of a Barrel Toroid (RT), two End-Cap Toroids (ECT) and a Ccntral Solenoid (CS). The overall dimensions of the system are 20 m in diameter by 26 m in length. B c h c underground installation all coils will be tested on surfacc fn a magnet test facility which Is under construction. Moreover two model coils are testcd as well ns siibsystemu. hi this paper the design and construction of the test facility Is presented, I. INTItOUUCTIONThe ATLAS Magnet System [ 1,2] comprises the superconducting magnets, the power supply system, the cryogenics system, thc vacuum system and thc control and sakety sysicm. The magtat system hm overall dimension of 26 meters in length and 20 meters in diameter (see Fig. 1 In order to verify the constniction concepts on BO and themafter the correct operation of thc othcr coils, the tests must represent the mal configuration. The iirfrastnicturc requircd to pcrform thc tcsts compriscs: a rather complex cryogenic plant with a He refrigerator, a pre-cooling unit, a cryostat with intcgratcd i m " e d centriflugal pumps for liquid He flows above 80 g/s to cool the magnct cold masses and a distribution system: the vacuum system with a pumping system sblc to provide 10" mbar; the electrical system fur coil cnergizing with R 6VIUkA power supply; appropriate qucnch protcction units as well as systems for control and diagnostics. Prcliminary test of the BO coil wirh a magnetic mirror to simulate thc clcclcomagiictic load and the full set of instrumcntation is planned by s u m " 2000. Duo to the exceptional size of the B'C system, each coil will be individually tested on the ground at nominal current with the magnetic mirror so as to reproduce the actual load, before lowering them down in the cavern. gach of the two ECT magnets and thc CS magnet will bc Cully asscmbled and testcd on the surface, before the installation as complete systems in the cavern. 11, THE BOO AN13 BO MODEL COnSThe first coil Single pancake winding made with CS conductor.

Mechanical behavior of the ATLAS B0 model coil

“…The short B0 toroid model coil (9 m 5 m) has been designed and fabricated by CEA Saclay and INFN/LASA to verify the mechanical operating behavior and validate some design parameters of BT. The test station including cryoplant, power supplies, magnetic mirror, monitoring and safety systems were set up at CERN [2] while the data acquisition systems were integrated in collaboration between the institutes and CERN. The use of the magnetic mirror reproduces the external EM forces level during power test to validate mechanical construction.…”

The ATLAS Superconducting Magnet System: Status of Construction & Installation

“…In parallel to the integration, the acceptance testing of the coils is performed. A test station with 2 test benches was built [22]. All 8 BT coils underwent an acceptance test up to a maximum current of 22 kA and realistic load.…”

Mechanical characteristics of the ATLAS B0 model coil

“…The B0 model coil has been mechanically characterized using a magnetic mirror [3]. The electromagnetic external forces, produced by the magnetic mirror, are reacted by three titanium tie rods, anchored to the casing and the vacuum vessel via pivot mechanisms.…”