The Superconducting Solenoid


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The momenta of charged particles will be determined from their curvature in the 2T magnetic field provided by a 2.7m long solenoid magnet. The superconducting (SC) solenoid, a two layer coil with mean radius of 60cm, has a stored energy of 5MJ (for reference the CDF coil is 30MJ). Inside the tracking volume the value of along the trajectory of any particle reaching the solenoid is uniform to within 0.5%. This uniformity is achieved in the the absence of a field-shaping iron return yoke by using two grades of conductor with higher current density near the ends of the coil. From the value of the field integral and the space point precision provided by the silicon and fiber tracking system:

The SC coil plus cryostat is about 0.9 radiation lengths thick. The solenoid is the first thin solenoid for a particle physics detector which operates at 2 Tesla.

The solenoid was built by Toshiba Corp. in Yokohama, Japan. The contract was awarded in January, 1995 and the magnet system completed and tested at the factory in March, 1997. The system, consisting of a magnet cryostat, control dewar, and service chimney which interconnects the two, was disassembled and shipped to Fermilab, arriving in May, 1997. After the new preshower detector is installed on the outer diameter of the magnet cryostat, the magnet and preshower detector will be installed into the center bore of the existing Central Calorimeter cryostat. When the balance of the magnet system is installed on the detector the system will be commissioned and the field mapped before the upgrade tracking system is installed in the bore of the solenoid.

A fieldmapping device was fabricated at Fermilab and shipped to Japan to make acceptance measurements of the field of the completed solenoid. This device will be reinstalled in the magnet for the complete field mapping exercise.

The cryogenic plant that supplies LHe for both the solenoid and the visible light photon counter (VLPC) readout devices has been installed and commissioned. Included in the plant were two helium compressors installed in the nearby DØ Tevatron cryogenic services building, which was enlarged to house the additional compressors. The balance of the cryogenic plant (expansion engines, heat exchanger stack, LHe storage dewar, transfer lines, and valve boxes) was installed in the DØ Assembly Building (DAB).

An electrical energization, control, and protection system has also been installed in DAB and this system will be commissioned soon. This system includes a reversing switch that will permit the field of the solenoid to be energized in either polarity.

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This page was created on Nov-10, 1997.
Last Modified: Mar 31, 2000
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