MI-65 NuMI Target Hall

The NuMI facility is approximately 4,000 feet in length from the Main Injector Stub to the end of the Near Detector Hall. There are two service buildings that provide access shafts to reach the underground facilities. MI-65 Target Service Building is one of them, and it provides access to the Target Hall which is located 40 m underground.

The target Hall is a long domed chamber, approximately 69 m long, 8.1 m wide, and 12.5 m high. It houses the baffle/target and the focusing horns together with their support structures and auxiliary equipment, the ultility support rooms, radioactive component work cell, and provides access to upstream Pre-Target tunnel and downstream Decay pipe walkway. The mezzanine houses HVAC equipment, including a large desiccant unit to supply dry air underground.

The Target Hall is a high radiation area, especially when the beam is operating, and as such it is under a personnel safety interlock system that is failsafe and redundant. Below-ground access is possible after underground access training is completed.

Beamline components are installed in the chase of a 6 m wide and 6 m deep pit, with steel/concrete shielding. The photos below show the Target Hall during the installation (left) and the hall with the radiation shielding blocks over the Target pit (right).

Used beam elements are radioactive. Provision has been made for remote handling of radioactive components for repair and replacement in the Work Cell, which is a wellshielded enclosure located at the downstream end of the Target Hall.

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