SHIELDING FOR THE MATERIALS TEST STATION

摘要

Most of the shielding required by the Materials TestrnStation (MTS) exists onsite in the form of blocks of steelrnand concrete. The dominant radiation source that drivesrnthe shield design are prompt neutrons generated when thernproton beam interacts with matter. These neutrons havernenergies that extend to the incident proton beam energy ofrn800 MeV.rnApproximately 10,000 tons of iron and steel, 3300rntons of concrete block, and 800 tons of magnetite powderrnwill be included in MTS's shielding structure. A tunnel,rn25m long, 4m wide, and 3m high houses the proton beamrntransport components. The walls of the tunnel contain 2mrnof steel and 1.8m of concrete. Thinner walls extend onrneach side of a 7m square, 4.2m high, helium tank filledrnwith cast iron slabs that houses the target assembly. Therntop of the shielding is 7m above the floor.rnTo create a seismically stable structure, the stackedrnblocks forming the tall walls will be tied together withrntrusses. A truss placed on top of each row of blockrnprovides a seat for the next layer of block. Beams tie therntrusses together. To provide additional protection to therntarget assembly, the cast iron slabs will be doweledrntogether and tied to steel plates that act as shearrndiaphragms.