preliminary magnet layout Renzo P.

The Used Model 1.The standard Panda Coils. 2.A very rough Steel 1010 Iron Shield. (a big octagonal pipe 100mm thick following Jim’s suggestions) The iron is saturated(B~2 T in the shield) Boundary condition (B field parallel to the Boundary) are imposed on the “box” at ~ 10 Metres from the IP Position (axis origin).

Mag Field On Axis 1.Coil Excitation 56% of Nominal Panda Coil 2.Peak field T Coil stresses ~60% of Nominal stresses in PANDA operation (safe) Field Homogeneity ~±2.5% Br field integral~2.5 mm

Field Homogeneity 1.The central tracker region is mostly enclosed inside the constant field region. 2.Only some edge is enclosed in the second level line. Distance between two level lines is 2.5%

Magnetic field around the magnet 1.Mag Field Magnitude on the median plane of the coil 2.The plot gives the Isolines of Mag(B) from 200mT to 0.5mT The dimensions of the box are 17x26 metres The red zone is the 200 mT The corner are 0.5 mT Comments It appears that roughly all the hall is over.5 mT and need a controlled access The region over 200 mT is quite restricted and close to the Iron end. We need to carefully evaluate the effect of the Magnetic Force on free object inside the experimental Hall.

Magnetic field around the magnet 1.Mag Field Magnitude on the plane 1 Metre below the iron (Hall Floor supposing some magnet support ) 2.The plot gives 10 Isolines of Mag(B) from 25mT to 0.5mT The dimensions of the box are 17x13 metres The corner are 0.5 mT

Magnetic field around the magnet 1.Mag Field Magnitude on the plane at the outer face of the iron. 2.The plot gives 10 Isolines of Mag(B) from 70mT to 0.5mt The dimensions of the box are 17x13 metres The corner are 0.5 mT

Evaluation of effect of magnetic Bodies Solid model of the Magnet and a couple of Steel 1010 pipes plus some Steel 1010 cubes to evaluate the effects of magnetic bodies close to the magnet. The bodies are Pipes 200mm  and 1000mm length (gas cylinder) and cubes 50x50x50 mm (hammer and tools) The bodies are placed a 1000mm from the iron end (bottles) and 750mm Hammers.

Plot on the median plane of the magnetic field modified by the steel bodies The Hammers are in the 0.1 T region The gas cylinders are in the 0.08 T region. Forces on the “hammers” are ~ N Forces on the “cylinders are ~ N Comment We need to Secure All the magnetic Bodies and to be careful when working around the magnet with magnetic tools.

Field with doors 10

Field with doors The fringe field is lowered The expected force on steel objects placed in front of the magnet is smaller The doors anyhow defend the detectors from “unrecognised flying objects BUT the force on the doors is ~40t… 11

Magnetic Force analysis At the moment we have not performed a thorough analysis of the forces on the magnet. The stresses are safe ~ 60% of the nominal in he Panda Coil Operation. Due to the symmetric construction the coil, position in the iron is stable, and the axial force is then in a minimum (nominal value from computation is ~10 Nt). We need to be careful in storing magnetic objects in the Hall, to preserve the magnetic force balance and keep low the stresses on the Cryostat-Iron connections. We need also to evaluate the effect of large magnetic objects (as cranes) moving in the Hall when the magnet is on.

Magnetic Force analysis (continued) At the moment a thorough analysis of the Forces (magnetic and weight) on the simple return Yoke is missing) and the evaluation of the resulting deformation. Together with a check of the possibility of having a more complete magnetic shielding using a sort of door at both ends. This solution will ease the mag field shielding but can increase in a serious way the design (and cost) of the Iron for the Juelich tests.