Design and development of vacuum chamber for the compression magnet

A 30 MeV RF electron linac-based neutron source will be set up by APPD, BARC at IGCAR, Kalpakkam. This facility will include neutron activation of sodium by photo neutrons for FBR shielding studies and Time of Flight (n-TOF) facility for various research applications. In the n-TOF facility, a 10 ns electron beam will be generated by an electron gun. It will be accelerated to 30 MeV by a standing wave linac. The electron pulse at the exit of the linac will have 40% energy spread. This beam will be further compressed to 1 ns using a compression magnet. It will be a 360 °, zero gradient, 5-sector DC magnet. To achieve the compression ratio of 10:1, a 0.1 T magnetic field will be required. The magnet size will be 3200 mm x 2700 mm x 400 mm and the weight will be 24 ton. The vacuum chamber will be sandwiched between the two poles of the magnet. The design of vacuum chamber is crucial as a limited space is available between the poles and since the diameter of the chamber will be large it will buckle when evacuated