Physics design study of separated function drift tube Linac

Separated Function Drift Tube Linac (SFDTL) is a normal conducting linear accelerator which can be used to accelerate proton/H- beam in the energy range 50-150 MeV. This is a special type of drift tube linac, where the focusing element is placed outside the tank, i.e., in the inter tank space. This makes the SFDTL simpler than DTL from mechanical engineering point of view and gives freedom to optimize different geometrical parameters. It is also an advantage from the viewpoint of mechanical engineering that no stabilizing devices are required in the SFDTL. For the normal conducting option for the low energy section of the 1 GeV injector linac, SFDTL is one of the options. In this paper, we present electromagnetic design study and beam dynamics study of SFDTL for the H- beam in the energy range from 40 MeV to 100 MeV at frequency 352.2 MHz. The peak current of the beam will be 30 mA with pulse width 0.5 ms and repetition rate 25 Hz. To accelerate the beam from 40 MeV to 100 MeV, total eighteen tanks will be used and each tank consists of five accelerating cells. The EM design study consists of tank parameter optimization, tolerance study of tank parameters, study of effect of tuners, power loss calculation of different wall segments of cells. (author)