Development of solenoids and combined function steering magnets for LEBT of proton linac

Focusing solenoids and large aperture (184 mm) combined function steering magnets are required for Low Energy Beam Transport (LEBT) line for transporting the negative hydrogen ion beam from the Ion source to Radio Frequency Quadrupole (RFQ) of H-injector Linac at RRCAT. The integral field strength (≀f(B_z)²) of water cooled solenoids is (3.5 kG)² x 30 cm and the integrated field strength (B_x.L and B_y.L) of steering magnets is 1500 G-cm. The technical challenges involved in development of these magnets are to satisfy the field quality requirements (spherical aberration coefficient, C1 < 30/m² for solenoids and field uniformity < 1% for steering magnets) and install them with support systems in the limited space available in between the ion source and RFQ of the high Energy proton Linac. The magnets were designed using POISSON 2D and OPERA 3D codes. Two water cooled solenoids and two combined function steering magnets with support systems have been developed. The details of magnet development with their support systems and results of magnetic field measurement will be discussed in this paper. (author)