Design, Construction and Performance of the INS RFQ Linac ´LITL´

An RFQ linac ´LITL´ (Lithium Ion Test Linac) was constructed and accelerated ion beams of H+, H+2, H+3, 3He+, 6Li+ and 7Li+. The machine was designed to accelerate particles with charge to mass ratio (q/A) of 1 ~ 1/7 injected at 5 keV/u up to 138 keV/u. The acceleration cavity of four vane structure is 56 cm in diameter and 138 cm in length. Transmission exceeding 90 % has been obtained for proton beam of 80 ¿A. The acceleration characteristics agree well with the computer simulation with PARMTEQ. For the acceleration of 7Li+, an rf power of 22 kW is fed with a loop coupler. In cw operation, an electric field of 205 kV/cm has been applied, which is required for 7Li+ acceleration and corresponds to 1.8 times the Kilpatrick´s criterion. A maximum field of 2.0 times the criterion has been achieved, in pulse operation, with a duration width of 5 ms and repetition period of 25 ms. Operation of the machine is easy and stable.