Author/Authors :
Kohara، نويسنده , , S and Goto، نويسنده , , A and Sakamoto، نويسنده , , N and Kamigaito، نويسنده , , O and Watanabe، نويسنده , , S and Teranishi، نويسنده , , T and Katayama، نويسنده , , T and Chiba، نويسنده , , Y and Kase، نويسنده , , M and Yano، نويسنده , , Y، نويسنده ,
Abstract :
A flattop acceleration system has been developed and installed in the RIKEN Azimuthally Varying Field (AVF) cyclotron in order to improve the transmission efficiency and energy spread of beams. The flattop accelerating voltage is generated by a superposition of voltages of the fundamental and third harmonics on the dee, by attaching an additional resonator capacitively coupled to the main resonator. The flattop voltage could be generated from 36 to 63 MHz corresponding to the third harmonic of the operating frequency range of 12–21 MHz. A beam acceleration test was carried out and beam emittance in the longitudinal phase space was measured using a spectrometer. With this flattop system, the single-turn extraction was achieved more easily and the momentum spread was reduced to one-third. The beam transmission efficiency through the AVF cyclotron as well as the RIKEN Ring Cyclotron (RRC) has also been improved.
Keywords :
RIKEN AVF cyclotron , Additional resonator , Flattop acceleration , Single-turn extraction , Measurement of longitudinal emittance , Improvement of beam energy spread and beam transmission efficiency
