CYCLOTRONS 2010 - List of Authors (Taguchi, M.)

Paper	Title	Page
MOPCP090	Progress in Formation of Single-Pulse Beams by a Chopping System at the JAEA/TIARA facility	233
	S. Kurashima, I. Ishibori, T. Nara, W. Yokota JAEA/TARRI, Gunma-ken, Japan M. Taguchi JAEA/QuBS, Takasaki, Japan
	The intervals of beam pulses from a cyclotron is generally tens of ns and they are too short for pulse radiolysis experiments which require beam pulses at intervals ranging from 1 μs to 1 ms (single-pulse beam). A chopping system, consisting of two types of high voltage kickers, is used at the JAEA AVF cyclotron to form single-pulse beam. The first kicker installed in the injection line generates beam pulses with repetition period of 1 μs to 1 ms. The pulse width is about a cycle length of the acceleration frequency. The other kicker in the transport line thins out needless beam pulses caused by multi-turn extraction. We could not provide single-pulse beam stably over 30 min since the magnetic field of the cyclotron gradually decreased by 0.01 % and the number of multi-turn extraction increased. The magnetic field was stabilized within 0.001 % by keeping temperature of the cyclotron magnet constant. In addition, a new technique to measure and control an acceleration phase has enabled us to reduce the number of multi-turn extraction easier than before. We have succeeded to provide single-pulse beam of a 320 MeV carbon without retuning of the cyclotron over 4 h, as a result.

Paper

Title

Page

Progress in Formation of Single-Pulse Beams by a Chopping System at the JAEA/TIARA facility

233

S. Kurashima, I. Ishibori, T. Nara, W. Yokota
JAEA/TARRI, Gunma-ken, Japan
M. Taguchi
JAEA/QuBS, Takasaki, Japan

The intervals of beam pulses from a cyclotron is generally tens of ns and they are too short for pulse radiolysis experiments which require beam pulses at intervals ranging from 1 μs to 1 ms (single-pulse beam). A chopping system, consisting of two types of high voltage kickers, is used at the JAEA AVF cyclotron to form single-pulse beam. The first kicker installed in the injection line generates beam pulses with repetition period of 1 μs to 1 ms. The pulse width is about a cycle length of the acceleration frequency. The other kicker in the transport line thins out needless beam pulses caused by multi-turn extraction. We could not provide single-pulse beam stably over 30 min since the magnetic field of the cyclotron gradually decreased by 0.01 % and the number of multi-turn extraction increased. The magnetic field was stabilized within 0.001 % by keeping temperature of the cyclotron magnet constant. In addition, a new technique to measure and control an acceleration phase has enabled us to reduce the number of multi-turn extraction easier than before. We have succeeded to provide single-pulse beam of a 320 MeV carbon without retuning of the cyclotron over 4 h, as a result.