HB2012 - List of Authors (Liu, Y.)

Paper

Title

Page

Study of Non-equi-partitioning Lattice Setting and IBS Effects for J-PARC Linac Upgrade

118

Y. Liu
IMP, Lanzhou, People's Republic of China
M. Ikegami
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

For the coming upgrade of J-Parc, the peak power of linac will be greatly increased. This may open many interesting questions. For instance, for efficient acceleration from 19 0MeV to 400 MeV the annular coupled structure (ACS) was applied with frequency jump from 324 MHz to 972 MHz. Upstream part of J-PARC linac from the frequency jump is set with the equi-partitioning (EP) condition, which prevents from the coherent resonances. If EP condition is kept for the downstream part, due to the frequency jump, the transverse focusing should also ‘jump' 3 times with shrink of envelop. The increased beam-density affects the interactions between particles, including the intra-beam stripping (IBS) effect in the H⁻ beam. The temperature ratio between transverse and longitudinal planes is used as a knob for studying the beam behavior for the cases away from equi-partitioning. The IBS effects, as well as strategies for setting downstream non-equi-partitioning lattice due to frequency jump are studied. The matching and beam evolution in the transition section from EP to non-EP (MEBT2) are also studied. The results help to reach an optimum with least risks from resonances and IBS effects and so on.

THO3A01

High Intensity Aspects of J-PARC Linac Including Re-commissioning after Earthquake

497

M. Ikegami, K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
T. Maruta, A. Miura, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan

We had a massive earthquake in March 2011, which forced us to shutdown J-PARC accelerators for nearly nine months due to its resultant damages. After significant restoration effort, we resumed the beam operation of J-PARC linac in December 2011 and user operation in January 2012. Subsequently, we restored the same beam power as just before the earthquake in March 2012. In the course of the beam commissioning after the earthquake, we have experienced beam losses which were not observed before the earthquake. We discuss the experimentally observed beam losses and its comparison with particle simulations.

Slides THO3A01 [5.249 MB]

Paper	Title	Page
MOP231	Study of Non-equi-partitioning Lattice Setting and IBS Effects for J-PARC Linac Upgrade	118
	Y. Liu IMP, Lanzhou, People's Republic of China M. Ikegami JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	For the coming upgrade of J-Parc, the peak power of linac will be greatly increased. This may open many interesting questions. For instance, for efficient acceleration from 19 0MeV to 400 MeV the annular coupled structure (ACS) was applied with frequency jump from 324 MHz to 972 MHz. Upstream part of J-PARC linac from the frequency jump is set with the equi-partitioning (EP) condition, which prevents from the coherent resonances. If EP condition is kept for the downstream part, due to the frequency jump, the transverse focusing should also ‘jump' 3 times with shrink of envelop. The increased beam-density affects the interactions between particles, including the intra-beam stripping (IBS) effect in the H⁻ beam. The temperature ratio between transverse and longitudinal planes is used as a knob for studying the beam behavior for the cases away from equi-partitioning. The IBS effects, as well as strategies for setting downstream non-equi-partitioning lattice due to frequency jump are studied. The matching and beam evolution in the transition section from EP to non-EP (MEBT2) are also studied. The results help to reach an optimum with least risks from resonances and IBS effects and so on.

THO3A01	High Intensity Aspects of J-PARC Linac Including Re-commissioning after Earthquake	497
	M. Ikegami, K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan Y. Liu KEK/JAEA, Ibaraki-Ken, Japan T. Maruta, A. Miura, J. Tamura JAEA/J-PARC, Tokai-mura, Japan
	We had a massive earthquake in March 2011, which forced us to shutdown J-PARC accelerators for nearly nine months due to its resultant damages. After significant restoration effort, we resumed the beam operation of J-PARC linac in December 2011 and user operation in January 2012. Subsequently, we restored the same beam power as just before the earthquake in March 2012. In the course of the beam commissioning after the earthquake, we have experienced beam losses which were not observed before the earthquake. We discuss the experimentally observed beam losses and its comparison with particle simulations.
	Slides THO3A01 [5.249 MB]