| Paper | Title | Page |
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| MOPEB009 | Low Leakage Field Septa for J-PARC Main Ring Injection System Upgrade | 295 |
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Injection into the J-PARC main ring is implemented by 4 kickers and 2 pulsed septa at 3 GeV in a long straight section. To accommodate the injection beam of 54 pmm.mrad, both septa have large physical acceptance of 81 pmm.mrad. However, large aperture leads to large end fringe field interfereing the circulating beam and causing beam loss, which has been observed even at low beam intensity during the beam commissioning. To provide users a proton beam with high beam power, the injection beam intensity will increase greatly in future, which creates difficulties for the present injection system. To accommodate these high intensity beams with low beam loss, the injection system needs to be upgraded. Taking account the strong space charge effects, even larger physical is needed to reduce the localized beam loss, which creates severer end fringe leakage field. This paper will discuss the problems encountered in operating the present septa, and give an optimized design for the new septa. |
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| MOPEB010 | Development of a High Radiation Resistant Septum for JPARC Main Ring Injection System | 298 |
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The J-PARC is a high intensity proton accelerator complex, which consists of a LINAC, a Rapid Cycling Synchrotron (RCS) and a Main Ring (MR). The MR injection system employs a high-field septum to deflect the incoming beam from the RCS, which has been used for the beam commissioning study with low beam intensity successfully. Relative large beam losses in the injection area have been observed, which is proportional to the injection beam intensity. In future, the beam intensity will increase about 100 times to realize high beam power (~MW) operation required from neutrino experiments. The beam loss at the injection region is expected increase greatly due to the space charge effects, which creates severe radiation problems. Since the present injection septum coil is organic insulated, which will be destroyed under such a severe irradiation quickly. To cope with this problem, a new high radiation resistant injection septum magnet is developed, which uses inorganic insulation material (Mineral Insulated Cable - MIC) to prevent the septum from radiation damage. This paper investigates different effects caused by the MIC and gives an optimization design. |