| Paper | Title | Page |
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| TUP06 | Results of the High-Power Conditioning and the First Beam Acceleration of the DTL-1 for J-PARC | 300 |
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| The first tank of the DTL for Japan Proton Accelerator Research Complex (J-PARC) was installed in the test facility at KEK. The DTL tank is 9.9 m in length and consists of the 76 cells. The resonant frequency of the tank is 324 MHz. After the installation of the tank, the high-power conditioning was carried out deliberately. Consequently the peak rf power of 1.3 MW (pulse repetition 50 Hz, pulse length 600 μs) was put into the tank stably. (The required power is about 1.1 MW for the designed accelerating field of 2.5 MV/m on the axis.) Following the conditioning, negative hydrogen beam, accelerated by the RFQ linac up to 3 MeV, was injected to the DTL and accelerated up to its design value of 19.7 MeV. The peak current of 30 mA was achieved with almost 100% transmission. In this paper, the conditioning history of the DTL and the result of the first beam test will be described. | ||
| TUP21 | Beam Dynamics Design of J-PARC Linac High Energy Section | 339 |
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| J-PARC linac consists of a 3 MeV RFQ linac, a 50 MeV DTL (Drift Tube Linac), a 190 MeV SDTL (Separate-type DTL), and a 400 MeV ACS (Annular-Coupled Structure) linac. Recently, the beam dynamics design of the ACS part has been slightly modified to reduce construction cost. Namely, the number of klystron modules are reduced from 23 to 21, and the number of accelerating cells in one klystron module is increased from 30 to 34 to maintain the total energy gain. This design change curtails the margin for RF power by around 5 %, and the total length of the ACS section is nearly unchanged. The beam matching section between SDTL and ACS is also revised correspondingly. These modifications of the design are described in this paper together with 3D particle simulation results for the new design. | ||
| TUP87 | Technologies of The Peripheral Equipments of The J-PARC DTL1 for the Beam Test | 480 |
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| First beam test of the DTL1 was performed in November of 2003 at KEK site. A 30 mA H- beam was successfully accelerated from 3 to 19.7 MeV. In order to prepare the beam test, various peripheral equipments were developed: the electrode plates for connecting the hollow-conductor coil and the power cable were developed since quadrupole electromagnets are built in all DTs (77 sets) of the DTL1, the water-cooled multiconductor copper tube (Control Copper Tube) were used as the power cable from the electrode plate to power supply, and the interlock system assembled by PLCs (Programmable Logic Controller) was also prepared for the surveillance of many cooling channel. | ||
| TUP90 | Improvements of RF Characteristics in the SDTL of the J-PARC Proton LINAC | 489 |
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A separated drift tube linac (SDTL)* was selected as an accelerator structure of Japan Proton Accelerator Complex (J-PARC), which follows DTL. The SDTL of J-PARC consists of 32 short tanks, ranging from 1.5 to 2.5 m in length. A design of frequency tuners of the SDTL was performed by taking account of 3-D field distribution calculated with MAFIA. The effects of stems on the resonant frequency and field distribution were also analyzed. An easy and effective compensation method for perturbation by stems of both end cells was proposed and applied to the SDTL tanks.
* T. Kato. Proposal of a Separated-type Proton Drift Tube Linac for a Medium-Energy Structure. KEK Report 92-10, (1992) |
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| THP69 | The Tuning Study of the Coupled Cavities for the RF Chopper System of J-PARC | 770 |
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| A 3 MeV medium-energy beam transport line (MEBT) is located between RFQ and DTL in the linac of the Japan Proton Accelerator Research Complex (J-PARC). MEBT accomplishes beam matching and chopping. An rf deflector (RFD), which is a heavily loaded cavity, was adopted as a chopper in J-PARC linac for chopping 500 μs long macropulses from the ion source into sub-pulses for injecting into the following 3 GeV rapid-cycling ring. A coupled RFD system was proposed in the design of chopper system for saving the cost of rf power source. The tuning of the coupled RFD system was successfully performed. The longer rise time of the second RFD and the delay of the second RFD excitation were found during the tuning of the coupled RFD system, and these phenomena were further analyzed and investigated. Both in the high power and beam tests, the chopper worked well without any discharge under 36 kW peak driving power. | ||
| THP89 | Measured RF Properties of the DTL for the J-PARC | 809 |
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| RF properties of the second DTL tank for J-PARC have been measured in KEK. The required flatness and stability of the accelerating field of the tank have been achieved by the tunung of the post-couplers, whose shape were modified to adjust the resonant frequency ?324 MHz). Because the third DTL tank has assembled, the rf measurement and the post-coupler tuning will be started soon. Thus the measured results for both tanks will be described in the paper. |