| Paper | Title | Page |
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| MOPC119 | Low-Output-Impedance RF System for the ISIS Second Harmonic Cavity | 343 |
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| Low-output-impedance RF system for the second harmonic cavity in the ISIS synchrotron has been developed by the collaboration between Argonne National Laboratory, US, KEK, Japan and Rutherford Appleton Laboratory, UK. Low output impedance is realized by the feedback from plate output to grid input of the final triode amplifier, resulting in less than 30 Ω over the frequency range of interest. Precise control of the second harmonic voltage can then be realized without considering beam loading effects. Beam test scenario in the ISIS synchrotron is discussed. | ||
| TUPD016 | Grounding and Induced Voltage Issues of the Injection Bump Magnet System of the 3-GeV RCS in J-PARC | 1461 |
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| The power supply of the injection shift bump magnets is required to rate a large current with high precision. The rating current is 20 kA and the pulse width is 1.3 ms. The power supply with the multiple connected two-quadrant IGBT choppers, which is controlled by the switching frequency over 48 kHz, realizes the tracking error less than 1.0 %. However, the switching noise due to the IGBT choppers caused damages to the control device and the measuring instrument. The ground cables were changed to copper sheets, so that the voltage due to the switching noise between the power supply board and the ground decreased from 800 V to 40 V. Furthermore, the output voltage of the RF shield was measured in connection with the several waveform patterns. These results showed the good agreement with the calculation and the experiment. The good performances of the shift bump magnet and power supply have been confirmed. | ||
| THPP105 | Beam Commissioning Results of the RCS Injection and Extraction at J-PARC | 3611 |
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| The beam commissioning of J-PARC (Japan Proton Accelerator Research Complex) 3 GeV RCS (Rapid Cycling Synchrotron) has been started from the end of year 2007. As injection is in the very first stage, an accurate and well controlled beam at the injection strongly related to the other part of the RCS commissioning, including extraction where, an well extracted beam directly reflects the overall commissioning result. In this paper, the beam commissioning results of the RCS injection and extraction will be reported. | ||
| THPP107 | Lifetime Comparisons of Single and Double Layered HBC-Foils using 3.2MeV Ne+ Ion Beam | 3617 |
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| The Japan-Proton Accelerator Research Complex (J-PARC) requires thick carbon stripper foils of 300-500 μg/cm2 thick to strip electrons from the H-beam supplied by the linac before injection into the RCS. The energy depositions upon foil by the intense circulating proton bunched beam as well as H-beam result in the foil temperature of ~1800K. Thus, conventional carbon stripper foils will rupture in a very short time and even a high quality diamond foil will be broken at around 1800 K. Therfore, thick carbon stripper foils with high durability even at 1800K are indispensable for such accelerators. We have developed HBC (Hybrid type Boron mixed Carbon)-foil. We have measured the lifetime of a double and single-layered HBC-foils, diamond (DM) foils and commercially available carbon (CM) foils for comparisons using 3.2 MeV Ne+ ion beam, in which a significant amount of energy loss is deposited in the foils. The lifetime of the double-layered HBC- foil (180 μg/cm2 x 2) was found to be long 18 and 446 times longer than those of DM-foil (360μg/cm2 x 1) and double-layered CM foils ( 207μg/cm2 x 2), respectively. | ||
| THPP108 | Temperature Measurements of Carbon Stripper Foil by Pulsed 650keV H- Ion Beam | 3620 |
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| Thick carbon foils (>300 mg/cm2) has been used for stripping of H- ion beam at the 3 GeV Rapid Cycling Synchrotron (3GeV-RCS) of the J-PARC. The carbon stripper foils with long lifetime against high temperature >1800 °K are strongly required. We have recently developed a new irradiation system for lifetime measurement using the KEK 650keV Cockcroft-Walton accelerator with high current pulsed and dc H- beams, which can simulate the high-energy deposition upon foils in the RCS. The experimental results from the measured temperature of carbon stripper foil by the pulsed 650keV H- ion beam (-6mApeak, 0.3ms, 25Hz) and the observed time structure in the beam spot by a photo-transistor are described. | ||
| THPP134 | Injection and Extraction DC Magnets Power Supplies for 3GeV Rapid Cycling Synchrotron of J-PARC | 3676 |
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Proton beams have been successfully accelerated to the design energy of 3 GeV in the RCS at the J-PARC*. In the injection, dump and extraction sections of the RCS, septum magnets, a quadrupole magnet, dc kicker magnets and steering magnets have been installed and operated at DC. For the septum magnets, there is little space area available for the septum coil and a magnetic shield**. Therefore the power supplies are required high excitation current. Maximum currents of the injection and dump septum magnets are less than 7 kA. The extraction septum magnets need the maximum current of 12 kA***. For saving the cost and the installation space of the extraction septum magnets power supplies, a main power supply, which excites three extraction septum magnets in series, and three auxiliary power supplies for adjusting the current to the each magnet are employed. Long-term stability and the current ripples are required to be less than the order of 100 ppm for those power supplies in order to provide the required acceptance for the beams. This presentation shows design and measurements of the the injection and extraction DC power supplies.
*JAERI Technical Report 2003-044 and KEK Report 2002-13. |