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Sako, Hiroyuki; Ueno, Akira; Okawa, Tomohiro*; Kondo, Yasuhiro; Morishita, Takatoshi; Ikegami, Masanori*; Akikawa, Hisashi*
Proceedings of 24th International Linear Accelerator Conference (LINAC 2008) (CD-ROM), p.260 - 262, 2009/00
In designed very high intensity proton beam of J-PARC LINAC, precise control of transverse beam dynamics is extremely important for suppression of beam loss. We present results of transverse beam matching and orbit corrections. Excellent matching performance has been achieved with mismatch factor less than 5% at beam current of 5 to 30 mA. Orbit deviations were suppressed within 1mm in horizontal and vertical directions in the whole LINAC.
Ueno, Akira
Proceedings of 24th International Linear Accelerator Conference (LINAC 2008) (CD-ROM), p.343 - 347, 2009/00
The J-PARC linac has been successfully commissioned up to its design energy of 181 MeV and almost the first stage design peak intensity of 30 mA. The following unique methods and hardware features adopted in the J-PARC linac are explained and those results are reported in this paper. The surface production dominating Cs-free H
IS with magnetic focus LEBT, macro-pulse generation method related with the J-PARC 30mA-RFQ design, stable one-shot operation method, beam suspending method for machine protection, RF-chopper system related with the operation parameter of the RFQ, one-turn injection method into the following J-PARC RCS, transverse matching using TRACE3D PMQ elements approximating the fringe field effects of the electro-quadrupole magnets, PR electroforming for high-duty compact DTQ coil and thick pure plating of DTL and SDTL and 2 cavity behaviour of SDTL fed with one Klystron.
Hasegawa, Kazuo; Asano, Hiroyuki; Chishiro, Etsuji; Hori, Toshihiko; Ito, Takashi; Kobayashi, Tetsuya; Kondo, Yasuhiro; Namekawa, Yuya; Oguri, Hidetomo; Okoshi, Kiyonori; et al.
Proceedings of 24th International Linear Accelerator Conference (LINAC 2008) (CD-ROM), p.55 - 57, 2009/00
The beam commissioning of the J-PARC linac started in November 2006 and 181 MeV acceleration was successfully achieved in January 2007. The linac has delivered beams to the 3 GeV Rapid Cycling Synchrotron for its commissioning, and then, the subsequent Main Ring Synchrotron and the neutron target commissioning. The linac uses a Cs-free LaB
-driven ion source and 20 units of 324 MHz klystrons. As of June 2008, the operation times are about 3,000 and 6,000 hours for the ion source and the RF source, respectively. The operating experience of the linac is described.
Kobayashi, Tetsuya; Chishiro, Etsuji; Suzuki, Hiroyuki; Anami, Shozo*; Fang, Z.*; Michizono, Shinichiro*; Yamaguchi, Seiya*
Proceedings of 24th International Linear Accelerator Conference (LINAC 2008) (CD-ROM), p.1054 - 1056, 2009/00
For the J-PARC linac low level RF system, a new function that switches the feed-forward control parameters in every pulse was installed into the digital accelerating-field control system, in order to compensate beam-loading change by pulses in the operation of 25-Hz repetition. The linac provides a 50-mA peak current proton beam to a 3-GeV rapid-cycling synchrotron (RCS). Then the RCS distributes the 3-GeV beam into a following 50-GeV synchrotron (main ring, MR) and the Materials and Life Science Facility (MLF), which is one of the experimental facilities in the J-PARC. The 500-us long macro pulses from the ion source of the linac should be chopped into medium pulses for injection into the RCS. The duty (width or repetition) of the medium pulse depends on which facility the RCS provides the beam to the MR or MLF. Therefore the beam loading compensation needs to be corrected for the change of the medium pulse duty in the 25-Hz operation.
Fang, Z.*; Anami, Shozo*; Michizono, Shinichiro*; Yamaguchi, Seiya*; Kobayashi, Tetsuya; Suzuki, Hiroyuki
Proceedings of 24th International Linear Accelerator Conference (LINAC 2008) (CD-ROM), p.1039 - 1041, 2009/00
In the J-PARC proton linac, each klystron drives two RF cavities. The RF amplitude and phase of the cavities are controlled by an FPGA-based digital feedback control system. The test results show that the variations in the cavity amplitude and phase are less than 
0.1% and 0.1 
without beam loading, or 0.3% and 0.2 with beam loading. The tuning of each cavity is also controlled by a DSP of this control system. The cavity auto-tuning is successfully controlled to keep the detuned phase within 1 degree. In our RF system, the tuning information including detuned frequency and phase, and Q-value of each cavity are measured in real-time and displayed in the PLC touch panel of the control system.
Yoshikawa, Hiroshi; Suzuki, Takahiro; Sakaki, Hironao; Ito, Yuichi; Kato, Yuko; Kawase, Masato; Sako, Hiroyuki; Shen, G.; Takahashi, Hiroki; Fukuta, Shimpei; et al.
Proceedings of 24th International Linear Accelerator Conference (LINAC 2008) (CD-ROM), p.52 - 54, 2009/00
LINAC of J-PARC began to operate in November, 2006, and a achieved an initial performance in January, 2007. Afterwards, the beam supply to RCS begins, and it is operating extremely with stability up to now. Here, the evaluation for comparison of the design and realities of architecture and performance of the LINAC control system are shown. Especially, the conceptual idea of function arrangement in the hierarchy of the control system architecture is shown. Now, the LINAC control system is in the second phase for the high power beam and reducing the beam loss, and the analysis of the system response identification for the high precision beam control is started.
