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Shirai, T.

Paper Title Page
MOPEA007 Fast Raster Scanning System for HIMAC New Treatment Facility 76
 
  • T. Furukawa, T. Inaniwa, Y. Iwata, K. Katagiri, K. Mizushima, K. Noda, S. Sato, T. Shirai, Y. Takei, E. Takeshita
    NIRS, Chiba-shi
 
 

Construction of new treatment facility as an extension of the existing HIMAC facility, in which all treatment room will be equipped with a 3D pencil beam scanning system, is in progress at NIRS. The challenge of this project is to realize treatment of a moving target by scanning irradiation, because pencil beam scanning is more sensitive to organ motions compared with the conventional broad-beam irradiation. To accomplish practical moving target irradiation, a prototype of the scanning irradiation system was constructed and installed into existing HIMAC physics experiment course. One of the most important features of the system to be tested is fast scanning toward moving target irradiation with a relatively large number of rescannings within an acceptable irradiation time. Commissioning of the prototype is successfully in progress cooperating with highly stabilized beam provided by the HIMAC accelerator complex. We will report the design of the system and the status of the beam study.

 
MOPEA008 Multiple-energy Operation with Quasi-DC Extension of Flattops at HIMAC 79
 
  • Y. Iwata, T. Furukawa, K. Mizushima, K. Noda, T. Shirai, E. Takada, E. Takeshita
    NIRS, Chiba-shi
  • T. Fujimoto, T. Kadowaki, Y. Sano, H. Uchiyama
    AEC, Chiba
 
 

Tumor therapy using energetic carbon ions, as provided by the HIMAC, has been performed since June 1994, and more than 5000 patients were treated until now. With the successful clinical results over more than ten years, we are constructing a new treatment facility. The new facility would have three treatment rooms; two of them have both horizontal and vertical fixed-irradiation-ports, and the other has a rotating-gantry-port. For all the ports, a scanning irradiation method is applied. The new facility is constructed in conjunction with the HIMAC, and heavy-ion beams will be provided by the HIMAC accelerators. To fulfill requirements for the scanning irradiation, we proposed multiple-energy operation with the quasi-DC extension of a flat top. With this operation, the beam energy can be successively varied within a single synchrotron-cycle, and therefore no energy degrader or the range shifter is required. The beam acceleration and extraction tests of the multiple-energy operation were successfully made. We will present the development of this operation as well as results of the beam acceleration tests.

 
MOPEA013 Laser-driven Proton Accelerator for Medical Application 88
 
  • M. Nishiuchi, P.R. Bolton, T. Hori, K. Kondo, A.S. Pirozhkov, A. Sagisaka, H. Sakaki, A. Yogo
    JAEA, Ibaraki-ken
  • Y. Iseki, T. Yoshiyuki
    Toshiba, Tokyo
  • S. Kanazawa, H. Kiriyama, M. Mori, K. Ogura, S. Orimo
    JAEA/Kansai, Kyoto
  • A. Noda, H. Souda, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • T. Shirai
    NIRS, Chiba-shi
 
 

The interaction between the high intensity laser and the solid target produces a strong electrostatic proton acceleration field (1 TV/m) with extraordinary small size, contributing to downsizing of the particle accelerator. The proton beam exhibits significant features. having very small source size(~10 um), short pulse duration (~ps) and very low transverse emittance. However it is a diverging beam (half angle of ~10 deg) with wide energy spread of ~100 %. Because of these peculiar characteristics the proton beam attracts many fields for applications including medical applications. To preserve these peculiar characteristics, which are not possessed by those beams from the conventional accelerators, towards the irradiation points, we need to establish a peculiar beam transport line. As the first step, here we report the demonstration of the proto-type laser-driven proton medical accelerator beam line in which we combine the laser-driven proton source with the beam transport technique already established in the conventional accelerator for the purpose of comparison between the data and the particle transport simulation code, PARMILA*.


*Harunori Takeda, 2005, Parmila LANL (LA-UR-98-4478).

 
MOPD071 Horizontal-Vertical Coupling for Three Dimensional Laser Cooling* 855
 
  • T. Hiromasa, M. Nakao, A. Noda, H. Souda, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • K. Jimbo
    Kyoto IAE, Kyoto
  • T. Shirai
    NIRS, Chiba-shi
 
 

In order to achieve three dimensional crystal beam, laser cooling forces are required not only in the longitudinal direction, but also in the transverse directions. With the resonance coupling method*, transverse temperature is transmitted into longitudinal direction, and we have already demonstrated horizontal laser cooling experimentally **. In the present paper, we describe an approach to extend this result to three dimensional cooling. The vertical cooling requires that the horizontal oscillation couples with the vertical oscillation. For achieving horizontal-vertical coupling, a solenoid in electron beam cooling apparatus is utilized with an experiment (Qx=2.07,Qy=1.07). For various solenoidal magnetic fields from 0 to 40Gauss, horizontal and vertical betatron tunes are measured by beam transfer function. For a certain region of the solenoidal magnetic field, these tunes are mixed up each other. By optimization of such a coupling, we aim to proceed to three dimensional laser cooling.


* H. Okamoto Phys. Rev. E 50, 4982 (1994)
** H. Souda et.al.,contribution to this conference

 
MOPD072 Optical Measurement of Transverse Laser Cooling with Synchro-Betatron Coupling* 858
 
  • M. Nakao, T. Hiromasa, A. Noda, H. Souda, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • M. Grieser
    MPI-K, Heidelberg
  • K. Jimbo
    Kyoto IAE, Kyoto
  • H. Okamoto
    HU/AdSM, Higashi-Hiroshima
  • T. Shirai
    NIRS, Chiba-shi
  • A.V. Smirnov
    JINR, Dubna, Moscow Region
 
 

Experiments of transverse laser cooling for 24Mg+ beam have been performed at the small ion storage and cooler ring, S-LSR. It is predicted that the longitudinal cooling force is transmitted to the horizontal direction with synchro-betatron coupling at the resonant condition*. The laser system consists of a 532nm pumping laser, a ring dye laser with variable wavelength around 560nm, and a frequency doubler. The horizontal beam size and the longitudinal momentum spread were optically measured by a CCD and a PAT (Post Acceleration Tube) respectively**, ***. The CCD measures the beam size by observing spontaneous emission from the beam and records in sequence of 100ms time windows the development of the beam profile. The time variation of the beam size after beam injection indicates the transverse cooling time. The initial horizontal beam size, which was about 1mm, was decreased by 0.13mm in 1.5s. The longitudinal momentum spread measured by PAT is increased at the resonant condition. This suggests transverse temperature was transferred to longitudinal direction by synchro-betatron coupling. Both measurements denote the horizontal cooling occurred only in the resonant condition ****.


* H. Okamoto, Phys. Rev. {E50}, 4982 (1994)
** M. Tanabe et. al, Appl. Phys. Express 1 (2008) 028001
*** T. Ishikawa Master Thesis, Kyoto Univ.(2008)
**** H. Souda et. al., contribution to IPAC10.

 
MOPD073 Transverse Laser Cooling by Synchro-betatron Coupling 861
 
  • H. Souda, T. Hiromasa, M. Nakao, A. Noda, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • M. Grieser
    MPI-K, Heidelberg
  • K. Jimbo
    Kyoto IAE, Kyoto
  • H. Okamoto
    HU/AdSM, Higashi-Hiroshima
  • T. Shirai
    NIRS, Chiba-shi
  • A.V. Smirnov
    JINR, Dubna, Moscow Region
 
 

Transverse laser cooling with the use of a synchro-betatron coupling is experimentally demonstrated at the ion storage/cooler ring S-LSR. Bunched 40keV 24Mg+ beams are cooled by a co-propagating laser with a wavelength of 280nm. Synchrotron oscillation and horizontal betatron oscillation are coupled by an RF drifttube at a finite dispersive section (D = 1.1m) in order to transmit longitudinal cooling force to the horizontal degree of freedom*. Time evolution of horizontal beam size during laser cooling was measured by a CCD camera**. Horizontal beam sizes were reduced by 0.13mm within 1.5s after injection when the tune values satisfy a difference resonance condition, νs - νh = integer, at the operating tunes of (νh, νv, νs)=(2.067, 1.104, 0.067) and (2.058, 1.101, 0.058). Without resonance condition, the size reduction was negligibly small. The momentum spread was 1.7x10-4 on the resonance otherwise 1.2x10-4. These results show that the horizontal heats are transferred to the longitudinal direction through the synchro-betatron coupling with the resonance condition and are cooled down by a usual longitudinal bunched beam laser cooling.


* H. Okamoto, Phys. Rev. E 50, 4982 (1994).
** M. Nakao et. al., contribution to this conference.

 
MOPD074 Beam Lifetime with the Vacuum System in S-LSR 864
 
  • H. Tongu, T. Hiromasa, M. Nakao, A. Noda, H. Souda
    Kyoto ICR, Uji, Kyoto
  • T. Shirai
    NIRS, Chiba-shi
 
 

S-LSR is a compact ion storage and cooler ring to inject beam of the 7MeV proton and the 40MeV Mg+. The average vacuum pressure measured by the vacuum gauges without beam was achieved up to about 4x10-9 Pa in 2007. Many experiments have been carried out using the proton and Mg beam, for example the one-dimensional beam ordering of protons utilizing the electron cooler, the extraction tests of the short bunched beam and the laser cooling for the Mg beam had been performed. The beam lifetime can be estimated with the vacuum pressure or the loss-rate of the beam energy. The values of the estimated lifetime are nearly equal to the measured lifetime values. The present status of the proton beam lifetime and the vacuum pressure is reported.

 
TUOCRA01 New Treatment Research Facility Project at HIMAC 1324
 
  • K. Noda, S. Fukuda, T. Furukawa, T. Himukai, T. Inaniwa, Y. Iwata, N. Kanematsu, K. Katagiri, A. Kitagawa, S. Minohara, S. Mori, T.M. Murakami, M. Muramatsu, S. Sato, T. Shirai, E. Takada, Y. Takei, E. Takeshita
    NIRS, Chiba-shi
  • T. Fujimoto, Y. Sano
    AEC, Chiba
 
 

Based on more than ten years of experience of the carbon cancer therapy with HIMAC, we have proposed a new treatment facility for the further development of the therapy with HIMAC. This facility will consist of three treatment rooms: two rooms equipped with horizontal and vertical beam-delivery systems and one room with a rotating gantry. For the beam-delivery system of the new treatment facility, a 3D hybrid raster-scanning method with gated irradiation with patient's respiration has been proposed. A R&D study has been carried out toward the practical use of the proposed method. In the R&D study, we have improved the beam control of the size, the position and the time structure for the proposed scanning method with the irradiation gated with patient's respiration. Further, owing to the intensity upgrade of the HIMAC synchrotron, we can successfully extend the flattop duration, which can complete one fractional irradiation with one operation period. The building construction of the new treatment facility will be completed at March 2010 and treatment of 1st patient is scheduled at March 2011. We will report the recent progress on the new treatment facility project at HIMAC.

 

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Slides

 
WEPD055 Semi-nondestructive Monitoring System for High-energy Beam Transport Line at HIMAC 3218
 
  • E. Takeshita, T. Furukawa, T. Inaniwa, Y. Iwata, K. Noda, S. Sato, T. Shirai
    NIRS, Chiba-shi
 
 

The development of the screen monitor system (SCN) at the Heavy Ion Medical Accelerator in Chiba (HIMAC) comprises the surveillance of the carbon beam. In the three-dimensional scanning system for the carbon therapy, the beam qualities, i.e., position, size and intensity of the beam, play a significant role for the patient's treatment. Therefore, we designed a semi-nondestructive monitoring system located on the the high-energy beam transport line to monitor the beam qualities by using a thin fluorescent screen and a high-speed charge-coupled device. The beam position and profile were obtained from the light emitting distribution of the screen. The SCN was checked on the prototype scanning system at HIMAC and succeeded to monitor the beam real-time in steps of about 10 msec, corresponding to a 100 Hz sampling rate. The developments steps will focus toward a operation at HIMAC's new therapy facility extension, recently. In the conference, we would like to report on details of the automatic beam tuning before starting the treatment and the interlock system during therapy using the SCN.

 
THPEB008 Insensitive Method to Power Supply Ripple in Resonant Slow Extraction 3894
 
  • K. Mizushima, T. Furukawa, K. Noda, T. Shirai
    NIRS, Chiba-shi
 
 

The betatron tune fluctuation due to the current ripple of power supplies brings the beam spill ripple through the stable area variation in resonant slow extraction. The effect becomes dominant especially in the case of the low beam rate extraction. The RF-knockout slow extraction method is insensitive to the tune ripple compared to the ordinary one because it uses the diffusion with the transverse RF field. However, the ripple effect appears even in the beam spill extracted by it. The amount of the separatrix fluctuation due to the tune ripple depends on the difference between the bare and the resonant tune, and the sextupole magnetic strength. We measured the correlation between the beam spill and the tune ripple which was the artificially generated with low and high frequency components of 67 Hz and 1167 Hz near those of the real current ripple. We confirmed the reduction of the beam spill ripple by setting the tune away from the resonance while keeping the separatrix area. The comparison between the experimental results, the analytical calculation and the simulation will be reported.