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septum

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TUPLT079 Opposite Field Septum Magnet System for the J-PARC 50GeV Ring Injection sextupole, injection, booster, laser 1339
 
  • I. Sakai, Y. Arakaki, K. Fan, Y. Mori, M. Muto, Y. Saitou, Y. Shirakabe, M. Tomizawa, M. Uota
    KEK, Ibaraki
  • K. Gotou, Y. Morigaki, A. Nishikawa, M. Takahashi
    IHI/Yokohama, Kanagawa
  • H. Mori, A. Tokuchi
    NICHICON, Shiga
  For the injection/extraction system of the high energy high intensity proton synchrotrons, high field wide aperture thin septum magnets are required. To solve these tight problems, new design concept of opposite-field septum magnet system has been invented. The same grade of opposite magnetic field is produced both inside and outside of the septum. The electromagnetic force and leakage flux around the septum conductor are cancelled out each other. The magnetic field of the circulating beam side is compensated by two sub-bending magnets set on the up-stream and down-stream of the opposite fields septum magnet. The beam-separation angle per magnet length is twice as large as normal septum magnet and the two sub-bending magnets also have a role to extend the injection/extraction angle. The newly developed method of the opposite field septum magnets system.is applied to the injection septum magnets for the J-PARC 50-GeV proton synchrotron to get the sufficient injection angle and clearance for low loss injection. The thin septum thickness and larger kick angle at the septum magnet can be obtained by the new system, which is applicable to many accelerators.  
 
TUPLT080 Design of the Beam Transportation Line from the Linac to the 3-GeV RCS for J-PARC sextupole, booster, linac, laser 1342
 
  • T. Ohkawa
    JAERI, Ibaraki-ken
  • M. Ikegami
    KEK, Ibaraki
  L3BT is beam transportation line from the linac to the 3-GeV RCS which is the part of the accelerators for the High-Intensity Proton Accelerator Facility Project, J-PARC. For the requirement of the beam loss minimization, the L3BT does not only connect the linac to the 3GeV RCS, but also modifies the linac beam to the acceptable shape for the 3-GeV RCS. The required beam parameters at the injection point of the RCS are momentum spread < ±0.1% (100%)and transverse emittance < 4pmm.mrad (99%). To achieve these beam qualities, the L3BT should have following functions: momentum compaction, halo scraping and beam diagnostics. In this paper, results of the design and beam simulation of the L3BT are presented.  
 
TUPLT081 Lattice Design of Large Acceptance FFAGs for the PRISM Project sextupole, booster, linac, laser 1345
 
  • A. Sato
    Osaka University, Osaka
  • S. Machida
    KEK, Ibaraki
  In order to realize a super muon beam that combines high-intensity, low-energy, narrow energy-spread and high purity, the PRISM project has been proposed. In this project, a FFAG ring is used as a phase rotator. In this paper, a method of designing the PRISM-FFAG lattice will be described. The PRISM-FFAG has to have both of large transverse acceptance and large momentum acceptance to achieve high intensity. Furthermore, long straight sections to install RF cavities are required to obtain a high surviving ratio of the muon. Therefore, the PRISM-FFAG requires its magnets to have large aperture and small opening angle. In such magnets, not only nonlinear effects but also magnetic fringing field are important to study the beam dynamics of FFAGs. Although using realistic 3D magnetic field maps made with programs such as TOSCA is the best solution to study the FFAG dynamics, it takes long time to make such field maps. On a design process of the PRISM-FFAG, quasi-realistic 3D magnetic field maps, which are calculated applying spline interpolation to POISSON 2D field, were used to study the beam dynamics. A program based on GEANT3.21 was used for particle tracking.  
 
TUPLT082 Generation of a Femtosecond Electron Beam for Nanoscience and Nanotechnology sextupole, electron, gun, booster 1348
 
  • J. Yang, T. Kozawa, S. Tagawa, Y. Yoshida
    ISIR, Osaka
  A new S-band femtosecond electron linear accelerator was developed in Osaka University for the study of radiation-induced ultrafast physical and chemical reactions in femtosecond time regions. The femtosecond electron accelerator was constructed with a laser driven photocathode RF gun, a linear accelerator (linac) and a magnetic pulse compressor. The RF gun was driven by a mode-locked Nd:YLF picosecond laser. The electron beam produced by the RF gun was accelerated in the linac with energy modulattion by adjusted the RF phase. The magnetic pulse compression, which was constructed with two 45o-bending magnets and four quadrupole magnets, is a technique to longitudinally focus a charged beam by rotating the phase space distribution in a magnetic field. The picosecond electron pulse, which was generated in the RF gun and accelerated in the linac with energy modulation, was compressed into femtosecond by adjusted the quadrupole magnetic fields. The femtosecond electron pulse is expected for the studies of ultrafast reactions in nano-space.  
 
TUPLT085 J-PARC Construction and its Linac Commissioning sextupole, electron, gun, booster 1351
 
  • Y. Yamazaki
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  The J-PARC(Japan Proton Accelerator Research Complex) accelerator is under construction in JAERI Tokai site. The beam commissioning will be started there by the end of 2006. Prior to this, the front end of the linac was beam-commissioned in 2003 at KEK. The negative hydrogen beam with a peak current of 30 mA was accelerated up to 20 MeV by the first tank of three DTL's following the 3-MeV RFQ linac. The 324-MHz DTL contains the electro quadrupole magnets with water-cooling channels specially fabricated by means of electroforming and wire-cutting technologies. The construction status of the J-PARC accelerator is also presented.  
 
TUPLT086 A 40MeV Electron Source with a Photocathode for X-ray Generation through Laser-compton Scattering sextupole, gun, electron, booster 1354
 
  • F. Sakai, N. Nakajyo, Y. Okada, T. Yanagida, M. Yorozu
    SHI, Tokyo
  .3 keV femtosecond X-ray generation through laser-Compton scattering with 14MeV electron source and a TW Ti:sapphire laser was achieved. In order to increase the X-ray energy up to 15 keV for some applications, e.g. protein crystallography, we modified the system to increase electron energy. Electron beams emitted from a S-band RF photocathode are accelerated up to 40MeV with two 1.5m standing-wave linacs. The beams are bended at 90 degree using an achromatic bending system, then focused with a triplet quadrupole-magnet to be interacted with laser pulses. The characteristics of electron beams, emittance, energy and energy dispersion, will be described.  
 
TUPLT087 Deflection Element for S-LSR sextupole, gun, electron, booster 1357
 
  • M. Ikegami, H. Fadil, A. Noda, T. Shirai, M. Tanabe, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • T. Fujimoto, K. Noda, H. Ogawa, S. Shibuya, T. Takeuchi
    NIRS, Chiba-shi
  • M. Grieser
    MPI-K, Heidelberg
  • H. Okamoto
    HU/AdSM, Higashi-Hiroshima
  Main lattice of the ion storage and cooler ring, S-LSR is composed of 6 dipole and 12 quadrupole magnets. The maximum magnetic field, the radius of curvature and gap height are 0.95 T, 1050 mm and 70 mm, respectively. The field measurement of the dipole magnets has been completed with use of Hall-probe position controlled by driving mechanism composed of stepping motors and ball-screws. In order to cancel out the momentum dispersion, the radial electric field is superposed with the magnetic field. The radial electric field is applied by the electrodes installed into the vacuum vessel set inside the rather limited gap of the dipole magnet. Good field quality is to be realized with use of intermediate electrodes. In the present paper, the results of the magnetic field measurements are presented together with the design of the superposed electric field.  
 
TUPLT088 Beam Cooling at S-LSR sextupole, gun, booster, ion 1360
 
  • A. Noda, H. Fadil, S. Fujimoto, M. Ikegami, T. Shirai, M. Tanabe, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • M. Grieser
    MPI-K, Heidelberg
  • I.N. Meshkov, E. Syresin
    JINR, Dubna, Moscow Region
  • K. Noda, T. Takeuchi
    NIRS, Chiba-shi
  • H. Okamoto, Y. Yuri
    HU/AdSM, Higashi-Hiroshima
  S-LSR is an ion accumulation and cooler ring with the circumference and maximum magnetic rigidity of 22.589 m and 1.0T.m, respectively. Electron beam cooling will be applied for laser-produced hot ion beam after phase rotation. Electron cooler for S-LSR is now under construction and the beam simulation is also going on. Laser cooling of Mg ion with low energy (35 keV) is also planned in 3-dimensional way with use of Synchro-Betatron coupling.so as to realize ultra cold beam. Cancellation of shear force due to orbit-length difference in the dipole section is to be studied with use of overlapping of the radial electric field inversely proportional to the curvature radius with the uniform vertical magnetic field. Possible experiments to approach to ultra-cold beam is also to be studied by computer simulation  
 
TUPLT089 Status of PEFP 3MeV RFQ Development sextupole, gun, booster, ion 1363
 
  • Y.-S. Cho, B.-H. Choi, S.-H. Han, J.-H. Jang, Y.H. Kim, H.-J. Kwon, C.-B. Shim
    KAERI, Daejon
  In the PEFP (Proton Engineering Frontier Project), a 350MHz, 3MeV RFQ (Radio Frequency Quadrupole) has been developed and tested. The tuning results showed that the resonant frequency is somewhat higher than 350MHz and other methods in addition to slug tuners should be used to tune the cavity correctly. To check the cavity characteristics, high power RF test has been done. The required peak RF power is 600kW and pulse width, repetition rate for initial test are 100 micro-s, 10Hz respectively. To solve the problems in PEFP RFQ, the upgrade design of 3MeV RFQ has been decided. The main concept of this upgrade design is constant vane voltage profile with the same length of RFQ. The other parameters (350MHz, 3MeV, 20mA) are the same with the previous RFQ. With constant vane voltage profile, fabrication of RFQ can be easier, and with the same mechanical dimension, other parts such as vacuum pumping station can be re-used. In this paper, the test results of the PEFP RFQ, and the details of beam dynamics design/engineering design of upgrade RFQ will be presented.  
 
TUPLT090 Combined Beam Dynamics Study of the RFQ and DTL for PEFP sextupole, gun, booster, proton 1366
 
  • J.-H. Jang, Y.-S. Cho, H.-J. Kwon
    KAERI, Daejon
  One of the goals of the Proton Engineering Frontier Project (PEFP) is to get 20 MeV proton beams of 20 mA through a 3 MeV RFQ and a 20 MeV DTL. This work is related to the combined beam dynamics study of the low energy proton accelerators in order to test the validity of the connection of the independently designed structures as well as to study the MEBT for beam transportation.  
 
TUPLT091 Fabrication Status of the PEFP 20 MeV DTL sextupole, gun, booster, ion 1369
 
  • M.-Y. Park, Y.-S. Cho, J.-H. Jang, Y.H. Kim, H.-J. Kwon
    KAERI, Daejon
  The PEFP (Proton Engineering Frontier Project) 20 MeV DTL have been constructed in KAERI site. The fabrication of the first tank is finished and the DT installation is in the process. We choose the pool-type electromagnets as the focusing magnet and 50 DTs will be installed on first tank. We tested the winding schemes of copper coils on the iron core and measured the magnetic field saturation.In this paper, the results of the tank fabrication and quadrupole magnet test are presented.  
 
TUPLT092 Optics and Magnet Design for Proton Beam Transport Line at PEFP sextupole, proton, gun, booster 1372
 
  • H.-S. Kang, H.S. Han, S.H. Jeong, Y.G. Jung, D.E. Kim, M. Kim, H.G. Lee, T.-Y. Lee, H.S. Suh
    PAL, Pohang
  The PEFP proton linac is designed to have two proton beam extraction lines at the 20-MeV and 100-MeV end, respectively. Each extraction line has 5 to 6 beamlines for proton beam users. The proton beam transport system for users? experiments will be prepared for this purpose. At the beginning, the beam optics for the proton beam transport system is designed with the TRACE code. The optics should be designed so as to meet the users? various requirements which might be to control the beam size and intensity at the beam target, and the timing of the proton beam. The magnet to distribute the proton beam to many beamlines is an AC magnet which has an AC frequency of 15 Hz, and is powered with a programmable AC power supply. In this paper, the result of the optics design will be presented and the magnet design will be described.  
 
TUPLT093 Tune Survey of Dynamic Apertures for High-brilliance Optics of the Pohang Light Source sextupole, proton, gun, booster 1375
 
  • E.-S. Kim
    PAL, Pohang
  The PLS storage ring is a 2.5 GeV light source and the dynamic apertures in a lattice for the low emittance in the ring have been investigated by a simulation method. The dynamic apertures that include effects of machine errors and insertion devices were obtained by a tune survey in the simulation. It was also shown that how large are the dynamic aperture compensated after corrections of a CODs. The betatron tune for the operation of the high-brilliance lattice are investigated based on the view point of dynamic apertures obtained from a tune survey.  
 
TUPLT095 Precision Field Mapping System for Cyclotron Magnet sextupole, proton, gun, booster 1378
 
  • K.-H. Park, Y.G. Jung, D.E. Kim, L.W.W. Lee
    PAL, Pohang
  • J.-S. Chai, Y.S. Kim
    KIRAMS, Seoul
  • B.-K. Kang, S.H. Shin, M. Yoon
    POSTECH, Pohang
  A 13 MeV cyclotron has been developed by KIRAMS for radio-isotopes production such as F-18 and O-15 for positron emission tomography(PET). To characterize the cyclotron magnet precisely, a Hall probe mapping system with very high precise positioning mechanism in the Cartesian coordinate has been developed. Hall probe assembly was translated in two dimensions by two stepping motors at both sides of the Hall-probe-carrier to keep synchronously rotation sharing one step-pulse source for x-axis and one motor for y-axis. The data acquisition time had reduced to 60 minutes in full mapping by 'flying' mode. The accuracy of the measurement system is better than during the entire mapping process. In this paper the magnetic field measurement system for the cyclotron magnet is described, and measurement results are presented.  
 
TUPLT096 RFQ Low Level RF System for the PEFP 100MeV Proton Linac sextupole, gun, booster, optics 1381
 
  • I.H. Yu, M.-H. Chun, K.M. Ha, Y.J. Han, W.H. Hwang, M.H. Jeong, H.-S. Kang, D.T. Kim, S.-C. Kim, I.-S. Park, J.S. Yang
    PAL, Pohang
  • Y.-S. Cho, K.T. Seol
    KAERI, Daejon
  The 100MeV Proton linear accelerator (Linac) for the PEFP (Proton Engineering Frontier Project) will include a 3MeV, 350MHz RFQ(Radio-Frequency Quadrupole) Linac. The RFQ accelerates a 20mA proton beam from 50keV to 3MeV. The low level RF system for RFQ provides field control. In addition to field control, it provides cavity resonance control. An accelerator electric field stability of ± 1% in amplitude and ± 1° in phase is required for the RF system. The low level RF system has been designed and is now being fabricated.  
 
TUPLT098 Vertical Beam Motion in the AGOR Cyclotron sextupole, gun, booster, optics 1384
 
  • M.A. Hofstee, S. Brandenburg, H. Post, W.K. van Asselt
    KVI, Groningen
  Large-scale vertical excursions have been observed in the AGOR cyclotron for light ionbeams at energies close to the focussing limit (E/A =200 Q/A MeV per nucleon). With increasing radius the beam gradually moves down out of the geometrical median plane by several mm, leading to internal beamlosses. It was concluded that this effect is caused by a vertical alignment error of the coils combined with the weak vertical focussing for the beams concerned. Moving the main coils by a total of 0.37 mm has significantly improved the situation at large radii, but results in internal beamlosses for certain beams at small radii due to a large upward excursion. A systematic study of the vertical beam dynamics as a function of beam particle and energy will be presented. Possible causes and solutions will be discussed.  
 
TUPLT099 A Kicker Pulse Power Supply with Low Jitter sextupole, kicker, gun, booster 1387
 
  • C.-S. Fann, J.-P. Chiou, S.Y. Hsu, K.-B. Liu
    NSRRC, Hsinchu
  The performance of kicker pulse power supplies is the main parameter to increase injection efficiency of storage ring that is an important issue for laboratory of synchrotron radiation research. The output current waveform of a kicker pulse power supply with low timing jitter is our goal for years that must satisfy the Top-Up mode injection requirement of NSRRC. In the past years kicker pulse power supplies of storage ring of NSRRC are immersed in isolation oil to sustain high voltage operational environment that led difficult to maintain, electronic component degrading and uneasy to tune parameters. Air-cooling and air-isolation is adopted in the new design structure for kicker pulse power supply system and an pre-trigger unit MA2709A is installed to trigger thyratron tube CX1536A, a kicker pulse power supply with low timing jitter 1~2ns(p-p) is obtained and could satisfy for Top-Up mode injection and maintenance is more easier than before.  
 
TUPLT102 Field Study of the 4T Superconducting Magnet for Rapid Cycling Heavy Ion Synchrotrons kicker, gun, booster, optics 1390
 
  • V.A. Mikhaylov, P.G. Akishin, A.V. Butenko, A.D. Kovalenko
    JINR, Dubna, Moscow Region
  The problem of the magnetic field optimization of a 4T dipole magnet with circular aperture of 100-110 mm for rapid cycling synchrotron is considered. A single layer low inductance coil made of hollow superconducting high current cable operating at 30 kA is used. The magnetic field ramp rate up to 4 T/s should be achievable. Mathematical method to minimize sextupole and higher order non-linearities to the tolerable values by variation of angular coil turn position is developed. The results of numerical simulation for 2D part magnetic field are presented. The further possibilities to improve the field quality for similar lattice magnets and their application for heavy ion synchrotrons and boosters are discussed.  
 
TUPLT103 Possibilities for Experiments with Rare Radioactive Ions in a Storage Ring Using Individual Injection ion, gun, booster, optics 1393
 
  • A.O. Sidorin, I.N. Meshkov, A.O. Sidorin, A. Smirnov, E. Syresin, G.V. Troubnikov
    JINR, Dubna, Moscow Region
  • T. Katayama
    CNS, Saitama
  • W. Mittig, P. Roussel-Chomaz
    GANIL, Caen
  A radioactive ion beam produced at a target bombarded with a primary beam has after a fragment separator a relatively large emittance and small production rate. For instance, typical flux of 132Sn isotope at the exit of fragment-separator is about 5×105 ions/s. Conventionally used scheme of the ion storage in a ring based on multitutrn injection and (or) RF stacking and stochastic cooling application can not provide a high storage rate at so pure intensity especially for short lived isotopes. In this report we discuss an alternative storage scheme which is oriented to the continuous ion beam from fragment separator at production rate of 104 ions/s or even less. It is based on the fact, that at low production rate the parameters of each particle can be measured individually with rather high accuracy. The particle trajectory can be individually corrected in a transfer channel from fragment separator to the storage ring using system of fast kickers. A fast kicker in the ring synchronized with a circulating bunch provides continuous injection of the ions. The scheme permits to store the ion number required for precise mass measurements and internal target experiment. A hope to obtain large luminosity of ion-electron collisions is related with a possibility of the ion beam crystallization at small particle number.  
 
WEPKF041 Permanent Magnet Generating High and Variable Septum Magnetic Field and its Deterioration by Radiation alignment, kicker, bunching, radiation 1696
 
  • T. Kawakubo, E. Nakamura, M. Numajiri
    KEK, Ibaraki
  • M. Aoki, T. Hisamura, E. Sugiyama
    NEOMAX Co., Ltd., Mishima-gun, Osaka
  Conventional high field septum magnet is fed by DC current or pulse current. In the case of DC, the problem of coil support is not very important, but the cooling of the coil is serious problem. While, in the case of pulse, the problem of support is much important than that of cooling. However, if the septum magnet is made of permanent magnet, those problems are dissolved. And the cost for electricity and cooling water can be exceedingly decreased. Therefore, we made the model septum magnet which has 1/4 scale of the real size and generates 1[T] with the variable range of ± 10%. The magnetic field distribution in the gap by changing the representative field is reported. When this permanent magnet is set in an accelerator, the deterioration of the permanent magnet by radiation will be serious problem. We also report the dependence of the magnetic fields generated by permanent magnet samples on accumulated radiation by various types of radiation source.  
 
WEPKF042 Installation and Operation of New Klystron Power Supply with Fast Solid-State Switch for Klystron Protection at the Photon Factory Storage Ring alignment, kicker, bunching, radiation 1699
 
  • S. Sakanaka, M. Izawa, T. Takahashi, K. Umemori
    KEK, Ibaraki
  In the 2.5-GeV Photon Factory storage ring at KEK, there are four klystron power supplies which typically operate at an output voltage of -40 kV with 8 A. We replaced one of these power supplies during 2003 and the new power supply is in operation. This power supply is equipped with a solid-state high-voltage (HV) switch for klystron protection. This HV switch is made up of eighty insulated gate bipolar transistors (IGBT), and it can turn the high-voltage off within a few tens of microseconds in cases of any discharges in the klystrons. We report the performance of this new power supply.