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cyclotron

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MOYBMH01 World-wide Efforts on Rare Isotope and Radioactive Beams ion, linac, target, ISOL 16
 
  • O. Kamigaito
    RIKEN Nishina Center, Wako
 
 

Study on atomic nuclei has expanded remarkbly to a broad range of region far from stability since 1980's when a number of accelerator facilities launched scientific programs on rare isotopes and radioactive beams. Today, second-generation accelerator facilities dedicated to research on the rare isotopes and radioactive beams are either operating, under construction, or being proposed. Various types of accelerators are currently used, depending on the goal of research on a variety of unstable nuclei. Based on the recent activity of the radioactive Ion Beam Facility at RIKEN, this presentation provides a world wide overview of the activity on radioactive beams.

 

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MOPEA002 Eye Tumour Therapy in Berlin ion, proton, target, heavy-ion 64
 
  • A. Denker
    HMI, Berlin
  • D. Cordini, J. Heufelder, R. Stark, A. Weber
    Charite, Berlin
  • C.R. Rethfeldt, J.R. Roehrich
    HZB, Berlin
 
 

The ion beam laboratory ISL at the Hahn-Meitner-Institute (HMI) Berlin supplied light and heavy ion beams for research and applications in solid state physics, industry, and medicine. Since 1998, eye tumours are treated with 68 MeV protons in collaboration with the University Hospital Benjamin Franklin, now Charité - Campus Benjamin Franklin. In autumn 2004 the board of directors of the HMI decided to close down ISL at the end of 2006. In December 2006, a cooperation contract between the Charité and the HMI was signed to assure the continuity of the eye tumour therapy, at the moment the only facility in Germany. The accelerator operation will be continued with reduced man-power, requiring changes in the set-up of the accelerators. A new, facile injector for protons is foreseen. Increasing the reliability will be a key issue. The last two years of operation of ISL as a full multi-purpose accelerator will be shown and examples of the research work will be demonstrated. The conversion of a multi-ion, variable energy accelerator to a dedicated accelerator for eye tumour therapy will be discussed.


The Helmholtz-Zentrum Berlin für Materialien und Energie has been formed by the merger of the Hahn-Meitner-Institut Berlin and the Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung

 
MOPEA018 Study of the Installtion of a Small Animal Experiment Equipment in a MC-50 Cyclotron LEPT Beam Line proton, simulation, target, controls 103
 
  • M.H. Jung, J.-K. Kil, K. R. Kim, S.J. Ra
    KAERI, Daejon
 
 

Proton therapy has features of minimal effect on tumor surrounding healthy tissue and huge damage on tumor volumes specifically. Due to these characteristics of proton therapy the number of patients with receiving proton therapy is increasing every year. Proton therapy is useful for tumor treatment but still not know mechanism of proton beam that how to kill the tumor cells. In korea, a lot of current research progressed at the cellular level by using a proton accelerator, the animal experiments was not held virtually because of the absence of the device. In this study, we installed a animal experiment device for proton beam irradiation in MC-50 cyclotron LEPT (Low Energy Proton Therapy) beam line. Bouls and collimator, we easily made to be installed and we used PMMA sheet in order to reduce the energy. In addition, we used ridge filter type modulator for making SOBP and depth-dose measurement system for a proton beam dosimetry.

 
MOPEA019 Study on the Injection System for Compact Cyclotron Mass Spectrometry injection, ion, extraction, dipole 106
 
  • D.G. Kim, H.-C. Bhang, J.Y. Kim
    SNU, Seoul
  • J.-W. Kim
    NCC, Korea, Kyonggi
  • C.C. Yun
    Chung-Ang University, Seoul
 
 

Accelerator mass spectrometry (AMS) using a cyclotron has been studied because the system can be more compact and economical compared to the widespread commercial Tandem AMS. However, the previous efforts to build such a system showed that it has weakness in stability and transmission efficiency. To increase transmission efficiency it is important for the injection system to match not only the transverse phase space of a beam but also the longitudinal phase space with cyclotron acceptance. We plan to adopt a sawtooth RF buncher to increase transmission efficiency in the acceleration region of the cyclotron and a radial injection beam line. A goal in designing the injection line is to minimize the number of beam line elements to keep the system compact. The design of the injection system was carried out using the codes such as TRANSPORT and TRACE-3D. A prototype of the injection system is being constructed, and some results will be presented.

 
MOPEA037 Activation and Discoloration of Polymer by Proton Beam proton, radiation, target, neutron 151
 
  • S.J. Ra, M.H. Jung, K. R. Kim
    KAERI, Daejon
 
 

During the beam irradiation experiments with more than a few MeV energetic protons, nuclear reactions are occurred in sample materials. Because of these nuclear reactions, the samples are activated so many kinds of additional problems for the post-processing of the samples are caused; such as time-loss, inconvenience of sample handling, personal radiation safety, etc. For in-vitro experiments, we observe death of tumor cells by proton irradiation. The use of large activated container material can cause erroneous results in this case. To solve these problems, we studied why the samples are activated and how the level of the activation can be reduced. In our proton beam irradiation experiments, the target materials can be defined as the container and sample itself. We could easily reduce activation of container material comparing to activation of sample itself. Therefore, we tried to find less activated container material by irradiating proton beam in PS (Polystyrene), PMP (Polymethypenten), and PMMA (Poly methacrylate). We used 45 MeV proton beams (MC-50 Cyclotron, KIRAM) with 10 nA.

 
MOPEA057 Social Aspects of Japanese High Energy Accelerators synchrotron, electron, FEL, collider 205
 
  • K. Hirata
    GUAS, Kanagawa
  • E. Kikutani, M. Sekimoto
    KEK, Ibaraki
  • Y. Takaiwa
    Tsukuba University of Technology, Kasuga Campus, Tsukuba, Ibaraki
 
 

Japanese research to build accelerators for high energy physics started with Electron Synchrotron at Institute of Nuclear Study, Tokyo (INS). The development was slow in the beginning, in particular before the construction of KEK-PS. After the experience of TRISTAN, KEKB, one of the best colliders in the world, was eventually constructed. We will review the history of high energy accelerators in Japan from physics, technological and particularly social points of view referring to documents at KEK and other archives. This is the first of a series of papers and will outline the over-all view.

 
MOPEA071 The Solid Target Control System for the RFT-30 30 MeV Cyclotron in KAERI target, controls, vacuum, status 241
 
  • I.J. Kim, S.M. Choi, M.G. Hur, S.W. Kim, J.H. Park, S.D. Yang
    KAERI, Daejon
 
 

The solid target of the RFT-30 30 MeV cyclotron in KAERI was designed to produce the metalic radioisotopes, such as Zn-62, Cu-67, Ge-68, Pd-103, and In-111. The target control system should provide high reliability to prevent any kind of failure. Moreover, the operating procedures and maintenance cycle should be optimized and well organized to cover the unexpected situations. In this study, a simulation of the control system for the solid target in KAERI was carried out to confirm the operability of the solid target transport system. The receiving and irradiation stations are connected each other through square tube, and the control software was also checked. The developed solid target control system controls vacuum, cooling, and the whole procedures before, during, and after the irradiation.

 
MOPEB035 Present Status of the RCNP Cyclotron Facility ion, neutron, plasma, cavity 349
 
  • K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, K. Nagayama, H. Okamura, T. Saito, H. Tamura, T. Yorita
    RCNP, Osaka
 
 

The RCNP accelerator cascade consists of an injector Azimuthally Varying Field (AVF) cyclotron (K=140) and a ring cyclotron (K=400). It provides ultra-high-quality beams and moderately high-intensity beams for a wide range of research in nuclear physics, fundamental physics, applications, and interdisciplinary fields. The maximum energy of protons and heavy ions are 400 and 100 MeV/u, respectively. Experimental apparatuses are used like a pair spectrometer, a neutron time of flight facility with a 100 m long tunnel, a radioactive nuclei separator, a super-thermal ultra cold neutron (UCN) source, a white neutron source, and a RI production system for nuclear chemistry. Such ultra high resolution measurements as dE/E = 5x10-5 are routinely performed with the Grand-Raiden spectrometer by utilizing the dispersion matching technique. The UCN density was observed to be 15 UCN/cm3 at the experimental port at a beam power of 400 W. Some topics on the research are discussed in the talk.

 
MOPEC038 Commissioning of FFAG Accelerator at Kyushu University kicker, alignment, extraction, pick-up 543
 
  • T. Fujinaka, T. Matsunaga, S. Mochizuki, H. Takase
    Kyushu University, Center for Accelerator and Beam Applied Science, Fukuoka
  • H. Arima, T. Hasuo, N. Ikeda, K. Ishibashi, T. Korenaga, K. Maehata, N. Shigyo, Y. Uozumi, G. Wakabayashi, Y. Yonemura
    Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
  • K. Fujita, T. Morikawa, T. Noro, T. Wakasa
    Kyushu University, Fukuoka
  • Y. Mori
    KURRI, Osaka
  • H. Nakayama, A. Takagi
    KEK, Ibaraki
  • T. Tomimasu
    SAGA, Tosu
 
 

150 MeV FFAG accelerator is under construction at Center for Accelerator and Beam Applied Science on Ito Campus to promote activities in all related scientific, medical, engineering and educational field at Kyushu University. In this paper, status of the development of hardware and the results of the beam commissioning of the injector are described.

 
MOPEC039 Developments for Beam Intensity Increase and Beam Quality Improvement in the RCNP Cyclotrons proton, ECR, acceleration, ion 546
 
  • M. Fukuda, K. Hatanaka, H. Kawamata, M. Kibayashi, T. Saito, H. Tamura, T. Yorita
    RCNP, Osaka
 
 

An upgrade program of the RCNP cyclotron facility for increase of beam intensity and improvement of beam quality is in progress to meet requirements from research in nuclear physics and industrial applications using secondarily produced particles such as neutrons, muons and radioisotopes. A 2.45 GHz ECR ion source using a set of permanent magnets was developed for high intensity proton beam production. The proton beam intensity more than 0.5 mA at an extraction energy of 15 keV has been obtained with a proton ratio more than 80 %. The quality of the pre-accelerated beam from the K140 injector AVF cyclotron has been improved by a flat-top(FT) acceleration system to enhance the beam transmission to the K400 ring cyclotron. Transversal resonant mode of a dee electrode with a span angle of 180 degrees was investigated to achieve the FT acceleration in the frequency region from 50 to 60 MHz. In this paper, developments for high intensity proton beam acceleration and beam quality improvement using the FT acceleration system of the AVF cyclotron will be mainly presented.

 
MOPEC041 Calculation of Second Order Moments for an Ion Beam in a Degrader ion, emittance, beam-transport, simulation 549
 
  • N.Yu. Kazarinov, V.I. Kazacha
    JINR, Dubna, Moscow Region
 
 

In order to decrease the energy of an ion accelerated in a cyclotron on value of some MeV/eau it is possible to run an ion beam through a thin metal foil (degrader). One can calculate the final ion energy, angular and energy stragglings, which the beam attains in the degrader, for example, by means of code LISE++. The formulae for calculation of the beam second order moments after degrader were obtained. The formulae for calculation of final beam momentum spread, new values of rms beam emittances, Twiss parameters and the dispersion functions were also obtained. The new ion beam parameters allow one to calculate the beam transportation along the beam line after degrader.

 
MOPEC042 Synchrocyclotron Preliminary Design for a Dual Hadrontherapy Center ion, synchro-cyclotron, linac, injection 552
 
  • A. Garonna
    EPFL, Lausanne
  • A. Garonna
    TERA, Novara
 
 

Hadrontherapy, the technique of tumor radiotherapy employing heavy ion beams, is developing rapidly(*). The TERA Foundation proposes an innovative dedicated accelerator, called Cyclinac(**). It is composed of a 230 MeV/u cyclotron providing fast pulsed beams of H2+, for proton therapy with standard techniques, or C6+, injected into a high gradient linac. Its energy can thus be modulated from pulse to pulse (up to 400 MeV/u), for optimal irradiation of solid tumors with the most modern techniques of dose active spreading. A preliminary design of a superconducting synchrocyclotron for this application is presented. Its advantages are the reduced construction and operating costs (small magnet and low RF power consumption), and the good adaptation of its beam characteristics to therapy (low current and fast repetition rate). The magnet features a central field of 5 T, which has azimuthal symmetry and decreases with the radius, ensuring radial and vertical focusing. The weight is around 300 t. Ions are produced in an EBIS, injected axially and resonantly extracted at 1 m radius. The RF is mechanically modulated by a rotating capacitor, providing the required 400 Hz repetition rate.


* U. Amaldi, G. Kraft, J.Rad. Res., 48 Suppl A (2007) 27
** U. Amaldi, S. Braccini, P. Puggioni, Reviews of Accelerator Science and Technology, Vol.2 (2009)

 
MOPD103 Development of an Apparatus for Measuring Transverse Phase-space Acceptance emittance, ion, beam-transport, brightness 945
 
  • H. Kashiwagi, I. Ishibori, T. Ishizaka, S. Kurashima, N. Miyawaki, T. Nara, S. Okumura, W. Yokota, K. Yoshida, Y. Yuri, T. Yuyama
    JAEA/TARRI, Gunma-ken
 
 

It is important to match the injection beam emittance to the acceptance of an accelerator for high beam transmission A system to evaluate transverse beam matching has been developed in the JAEA AVF cyclotron facility. In this presentation, concepts of an apparatus for transverse acceptance measurement will be reported. The apparatus consists of a phase-space collimator in the injection beam line and beam current monitor after the cyclotron. The collimator consists of two pairs of position defining slits and angle defining slits to inject an arbitrarily small portion of transverse phase-space into the cyclotron. Measurement of the acceptance is made by testing every portion in the whole phase-space, which should large enough to cover the acceptance. The acceptance can be estimated from the sum of the portions of the beam which passes through the system.

 
TUYRA03 Production of a 1.3 MW Proton Beam at PSI target, proton, extraction, space-charge 1309
 
  • M. Seidel, S.R.A. Adam, A. Adelmann, C. Baumgarten, R. Dölling, H. Fitze, A. Fuchs, J. Grillenberger, M. Humbel, D.C. Kiselev, A.C. Mezger, D. Reggiani, M. Schneider, H. Zhang
    PSI, Villigen
  • Y.J. Bi, J.J. Yang, T.J. Zhang
    CIAE, Beijing
 
 

With an average beam power of 1.3MW the PSI proton accelerator facility is presently at the worldwide forefront of high intensity accelerators. This talk describes critical aspects and recent improvements related to generation and transport of the high intensity beam in a cyclotron based facility. The installation of new accelerating resonators in the second of two cyclotrons led to a significant improvement in view of beam intensity but also the reliability of the facility. Besides the overall performance and further upgrade plans the discussed topics include: space charge dominated beam dynamics, beam loss handling, activation and specialized technical interlock systems.

 

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TUZRA01 The Role of Accelerators in the Energy Problem linac, neutron, target, cavity 1314
 
  • R.L. Sheffield, E.J. Pitcher
    LANL, Los Alamos, New Mexico
 
 

Nearly all risks to future generations arising from long-term disposal of used LWR nuclear fuel are attributable to the transuranic elements and long-lived fission products, about 2% of its content. The transuranic elements of concern are plutonium, neptunium, americium, and curium. Long-lived (>100,000-year half-life) isotopes of iodine and technetium are also created by nuclear fission of uranium. If we can reduce or otherwise securely handle this 2% of the used fuel, the toxic nature of the remaining used fuel after a few centuries of cooling is below that of the natural uranium ore that was originally mined for nuclear fuel. Only a small fraction of the available energy in the fuel is extracted on a single pass and the majority of the 'problem wastes' could be burned in fast-neutron spectrum reactors or sub-critical accelerator driven transmuters. The goals of accelerator transmutation are some or all of the following: 1) to significantly reduce the impacts due to the minor actinides on the packing density and long-term radiotoxicity in the repository design, 2) preserve/use the energy-rich component of used nuclear fuel, and 3) reduce proliferation risk.

 

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TUZRA02 Accelerator Applications for Basic and Applied Research at JINR ion, neutron, target, proton 1319
 
  • I.N. Meshkov, A.N. Sissakian, G.V. Trubnikov
    JINR, Dubna, Moscow Region
 
 

This presentation will describe the accelerators - basic facilities at JINR and briefly discuss research programs for applications and basic research, which are performed at these accelerators.

 

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TUPD019 Theoretical Studies of TE-Wave Propagation as a Diagnostic for Electron Cloud electron, plasma, polarization, simulation 1961
 
  • G. Penn, J.-L. Vay
    LBNL, Berkeley, California
 
 

The propagation of TE waves is sensitive to the presence of an electron cloud primarily through phase shifts generated by the altered dielectric function, but can also lead to polarization changes and other effects, especially in the presence of magnetic fields. These effects are studied theoretically and also through simulations using WARP-POSINST. Full electromagnetic simulations are performed for CesrTA parameters, and used as a benchmark for simplified phase shift estimates that are also implemented in WARP/POSINST. Nonlinear effects such as electron heating are also examined.

 
WEIRA02 Present Status of the Accelerator Industry in Asia linac, electron, proton, synchrotron 2447
 
  • C.-X. Tang
    TUB, Beijing
 
 

Different kinds of accelerators, such as electron linacs, cyclotrons, microtrons, HV DC accelerators, synchrotrons and betatrons, can be used in radiotherapy, Non-Destructive Test, and irradiations. The accelerator industry in Asia almost covers all of the accelerators and application areas above. In this paper, the status and the trend of the accelerator industry in Asia will be introduced. Typical examples, in the areas of medial and industrial applications, will be described about their technology, achievement and relationship with universities or institutes. For the accelerator technology is strongly relied on the development of components, we will also briefly introduce the industry in Asia of some components, such as rf power sources, HV power sources (modulator), magnets and so on.

 

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WEIRA06 Status of the Accelerator Industry in North America electron, linac, proton, isotope-production 2461
 
  • J.E. Clayton
    Varian Medical Systems, Oncology Systems, Palo Alto
 
 

Several projects for synchrotron light source facilities and medical accelerators are proposed in North America. Application of accelerators for homeland security system is also under consideration. Project X is a typical example of a big next generation accelerator project. The current status of the accelerator industry in North America will be presented.

 

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THPEA001 Fabrication and Installation of Radio Frequency System for K500 Superconducting Cyclotron at Kolkata cavity, vacuum, site, radio-frequency 3673
 
  • M. Ahammed, D. Adak, R.K. Bhandari, P. Bhattacharyya, J. Chaudhuri, M.K. Dey, A. Dutta Gupta, B. Hemram, B.C. Mandal, B. Manna, S. Murmu, H.K. Pandey, S. Saha, S. Sarkar, S.K. Singh, T. Viswanathan
    DAE/VECC, Calcutta
 
 

K500 Superconducting Cyclotron (SCC) is already commissioned successfully at VECC, Kolkata by accelerating Ne3+ internal beam with 70 nA beam current at 670 mm extraction radius. The Radio Frequency cavity of SCC is successfully operational since last two years. All these years were very challenging and worthy period from the point of view of gaining experience and knowledge by solving fabrication and assembly problems faced during construction of 10 m tall copper made coaxial RF cavities and tackling RF related commissioning problems. RF system operates within the frequency range of 9 to 27 MHz for generating maximum 100 kV DEE voltage. The construction of the RF system demands making of numerous critical soldering and brazing joints including joints between ceramic and copper along with maintaining close dimensional accuracies, assembly tolerances, mirror symmetricity, surface finish and utmost cleanliness. This paper presents the details of fabrication and installation procedures and their effects on the final performance of the cavities. It also highlights the problems faced during the commissioning process of the RF cavities.

 
THPEA016 Developments of Magnetic Alloy Cores with Higher Impedance for J-PARC Upgrade cavity, acceleration, synchrotron, impedance 3711
 
  • C. Ohmori, K. Hasegawa, A. Takagi
    KEK, Ibaraki
  • K. Hara, T. Shimada, H. Suzuki, M. Tada, M. Yoshii
    KEK/JAEA, Ibaraki-Ken
  • M. Nomura, A. Schnase, F. Tamura, M. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
 
 

Magnetic alloy cavities are successfully used for J-PARC synchrotrons. These cavities generate much higher RF voltage than ordinary ferrite cavities. For future upgrades of J-PARC facilities, a higher field gradient is necessary. It was found that the characteristics of magnetic alloy is improved by a new annealing scheme under magnetic field. A large production system using an old cyclotron magnet is under construction for the J-PARC upgrade. The status of core development will be reported.

 
THPEA030 Design and Analysis of RF Cavities for the Cyclotron CYCHU-10 cavity, simulation, vacuum, acceleration 3744
 
  • T. Hu, X. Hu, J. Huang, D. Li, P. Tan, J. Yang, T. Yu
    HUST, Wuhan
 
 

The design study of a 10MeV compact cyclotron CYCHU-10 has been developed at Huazhong University of Science and Technology (HUST). We developed the basic shapes and dimensions and carried out the simulations for the CYCHU-10 cavities with 3D numerical calculation softwares in this paper. The distributions of electromagnetic field are illustrated by means of the electromagnetic and structural analysis, and the wooden model test is preformed as well. In addition, this paper gives mechanical tolerance effects which deformed due to the limit of mechanical working of cavities under practical conditions. This work helps to evaluate the performances of capacitive frequency trimmer design.

 
THPEB034 The Design of the MEBT for the PAMELA Medical FFAG proton, injection, dipole, quadrupole 3960
 
  • M. Aslaninejad, M.J. Easton, J. Pasternak, J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London
  • K.J. Peach, T. Yokoi
    JAI, Egham, Surrey
 
 

The PAMELA medical FFAG complex under design in the UK, aims to operate with both proton and carbon beams for hadron therapy. Medium energy beam transfer(MEBT) of PAMELA consists of the proton beam line coming out of the injector cyclotron, carbon beam transfer from the independent carbon 6+ injector linac, switching dipole when both beam merge and transfer line toward the PAMELA NS-FFAG. The MEBT layout and design, which needs to incorporate the beam chopper for the intensity modulation are discussed. The careful matching of optical functions between various components in the MEBT and beam dynamics simulations are presented.

 
THPEC041 Uniform Beam Distribution by Nonlinear Focusing Forces scattering, octupole, sextupole, target 4149
 
  • Y. Yuri, I. Ishibori, T. Ishizaka, S. Okumura, T. Yuyama
    JAEA/TARRI, Gunma-ken
 
 

To achieve ultra-low-fluence large-area uniform irradiation of ion beams for advanced applications in the field of materials sciences and biotechnology, a uniform-beam irradiation system has been developed using multipole magnets at the Japan Atomic Energy Agency (JAEA) cyclotron facility. The system consists of a beam attenuator for the wide-range intensity control, an electrostatic beam chopper for the control of irradiation time, scattering foils for conditioning of the initial beam distribution, octupole magnets for transverse tail-folding, sextupole magnets for the correction of the beam misalignment, and the diagnostic station of the two-dimensional beam profile. In this paper, recent experimental results are described, especially on the formation of a beam with a uniform transverse distribution by the combination of the sextupole and octupole magnets.

 
THPEC056 Recent Development of ECR Ion Souces at RCNP plasma, ion, ECR, controls 4182
 
  • T. Yorita, M. Fukuda, K. Hatanaka, M. Kibayashi, S. Morinobu, A. Tamii
    RCNP, Osaka
 
 

The upgrade program of the AVF cyclotron is in progress since 2004 at Research Center for Nuclear Physics (RCNP), Osaka Univ., for improving the quality, stability and intensity of accelerated beams. An 18 GHz superconducting ECRIS has been installed to increase beam currents and to extend the variety of ions, especially for highly charged heavy ions which can be accelerated by RCNP cyclotrons. The production development of several ion like B, C ~ Xe by gas mixing or MIVOC has been performed. In order to extend the variety of ions more, metal viper or spatter system has also been installed to 10GHz NEOMAFIOS with minimum modifications. The details of these recent developments will be presented.

 
THPD022 FFAG Tracking with Cyclotron Codes lattice, TRIUMF, proton, ion 4319
 
  • M.K. Craddock
    UBC & TRIUMF, Vancouver, British Columbia
  • Y.-N. Rao
    TRIUMF, Vancouver
 
 

This paper describes tracking studies of non-scaling (NS) FFAGs using cyclotron codes in place of the more conventional lumped-element synchrotron codes. The equilibrium orbit code CYCLOPS determines orbits, tunes and period at fixed energies, while the general orbit code GOBLIN tracks a representative bunch of particles through the acceleration process. Results will be presented for the EMMA linear NS-FFAG under construction at Daresbury (10-20 MeV electrons), and for two non-linear NS-FFAG designs: Rees's isochronous IFFAG (8-20 GeV muons) and Johnstone's design for ADSR (250-1000 MeV protons). Our results are compared with those obtained using lumped-element codes. In the case of EMMA, results are presented for both the measured and design fields.

 
THPD036 Electron Acceleration by a Whistler Pulse electron, laser, plasma, acceleration 4358
 
  • R. Singh
    Indian Institute of Technology Delhi, Plasma Physics Group, New Delhi
  • A.K. Sharma
    Indian Institute of Technology Delhi, New Delhi
 
 

A Gaussian whistler pulse is shown to cause ponderomotive acceleration of electrons in a plasma when the peak whistler amplitude exceeds a threshold value. The threshold amplitude decreases with the ratio of plasma frequency to electron cyclotron frequency ωp / ωc. However above the threshold amplitude the acceleration energy decreases with ωp / ωc. The electrons gain velocities about twice the group velocity of the whistler. For acceleration of electrons one requires a whistler pulse of ω > ωc/2. It is seen that to enhance the energy gain the value of peak laser amplitude should be above a threshold value.

 
THPE012 U400 Cyclotron Spiral Inflector with Beam Vertical Focusing Effect ion, emittance, beam-losses, focusing 4536
 
  • I.A. Ivanenko, B. Gikal, G. Gulbekyan
    JINR, Dubna, Moscow Region
 
 

The main losses of the injected beam are localized at the centre region of the cyclotron. One of the problems is the defocusing action of the spiral inflector. At the present work the method of decreasing of the vertical defocusing effect of the spiral inflector is presented. The decreasing of the vertical defocusing is achieved by means of special form of the inflector electric field. At FLNR, JINR, the new type of the inflector was investigated and manufactured. At the present time the inflector is installed and works at the U400 cyclotron. The experiments with the new inflector have shown the increasing of the beam intensity and more tuneble work of the cyclotron.