• G. Gulbekyan, I. Ivanenko
  JINR/FLNR, Dubna

At the present time, the activities on creation of the new multi-purpose isochronous cyclotron U400R are carried out at the FLNR, JINR. The isochronous cyclotron U400R is intended for obtaining the beams of the accelerated ions from ⁴He¹⁺ (A/Z=4, W=27MeV/u) up to ¹³²Xe¹¹⁺ (A/Z=12, W=3.5MeV/u). The cyclotron magnetic field can be changed from 0.8T to 1.8T and allow the smoothly variation of the ion beam energy at the range ±35% from nominal. The cyclotron RF system keeps up 2 - 6 harmonic modes. The aim of the present work is to investigate the optimal geometry of U400R cyclotron center for the wide range of acceleration regimes. The computation of the beams acceleration is carried out by means of the computer code CENTR.

• G. Gulbekyan, O.N. Borisov, V.I. Kazacha
  JINR, Dubna

Accelerated heavy ions get a charge spectrum on passing a thing target. The charge dispersion and its maximum depend on the ion type, its energy, material, and the foil thickness. Change of the ion charge leads to change of the ion magnetic rigidity. Heavy ion beam extraction from the AVF cyclotrons by stripping in the thing targets is based on loss of the radial stability of the accelerated beam after its magnetic rigidity change. Property data of carbon foils used for the heavy ion beam extraction by stripping are given. Experience of using heavy ion beam extraction from the AVF cyclotrons of FLNR (Dubna) by stripping is considered.

• D. H. An, J. Kang, Y.S. Kim
  KIRAMS, Seoul

This paper concentrates on the design of the low energy beam transport line between an ECR ion source and the spiral inflector of K120 cyclotron. The K120 superconducting cyclotron is under design at KIRAMS, Korea. The cyclotron has about 3.13 Tesla at the cyclotron center and accelerates the C⁶⁺ ions up to 30 MeV/amu. The magnetic field distributions for all magnetic elements and the electric field distributions for all electrostatic elements have been obtained by OPERA3D, TOSCA. The integration of the equation of motion for beam simulation with the calculated field distributions has been carried out with Mathematica. This paper includes the resultant specifications of all elements and the results of beam simulation of the injection system of K120 superconducting cyclotron.

• G. Sénécal, T. André, P. Anger, J. L. Baelde, C. Doutressoulles, B. Ducoudret, C. Jamet, E. Petit, E. Swartvagher
  GANIL, Caen

In order to provide several kilowatt stable ion beams for radioactive ion beam production, the Grand Accélérateur National d’Ions Lourds (GANIL) upgraded several devices. A High Intensity Transport (THI) safety system has also been studied in 1995 and validated in 1998. By monitoring beam losses all along the cyclotrons and lines and shutting down the beam in case of problem, this system allows accelerating and sending onto targets up to 6kW power beams (instead of 400W in standard mode). Beam losses diagnostics, the associated electronics and software will be depicted (principle, location) as well as the tuning method of the machine to reach step by step the needed power.

• G. Tranquille
  CERN, Geneva

Electron cooling is central in the preparation of dense bunches of lead beams for the LHC. Ion beam pulses from the Linac3 are transformed into short high-brightness bunches using multi-turn injection, cooling and accumulation in the Low Energy Ion Ring, LEIR. The LEIR cooler was the first of a new generation of coolers utilising high-perveance variable-density electron beams for the cooling and accumulation of heavy ion beams. It was commissioned in 2006 at the same time as the LEIR ring and has since been used to provide lead ions for the commissioning of the LHC injector chain. We report briefly on the status of the LHC ion injector chain and present results of measurements made to check and to better understand the influence of the electron beam size, intensity and density profile on the cooling performance. Future plans to improve the performance of the device will also be presented.

• A. Noda, M. Nakao, H. Souda, H. Tongu
  Kyoto University/ICR, Kyoto
• A.V. Smirnov
  JINR, Dubna
• T. Shirai
  NIRS, Chiba-shi
• K. Jimbo
  Kyoto University/IAE, Kyoto
• M. Grieser
  MPI-K, Heidelberg

Funding: The present work was supported by Advanced Compact Accelerator Development program by MEXT of Japanese Government. Support from Global COE, The Next Generation of Physics, is also greatly appreciated.

Laser cooling for bunched Mg ion beam with the kinetic energy of 40 keV has been applied with S-LSR at ICR, Kyoto University. Up to now, clear peaking of equilibrium momentum spread after laser cooling has been observed at such a synchrotron tune as resonates with the horizontal betatron tune, which is considered to be due to heat transfer from the horizontal degree of freedom to the longitudinal one. In order to demonstrate transverse cooling by observation of reduction of the horizontal beam size, spontaneous emission from laser induced excited state of the Mg ion, has been observed with the use of CCD camera. Some reduction of horizontal beam size has been observed with a certain synchrotron tune, a little bit smaller compared with the fractional part of the horizontal tune.

• H. Yim, D. H. An, G. Hahn, Y.-S. Kim
  KIRAMS, Seoul

A magnet lattice of the carbon-ion synchrotron was studied for cancer therapy, which requires maximum 400 MeV/u carbon beam, at KIRAMS. In the study, we optimized the magnet lattice configuration to fit into the therapy purpose. Major requirements for the purpose are (1) long extraction time (about 1 second), (2) compact size, and (3) low cost. For the requirement (1), a slow extraction scheme was adopted by the use of third integer resonance. For (2) and (3), we minimized the circumference as 69.6m and a number of the magnet elements as 16 and 20 for bending magnet and quadrupole magnet, respectively. The study was carried out by the use of a simulation codes for beam particle dynamics and optics. A detail of the conceptual lattice design of the carbon-ion synchrotron is described in the paper.

• V. Zhabitsky
  JINR, Dubna

The stability of an ion beam in synchrotrons with digital filters in the feedback loop of a transverse damper is treated. Solving the characteristic equation allows to calculate the achievable damping rates as a function of instability growth rate, feedback gain and parameters of the signal processing. A transverse feedback system (TFS) is required in synchrotrons to stabilize the high intensity ion beams against transverse instabilities and to damp the beam injection errors. The TFS damper kicker (DK) corrects the transverse momentum of a bunch in proportion to its displacement from the closed orbit at the location of the beam position monitor (BPM). The digital signal processing unit in the feedback loop between BPM and DK ensures a condition to achieve optimal damping. Transverse Feedback Systems commonly use digital FIR (finite impulse response) and IIR (infinite impulse response) filters for the signal processing. A notch filter is required to remove the closed orbit content of the signal and correct for the imperfect electric centre of the BPM. Further processing is required to adjust for the betatron phase advance between the beam pick-up (BPM) and the damper kicker (DK). Damping rates of the feedback systems with digital notch, Hilbert and all-pass filters are analysed in comparison with those in an ideal feedback system.

• Y. Jongen, M. Abs, A. Blondin, W. Kleeven, S. Zaremba, D. Vandeplassche
  IBA, Louvain-la-Neuve
• V. Alexandrov, S. Gursky, G. Karamysheva, N. Kazarinov, S. Kostromin, N. Morozov, V. Romanov, N. Rybakov, A. Samartsev, E. Samsonov, G. Shirkov, V. Shvetsov, E. Syresin, A. Tuzikov
  JINR, Dubna

Carbon therapy is most effective method to treat the resistant tumors. A compact superconducting isochronous cyclotron C400 has been designed by IBA-JINR collaboration. This cyclotron will be used for radiotherapy with proton, helium and carbon ions. The ¹²C⁶⁺ and ⁴He²⁺ ions will be accelerated to the energy of 400 MeV/amu and will be extracted by electrostatic deflector, H₂⁺ ions will be accelerated to the energy 265 MeV/amu and protons will be extracted by stripping. The magnet yoke has a diameter of 6.6 m, the total weight of the magnet is about 700 t. The designed magnetic field corresponds to 4.5 T in the hills and 2.45 T in the valleys. Superconducting coils will be enclosed in a cryostat; all other parts will be warm. Three external ion sources will be mounted on the switching magnet on the injection line located bellow of the cyclotron. The main parameters of the cyclotron, its design, the current status of development work on the cyclotron systems and simulations of beam dynamic will be presented.