Sergey Kostromin

Testing of the Superconducting Magnets for the FAIR Project

The Facility for Antiproton and Ion Research (FAIR) is currently being constructed at GSI Darmstadt. Around 500 superconducting magnets are being procured for the heavy ion synchrotron SIS100, and around 180 are being procured for the Super Fragment Separator (Super-FRS). All these magnets have to be tested at cryogenic temperature in order to verify and guarantee their performances before they are installed in the tunnel. Test stations, measurement equipment, and the required infrastructure are being built up at the host laboratory and, due to the large number of magnets and testing requirements, at CERN and JINR. We report on the plans, testing strategy, developments, and, particularly, the status of preparations for testing of the SIS100 dipoles at GSI.

Beam-cooling methods in the NICA project

The Nuclotron-based Ion Collider Facility (NICA) is a new accelerator complex under construction at the Joint Institute for Nuclear Research (JINR) for experiments with colliding beams of heavy ions up to gold at energies as high as 4.5 × 4.5 GeV/u aimed at studying hot and dense strongly interacting nuclear matter and searching for possible indications of the mixed phase state and critical points of phase transitions. This facility comprises an ion source of the electron-string type, a 3-MeV/u linear accelerator, a 600-MeV/u superconducting booster synchrotron (Booster), a Nuclotron (upgraded superconducting synchrotron with a maximum energy of 4.5 GeV/u for ions with the charge-to-mass ratio Z/A = 1/3), and a collider consisting of two vertically separated superconducting rings with an average luminosity of 1027 cm−2 s−1 in an energy range over 3.0 GeV/u. Beam cooling is supposed to be used in two NICA elements, the Booster, and the collider rings. The Booster is intended for the storage of 197Au31+ ions to an intensity of about 4 × 109 particles; their acceleration to the energy 600 MeV/u, which is sufficient for the complete stripping of nuclei (an increase in the injection energy and the charge state of ions makes the requirements for vacuum conditions in the Nuclotron less stringent); and the formation of the necessary beam emittance using the electron cooling system. Two independent beam-cooling systems, a stochastic one and an electron one, are supposed to be used in the collider. The parameters of the cooling systems, the optimum mode of operation for the collider, and the arrangement and design of the elements of the systems are discussed.

Trends in Accelerator Technology for Hadron Therapy

Hadron therapy with protons and carbon ions is one of the most effective branches in radiation oncology. It has advantages over therapy using gamma radiation and electron beams. Fifty thousand patients a year need such treatment in Russia. A review of the main modern trends in the development of accelerators for therapy and treatment techniques concerned with respiratory gated irradiation and scanning with the intensity modulated pencil beams is given. The main stages of formation, time structure, and the main parameters of the beams used in proton therapy, as well as the requirements for medicine accelerators, are considered. The main results of testing with the beam of the C235-V3 cyclotron for the first Russian specialized hospital proton therapy center in Dimitrovgrad are presented. The use of superconducting accelerators and gantry systems for hadron therapy is considered.

Diagnoctics development at JINR for ILC and FEL ultrashort electron bunches

Different methods for diagnostics of ultrashort electron bunches are developed at JINR-DESY collaboration within the framework of the FLASH and XFEL projects and JINR participation in the ILC project. The main peculiarity of these accelerator complexes is related to formation of ultrashort electron bunches with r.m.s. length 20–300 μm. Novel diagnostics is required to provide femtoscaie time resolution in the modem FEL like FLASH and future XFEL and ILC projects. Photon diagnostics developed at JINR-DESY collaboration for ultrashort bunches is based on calorimetric measurements and detection of undulator radiation. The MCP-based radiation detectors are effectively used at FLASH for pulse energy measurements. The infrared undulator constructed at JINR and installed at FLASH is used for longitudinal bunch shape measurements and for two-color lasing provided by the FIR and VUV undulators. Two-color lasing in pump-probe experiments permits one to investigate dynamics of atomic and molecular systems with time resolution of 100–500 fs. A special magnetic spectrometer is planning to be used at ILC for measurements of average electron energy in each bunch. The first test spectrometer measurements were performed within the JINR-DESY-SLAC collaboration. A special synchrotron radiation detector applied for measurement of bunch average electron energy was constructed at JINR.

Simulation of beam extraction from C235 cyclotron for proton therapy

The extraction of an accelerated beam from C235 cyclotron (IBA, Belgium) for proton therapy is simulated. The results of optimizing the parameters of the extraction system to increase the beam extraction efficiency are presented. Our theoretical results agree well with the experimental data. A new configuration of electrostatic deflector is proposed based on the numerical results; using this configuration essentially increases the efficiency of the cyclotron extraction system.

Low-noise pulsed current source for magnetic-field measurements of magnets for accelerators

The schematic diagram, design, and technical characteristics of the pulsed current source developed and produced for the magnetic-field measurement system of superconducting magnets for accelerators are described. The current source is based on the current regulator with pass transistor bank in the linear mode. Output current pulses (0–100 A) are produced by utilizing the energy of the preliminarily charged capacitor bank (5–40 V), which is additionally charged between pulses. The output current does not have the mains frequency and harmonics ripple. The relative noise level is less than–100 dB (or 10–5) of RMS value (it is defined as the ratio of output RMS noise current to a maximal output current of 100 A within the operating bandwidth, expressed in dB). The work was performed at the Veksler and Baldin Laboratory of High Energy Physics, Joint Institute for Nuclear Research (JINR).

Superconducting Magnets for the NICA Accelerator Collider Project

Nuclotron-based Ion Collider fAcility (NICA) is a new accelerator collider complex under construction at the Joint Institute for Nuclear Research. The facility is aimed at providing collider experiments with heavy ions up to Gold in the center of mass energy from 4 to 11 GeV/u and an average luminosity up to 1 · 1027 cm-2s-1 for Au79+. The collisions of polarized deuterons are also foreseen. The facility includes two injector chains, a new superconducting booster synchrotron, the existing 6-AGeV superconducting synchrotron Nuclotron, and a new superconducting collider consisting of two rings, each 503 m in circumference. The booster synchrotron and the NICA collider are based on an iron-dominated “window frame”-type magnet with a hollow superconductor winding analogous to the Nuclotron magnet. The status of the serial production and test of the magnets for the booster synchrotron and the development of the full-size model magnets for the NICA collider is presented. The test results of magnets are discussed. The status of the construction of the facility for serial tests of superconducting magnets for the NICA project is described.

C235-V3 cyclotron for a proton therapy center to be installed in the hospital complex of radiation medicine (Dimitrovgrad)

Proton therapy is an effective method of treating oncologic diseases. In Russia, construction of several centers for proton and ion therapy is slated for the years to come. A proton therapy center in Dimitrovgrad will be the first. The Joint Institute for Nuclear Research (Russia) in collaboration with Ion Beam Application (IBA) (Belgium) has designed an C235-V3 medical proton cyclotron for this center. It outperforms previous versions of commercial IBA cyclotrons, which have already been installed in 11 oncologic hospital centers in different countries. Experimental and calculation data for the beam dynamics in the C235-V3 medical cyclotron are presented. Reasons for beam losses during acceleration are considered, the influence of the magnetic field radial component in the midplane of the accelerator and main resonances is studied, and a beam extraction system is designed. In 2011–2012 in Dubna, the cyclotron was mounted, its magnetic field was properly configured, acceleration conditions were optimized, and beam extraction tests were carried out after which it was supplied to Dimitrovgrad. In the C235-V3 cyclotron, an acceleration efficiency of 72% and an extraction efficiency of 62% have been achieved without diaphragming to form a vertical profile of the beam.

Beam dynamics in a C253-V3 cyclotron for proton therapy

In recent years, oncologic diseases have become a severe issue in developed countries. Proton therapy is viewed as one of the most efficient methods of treating oncologic diseases. The results of computing the beam dynamics in a C235 medical cyclotron intended for proton therapy are presented. The cyclotron was modified by teams of researchers at the Joint Institute for Nuclear Research and Ion Beam Application (IBA Group, Belgium). Possible reasons for losses in the beam under acceleration are considered, and the influence of the magnetic field radial component in the median plane of the accelerator is studied. The results of analysis and upgrading of the beam extraction system are presented. Based on analytical data, the design of the commercial C235 cyclotron is considerably modified. A new version of the C235-V3 cyclotron will be placed in commission at the Dimitrovgrad center of radiation medicine.

Development of radiation medicine at DLNP, JINR

The Dzhelepov Laboratory of Nuclear Problems’ activity is aimed at developing three directions in radiation medicine: 3D conformal proton therapy, accelerator techniques for proton and carbon treatment of tumors, and new types of detector systems for spectrometric computed tomography (CT) and positron emission tomography (PET). JINR and IBA have developed and constructed the medical proton cyclotron C235-V3. At present, all basic cyclotron systems have been built. We plan to assemble this cyclotron at JINR in 2011 and perform tests with the extracted proton beam in 2012. A superconducting isochronous cyclotron C400 has been designed by the 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 an energy of 400 MeV/amu, the protons will be extracted at the energy 265 MeV. The construction of the C400 cyclotron was started in 2010 within the framework of the Archarde project (France). Development of spectrometric CT tomographs may allow one to determine the chemical composition of a substance together with the density, measured using traditional CT. This may advance modern diagnostic methods significantly. JINR develops fundamentally new pixel detector systems for spectrometric CT. The time-of-flight (TOF) system installed in the positron emission tomograph (PET) permits essential reduction in the detector noise from occasional events of different positron annihilations. The micropixel avalanche photodiodes (MAPDs) developed at JINR allow a factor of 1.5 reduction in the resolution time for the PET TOF system and suppression of the noise level as compared to commercial PET. The development of a combined PET/MRI is of considerable medical interest, but it cannot be made with the existing PET tomographs based on detectors of compact photomultipliers due to strong alternating magnetic field of MRI. Change-over to detectors of micropixel avalanche photodiodes permits making a combined PET/MRI.