Author: Chakrabarti, A.
Paper Title Page
MO1PB03 Current Status of the Superconducting Cyclotron Project at Kolkata 11
  • J. Debnath, A. Chakrabarti, M.K. Dey
    VECC, Kolkata, India
  The commissioning of Kolkata superconducting cyclotron with internal ion beam had been reported in the last cyclotron conference. At that time, there was gradual beam loss due to poor vacuum. After installing a higher capacity liquid helium plant the cryo-panels were made functional leading to a substantial increase in the beam intensity. It was hoped that higher beam intensity would help in extraction of a measurable fraction of the beam, but that did not happen. Detailed investigation of beam behavior with the help of three beam probes, installed temporarily at three sectors, revealed that the beam goes highly off-centered while passing through the resonance zone. A plastic scintillator based phase probe was mounted on the radial probe and beam phase was measured accurately. It was quite clear that large amount of field imperfection was prohibiting the beam to be extracted. So magnetic field measurement has been started again and considerable amount of harmonic and average field errors have been found. In this paper we report the important developments since 2010.  
slides icon Slides MO1PB03 [13.028 MB]  
TUPPT013 Simulation of Sufficient Spindle Cusp Magnetic Field for 28 GHz ECRIS 180
  • M.H. Rashid, A. Chakrabarti
    VECC, Kolkata, India
  A cusp magnetic field (CMF) configuration is proposed for achieving more plasma confinement. It is an improved version of CMF compared to the classical one used earlier to design arbitrarily ECR ion source (ECRIS) of low frequency. The CMF has been reconfigured here adopting a simple, novel and cost-effective technique to shrink the loss area and to achieve denser plasma than in traditional ECRIS. The strength of the electron (plasma) confinement is demonstrated through electron simulations. It consists of a mid-iron disk, two end-plugs and a pair of superconducting magnet coils cooled by cryo-coolers. It is designed for high-B mode operation of the cusp ECRIS of as high as 28 GHz RF frequency for producing an intense beam of highly charged heavy ions. The electric current in the coil at the extraction end can be manipulated to optimize the operation to achieve high extracted beam current of highly charged ions.  
WEPPT003 Beam Optical Simulation in a Proposed Magnetic Einzel Lens 323
  • M.H. Rashid, A. Chakrabarti
    VECC, Kolkata, India
  Magnetic scalar potential and field distributions along the central axis of a magnetic einzel lens consisting of a pair of axisymmetric iron yoked anti-solenoids have been evaluated using a simple closed form of analytical expressions. The magnetic field distribution is used to track single charged particles as well as ion beam through lens segmentation method. The method facilitates in evaluation of optical properties as well as aberration coefficients of the lens. Application of such doublet solenoid lens in transporting low energy ion beam introduces minimal rotation of the beam as well as least entangling between transverse phase spaces of the beam.  
WEPPT011 Measurement of Radial Oscillation and Phase of Accelerating Beam in Kolkata Superconducting Cyclotron 344
  • J. Pradhan, A. Agarwal, U. Bhunia, A. Chakrabarti, J. Debnath, M.K. Dey, A. Dutta, Z.A. Naser, S. Paul, V. Singh
    VECC, Kolkata, India
  This paper describes various measurements performed on the beam behavior with the help of the main probe and the differential probe to have a clear insight of the accelerating beam and the difficulties of beam -extraction process in the K500 superconducting cyclotron at Kolkata. Beam shadow measurements with three probes at three sectors were done to get the information of beam-centering and radial oscillations. The radial oscillation amplitude is estimated from the measurements. A differential probe was used to measure the turn separation and its modulation due to radial oscillation. With the help of magnetic field detuning method, the beam phase history was also measured.  
WEPPT012 Beam Dynamics in Presence of Imperfection Fields Near the Extraction Zone of Kolkata Superconducting Cyclotron 347
  • J. Debnath, U. Bhunia, A. Chakrabarti, M.K. Dey, A. Dutta, Z.A. Naser, S. Paul, J. Pradhan, V. Singh
    VECC, Kolkata, India
  Funding: VECC, DAE
The superconducting cyclotron at Kolkata has accelerated the ion beams up to the extraction radius producing neutrons via nuclear reactions. After that the beam extraction process has been tried exhaustively. But rigorous beam extraction trials indicate towards some kind of error field, which was not possible to balance with the trim coil operated in harmonic-coil mode. It is found that the beam is being off-centered by a large amount after crossing the resonance zone and it is not reaching the extraction radius in proper path. This paper will be emphasizing the effect of various kind of error field on the beam. However, the magnetic field is being measured again to know the exact distribution of the field.
TH2PB01 Design of Ultra-Light Superconducting Proton Cyclotron for Production of Isotopes for Medical Applications 446
  • M.K. Dey, A. Chakrabarti, A. Dutta Gupta
    VECC, Kolkata, India
  A new design has been explored for a superconducting-coil-based compact cyclotron, which has many practical benefits over conventional superconducting cyclotrons. The iron yoke and poles in conventional superconducting cyclotrons have been avoided in this design. The azimuthally varying field is generated by superconducting sector-coils. The superconducting sector-coils and the circular main-coils have been housed in a single cryostat. It has resulted in an ultra-light 25 MeV proton cyclotron weighing about 2000 kg. Further, the sector coils and the main coils are fed by independent power supplies, which allow flexibility of operation through on-line magnetic field trimming. Here, we present design calculations and the engineering considerations, focused on making the cyclotron ideally suited for the production of radioisotopes for medical applications.  
slides icon Slides TH2PB01 [9.625 MB]