| Paper |
Title |
Other Keywords |
Page |
| TUPMA097 |
Characteristics of the Magnetic Channel in the Yoke Hole of K-500 Superconducting Cyclotron
|
ion, extraction, beam-transport, simulation |
241 |
| |
- J. Pradhan, R. K. Bhandari, S. Bhattacharya, U. Bhunia, J. Debnath, M. K. Dey, A. Dutta, C. Mallik, Z. A. Naser, S. Paul
DAE/VECC, Calcutta
| |
The detail magnetic field measurement of K-500 superconducting cyclotron has been carried out. The last magnetic channel of the extraction system placed in the yoke hole of the cyclotron before external beam line is active, unlike others, which are all passive. This channel comprises a coil and a special shaped iron to produce both quadrupole and dipole field for focussing and radially aligning the different ion species coming out from the cyclotron, with the external beam transport line. The magnetic field inside the channel along with the outside stray field has been measured for different channel currents as well as main magnet excitations. A 3-D model of the full magnet is constructed using magneto- static code RADIA [2] to simulate the yoke field. This paper reports the comparative study of measured and calculated field and studies the trajectories for the representative ions through the stray field calculated from the model. The later being used to locate the starting point (or matching point) for the external beam transport line
|
|
|
|
| TUPMA116 |
Periodic Ion Current Burst in 6.4 GHz ECR Source
|
ion, electron, plasma, ion-source |
268 |
| |
- G. S. Taki, R. K. Bhandari, P. R. Sarma
DAE/VECC, Calcutta
- A. G. Drentje
KVI, Groningen
- T. Nakagawa
RIKEN/RARF/CC, Saitama
- P. K. Ray
Bengal Engineering and Science University, Howrah
| |
We studied the enhancement in extracted ion current in the 6.4 GHz ECR ion source at VECC, Kolkata by inserting a negatively biased disc in the main stripping stage. In addition to the expected increase in current, we observed a sudden jump in the current at some low bias voltage. The jump amplitude is larger for higher charge states. In order to understand the origin of the jump, we recently measured the time spectra of high charge state ion current for neon. The time spectra revealed the presence of a burst frequency in the kilohertz range. This frequency shows a correlated jump with the ion current described above. Another feature is that the observed burst frequency shows a good linear correlation with the extracted ion current. This may signify that current per burst is a constant factor, higher current means that there are more number of bursts.
|
|
|
|
| WEZMA04 |
Superconducting Cyclotron Project at VECC
|
extraction, injection, cryogenics, controls |
320 |
| |
- R. K. Bhandari
DAE/VECC, Calcutta
| |
Construction of the K-500 superconducting cyclotron at Kolkata is now in final stages. The main magnet was operated satisfactorily for alomost one year during 2005. The coil was continuously kept cooled at 4.2K temperature during the entire period. Extensive magnetic field measuremens were done for correction of the imperfections, centering of the main coil, calculation of operational settings, calculation of extraction trajectory etc. Subsequently in April 2006 the coil has been warmed up to facilitate assembly of the other systems of the machine. All major systems have been fabricated and the assembly is currently going on. We plan to start the commissioning tests in the first half of year 2007. In this paper our experience with the operation of the main superconducting magnet and magnetic field measurements will be discussed. Developmental highlights of various systems will be briefly presented.
|
|
|
Slides
|
|
|
| WEZMA05 |
Status and Plans for the TRIUMF ISAC Facility
|
target, ion, ion-source, linac |
325 |
| |
- P. Schmor
TRIUMF, Vancouver
| |
The ISAC facility at TRIUMF uses the ISOL technique to create exotic isotopes in a thick target mainly through spallation from 500 MeV protons. The ISAC target area has operated for isotope production with up to 50 kW of beam power from the TRIUMF 500 MeV cyclotron. An ion beam formed from these exotic isotopes is transported at energies either to a linac for further acceleration or to any one of a suite of low energy experimental stations. For accelerating the isotopes an RFQ is followed by a five-tank drift tube linac that provides variable-energy accelerated exotic-beams from 0.15 to 1.8 MeV/u, primarily for nuclear astrophysics experiments. Twenty super conducting rf cavities have been recently added to the linac chain and commissioned with beams of stable isotopes, to increase in the maximum energy of the exotic beams to 4.3 MeV/u. Another 20 cavities will be added in 2009 to bring the energy to 6.5 MeV/u. A second proton beam line from the cyclotron and new target station for target and ion source development have been proposed for ISAC. In the future this new target station could be used as an independent simultaneous source of exotic beams for the experimental program.
|
|
|
|
Slides
|
|
|
| WEPMA005 |
Magnetic Field Calculations of a 10 MeV High Current Compact Cyclotron
|
betatron, extraction, injection, focusing |
342 |
| |
- V. S. Pandit, A. Goswami, P. R. Sarma, P. Sing Babu
DAE/VECC, Calcutta
| |
A 10MeV, 5-10mA 4-sector compact proton cyclotron, is being developed at VECC. A 2.45 GHz microwave ion source will produce ~30mA of proton beam at 100keV. It will be bunched and injected axially in the central region of the cyclotron where a spiral inflector will place the beam on the proper orbit. Two delta type resonators located in the opposite valleys will be used for providing acceleration to the beam. Beam will be extracted using an electrostatic deflector. The main aim of this project is to study and settle various physics and technological problems associated with the handling of high intensity beams. In this paper we present the results of design studies of the main magnet. The conceptual dimensions of the magnet and the properties of equilibrium orbits were first obtained using hard edge approximations and matrix method. The primary size of the magnet was estimated using 2D POISSON code. Finally a 3D code was utilized for the field calculation and optimization. The profile of magnet sectors was optimized to get the desired values of isochronous field and the betatron tunes.
|
|
|
|
| WEPMA015 |
Characteristics of Beam Extraction System of K500 Superconducting Cyclotron
|
extraction, ion, beam-transport, emittance |
357 |
| |
- S. Paul, R. K. Bhandari, J. Debnath, M. K. Dey, A. Dutta, C. Mallik, J. Pradhan
DAE/VECC, Calcutta
| |
Extensive Magnetic Field measurement of the K500 Superconducting Cyclotron has been completed. In this paper we report the beam dynamical calculations along the extraction system based on the measured magnetic field data. The beam matching to the external beam transport system, for different ion species spanning the operating region is also explored.
|
|
|
|
| WEPMA089 |
Control and Instrumentation for the VEC Superconducting Cyclotron Cryogen Delivery System
|
controls, instrumentation, monitoring, vacuum |
452 |
| |
- T. Bhattacharyya, R. K. Bhandari, T. D. Das, C. N. Nandi, G. P. Pal
DAE/VECC, Calcutta
| |
The cryogen delivery system for the superconducting cyclotron supplies liquid helium to the superconducting main magnet coil and three cryopanels. It also supplies liquid nitrogen to the thermal shield of the liquid helium chamber housing superconducting coil and the thermal shield and baffles surrounding the cryopanels. A suitable efficient piping network comprising vacuum jacketed cryogenic transfer lines, liquid nitrogen shielded transfer line and distribution manifold is used in the superconducting cyclotron for distribution of cryogens. A liquid helium pump ensures the required flow of liquid helium through the cryopanels. The cryogen delivery system is fitted with necessary field instrumentation and controllers to monitor and automatically control certain important process variables. The control system is a PLC based system which takes care of cool down, steady state, quench protection and warm up mode and generates alarm and interlock signals whenever necessary. The SCADA communicates with the PLC through dedicated control LAN and enables the operator to monitor, control and data log. This paper reports the overall control and instrumentation for the cryogen delivery system.
|
|
|
|
| WEPMA104 |
Drive System Instrumentation For VEC SCC Axial-Hole Magnetic Field Measurement
|
controls, instrumentation, extraction |
467 |
| |
- T. Bhattacharyya, R. K. Bhandari, T. D. Das, C. Mallik, C. N. Nandi, G. P. Pal
DAE/VECC, Calcutta
| |
Charged particle from the ECR ion source is injected axially into the VEC superconducting cyclotron. The ion beam passes through the vertical section of the axial injection system and the axial hole at the centre of the superconducting cyclotron before reaching the spiral inflector. An accurate knowledge of the magnetic field in the axial hole is essential to properly inject and accelerate the ion beam in the superconducting cyclotron. Three channel F. W. Bell tesla meter with both axial and transverse probes were used to measure the magnetic field. A probe drive with high resolution and repeatability was developed to map the field along this hole from median plane upto 3m above. Stepper motor drives three lead screws which move the hall probe assembly and position them correctly at regular intervals. The basic hardware includes a stepper motor, its drive control unit, PC with National Instrument PCI-6052E data acquisition card and RS232 interface for tesla meter. The GUI developed using Labview takes care of the stepper motor drive control, measurement of the field and statistical error analysis. This paper describes the set up and control system of this measurement.
|
|
|
|
| WEPMA110 |
Development of 100 kW RF Amplifier for Superconducting Cyclotron at VECC
|
impedance, power-supply, higher-order-mode, controls |
476 |
| |
- S. S. Som, M. B. Banerjee, D. S.B. Bhattacharyay, S. B. Biswas, P. G. Gangopadhyay, A. Mandal, S. K. Manna, A. K. Mukherjee, S. P. Pal, J. S.P. Prasad, P. R. Raj, M. S. Saha, S. Saha, S. Seth, K. V. krishnaiah
DAE/VECC, Calcutta
| |
High power rf amplifiers (3 nos.) have been developed at our centre for feeding power to three nos. of coaxial rf cavities of the k500 Superconducting Cyclotron. Each of this amplifier can supply output power of 100 kW (max.) at 50 Ω impedance within the frequency range of 9 MHz to 27 MHz. The amplifier, based on Eimac 4CW 150,000E water-cooled tetrode, is tuned by moving the sliding short of the coaxial cavity within the said frequency range. An inductive coupling loop is inserted along one side of the coaxial cavity through the sliding short and is matching the output impedance of 50 ohm. The four identical Bridge-T network in the grid of the final amplifier are driven with equal power levels of up to 150 watts. The amplifier is operated in Class-AB mode with power gain of 22 dB. A PC-based stepper motor controlled sliding short movement system have been done. The frequency response of the input circuit of the amplifier has been measured using Vector Network Analyzer and the result is very satisfactory.
|
|
|
|
| THZH101 |
Review of Hadron Machines for Cancer Therapy
|
proton, ion, linac, synchrotron |
573 |
| |
- M. Kanazawa
NIRS, Chiba-shi
| |
Charged particle therapy is now taking a long step from research stage to routine treatment. Highly reliable and sophisticated systems are required at reasonable cost. There are about two dozens of therapy accelerators working in the world. Besides the proton beams, carbon beam is being watched with keen interest because of its excellent clinical effects in cancer treatments. Accelerators which deliver heavy charged particles for cancer therapy will be reviewed.
|
|
|
|
Slides
|
|
|
| THZH102 |
Use of Microbeam at JAEA Takasaki
|
ion, heavy-ion, acceleration, radiation |
588 |
| |
|
|
| THC3H102 |
Practical Considerations in the Design of a High Current Commercial H-minus Cyclotron
|
injection, ion, ion-source, vacuum |
625 |
| |
- M. P. Dehnel, P. T. Jackle, M. Roeder, T. M. Stewart, J. E. Theroux
D-Pace, Nelson, British Columbia
| |
High current H-minus cyclotrons (>1000 micro-Ampere) are being developed and implemented for radioisotope production, radioactive therapeutic implants and other applications. The beam dynamics and general physics design of these cyclotron systems must be well done. However, in order not to compromise an elegant and effective physics design, practical engineering considerations must be carefully considered and then implemented. Based on our experience in the design, upgrading, and maintenance of commercial H-minus cyclotron systems, we offer "best practices" to be considered in the engineering design and implementations of such systems.
|
|
|
|
Slides
|
|
|
| THPMA016 |
Median Plane Magnetic Field Mapping for Superconducting Cyclotron (SCC) in VECC
|
controls, monitoring, extraction, shielding |
652 |
| |
- A. Roy, T. Bhattacharjee, R. B. Bhole, U. Bhunia, Chaddha, N. Chaddha, J. Debnath, M. K. Dey, A. Dutta, C. Mallik, C. N. Nandi, Z. A. Naser, G. P. Pal, S. Pal, S. Paul, J. Pradhan
DAE/VECC, Calcutta
| |
The magnetic field upto 29 inch radius on median plane of SCC Magnet (Peak field 5.8T) is measured over its operating range. A client-server system is developed to minimise mapping time and human intervention. The magnetic field is mapped at radial interval of 0.1 inch and angular interval of 1 degree. The complete map of 360 degree comprised of about 100K field points is obtained in less than 100 minutes. The field mapping system is designed to work as PC based TCP Client-Server to reduce the design complexity, system overload and debugging effort. The Server program is developed as windows console in ‘C’ and the Client is developed using LabView to provide a user friendly operation console along with online preliminary display and analysis of field data. This architecture provides a reliable and easily modifiable control s/w. The correctness of the magnet assembly is calculated from the acquired data, which in-turn represents the correctness of measurement system. A detailed study of the magnet characteristic is done. The first harmonics of the fields at different radii are obtained at all magnet excitation and corrected by coil-centering and shims placement.
|
|
|
|
| THPMA017 |
Mathematical Model for Fast and Slow Dumping of K-500 Superconducting Cyclotron Magnet
|
dumping, power-supply, monitoring, vacuum |
655 |
| |
- A. De, S. Saha, S. K. Thakur
DAE/VECC, Calcutta
| |
A superconducting cyclotron (K-500) is under construction at Variable Energy Cyclotron Centre. Two superconducting coils ' named 'Alpha' and 'Beta' ' generates the main magnetic field of the cyclotron. Subsequent to the in-house fabrication of the two coils, it was assembled into the cryostat and the magnet assembly completed. Immediately after the cool down, the superconducting coils were energized. Two dump resistors ' slow and fast ' serve to dissipate the energy stored in the coils externally depending upon the situation. Various sets of data were collected during these dumping conditions and based on these an approximate mathematical model was constructed to simulate the dumping characteristics. This model took into account the lead drops, the cable and the joint resistances along with the dump resistor values and the self and mutual inductances (that varied with current) of the coil.
|
|
|
|
| THPMA022 |
Design of the Proposed 250 Mev Superconducting Cyclotron Magnet
|
superconducting-magnet, focusing, proton, radiation |
661 |
| |
- M. K. Dey, R. K. Bhandari, U. Bhunia, J. Chaudhuri, A. Dutta, A. Dutta Gupta, C. Mallik, S. Murali, J. Pradhan, S. Saha, S. S. Sur
DAE/VECC, Calcutta
| |
VECC has proposed a project for the design and development of a 250 MeV superconducting proton cyclotron, which may be used in therapy. In this paper we describe the preliminary design calculations for the superconducting magnet. Hard-edge approximation method has been adopted for finding the poletip geometry to meet the basic focusing requirements of the beam. The uniform-magnetization method has been applied to calculate the 3D magnetic field distribution due to saturated iron poletips, to verify the beam dynamical issues and optimize the poletip geometry. GM type closed cryo-cooler technology is being considered for steady state liquifaction of evapourated He gas from magnet cryostat.
|
|
|
|
| THPMA048 |
Study of Vacuum Related Problems During the Energization of K500 Superconducting Cyclotron
|
vacuum, superconducting-magnet |
694 |
| |
- Z. A. Naser, D. L. Bandapadhaya, R. K. Bhandari, U. Bhunia, J. Debnath, M. Dutta, C. Mallik, S. Paul, A. Polley, J. Pradhan, A. Sur
DAE/VECC, Calcutta
| |
The K500 superconducting cyclotron main magnet has been commissioned successfully in VECC, Kolkata. During the process of energization, it has been observed that there was vacuum deterioration in the cryostat vacuum chamber with excitations. Detail studies have been carried out to examine the occurrence of such a situation. The electro-magnetic stress in the cryostat wall due to Lorentz force increases with current, and is more pronounced in the median plane of cryostat wherefrom various penetrations come out. This could be the possible reason for the OVC vacuum degradation. The paper reports the observations on vacuum deterioration during energization. An extensive study has been carried out to understand and explain the situation.
|
|
|
|
| THPMA058 |
Cyclotron RF Structures Leaks, Causes and Repair
|
vacuum, ion, radioactivity, scattering |
706 |
| |
- D. P. Hajra, D. Adak, R. K. Bhandari, J. Chaudhuri, B. C. Mondal
DAE/VECC, Calcutta
| |
Cyclotron at VECC, Kolkata, is delivering beam since 1977. Water leaks develops inside cyclotron after 30 years operation. Major leaks appear on thin walled copper cooling tube-brazed joints with sheet of R. F. panels, D-stem structures and aluminum & copper tubes trimmer capacitator. Radioactivity enhances ozone and nitrogen oxide, which also formed due to discharge of high electric field and subsequently formation of acid on copper tube and corrodes. Another source of corrosion is free chlorine ions from irradiated halogen containing products like cables etc, residual of cleaning chemicals and trapped brazing flux. Improper selection of brazing filler containing high percentages of zinc, cadmium and phosphorous which will promote porosity due to metal vaporization under high vacuum. Joining of different electro chemical potentials metal as done in trimmer capacitor causes corrosion.μleaks have been detected by MSLD then repaired by torch / TIG brazing with appropriate filler and fluxes has been cleaned thoroughly. Quality performance test has been conducted after repair by MSLD followed by hydraulic test repeated by MSLD both individual and gross leak.
Cycloron down time increases becaues of water leaks and became major concern for smooth operation. Referance:1. CERN Accelerator School on Vacuum Technology -'992. ASM Handbook volume-6
|
|
|
|