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| WEPMA110 |
Development of 100 kW RF Amplifier for Superconducting Cyclotron at VECC
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476 |
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- 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
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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.
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| THPMA017 |
Mathematical Model for Fast and Slow Dumping of K-500 Superconducting Cyclotron Magnet
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655 |
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- A. De, S. Saha, S. K. Thakur
DAE/VECC, Calcutta
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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.
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| THPMA022 |
Design of the Proposed 250 Mev Superconducting Cyclotron Magnet
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661 |
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- 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
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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.
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