| Paper | Title | Other Keywords | Page |
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| MOPCP025 | Construction of New Injector LINAC at RIBF | linac, rfq, ion, vacuum | 102 |
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| A new additional linac injector called RILAC2 has been constructed at the RIKEN Nishina Center so that RIBF experiments and synthesis of super-heavy element can be carried out independently. The RILAC2 consists of a 28-GHz superconducting ECR ion source (SC-ECRIS), a low-energy beam transport with a prebuncher, a four-rod RFQ linac, three drift-tube linac tanks (DTL1-3), a rebuncher between the RFQ and DTL1, and strong quadrupole magnets that were placed between the rf resonators for the transverse focusing. Very heavy ions with mass-to-charge ratio of 7, such as 136Xe20+ and 238U35+, are accelerated up to an energy of 680 keV/u in the cw mode and injected into the RRC without charge stripping. The rf resonators excluding the pre-buncher are operated at a fixed rf frequency of 36.5 MHz, whereas the pre-buncher is operated at 18.25 MHz. The basic design of the RILAC2 was finished in 2006 and the construction has started since the budget was approved at the end of FY2008. The SC-ECRIS is installed in a new room, and other equipments are placed in the existing AVF-cyclotron vault. This contribution mainly presents the details of the construction of linac part. | |||
| MOPCP058 | Commissioning Experience of the RF System of K500 Superconducting Cyclotron at VECC | cyclotron, controls, vacuum, radio-frequency | 162 |
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Funding: Department of Atomic Energy, Govt. of India. Radio frequency system of Superconducting cyclotron at VECC, has been developed to achieve accelerating voltage of 100 kV max. with frequency, amplitude and phase stability of 0.1 ppm, 100 ppm and ±0.5 degree respectively within 9~27 MHz frequency. Each of the three half-wave coaxial cavity is fed with rf power (80kW max.) from a high power final rf amplifier based on Eimac 4CW150,000E tetrodes. Initially, the whole three-phase RF system has been tuned for operation with RF power to the cavities at 19.1994 MHz and thereafter commissioned the cyclotron with neon 3+ beam at external radius at 14.0 MHz. In this paper, we present brief description of the rf system and behaviour observed during initial conditioning of the cavities with rf power and the way to get out of multipacting zone together with discussion on our operational experience. We have so far achieved dee voltage up to 52 kV at 14 MHz with 20 kW of RF power fed at each of the three dees and achieved vacuum level of 4.5 x 10-7 mbar inside the beam chamber. We also present discussion on the problems and failures of some RF components during commissioning stage and rectifications done to solve the same. |
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| MOPCP064 | Amplifier Test Stand for the CRM Cyclotron | cyclotron, resonance, simulation, feedback | 177 |
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| Abstract: The final stage amplifier stability proves to be an important issue in the process of commissioning CRM cyclotron at CIAE. An air cooled 4CX15,000 tube final stage has been designed to evaluate the anode circuit and neutralization, both of which are weak points of the CRM cyclotron amplifier. Instead of strip line, the design of the new anode structure adopts coaxial form, resulting in less chance of parasitic resonance in the circuits. A tunable neutralization circuits is also included in the design, giving an opportunity to better stability in high power operations. First, the instability in CRM RF system will be analyzed in this paper followed with the new amplifier designs including the tube working line calculations, input/output circuit calculations and finite integral simulations. The mechanical design for tube socket and the anode tank have been successfully carried out using the data provided in this paper. The final stage amplifier is then fabricated, assembled and commissioned. In the power test with dummy load, more than 9.2kW RF fundamental power is provided at the frequency of 44MHz. | |||
| MOPCP065 | Closed Loop RF Tuning for Superconducitng Cyclotron at VECC | controls, cyclotron, coupling, pick-up | 180 |
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| The RF system of Superconducting cyclotron has been operational within 9 - 27 MHz frequency. It has three tunable half-wave coaxial cavities as main resonators and three tunable RF amplifier cavities. A PC-based system takes care of stepper motor driven coarse tuning of cavities with positional accuracy ~20 μm and hydraulically driven three couplers and three trimmers. The couplers, in open loop, match the cavity impedance to 50 Ω in order to feed power from RF amplifier. Trimmers operate in closed loop for fine tuning the cavity, if detuned thermally at high RF power. The control logic has been simulated and finally implemented with Programmable Logic Controller (PLC). Precision control of trimmer (~20 μm) is essential to achieve the accelerating (Dee) voltage stability better than 100 ppm and also minimizing the RF power to maintain it. Phase difference between Dee-in and Dee-pick-off signals and the reflected power signals (from cavity) together act in closed loop for fine tuning of the cavity. The close loop PID control determines the final positioning of the trimmer in each power level and achieved the required voltage stability. | |||
| MOPCP067 | Design and Primary Test of Full Scale Cavity of CYCIAE-100 | simulation, cyclotron, coupling, resonance | 183 |
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The engineering of the RF cavity for cyclotron concerns several aspects of the system including vacuum, cooling, mechanical support etc, Sometime it is even more complex than the RF design itself. With limit space in a compact cyclotron, in order to achieve a voltage distribution of 60kV in central orbit and 120kV for outer orbit, a double stem double gap λ by 2 cavities has been designed for CYCIAE-100[1]. The RF resonance of the cavity is simulated [1] by finite integral codes, while the thermal analysis and mechanical tolerance are studied using other approaches [2, 3]. The mechanical design and fabrications is then carried out under these directions, resulting in a full scale cavity model. The simulations and the mechanical design will be reported in this paper, followed with low level measurement results of quality factor, shunt impedance curve along accelerating gap etc. After surface polishing, the measurement yields an unloaded Q value of 9300, which matches well with the simulation with a neglectable difference of several hundreds. The high power test of the cavity will be carried out later, and will be given in separate paper presented at this conference.
[1] Tianjue Zhang,et al, 100 MeV H− Cyclotron as an RIB Driving Accelerator, CYC 2004 [2] Yuanjie Bi, et al, The Study on RF Cavity Tolerance for CYCIAE-100, CYC 2007 [3] S.M. Wei, et al, Thermal Analysis of RF Cavity for CYCIAE-100, CYC 2007 |
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