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| MOPAN007 |
A Non-intercepting Beam Current Monitor for the ISAC-II SC-linac
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155 |
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- W. R. Rawnsley, R. E. Laxdal, A. K. Mitra
TRIUMF, Vancouver
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A personnel protection system will monitor the ion beam current into the experimental hall from the ISAC-II SC-linac. It will use continuous self-test and redundancy and have an accuracy of ±10% from 1 to 200enA. The system, based on an Atlas design, will use capacitive pickups with rf resonators and buffer amplifiers. Ion charge, velocity and bunch width will affect the sensitivity so periodic calibration with dc Faraday cups will be needed. The signal from each 13cm long, 5cm diameter pickup tube will pass through a vacuum feedthrough to a helical resonator. An AD8075 IC with an input impedance of 87kΩ at 35MHz will allow a high coil tap. The ISAC beam, bunched at 11.8MHz, is injected into the ISAC-II SC-linac via a 25m long transfer line. Monitors will be placed in the transfer line and downstream of the linac before the experimental hall. A 35MHz and a 70MHz coil (3 and 6 harmonic) have loaded Q's of 600. A test in the transfer line of the 35MHz coil gave a sensitivity 0.09mV/enA from the unity gain buffer using 20Ne+5 ions at 1.5MeV/u. The background was equivalent to 1enA. The 70MHz coil gave 0.04mV/enA using 22Ne+4 ions. System design and test data will be presented.
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| FROAC02 |
RF Amplifier Choice for the ISAC Superconducting Linac
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3798 |
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- I. V. Bylinskii, K. Fong, J. Lu, A. K. Mitra, C. Owen
TRIUMF, Vancouver
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A superconducting linac is being commissioned at TRIUMF as an extension to the existing room temperature accelerator of exotic ions at ISAC. It will increase the isotope final energy from 1.5 to 6.5 MeV/u. Acceleration is accomplished in 40 bulk niobium quarter wave superconducting cavities operating at 106 and 141 MHz. Each cavity is energized from an independent RF amplifier with power rating up to 1 kW cw. Both vacuum tube and solid state amplifiers were considered as a viable option for the drivers. The paper compares many important parameters of these 2 amplifiers such as reliability, serviceability, capital and maintenance costs, as well as operating characteristics: gain linearity, phase noise, phase drift and others. Test results of prototypes of both types of amplifiers and 1 year operational experience of 20 tube amplifiers are discussed. Based on that the amplifier design requirements are formulated.
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Slides
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