BNL, Upton, Long Island, New York
Hundred megawatt level fast ramping power converters to drive proton and heavy ion machines are under research and development at accelerator facilities in the world. This is a leading edge technology. There are several topologies to achieve this power level. Their advantages and related issues will be discussed.
BNL, Upton, Long Island, New York
The Brookhaven AGS Main Magnet Power Supply is a thyristor control supply rated at 5.5KAmps, ±9KV. The peak magnet power is 50MW,which is fed from a motor/generator manufactured by Siemens. During rectify and invert operation, the P Bank power supplies are used. During the flattops the F Bank power supplies are used. The P Bank power supplies are fed from two 23MVA transformers and the F Bank power supplies are fed from two 5.3 MVA transformers. The fundamental frequency of the F Bank power supplies is 1440Hz while the P banks were 720Hz. It was very important to reduce the ripple during rectify to improve polarized proton operations. For this reason and also because the original transformers were 45 years old we replaced these transformers with new ones and we made the fundamental frequency of both P and F banks 1440 Hz. This paper will highlight the major hurdles that were involved during the installation of the new transformers. It will present waveforms while running at different power levels up to 6MW full load and show the transition from the F-Bank power supplies to the P-Banks and also show the improvements in ripple made on the P-Bank power supplies.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC underContract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In order to cross more rapidly the 82 weak resonances caused by the horizontal tune and the partial snakes, we plan to jump the horizontal tune 82 times during the acceleration cycle, 41 up and 41 down*. To achieve this, the magnets creating this tune jump will pulse on in 100 micro-seconds, hold the current flat for about four milli-seconds and zero the current in another 100 micro-seconds. The magnets are old laminated beam transport magnets with longitudinal shims closing the aperture to reduce inductance and power supply current. The power supply uses a high voltage capacitor discharge to raise the magnet current, which is then switched to a low voltage supply, and then the current is switched back to the high voltage capacitor to zero the current. The current in each of the magnet pulses must match the order of magnitude change in proton momentum during the acceleration cycle. The magnet, power supply and cabling will be described with coast saving features and operational experience.
*Overcome Horizontal Depolarizing Resonances in the AGS with Tune Jump