| Paper |
Title |
Page |
| MOPAN002 |
Active Shunts for the LNLS Storage Ring Quadrupoles
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143 |
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- C. Rodrigues, A. R. Silva
LNLS, Campinas
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The quadrupoles of the LNLS storage ring are divided into families with two or six units, each one being supplied by an only current source. Some experiments performed by the accelerator physics team require different currents for quadrupoles of a same family. Moreover, there is an interest in obtaining lower steps in the control of their currents. These were the main reasons that required the development of an active shunt. A prototype was built with range of -3A to +3A, what is approximately 3% of the maximum quadrupole current (200A). It was tested with a two-quadrupole family power supply. The full bridge topology was chosen, where the pulse width for the positive and negative output voltages are not the same, which gives an average output current different from zero. Some waveforms and results are shown, such as the long-term stability and output current ripple. Some measurements made in the storage ring electron beam using the active shunt are also described.
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| MOPAN003 |
A New Family of Power Supplies for the LNLS Orbit Correctors
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146 |
| |
- C. Rodrigues, L. H. Oliveira, A. R. Silva
LNLS, Campinas
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Recently the substitution of the older family of orbit corrector power supplies of the LNLS electron storage ring was proposed and a new family has been developed. The new model incorporates additional features such as natural ventilation, unit power factor and shorter response time to reference changes. Moreover, higher efficiency and lower weight and size were obtained. At the moment eight units are operating with storage ring orbit correctors, with current and output voltage up to 10A/10V. This family has three stages of power processing. The first one is a power factor corrector using the boost topology, which gives to the second stage a DC voltage about 400V with regulation and ripple better than 1%. The second stage is an isolated half-bridge with two symmetric adjustable DC outputs from 0 to 40V. The last stage consists of a bipolar series linear regulator using Bipolar Transistors (BJT). Some results obtained for this power supply were: output current ripple and one day stability better than 150ppm, reference voltage step response better than 500A/s with the existing orbit corrector magnet, efficiency higher than 62% and power factor better than 98.5%.
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| MOPAN005 |
Injector Improvements at the Brazilian Synchrotron Light Source
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152 |
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- P. F. Tavares, F. Arroyo, R. H.A. Farias, L. C. Jahnel, C. Pardine, C. Rodrigues
LNLS, Campinas
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We present the results of hardware, software and operational improvements implemented at the injector complex of the 1.37 GeV electron storage ring of the Brazilian Synchrotron Light Source (LNLS) with the aim of improving injector stability and reliability, thus reducing the injection time. The improvements include changes to the 120 MeV injector LINAC RF system and high power modulators, injection automation and the implementation of a new procedure for reusing the current at the end of each user's shifts before injection by ramping the energy back down to 500 MeV (the injection energy) without dumping the beam. All of these changes allowed us to significantly reduce the overall time from the end of a shift to the delivery of beam in the following shift with a positive impact on the reduction of injection thermal transients for the storage ring and beamlines. Further improvements are expected in the near future as a result of planned changes to the injection timing system and of the installation of a recently assembled upgrade of the 500 MeV booster synchrotron RF system
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| FRPMN005 |
Design of Button Beam Position Monitor for the Brazilian Synchrotron Light Source
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3871 |
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- S. R. Marques, O. R. Bagnato, R. H.A. Farias, M. J. Ferreira, J. B. Gonzalez, C. Rodrigues, P. F. Tavares
LNLS, Campinas
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We present the electric and mechanical design of a button beam position monitor (BPM) recently developed and installed in the UVX electron storage ring at the Brazilian Synchrotron Light Laboratory (LNLS). The first commissioning results will also be presented. This development started when we observed strong correlation between false stripline BPM readings and the external temperature of this BPM. Simulations indicate that the temperature gradient in the BPM body can cause deformations that could explain the false readings in some BPMs. The small dimension of the button compared to the stripline and the better thermal isolation between the button and the BPM body should contribute to minimize this problem.
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