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Title: AGS tune jump power supply design and test

Abstract

A horizontal tune jump system has been installed to overcome the horizontal intrinsic spin resonances, which requires jumping the horizontal tune 0.04 units 82 times, 41 up and 41 down. Two quadruple magnets have been installed in AGS ring to perform this. The pulsed magnet current ranges from about 140A near injection to about 1400A later. The current pulse rise and fall time are around 100uS and flat tops time is around 4mS. These quadruples have separated supplies. This tune jump pulse power supply employees all semiconductor parts as well as the main switches. During dummy load and magnet testing, the test results showed that the power supply could meet the specification. This article will describe some details of power supply simulation, design and testing. Some test waveforms and pictures are presented in this paper.

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) Alternating Gradient Synchrotron
Sponsoring Org.:
DOE - Office Of Science
OSTI Identifier:
1012587
Report Number(s):
BNL-94141-2011-CP
R&D Project: KBCH139; 18037; KB0202011; TRN: US1102329
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Conference
Resource Relation:
Conference: 2011 Particle Accelerator Conference (PAC'11); New York, NY; 20110328 through 20110401
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; AVAILABILITY; DESIGN; MAGNETS; PERSONNEL; SIMULATION; SPIN; SWITCHES; TESTING; WAVE FORMS; alternating gradient synchrotron

Citation Formats

Mi, J., Glenn, J.W., Huang, H., Marneris, I., Rosas, P., Sandberg, J., Tan, Y., and Zhang, W. AGS tune jump power supply design and test. United States: N. p., 2011. Web.
Mi, J., Glenn, J.W., Huang, H., Marneris, I., Rosas, P., Sandberg, J., Tan, Y., & Zhang, W. AGS tune jump power supply design and test. United States.
Mi, J., Glenn, J.W., Huang, H., Marneris, I., Rosas, P., Sandberg, J., Tan, Y., and Zhang, W. Mon . "AGS tune jump power supply design and test". United States. doi:. https://www.osti.gov/servlets/purl/1012587.
@article{osti_1012587,
title = {AGS tune jump power supply design and test},
author = {Mi, J. and Glenn, J.W. and Huang, H. and Marneris, I. and Rosas, P. and Sandberg, J. and Tan, Y. and Zhang, W.},
abstractNote = {A horizontal tune jump system has been installed to overcome the horizontal intrinsic spin resonances, which requires jumping the horizontal tune 0.04 units 82 times, 41 up and 41 down. Two quadruple magnets have been installed in AGS ring to perform this. The pulsed magnet current ranges from about 140A near injection to about 1400A later. The current pulse rise and fall time are around 100uS and flat tops time is around 4mS. These quadruples have separated supplies. This tune jump pulse power supply employees all semiconductor parts as well as the main switches. During dummy load and magnet testing, the test results showed that the power supply could meet the specification. This article will describe some details of power supply simulation, design and testing. Some test waveforms and pictures are presented in this paper.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Mar 28 00:00:00 EDT 2011},
month = {Mon Mar 28 00:00:00 EDT 2011}
}

Conference:
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  • A new horizontal tune jump mechanism has been proposed to overcome the horizontal intrinsic resonances and preserve the polarization of the proton beam in the Alternating Gradient Synchrotron (AGS) during the energy ramp. An adiabatic change of the AGS lattice is needed to avoid the emittance growth in both horizontal and vertical planes, as the emittance growth can deteriorate the polarization of the proton beam. Two critical questions are necessary to be answered: how fast can the lattice be changed and how much emittance growth can be tolerated from both optics and polarization points of view? Preliminary simulations, using amore » realistic AGS lattice and acceleration rate, have been carried out to give a first glance of this mechanism. Results with different optics are presented in this paper.« less
  • Two partial snakes overcome the vertical depolarizing resonances in the AGS. But a new type of depolarizing intrinsic resonance from horizontal motion appeared. We reduce these using horizontal tune jumps timed to these resonances. We gain a factor of six in crossing rate with a tune jump of 0.05 in 100 {micro}s. Two quadrapoles, we described in 2009, pulse 42 times, the current matching beam energy. The power supplies for these quads are described in detail elsewhere in this conference. The controls for the Jump Quad system is based on a BNL designed Quad Function Generator. Two modules are used;more » one for timing, and one to supply reference voltages. Synchronization is provided by a proprietary serial bus, the Event Link. The AgsTuneJump application predicts the times of the resonances during the AGS cycle and calculates the power supply trigger times from externally collected tune and energy versus time data and the Low and High PS voltage functions from a voltage to current model of the power supply. The system was commissioned during runs 09 & 10 and is operational. Many beam effects are described elsewhere. The TuneJump system has worked well and has caused little trouble save for the perturbations in the lattice having such a large effect due to our need to run with the vertical tune within a few thousandths of the integer tune. As these problems were mostly sorted out by correcting the 6th harmonic orbit distortions which caused a large 18 theta beta wave. Also running with minimal chromaticity reduces emittance growth. There are still small beta waves which are being addressed. The timing of the pulses is still being investigated, but as each crossing causes minimal polarization loss, this is a lengthy process.« less
  • This paper describes the principle and test results of the prototype RHIC Gamma Transition Jump Power Supply. The jump power supply principle is introduced and illustrated along with diagrams in this paper. The prototype is built with Insulated Gate Bipolar Transistors (IGBT) as current direction switch components. Optically coupled IGBT drivers are used for the jump control switch. The jump time among the power supplies is synchronized from 40 to 60 milliseconds to meet the RHIC beam transition-crossing requirement. The short jump time is needed to avoid particle loss and to preserve the initial bunch area during the transition, thusmore » successfully transferring the ion beams from the acceleration RF system to storage system. There are a total of twenty four jump power supplies that will be used. They synchronously switch the direction of the magnets current while the beam is being accelerated through the transition to reach the top storage energy. Each power supply will energize a group of super conducting magnets, which consists of four magnets that are connected in series. At the end, test results are listed, accompanied with the dummy load current waveform and prototype power supply picture.« less
  • In order to cross more rapidly the 82 weak spin resonances caused by the horizontal tune and the partial snakes, we plan to jump the horizontal tune 82 times during the acceleration of polarized protons. The current in the magnets creating this tune jump will rise in 100 {micro}s, hold flat for about 4 ms and fan to zero in 100 {micro}s. Laminated beam transport quadrupole magnets have been recycled by installing new two turn coils and longitudinal laminated pole tip shims that reduce inductance and power supply current. The power supply uses a high voltage capacitor discharge to raisemore » 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 operational experience are described.« less
  • To meet neutral-beam source requirements, a combination series switch/regulator system has been developed that can provide up to 40-kV at 80A output for 10-ms from the continuously decaying voltage of a charged capacitor bank. The system uses 100% feedback control of a series hard tube regulator. This feedback regulator is able to maintain a 40-kV output level for 100% load variations while the source voltage for the capacitor bank is drained from an initial 55-kV down to as low as 43-kV during a 10-ms pulse. In addition to controlling the output voltage, the series regulator tube also serves the dualmore » role of a disconnect or interrupt switch at the end of each pulse and during the frequent occurrence of a neutral-beam source fault. In the interrupt mode, complete disconnect is achieved in less than 2-..mu..s after first observance of a fault condition; recovery times to normal operation of less than 10-..mu..s after fault clearance can be attained if desired.« less