Cavity voltage phase modulation to reduce the high-luminosity Large Hadron Collider rf power requirements
The Large Hadron Collider (LHC) radio frequency (rf) and low-level rf (LLRF) systems are currently configured for constant rf voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal LHC beam current (0.55 A dc) and cannot be sustained for the high-lum...
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2017-10-01
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Series: | Physical Review Accelerators and Beams |
Online Access: | http://doi.org/10.1103/PhysRevAccelBeams.20.101003 |
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doaj-c0a473e95267475aa1404690e09a23b42020-11-24T23:44:21ZengAmerican Physical SocietyPhysical Review Accelerators and Beams2469-98882017-10-01201010100310.1103/PhysRevAccelBeams.20.101003Cavity voltage phase modulation to reduce the high-luminosity Large Hadron Collider rf power requirementsT. MastoridisP. BaudrenghienJ. MolendijkThe Large Hadron Collider (LHC) radio frequency (rf) and low-level rf (LLRF) systems are currently configured for constant rf voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal LHC beam current (0.55 A dc) and cannot be sustained for the high-luminosity (HL-LHC) beam current (1.1 A dc), since the demanded power would exceed the peak klystron power. A new scheme has therefore been proposed: for beam currents above nominal (and possibly earlier), the voltage reference will reproduce the modulation driven by the beam (transient beam loading), but the strong rf feedback and one-turn delay feedback will still be active for loop and beam stability. To achieve this, the voltage reference will be adapted for each bunch. This paper includes a theoretical derivation of the optimal cavity modulation, introduces the implemented algorithm, summarizes simulation runs that tested the algorithm performance, and presents results from a short LHC physics fill with the proposed implementation.http://doi.org/10.1103/PhysRevAccelBeams.20.101003 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
T. Mastoridis P. Baudrenghien J. Molendijk |
spellingShingle |
T. Mastoridis P. Baudrenghien J. Molendijk Cavity voltage phase modulation to reduce the high-luminosity Large Hadron Collider rf power requirements Physical Review Accelerators and Beams |
author_facet |
T. Mastoridis P. Baudrenghien J. Molendijk |
author_sort |
T. Mastoridis |
title |
Cavity voltage phase modulation to reduce the high-luminosity Large Hadron Collider rf power requirements |
title_short |
Cavity voltage phase modulation to reduce the high-luminosity Large Hadron Collider rf power requirements |
title_full |
Cavity voltage phase modulation to reduce the high-luminosity Large Hadron Collider rf power requirements |
title_fullStr |
Cavity voltage phase modulation to reduce the high-luminosity Large Hadron Collider rf power requirements |
title_full_unstemmed |
Cavity voltage phase modulation to reduce the high-luminosity Large Hadron Collider rf power requirements |
title_sort |
cavity voltage phase modulation to reduce the high-luminosity large hadron collider rf power requirements |
publisher |
American Physical Society |
series |
Physical Review Accelerators and Beams |
issn |
2469-9888 |
publishDate |
2017-10-01 |
description |
The Large Hadron Collider (LHC) radio frequency (rf) and low-level rf (LLRF) systems are currently configured for constant rf voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal LHC beam current (0.55 A dc) and cannot be sustained for the high-luminosity (HL-LHC) beam current (1.1 A dc), since the demanded power would exceed the peak klystron power. A new scheme has therefore been proposed: for beam currents above nominal (and possibly earlier), the voltage reference will reproduce the modulation driven by the beam (transient beam loading), but the strong rf feedback and one-turn delay feedback will still be active for loop and beam stability. To achieve this, the voltage reference will be adapted for each bunch. This paper includes a theoretical derivation of the optimal cavity modulation, introduces the implemented algorithm, summarizes simulation runs that tested the algorithm performance, and presents results from a short LHC physics fill with the proposed implementation. |
url |
http://doi.org/10.1103/PhysRevAccelBeams.20.101003 |
work_keys_str_mv |
AT tmastoridis cavityvoltagephasemodulationtoreducethehighluminositylargehadroncolliderrfpowerrequirements AT pbaudrenghien cavityvoltagephasemodulationtoreducethehighluminositylargehadroncolliderrfpowerrequirements AT jmolendijk cavityvoltagephasemodulationtoreducethehighluminositylargehadroncolliderrfpowerrequirements |
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