Vector Modulator Card for MTCA-Based LLRF Control System for Linear Accelerators

Igor Rutkowski , Krzysztof Marek Czuba , Dariusz Makowski , Aleksander Mielczarek , H. Schlarb , Frank Ludwig


Modern low-level radio frequency (LLRF) control systems of linear accelerators are designed to achieve extremely precise field amplitude and phase regulation inside superconducting cavities. One of the crucial components of the feedback loop is a vector modulator used to drive the high-power RF chain supplying the accelerating cavities. The LLRF control systems for the Free Electron Laser in Hamburg (FLASH) and European X-ray Free Electron Laser (XFEL) are based on the emerging Micro-Telecommunications Computing Architecture (MTCA.4) platform offering numerous advantages for high-performance control systems. This paper describes the concept, design, and performance of the first vector modulator (uVM) module dedicated for RF controls compliant with the MTCA.4 specification developed by PCI Industrial Computer Manufacturers Group (PICMG). The uVM module has been built as a double-width, mid-size rear transition module (RTM) that is accessed by an advanced mezzanine card (AMC). The uVM module incorporates digital, analog, and diagnostic subsystems. The digital part is based on Xilinx Spartan 6 family field-programmable gate array (FPGA), with several fast gigalink connections to a control module. The uVM module is equipped with an intelligent platform management interface (IPMI) circuit required by the MTCA.4 standard. The FPGA controls the analog part, which includes fast, high-precision digital-to-analog converters (DACs), In-phase and quadrature modulator chips, programmable attenuators, power amplifiers, and fast RF gates for an external interlock system. The RF chain can be adopted to different carrier frequencies covering a frequency range from 50 MHz to 6 GHz. The design has been carefully optimized for high linearity and low-output signal phase noise. The diagnostic system of the RF chain allows monitoring of input and output power levels and failure detection in the RF circuits. A low-noise and high-performance clocking system makes the uVM a universal device- extending the scope of applications beyond the LLRF control systems. Extensive tests of the board were performed, and the measurement results are presented and discussed in this paper.
Author Igor Rutkowski (FEIT / PE)
Igor Rutkowski,,
- The Institute of Electronic Systems
, Krzysztof Marek Czuba (FEIT / PE)
Krzysztof Marek Czuba,,
- The Institute of Electronic Systems
, Dariusz Makowski - [Lodz University of Technology]
Dariusz Makowski,,
, Aleksander Mielczarek - [Lodz University of Technology]
Aleksander Mielczarek,,
, H. Schlarb - [Deutsche Elektronen-Synchrotron]
H. Schlarb,,
, Frank Ludwig - [Deutsche Elektronen-Synchrotron]
Frank Ludwig,,
Journal seriesIEEE Transactions on Nuclear Science, ISSN 0018-9499
Issue year2013
Publication size in sheets0.5
Keywords in Englishaccelerator RF systems accelerator cavities digital-analogue conversion field programmable gate arrays free electron lasers linear accelerators
ASJC Classification2208 Electrical and Electronic Engineering; 2104 Nuclear Energy and Engineering; 3106 Nuclear and High Energy Physics
Languageen angielski
Score (nominal)35
Score sourcejournalList
ScoreMinisterial score = 30.0, 23-09-2020, ArticleFromJournal
Ministerial score (2013-2016) = 35.0, 23-09-2020, ArticleFromJournal
Publication indicators Scopus Citations = 11; WoS Citations = 11; GS Citations = 18.0; Scopus SNIP (Source Normalised Impact per Paper): 2013 = 1.564; WoS Impact Factor: 2013 = 1.455 (2) - 2013=1.579 (5)
Citation count*18 (2020-08-28)
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* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.
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