Libera Spark ERXR

Libera Spark ERXR is a compact electron beam position processor that offers high-precision position measurement. It is optimized to work with button and stripline pickups. The digital signal processing supports detailed adjustment of the processing window and position measurement in various regimes and bandwidths. Optionally, it supports the pilot tone processing, too. The data available to the user ranges from bunch-to-bunch, turn-by-turn to slow data stream. The instrument is typically used in booster or storage rings.

Product Description


  • Best price/performance ratio
  • Compact and robust design
  • Power over Ethernet
  • No maintenance required
  • Source code available
  • Variety of interfaces (e.g. EPICS, TANGO, HTTP, MATLAB, etc.)

Data Processing:

Signals from the BPM pickups are filtered and sampled at 100-125 MHz PLL-controlled sampling frequency. Raw ADC data is stored in a buffer and further processed through a time-domain processing block (TDP) and frequency-domain processing block (DDC, I&Q demodulation). Optionally, a special instrument’s version supports additional DDC block for pilot-tone signal.

The turn-by-turn processing blocks can be fine-tuned with processing delay, offset and masking window. Turn-by-turn data from both sources is written to circular buffers which accommodate few millions of turns. Data can be read in various modes: triggered, on-demand, with +/- offset, etc.

Turn-by-turn data from the Time domain processing block is particularly useful for machine commissioning and/or measurement of a single-bunch single-turn trajectory.

The Fast and Slow data are both generated from the turn-by-turn data using FIR filters with 2 kHz and 5 Hz bandwidths, respectively. Optionally, the Fast data can be output through a dedicated RJ-45 interface as a real-time data stream.


  1. Additional RJ-45 interface for fast data streaming (optional).
  2. Memory card slot.
  3. Serial console (Micro-B USB).
  4. RJ-45 for 1000Base-T Cu GbE connection and Power-over-Ethernet.
  5. USB slot.
  6. SMA connectors for connections to the beam pickups.
  7. LEMO coaxial, used for various trigger signals (e.g. revolution clock, injection trigger).
Hardware capabilities and specifications of Libera Spark ERXR
Libera Spark ERXR
General product codeLSXR
Input frequency range< 750 MHz
Maximum input signal< -10 dBm (continuous)
A/D conversion125 MHz, 14-bit
CalibrationLook-up table / Pilot tone
Gain/attenuation31 dB programmable
Real-time data linkRJ-45, GbE
Power supplyPower-over-Ethernet (<15 W)
Timing signalsElectrical, 3 inputs
Measurement performance
Typical value
Temperature drift, typical< 2 μm/°C
Position RMS at turn-by-turn data rate0.3 μm
Position RMS at fast 10 kHz data rate0.04 μm
Position RMS at slow 10 Hz data rate0.02 μm
Position RMS at single bunch< 10 μm
User Interfaces

The instrument runs on a Libera BASE software infrastructure. The infrastructure supports various plugins (interface servers) that are compatible with most common control system interfaces on users’ side:

  • EPICS: libera-ioc
  • TANGO: libera-ds
  • MATLAB/LabVIEW: libera-telnet-server
  • HTTP/WEB: libera-http-plugin
  • C++ : libera-mci
  • PYTHON: libera-pymci

Graphical user interface for TANGO users is built by the AtkPanel tool automatically. EPICS users have various options: from EDM, caQtDM to CSS.

As an example, the gallery below shows the GUI panels built on the EDM technology.

Contact us

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Libera Spark ERXR
Clear filters
BPM Processor Upgrades At SPEAR3
Beam Measurements Results Of A BPM System Implementing The Pilot-tone Stabilization Concept
Machine Studies With Libera Instruments At The SLAC SPEAR3 Accelerators
Commissioning results of the new BPM electronics of the ESRF booster synchrotron* (IPAC’15, Richmond, VA, USA)
Spark EL Single Pass BPM (FEL 2015, Daejaon, S. Korea)
Engineering Executive
NDA locked

The prototyping and development Instrumentation Technologies has provided for our team has been exceptional.

Engineering Executive
NDA locked

The prototyping and development Instrumentation Technologies has provided for our team has been exceptional.

Libera Spark ERXR is used at the following labs:

  • DIAMOND Light Source (United Kingdom)
  • SACLA – Spring-8 (Japan)
  • Synchrotron Light Research Institute – SLRI (Thailand)
  • The European Synchrotron Radiation Facility – ESRF (France)
  • Argonne National Laboratory – APS (United States)
  • National Institutes of Natural Sciences, Institute of Molecular Science – UVSOR facility (Japan)
  • Cornell University – CHESS (United States)