Libera Spark ERXR / ERPT

The Libera Spark ERXR / ERPT is a state-of-the-art electron beam position processor designed for synchrotron instrumentation. It supports the readout from a single beam position monitor (BPM with 4 channels) and processes data in both frequency and time domains. The ERPT version additionally supports the Libera Pilot Tone FE, handling input signals at two RF frequencies. This instrument is capable of real-time data streaming (e.g., at 10 kHz) and integration with machine protection systems (Interlock detection).


Product Description

Key Features of Libera Spark ERXR/ ERPT

  • High Measurement Resolution: Typically sub-micron RMS at turn-by-turn data rate. 
  • Programmable Attenuators: A 15 dB input attenuator and 31 dB internal attenuator ensure optimal signal range adjustment. 
  • Synchronization Capabilities: Multiple instruments can be synchronized via a reference clock (turn-by-turn) and a PLL, ensuring seamless integration and accurate measurements across devices. 
  • Efficient Hardware Platform: Designed for low power consumption and is powered through Power-over-Ethernet. It generates no noise and does not require forced cooling. 
  • Control System Compatibility: Supports EPICS and TANGO control systems out-of-the-box, with support for other interfaces (Python, HTTP, telnet). 

Signal Processing: 

Input signals are sampled at nominal sampling frequency which can be generated internally (PLL-controlled) or externally. A/D converters have 14-bit resolution and support the sampling frequency up to 125 MHz.
The beam position calculation equation can be configured for diagonal or orthogonal pickup orientation and supports scaling and offset parameters. Position is calculated at turn-by-turn data rate and further filtered to lower data rates and bandwidths.
Data from buffers is available to multiple clients in parallel. Additionally, a real-time data stream can be read independently from the CPU and is intended for real-time applications (e.g. feedback loops). 

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.


Comparison of technical specifications of Libera Spark ERXR and Libera Spark ERPT
Libera Spark ERXRLibera Spark ERPT
General product codeLSXRLSPT
BPM Slots11
Supported input frequency range< 750 MHz< 750 MHz
A/D conversion125 MHz, 14-bit125 MHz, 14-bit
Power supply PoEPoE
Timing signalsElectrical, 3 inputsElectrical, 3 inputs
CalibrationManualPilot Tone (does not come in the package)
Fast data linkRJ-45RJ-45
Maximum input signal< +5 dBm (continuous)< - 10 dBm (continous)
Input gain/attenuation31 dB programmable31 dB programmable
Temperature drift, typical2 μm/°C< 1 μm/°C
Position RMS at turn-by-turn data rate0.3 μm1 μm
Position RMS at fast 10 kHz data rate0.04 μm0.1 μm
Position RMS at slow10 kHz data rate0.02 μm0.05 μm
Position RMS at single bunch<10 μm/


Software and FPGA code runs in Zynq 7020 which combines the Programmable Logic (PL) and Processing Subsystem (PS). Libera BASE software framework hosts the application software and establishes communication with the FPGA and upper layer software interfaces. The interface servers are compatible with most common control system interfaces such as: 

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


If we have not yet convinced you, here is a list of benefits SPARK ERXR/ERPT have in comparison with other similar products: 

    • 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.)


Contact us

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Libera Pilot Tone FE

Pilot Tone FE is an analog front-end installed in the tunnel and connected between the BPM pickup and PBM electronics.

Libera Spark ERXR / ERPT
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)

For demonstration purposes, Libera Spark can be fully controlled with a Qt Graphical User Interface. It uses a netcat utility that connects to Libera Spark via SCPI set/read commands. Check example figures and tutorial videos.

Libera Spark – ADC

Libera Spark – FFT

Libera Spark – Parameters

Libera Spark – TBTXY


Getting started with GUI

Set up the custom ADC sampling frequency

ADC data readout


Libera Spark ERXR is used at the following labs:

  • Argonne National Laboratory – APS (United States)
  • CELLS – ALBA (Spain)
  • Cornell University – CHESS (United States)
  • DESY – DESY IV (Germany)
  • DIAMOND Light Source (United Kingdom)
  • Helmholtz-Zentrum Berlin, HZB – BESSY II (Germany)
  • High Energy Accelerator Research Organization, KEK – PF (Japan)
  • Hiroshima Synchrotron Radiation Center – HiSOR (Japan)
  • Karlsruhe Institute of Technology, KIT – ANKA (Germany)
  • National Institutes of Natural Sciences, Institute of Molecular Science – UVSOR facility (Japan)
  • National Synchrotron Radiation Research Center – TPS (Taiwan)
  • Pohang Accelerator Laboratory – EUV (S. Korea)
  • SACLA – Spring-8 (Japan)
  • Synchrotron Light Research Institute – SLRI (Thailand)
  • The European Synchrotron Radiation Facility – ESRF (France)