Libera Single Pass E

The aim of a single pass position measurement is to resolve the bunch position from the very short signals produced by a bunch that is passing the beam position detector.

Libera Single Pass E enables high accuracy in bunch position measurements. Via the implemented fast communication protocols, it represents a reliable and deterministic building block for fast-feedback building as well as for fast-forward loops, and thus enables attainment of high beam stability.

Product Description


  • Analog and real-time digital signal processing and high-level software
  • Internal phase alignment of input signals
  • Up to four beam processors in one chassis
  • Easy to integrate in any control system

Data processing:

The signal processing chain on the Libera Single Pass E is composed of analog signal processing, digitalization on fast ADCs and digital signal processing. It may handle the following beam modes:

  • Single-bunch mode
  • Bunch train mode
  • CW – Continuous Wave
  • Various bunch structures

Data processing is initiated on the external trigger signal. The short signal from the detector is first lengthened by the bandpass filters on the analog board (filters are designed in relation to the accelerator parameters). Further signal processing is defined by various parameters defining the processing window for a certain beam mode.

The signal energy is calculated from the signal defined by the processing window. After calculating all four amplitudes, position is calculated using formulas for X and Y. Four options can be used for position calculation:

  • Orthogonal pickup orientation
      • Linear formula
      • Polynomial formula – 3rd order
  • Diagonal pickup orientation
      • Linear formula
      • Polynomial formula – 3rd order

In the case of longer beam structures a similar data processing is used – based on the appropriate signal windowing. The data calculation is initiated on the external trigger and is automatically stopped after the bunch structure is over. The decimated batch of data is available to the control system. In the case of CW operation, the unit continuously processes and outputs the decimated beam position data. The external low frequency reference trigger signal needs to be provided for this case.


1. Intel ATOM COM Express with extensive communication interfaces: The FPGAs and a powerful personal computer based on the PCIe interface offer good resources for the implementation of low-latency control algorithms, real-time data processing and dedicated RF system diagnostics tools.

2. Up to four RF acquisition modules: The system is configured to have four satellite modules, and each of them can process 4 RF inputs. One channel on each board is used as the RF reference signal for measurement.

3. GDX module (optional): Primarily intended for fast serial data streaming. Unidirectional Gigabit Ethernet connection as a standard solution for data streaming is provided. This module is also a playground with resources for further development of signal processing and for application development.

4. EvRX timing module: Fast signal interfaces used for triggering, interlock and synchronization purposes.


Libera Single Pass E Performance
Beam modeResolutionNote
Single-bunchµm rangedepending on data processing requirements
Longer bunch structure< 1 µm depending on decimation rate
CW operation< 1 µm depending on decimation rate
Libera Single Pass E Parameters
Number of input channels (measuring)16 (Libera Single Pass E 4/4) / 4 channels/module
ADC resolution 16 bits
ADC sampling clock frequency up to 160 MHz

Contact us

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Libera Single Pass E
Clear filters
Compact Single Pass BPM (IPAC’15, Richmond, VA, USA)
Light proton therapy LINAC LLRF system development (LINAC’18, Beijing, China)
3 BPM Study at PAL ITF (LINAC14, Geneva, Switzerland)
New Digital BPM Electronics for Single Pass Applications (European XFEL Users’ Meeting, Hamburg, Germany)

Libera Single Pass E is used at the following labs:

  • Shanghai Synchrotron Radiation Facility (SINAP) – SSRF (China)
  • High Energy Accelerator Research Organization (KEK) – LINAC (Japan)
  • Lund University – MAX III, MAX IV (Sweden)
  • Tsinghua University (China)
  • Jagiellonian University – SOLARIS (Poland)
  • Institute of High Energy Physics, IHEP – ADS (China)
  • Pohang Accelerator Laboratory (PAL) – PLS II, PAL BTF (South Korea)
  • National Synchrotron Radiation Laboratory (NSRL) – HLSII (China)
  • Laboratori Nazionali di Frascati dell‘INFN (INFN) – Daphne, ELI-NP, STAR project (Italy)
  • Brookhaven National Laboratory (BNL) – RHIC (United States)
  • Danfysik A/S (Denmark)