Libera BLM

The Libera BLM is a processor for signals coming from the beam-loss detectors.  Losses are measured with a high level of detectability and time resolution (8 ns). In contrast to other BLM systems, it detects losses ranging from a single electron to the huge losses that usually occur during injection. Thanks to its high time resolution and 50 Ohm input termination, it provides detailed insight into sub-turn and intra-pulse losses. When switched to a high-impedance input termination, it is able to detect very small losses.

The instrument connects to up to four beam-loss detectors and provides them with power and gain-control voltage. A beam loss detector must be placed on hot spots, usually behind the dipole magnet. The electro-magnetic shower caused by lost electrons will hit the detector and produce a visible light. The photo-multiplier converts the light into an electrical pulse that is detected by the Libera BLM at the end.

Product Description


  • Portable system, easy to deploy and use
  • Compact and robust design
  • Power over Ethernet for complete system
  • Re-configurable processing scheme
  • No maintenance required
  • Variety of interfaces (e.g. EPICS, TANGO, HTTP, MATLAB, etc.)

Data processing:

The signal from the beam loss detector (usually a photo-multiplier tube) is typically a unipolar pulse or train of pulses with negative polarity. It is possible to detect huge losses and very small losses thanks to the switchable front-end input impedance. The input signal is sampled by a PLL-controlled sampling clock.

The raw sampled data is stored in a buffer upon a trigger event. Further down the processing chain, the data is processed in order to remove the static offset and apply averaging and integration factors. The buffered data provides a quantitative view of the loss shape.

In parallel, losses are continuously monitored and counted at a rate of 8 ns. Counting modes are fully configurable for static and dynamic loss thresholds. Being locked to a sampling clock and an external clock, it is possible to adjust up to two configurable detection windows that monitor only a selected part of the fill pattern.

With up to four beam loss detectors connected to the same instrument, an algorithm can automatically detect if the loss was detected in all detectors at the same time (coincidence counting mode). Coincidence is monitored in a configurable time window.



Hardware capabilities are given in the table below:

Typical applications that are covered by Libera BLM are shown in the table below:

Libera BLM
Clear filters
Prototype results with a complete Beam Loss Monitor System optimized for synchrotron light sources (IPAC’15, Richmond, VA, USA)
Kees Scheidt
Diagnostics Head (ESRF, Grenoble)

On our Booster beam, we collected much data and features, that we could not measure or even detect before.

Engineering Executive
NDA locked

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

Libera BLM is used at the following labs:

  • The European Synchrotron Radiation Facility – ESRF (France)
  • Deutsches Elektronen-Synchrotron (DESY) – PETRA III (Germany)
  • National Synchrotron Radiation Research Center (NSRRC) – TPS, TLS (Taiwan)
  • Synchrotron Light Research Institute – SLRI (Thailand)
  • The Synchrotron-Light for Experimental Science and Applications in the Middle East (SESAME) – SESAME (Jordan)
  • SACLA – Spring-8 (Japan)
  • Diamond Light Source (United Kingdom)
  • Pohang Accelerator Laboratory (PAL) – PLS II, XFEL ITF (South Korea)
  • Hiroshima Synchrotron Radiation Center – HiSOR (Japan)
  • Cornell University – CHESS (United States)