Department Optics and Beamlines

Monochromator-Control

The monochromator as an optical element of a beamline is located outside of the actual storage ring along the beamlines. On its way through the beamline, the synchrotron light can be adjusted to the special needs of the connected experiment, the monochromator is responsible for the spectral isolation of the relevant wavelength.

There are different types of monochromators: the Plane Grating Monochromator (PGM), the Spherical Grating Monochromator (SGM), the Normal Incidence Monochromator (NIM) and the Double Crystal Monochromator (DCM).

The monochromator group focuses on the efficient control of all monochromators, programming and configuring their components. Motors, as well as controller cards responsible for mirrors, gratings and crystals inside of the monochromators have to be moved very precisely. The user interface to controll all devices is programmed by the monochromator group aswell. Each monochromator requires individual customization of hard- and software according to the attached experiment of the beamline.

Publications and Presentations

Papers and Proceedings

• A Python-based serial communication framework for legacy PMAC controllers, ICALEPCS 2025
• HASMI: A configurable Python framework for automated harmonic analysis and scan orchestration at EMIL, ICALEPCS 2025
• Double Crystal Monochromator Control System for Energy Materials in-situ Laboratory Berlin (EMIL), ICALEPCS 2019
• Status of the Continuous Mode Scan for Undulator Beamlines at BESSY II, ICALEPCS 2015
• Diagnostics and optimization procedures for beamline control at BESSY, ICALEPCS 2005

Published Software and Documentation

• pmacpy
  

  pmacpy is a modular Python toolkit for communicating with Delta Tau Power PMAC and Geo Brick motion controllers.
  It provides command-line utilities, a background manager, and a GUI interface for serial/network communication, variable monitoring, and batch command execution.

  This package is designed for use in beamline environments (e.g. BESSY II) and laboratory automation setups where PMAC-based motion systems are controlled via Python or EPICS.

• kiwi-scan: GitHub, PyPI

  A Modular Scan Framework for Commissioning and Diagnostics in EPICS Environments

  Actuators, detector PVs, triggers, subscriptions, plugins, and metadata sidecars are configured via YAML. Scan engine (scan type) and scan dimensions are chosen by command line or API. Results are written to timestamped text files. Optional metadata sidecars can record constants and monitored PVs in parallel.

Presentations and Slides

• kiwi-scan: A Modular Scan Framework for Commissioning and Diagnostics in EPICS EnvironmentsICALEPCS 
• HASMI: A configurable Python framework for automated harmonic analysis and scan orchestration at EMIL
• Double Crystal Monochromator Control System for Energy Materials In-Situ Laboratory Berlin (EMIL)
• Status of the Continuous Mode Scan for Undulator Beamlines at BESSY II

E-Mail Contact

To get in touch with all group members, please use the following e-mail list:

mono@helmholtz-berlin.de

On-call service

To ensure the trouble-free operation of BESSY II for all users, the monochromator group set up a component on-call service "Beamline- and monochromator controls".

© 03/25 AZ and smalerz
© 2026 AB and PS