Creating of HDF5 Files as Data Source forAnalyses Using the Example of ALPS IIc andDOOCS Control System
S. Karstensen1, P. Gonzalez-Caminal3, G. Günther2, A. Lindner1, O. Mannix2, I. Oceano1, V. Rybnikov1,K. Schwarz1, G. Sedov1,1
Deutsches Elektronen Synchrotron DESY, Hamburg, Germany
2
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Germany
3
Fusion for Energy (ATG Science & Technology, S.L.), Barcelona, Spain
Abstact

A versatile and graphical HDF5 file generation project. In the realm of physical experiments, data is typically gathered through the utilization of measurement devices intricately integrated into control systems. These control systems employ diverse methods for archiving historical data. Nevertheless, users consistently grapple with a recur-ring challenge: how to access the data, decipher the intri-cacies of the control system's structure, and understand the formatting. The prevailing approach involves the crea-tion of scripts
or programs tasked with extracting data from these control systems, and if necessary followed by the requisite data pre-processing
for subsequent analysis. Typically, this pre-processing is carried out in formats known exclusively to the individual user. Moreover,the longevity of data utility often teeters on the brink when users depart or deviate from established conventions.
To address these challenges, we are actively developing software that serves a dual purpose: firstly, to provide an API for a control
system (in this instance, DOOCS), and secondly, to transform the extracted data into a universally recognized format, such as HDF5,
complete with all relevant metadata.

HDF5 Generator

GUI Capabilities

The diagram provides a comprehensive overview of the HDF5 data generation
process.
To the left, control system data is received and meticu-lously processed via anAPI. Metadata containing essen-tial information about the control system dataand setup of the whole experiment for potential source reconstruc-tion, follows
a parallel procedure. Additionally, certain metadata serves the crucial role offurnishing users with a tailored graphical interface, simplifying the process ofdata selection. These elements are seamlessly amalgamated by the processor
and subsequently archived as an HDF5 file.

The graphical interface encompasses all experiment-related devices andchannels, providing the user with the capability to choose which data torecord in the HDF5 file. Each data value is supplemented with metadata, facilitating precise one-to-one associations. The graphical structure is documented and stored in a JSON file, ensuring a well-defined structure for easeof reading. As a proof of concept, we initially utilized Node-RED to conduct afeasibility analysis, with the final product slated to feature a distinct GUI.

Control system

DOOCS, the Distributed
ObjectOrientedControl
System was designed forFLASH. Currently it is usedalso to control the European
XFEL accelerator, PETRA IV
and a bunch of smaller detectors like ALPS, BabyIAXO
and MADMAX.
Recent developments for theclient side applications are written in JAVA to allow them to be used on many
computer platforms. This object oriented abstraction model helps for clean
programming interfaces and in the overall system design including the hardware for a machine and is a significant step forward in the goal to improve
software productivity and quality.

Detector
280m

The ALPS (Any Light ParticleSearch)experiment,
whichstretches a total length of 280
metres, is looking for a particularly light type of new elementaryparticle.
The international research team wants to search for new particles, the axion
and axion-like particles, that can justify some anomalies observed in theselatest years. To do so the experiment is using twenty-four recycled superconducting magnets from the HERA accelerator, an intense laser beam, precision interferometry and highly sensitive detectors. Such particles are believed to react only extremely weakly with known kinds of matter, whichmeans they cannot be detected in experiments using accelerators. ALPS istherefore resorting to an entirely different principle to detect them: in a strong
magnetic field, photons – i.e. particles of light – could be transformed into
these mysterious elementary particles and back into light again.

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