Orbit correction - Delta - TU Dortmund

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Location & approach

By car

The campus of the Technical University of Dortmund is located near the freeway junction Dortmund West, where the Sauerland line A45 crosses the Ruhr expressway B1/A40. The Dortmund-Eichlinghofen exit on the A45 leads to the South Campus, the Dortmund-Dorstfeld exit on the A40 leads to the North Campus. The university is signposted at both exits.

By bus and train

The "Dortmund Universität" S-Bahn station is located directly on the North Campus. From there, the S-Bahn line S1 runs every 15 or 30 minutes to Dortmund main station and in the opposite direction to Düsseldorf main station via Bochum, Essen and Duisburg. In addition, the university can be reached by bus lines 445, 447 and 462. Timetable information can be found on the homepage of the Rhine-Ruhr Transport Association, and DSW21 also offer an interactive route network map.

Translated with www.DeepL.com/Translator (free version)

By H-Bahn

One of the landmarks of the TU Dortmund is the H-Bahn. Line 1 runs every 10 minutes between Dortmund Eichlinghofen and the Technology Center via Campus South and Dortmund University S, while Line 2 commutes every 5 minutes between Campus North and Campus South. It covers this distance in two minutes.

By plane

From Dortmund Airport, the AirportExpress takes just over 20 minutes to Dortmund Central Station and from there the S-Bahn (suburban train) takes you to the university. A wider range of international flight connections is offered by Düsseldorf Airport, about 60 kilometers away, which can be reached directly by S-Bahn from the university's train station.

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Cafeteria menus

To overview

Location & approach

By car

The campus of the Technical University of Dortmund is located near the freeway junction Dortmund West, where the Sauerland line A45 crosses the Ruhr expressway B1/A40. The Dortmund-Eichlinghofen exit on the A45 leads to the South Campus, the Dortmund-Dorstfeld exit on the A40 leads to the North Campus. The university is signposted at both exits.

By bus and train

The "Dortmund Universität" S-Bahn station is located directly on the North Campus. From there, the S-Bahn line S1 runs every 15 or 30 minutes to Dortmund main station and in the opposite direction to Düsseldorf main station via Bochum, Essen and Duisburg. In addition, the university can be reached by bus lines 445, 447 and 462. Timetable information can be found on the homepage of the Rhine-Ruhr Transport Association, and DSW21 also offer an interactive route network map.

Translated with www.DeepL.com/Translator (free version)

By H-Bahn

One of the landmarks of the TU Dortmund is the H-Bahn. Line 1 runs every 10 minutes between Dortmund Eichlinghofen and the Technology Center via Campus South and Dortmund University S, while Line 2 commutes every 5 minutes between Campus North and Campus South. It covers this distance in two minutes.

By plane

From Dortmund Airport, the AirportExpress takes just over 20 minutes to Dortmund Central Station and from there the S-Bahn (suburban train) takes you to the university. A wider range of international flight connections is offered by Düsseldorf Airport, about 60 kilometers away, which can be reached directly by S-Bahn from the university's train station.

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Controlling the beam position

Methods of machine learning (ML) have found applications in a wide range of tasks for controlling accelerator systems. For instance, neural networks (NN) can be used for the automatic correction of electron beam trajectory (orbit). At DELTA, the orbit is measured at 54 points around the storage ring roughly every second using Beam Position Monitors (BPMs, see image on the right). Undesired deviations of the beam position from the ideal reference orbit are minimized using 56 correction magnets (30 horizontal and 26 vertical) and a software feedback system.

The 3D-plot shows the horizontal and vertical orbital deviations in millimetres at 108 beam position monitors for 3000 data sets. — Horizontal and vertical orbit deviations at the beam position monitors (BPM) caused by variations in the strength of the correction magnets.

The image shows a neural network (NN) for ML-based beam position correction. The NN consists of approx. 17,700 connections (red lines, only partially shown here). — Neural network (NN) for ML-based beam position correction. The NN consists of approx. 17,700 connections (red lines, only partially shown here).

ML-based studies on this topic, initially based on simulations, have been successfully transferred to real accelerator operation at the 1.5 GeV electron storage ring of the DELTA accelerator facility. For this purpose, classical fully connected multi-layer feed-forward networks were trained using supervised learning with measured beam position data and corresponding corrector strengths. The trained networks can subsequently be used for local and global beam position corrections. The supervised NN training was performed using various conjugate gradient backpropagation learning algorithms.

Subsequently, the performance of the ML-based beam position correction was compared with conventional numerical-based computational methods. Here, the ML-based approach showed competitive orbit correction quality, but with a lower number of correction steps. Further details can be found in the internal report and conference publications(IoP, IPAC-22).

The picture shows the iterative correction of the beam position. Here exemplary for four (a-d) different disturbing sources. — Iterative correction of the beam position. Here as an example for four different disturbing sources (a-d).