Together with about 20 co-workers, I am working on the development and construction of an experiment for the new MESA electron accelerator. We named the experiment MAGIX: It consists of a windowless gas target and two movable spectrometers. I am responsible for the conception and construction of the target.

What’s special about MAGIX: The accelerated electron beam is scattered only by the gas – the actual target – and the scattering process is not disturbed by container walls. To achieve this, co-workers from Münster built a device that injects extremely cold gas at supersonic speed into a high vacuum. In Mainz, we essentially implemented the surrounding setup: Later in the experiment, the electron beam will pass through here, and a small portion of the accelerated electrons will collide with the gas flow.

With MAGIX, we aim to answer some of the most fundamental questions in modern physics – and with unprecedented precision: How big is the proton really? Can we find clues for dark photons? Can we better understand the fusion of carbon to oxygen in the sun? At the beginning of my Diplom, MAGIX only existed on paper. Today, four years later, we have installed the target in the A1 spectrometer of our existing MAMI accelerator – to test the system, but also to already collect initial data on the proton radius.

What drives and motivates me in my work? To plan and build an experiment from the ground up – to essentially lift it out of its infancy and create something completely new in the process. I find all of this in my current research project: It’s MAGIX!”

Stephan Aulenbacher completed his Diplom at the Institute for nuclear physics and is currently close to completing his doctorate. Already during his program of study, he worked as a student assistant (HiWi) at the A1 Experiment. There he met Prof. Dr. Achim Denig – and the topic for his Diplom and doctoral thesis was perfectly set. In addition to his research activities, Stephan Aulenbacher has been the project manager for the Hadron Physics node under the umbrella of the “Network Particle World” since early 2020.