Sunday, February 21, 2021

Who Reads my Books? Joerg Mosthaf

My name is Joerg Mosthaf and I work as physicist and team lead in the accelerator control system team of the Heidelberg Ion Beam Therapy Center HIT in Heidelberg, Germany ( or ). 

I did my “Wehrersatzdienst” (which used to be an alternative to mandatory military service in the late 20th century in Germany) as a paramedic for the red cross and afterwards studied physics with a minor in neurophysiology at the Ruprecht-Karls-University Heidelberg. During my final years there, I worked as a scientific assistant at the institute of medical informatics and did my thesis on real time temperature measurements via T1 relaxation times variation in MRI during RF ablation therapy. After a few years of working in IT/web project management and first level support I got the job in the accelerator control system team for the then newly built (partly still in construction) synchrotron accelerator at the Heidelberg university hospital. 

The Heidelberg Ion Therapy Centre (HIT) is a dedicated hadron accelerator facility for radio-therapeutical treatment of tumour patients. The two horizontally fixed treatment places, the 360° gantry, as well as the experimental area can be served with proton and carbon beams with qualified beam parameters, helium is available for the experimental area and soon for treatment, and oxygen is being tested.

The achieved energy range of 88-430 MeV/u for carbon ions and 48-221 MeV/u for protons is sufficient to reach a penetration depth of 20-300 mm in water. We use virtual accelerators (VAccs) to model all the different possible beamlines and used beam parameters (MEFI – Mass, Energy, Focus, Intensity). The MEFI consist of 4 ion types (M), 255 energy steps (E), 4 beam widths (F) and 10 ion flux steps (I). The beam is then applied with fast scanning magnets in a raster scan application to the tumor in the patient.

I work as team lead for the accelerator control system. My job is to keep the server system running that maintains all the different parameters for all the devices in the accelerator and sends them to the device control units (DCU) that control magnets, rf systems and so on. We use redundant host servers and a redundant SAN storage for our database and main control servers running in a virtual environment. The accelerator control room houses 18 acs clients on which our acs software clients run and is manned 24/7 by at least two people. We work 8 hour rotating shifts with 24h on call status thrown in. Therapy runs for about 10-12 hours a day for 5 days (mon-sat) with the rest of the time used for QA, beam conditioning and research. The research time is used by several institutes for anything from treatment research to material and electronics research.

I am also part of the beam conditioning team, that is responsible for correcting beam position, intensity and width in night shifts to get verified and validated beam parameter sets for use in therapy plans.

I also read Neals books and other science fiction and fantasy books. I specially like military science fiction books and books about first contact. My favorite authors (besides Neal of course) are Alastair Reynolds, James S.A. Corey, John Scalzi, Ian Banks, Evan Currie, Marco Kloos, Dennis E. Taylor, Jay Allen, Jodi Taylor, Mary Robinette Kowal but also Fantasy authors like Seanan McGuire, Terry Pratchet, Jim Butcher, Steven Brust and the classics like Robert Heinlein, A.E. van Vogt, Isaac Asimov and so on.

Other hobbies are RPGs - I play and DM mainly Pathfinder, Starfinder, Traveller, Cyberpunk 2020 and german RPG systems like Das Schwarze Auge (the dark eye in English), Die SchwarzeKatze and Hexxen 1733 – and computer games (Cyberpunk 2077, Division 1 and 2, Deep Rock Galactic AC Valhalla…) and watching tv series (Expanse, Star Trek, Enchanted, Bridgerton…)

I try to keep active but with my work schedule it is hard to get any organised sport in and I usually am to lazy after 10 hours of night shift to do anything else than read, play or watch tv 😉) 

Here a few pictures of HIT:

Figure 1 Accelerator overview

1. Ion sources (2 ECR ion sources for carbon/oxygen, hydrogen/protons and helium)

2. Linear accelerator up to ~0.10 c

3. Synchrotron accelerator up to ~0.75 c

4. High energy beam line to the patient treatment rooms

5. Nozzle in patient treatment room

6. Patient position control with digital x-ray system

7. 360° rotating ion gantry with sub millimetre precision

8. Gantry patient treatment room with rotating x-ray systems

9. Experimental room for research

Figure 2 External view of the HIT facility

Figure 3 Gantry treatment room with nozzle at 0°

 Figure 4 Gantry back room with the rotating part of the gantry visible, nozzle at 90°

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