Advancements in the modeling of IH-DTL cavities for control applications

Authors

DOI:

https://doi.org/10.17979/ja-cea.2026.47.13744

Keywords:

Identification for control, Model validation, Grey box modeling, Lumped-parameter models, Control applications

Abstract

Active control of resonant cavities is essential for optimizing particle accelerator performance. This requires accurate modeling to characterize cavity responses to various controllable parameters. A compact and efficient architecture for low-to-medium energy acceleration is the Interdigital H-Mode Drift Tube Linac (IH-DTL). However, current literature lacks models suitable for control-oriented simulations because standard approaches treat the cavity as a monolithic entity. This prevents the modeling of crucial positional effects, such as localized tuning. This work introduces a methodology to characterize individual accelerating sections as standard electrical components and validates it by applying it to an actual IH-DTL structure. Building upon this discretization, we present a novel distributed equivalent circuit designed to capture localized spatial dependencies. This
lumped-element representation is particularly advantageous, as it enables seamless integration and simulation within standard computational frameworks used in control engineering.

Author Biographies

  • Beñat Gonzalez, Euskal Herriko Unibertsitatea (EHU)

    Beñat Gonzalez received the bachelor’s degree in physics and electronic engineering from the University of the Basque Country (EHU), Leioa, Spain, in 2024, where he is currently pursuing the master’s degree in the European Master for Industry in Microwave Electronics and Photonics (EMIMEP) programme. His main research interests include electromagnetic simulation and structures for particle acceleration.

  • Iñigo Arredondo, Euskal Herriko Unibertsitatea (EHU)

    I˜nigo Arredondo received the bachelor’s degree in electronic engineering from the University of the Basque Country (UPV/EHU), Leioa, Spain, in 2003, the degree in physics from the University of Cantabria, Santander, Spain, in 2004, and the Ph.D. degree from UPV/EHU, in 2009. He was with the Control Group of the European Spallation Source Consortium Bilbao, Zamudio, Spain, from 2009 to 2014, where he was promoted to the Head of the Group. He then went on to take up a teaching position at the Digipen-Europe Technological Institute, Bilbao, Spain, from 2014 to 2016. He is currently an Associate Professor of Electronics and Automation at the UPV/EHU. His main research interests include design and control of particle accelerators and control of nonlinear systems.

  • Joaquín, Euskal Herriko Unibertsitatea (EHU)

    Joaqu´ın Portilla received the bachelor’s degree in physics, specializing in electronics from the University of Cantabria, Santander, Spain, in 1990, and the Ph.D. degree from the University of Limoges, Limoges, France, in 1994. In 1994, he joined the Department of Communications Engineering,
    University of Cantabria, working on research and development projects in RF and microwave circuits for radiocommunications. He conducted his Ph.D. research at IRCOM (now XLIM), University of Limoges. He also collaborated in teaching within the Telecommunications Engineering Program. In 1997, he joined the Institute of Physics of Cantabria (IFCA), Santander, to develop radiometers for the ESA’s Planck Project. In 1998, he became part of the Department of Electricity and Electronics, University of the Basque Country (UPV/EHU), Leioa, Spain, where he coleads the RF and microwave research group and participates in research and development projects in radiocom- munications and scientific instrumentation. He has held various academic management roles and is currently part of the the team driving the Erasmus Mundus Master on Innovative Electronics and Photonics.

  • Markel Larrea-Undabeitia, Euskal Herriko Unibertsitatea (EHU)

    Markel Larrea-Undabeitia received the bachelor’s degree in physics and electronic
    engineering from the University of the Basque Country (EHU), Leioa, Spain, in 2024, where he is currently pursuing the master’s degree in the European Master for Industry in Microwave Electronics and Photonics (EMIMEP) programme. His main research interests include electromagnetic simulation, magnetrons and high-power electronics.

References

Dassault Systèmes, 2024. CST Studio Suite. Dassault Systèmes, Darmstadt, Germany, version 2024.01.

Feuchtwanger, J., Elxcharria, V., Portilla, J., Jugo, J., Arredondo, I., Badillo, I., Asua, E., Vallis, N., Elorza, M., Alberdi, B., Enparantza, R., Ariz, I., Muñoz, I., Extbese, U., Hernandez, I., 2022. New generation compact linear accelerator for low-current, low-energy multiple applications. Applied Sciences 12 (9). DOI: 10.3390/app12094118

Ginzton, E. L., 1957. Microwave Measurements. International Series in Pure and Applied Physics. McGraw-Hill, New York, NY.

Grespan, F., De Michèle, G., Ramberger, S., Vicentem, M., 2010. Circuital Model for Post Coupler Stabilization in a Drift Tube Linac. Tech. rep., CERN, Geneva.

Jia, X.-Y., Zheng, S.-X., Dec. 2013. Analyzing the effects of post couplers in dtl tuning by the equivalent circuit model. Chinese Physics C 37 (12), 127005. DOI: 10.1088/1674-1137/37/12/127005

Keysight Technologies, 2024. Advanced Design System (ADS). Keysight Technologies, Santa Rosa, CA, USA, version 2024.

Lu, Y., Ratzinger, U., Schlitt, B., Tiede, R., 2007. The general rf tuning for ih-dtl linear accelerators. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 582 (2), 336–344. DOI: [https://doi.org/10.1016/j.nima.2007.08.177](https://doi.org/10.1016/j.nima.2007.08.177)

Ratzinger, U., 2005. H-type linac structures. Tech. rep. DOI: 10.5170/CERN-2005-003.351

Tan, Q., Easton, M., Qi, F., Gan, P., Li, H., Lu, Y., Wang, Z., 05 2018. Multiphysics analysis of a cw ih-dtl for cifnef. DOI: 10.18429/JACoW-IPAC2018-TUPAL052

Wangler, T. P., 2008. RF Linear Accelerators, 2nd Edition. Wiley-VCH, Weinheim, Germany. DOI: 10.1002/9783527623426

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Published

2026-09-01

Issue

No. 47 (2026)

Section

Modelado, Simulación y Optimización

License

Copyright (c) 2026 Beñat González, Iñigo Arredondo, Joaquín Portilla, Markel Larrea, Jorge Feuchtwangera, Andoni Egurrola

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