Øystein Midttun

• Zakariya, Yusuf F.; Midttun, Øystein; Nyberg, Svein Olav Glesaaen & Gjesteland, Thomas (2022). Reforming the Teaching and Learning of Foundational Mathematics Courses: An Investigation into the Status Quo of Teaching, Feedback Delivery, and Assessment in a First-Year Calculus Course. Mathematics. 10(13). doi: 10.3390/math10132164. Full text in Research Archive
• Garoby, Roland; Vergara, Antonio; Danared, Håkan; Alonso, Isabel; Bargalló, Enric & Cheymol, Benjamin [Show all 74 contributors for this article] (2018). The European Spallation Source Design. Physica Scripta. ISSN 0031-8949. 93:129501, p. 1–128. doi: 10.1088/1402-4896/aa9bff. Full text in Research Archive
• Fink, Daniel A; Kalvas, T.; Lettry, J.; Midttun, Øystein & Noll, Daniel (2018). H- extraction systems for CERN’s Linac4 H- ion source. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 904, p. 179–187. doi: 10.1016/j.nima.2018.07.046. Full text in Research Archive
• Midttun, Øystein; Cheymol, B; Miyamoto, R; Thomas, C; Celona, L & Neri, L (2018). Measurements and simulations of the beam extraction from the ESS proton source. AIP Conference Proceedings. ISSN 0094-243X. 2011, p. 1–3. doi: 10.1063/1.5053377. Full text in Research Archive
• Neri, L; Allegra, L; Amato, A; Calabrese, G; Caruso, AC & Castro, G [Show all 25 contributors for this article] (2017). Commissioning of the High Intensity Proton Source Developed at INFN-LNS for the European Spallation Source, Proceedings of the 28th Linear Accelerator Conference. JACoW. ISSN 9783954501694. p. 261–263. doi: 10.18429/JACoW-LINAC2016-MOPLR057. Full text in Research Archive
• Wittmer, W; Gustavsson, PO; Hellström, F; Hulla, G; Bustinduy, I & González, PJ [Show all 20 contributors for this article] (2017). European Spallation Source (ESS) Normal Conducting Front End Status Report, Proceedings of the 28th Linear Accelerator Conference. JACoW. ISSN 9783954501694. p. 274–276. doi: 10.18429/JACoW-LINAC2016-MOPLR062. Full text in Research Archive
• Tuske, O; Daniel-Thomas, P; Denis, JF; Gauthier, Y; Joannem, TJ & Misiara, N [Show all 18 contributors for this article] (2017). ESS Emittance Measurements at INFN CATANIA, Proceedings of the 8th International Particle Accelerator Conference. JACoW. ISSN 9783954501823. p. 123–125. doi: 10.18429/JACoW-IPAC2017-MOPAB023. Full text in Research Archive
• Midttun, Øystein; Levinsen, Yngve Inntjore; Miyamoto, R & Plostinar, DC (2017). Benchmarking of the ESS LEBT in TraceWin and IBSimu, Proceedings of the 8th International Particle Accelerator Conference. JACoW. ISSN 9783954501823. p. 4445–4447. doi: 10.18429/JACoW-IPAC2017-THPVA013. Full text in Research Archive
• Thomas, CA; Shea, TJ; Fils, J; Lussignol, Y; Mattei, P & Midttun, Øystein [Show all 9 contributors for this article] (2017). Development and Commissioning of the Doppler-Shift Unit for the Measurement of the Ion Species Fractions and Beam Energy of the ESS Proton Source, Proceedings of the 8th International Particle Accelerator Conference. JACoW. ISSN 9783954501823. p. 936–938. doi: 10.18429/JACoW-IPAC2017-MOPVA037. Full text in Research Archive
• Valerio-Lizarraga, Cristhian A.; Lallement, Jean-Baptiste; Leon-Monzon, Ildefonso; Lettry, Jacques; Midttun, Øystein & Scrivens, Richard (2014). Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions. Review of Scientific Instruments. ISSN 0034-6748. 85(2). doi: 10.1063/1.4847196. Full text in Research Archive
• Midttun, Øystein; Lettry, Jacques & Scrivens, Richard (2014). Measurements of Linac4 H− ion source beam with a magnetized Einzel lens electron dump. Review of Scientific Instruments. ISSN 0034-6748. 85(2). doi: 10.1063/1.4824814. Full text in Research Archive
• Midttun, Øystein; Kalvas, T.; Kronberger, M.; Lettry, J.; Pereira, H & Scrivens, Richard (2013). A magnetized Einzel lens electron dump for the Linac4 H- ion source. AIP Conference Proceedings. ISSN 0094-243X. 1515, p. 481–490. doi: 10.1063/1.4792819. Full text in Research Archive
• Midttun, Øystein; Kalvas, Taneli; Kronberger, Matthias; Lettry, Jacques; Pereira, Hugo & Schmitzer, Claus [Show all 7 contributors for this article] (2012). A new extraction system for the Linac4 H- ion source. Review of Scientific Instruments. ISSN 0034-6748. 82(2). doi: 10.1063/1.3670344. Full text in Research Archive
• Kronberger, Matthias; Küchler, Detlef; Lettry, Jacques; Midttun, Øystein; O'Neil, Michael & Paoluzzi, Mauro [Show all 7 contributors for this article] (2010). Commissioning of the new H- source for Linac4. Review of Scientific Instruments. ISSN 0034-6748. 81(2). doi: 10.1063/1.3278587. Full text in Research Archive

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• Midttun, Øystein & Gjesteland, Thomas (2025). Portfolio assessment in mathematics promotes active learning. doi: https:/www.sefi.be/publication/mathematics-sig-seminar-2025-proceedings/. Full text in Research Archive Show summary

  This paper introduces a portfolio assessment in mathematics for first-year engineering students that was implemented at the University of Agder (UiA) in 2022. The portfolio consists of two key components, contributing 60% and 40% of the final grade, respectively: 1. Four computer-aided assessment (CAA) tests under supervision, providing immediate feedback on the students’ performance. The students can take each test up to four times, with their best attempt counting toward their final grade. 2. A written assignment, where students apply mathematical concepts from the curriculum to solve an engineering problem. We observe that the students take advantage of multiple test attempts, and that after each test, they organically form groups to discuss the problems with each other. Additionally, the university's math support center sees increased usage during test periods. Biggs et al. (2007) claim that learning is a result of what the student does and that active students foster deep learning. We argue that this assessment design encourages the students to become active in their own learning. The written assignment also helps students to relate mathematical competence to realistic engineering problems, thus making the subject more relevant to their studies. We claim that this competence is equally important for engineers as it is to solve difficult calculus problems by hand.

• Garoby, Roland; Vergara, A.; Danared, H.; Alonso, I.; Bargallo, E. & Cheymol, B. [Show all 73 contributors for this article] (2018). Erratum: The European spallation source design (Physica Scripta (2018) 93 (014001) DOI: 10.1088/1402-4896/aa9bff). Physica Scripta. ISSN 0031-8949. 93(12). doi: 10.1088/1402-4896/aaecea. Full text in Research Archive
• Midttun, Øystein (2014). Improved beam extraction for a negative hydrogen ion source for the LHC injector chain upgrade, Linac4. Universitetet i Oslo. Full text in Research Archive Show summary

  In the scope of an upgrade of the injector chain of CERN’s accelerator complex, a new linear accelerator, Linac4, is under construction. This accelerator will replace the existing 50 MeV proton linac, Linac2. By increasing the beam energy to 160 MeV, Linac4 makes it possible to double the brightness in the PSB, and ultimately increase the luminosity in the LHC. Linac4 will accelerate beams of negative hydrogen (H−) to be injected into the PSB by multi-turn, charge exchange injection. The ion source was initially based on the non-caesiated RF-volume source from DESY. However, the beam extraction from this source could not handle the 45 keV beam energy required by the RFQ. A new beam extraction system has therefore been designed, via IBSimu simulations [1], to extract and transport the H− ion beam respecting the Linac4 requirements. Key features of the extraction system is a tuneable puller voltage to adapt the extraction field to the ion and electron beam currents, and a magnetized Einzel lens to dump the co-extracted electrons with an energy below 10 keV. This new extraction system has been successfully commissioned at the Linac4 ion source test stand, and is currently being used during the commissioning of the components of Linac4. An H− beam peak current of 60 mA has been measured at the test stand, and long-term stable H− beams of 35 mA have been demonstrated. The extraction system is flexible for the connection of different plasma generators, and can also be used to extract a proton beam by inverting the polarities of the high voltage transformers.

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