Håvard Ervik Gjersdal

• Glöggler, L.; Caravita, R.; Auzins, M.; Bergmann, B.; Brusa, R.S. & Burian, P. [Show all 45 contributors for this article] (2022). High-resolution MCP-TimePix3 imaging/timing detector for antimatter physics. Measurement Science and Technology. ISSN 0957-0233. 33(11). doi: 10.1088/1361-6501/ac8221. Full text in Research Archive
• Mariazzi, Sebastiano; Caravita, Ruggero; Zimmermann, Christian; Rienaecker, Benjamin; Camper, Antoine Yves Marie Charles & Belov, Alexander Stepanovich [Show all 27 contributors for this article] (2021). High-yield thermalized positronium at room temperature emitted by morphologically tuned nanochanneled silicon targets. Journal of Physics B: Atomic, Molecular and Optical Physics. ISSN 0953-4075. doi: 10.1088/1361-6455/abf6b6. Full text in Research Archive
• Görgen, Andreas; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Siem, Sunniva; Adli, Erik & Edin, Nina Frederike J [Show all 14 contributors for this article] (2021). The Oslo Cyclotron Laboratory. The European Physical Journal Plus. ISSN 2190-5444. 136, p. 1–13. doi: 10.1140/epjp/s13360-021-01150-3. Full text in Research Archive
• Ibison, M.G.; Welsch, C.P.; Adli, Erik; Gjersdal, Håvard; Christoforo, Mark Greyson & Shea, T. [Show all 8 contributors for this article] (2020). Development of a beam imaging system for the European spallation source tuning dump. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 950. doi: 10.1016/j.nima.2019.162790. Full text in Research Archive
• De La Cour, Naja; Wilborgsson, Mattias; Shea, Thomas; Thomas, Cyrille; Rey, Fabien & Ghatnekar, Sara [Show all 12 contributors for this article] (2018). Implementation of the proton beam instrumentation into the proton beam instrumentation plug. Journal of Physics: Conference Series (JPCS). ISSN 1742-6588. 1021(1), p. 1–5. doi: 10.1088/1742-6596/1021/1/012082. Full text in Research Archive
• Abbott, Brad; Albert, Justin B.; Alberti, Fabrizio A.; Alex, Markus; Alimonti, Gianluca & Alkire, Steven [Show all 53 contributors for this article] (2018). Production and integration of the ATLAS Insertable B-Layer. Journal of Instrumentation (JINST). ISSN 1748-0221. 13(5), p. 1–93. doi: 10.1088/1748-0221/13/05/T05008. Full text in Research Archive
• Frühwirth, R.; Bergauer, T.; Friedl, M; Gjersdal, Håvard; Irmler, C. & Spielauer, T. [Show all 8 contributors for this article] (2013). Analysis of beam test data by global optimization methods. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 732, p. 79–82. doi: 10.1016/j.nima.2013.05.038. Show summary

  Successful track reconstruction in a silicon tracking device depends on the quality of the alignment, on the knowledge of the sensor resolution, and on the knowledge of the amount of material traversed by the particles. We describe algorithms for the concurrent estimation of alignment parameters, sensor resolutions and material thickness in the context of a beam test setup. They are based on a global optimization approach and are designed to work both with and without prior information from a reference telescope. We present results from simulated and real beam test data.

• Gjersdal, Håvard; Frühwirth, Rudolf; Nadler, Moritz & Strandlie, Are (2013). Optimizing track reconstruction by simultaneous estimation of material and resolutions. Journal of Instrumentation (JINST). ISSN 1748-0221. 8. doi: 10.1088/1748-0221/8/01/P01009. Show summary

  We present methods to improve the fit quality of reconstructed particle tracks by simultaneously estimating the amounts of traversed material and the sensor resolutions from tracker data. The performance of the methods has been compared by simulation studies. The methods have also been validated on real test beam data. Results from this validation, showing an improved quality of the track fit, are presented.

• Micelli, A.; Helle, Kristine Indahl; Sandaker, Heidi; Stugu, Bjarne; Barbero, M & Hugging, F [Show all 92 contributors for this article] (2011). 3D-FBK pixel sensors: Recent beam tests results with irradiated devices. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 650(1), p. 150–157. doi: 10.1016/j.nima.2010.12.209. Show summary

  The Pixel Detector is the innermost part of the ATLAS experiment tracking device at the Large Hadron Collider, and plays a key role in the reconstruction of the primary vertices from the collisions and secondary vertices produced by short-lived particles. To cope with the high level of radiation produced during the collider operation, it is planned to add to the present three layers of silicon pixel sensors which constitute the Pixel Detector, an additional layer (Insertable B-Layer, or IBL) of sensors. 3D silicon sensors are one of the technologies which are under study for the IBL. 3D silicon technology is an innovative combination of very-large-scale integration and Micro-Electro-Mechanical-Systems where electrodes are fabricated inside the silicon bulk instead of being implanted on the wafer surfaces. 3D sensors, with electrodes fully or partially penetrating the silicon substrate, are currently fabricated at different processing facilities in Europe and USA. This paper reports on the 2010 June beam test results for irradiated 3D devices produced at FBK (Trento, Italy). The performance of these devices, all bump-bonded with the ATLAS pixel FE-I3 read-out chip, is compared to that observed before irradiation in a previous beam test.

• Grenier, Philippe; Alimonti, G; Barbero, M; Bates, R; Bolle, Erlend & Borri, M [Show all 92 contributors for this article] (2011). Test beam results of 3D silicon pixel sensors for the ATLAS upgrade. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 638(1), p. 33–40. doi: 10.1016/j.nima.2011.01.181. Show summary

  Results on beam tests of 3D silicon pixel sensors aimed at the ATLAS Insertable B-Layer and High Luminosity LHC (HL-LHC) upgrades are presented. Measurements include charge collection, tracking efficiency and charge sharing between pixel cells, as a function of track incident angle, and were performed with and without a 1.6 T magnetic field oriented as the ATLAS inner detector solenoid field. Sensors were bump-bonded to the front-end chip currently used in the ATLAS pixel detector. Full 3D sensors, with electrodes penetrating through the entire wafer thickness and active edge, and double-sided 3D sensors with partially overlapping bias and read-out electrodes were tested and showed comparable performance.

• Gjersdal, Håvard; Bolle, Erlend; Borri, M; Da Via, C; Dorholt, Ole & Fazio, S [Show all 27 contributors for this article] (2011). Tracking efficiency and charge sharing of 3D silicon sensors at different angles in a 1.4T magnetic field. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 636, p. S42–S49. doi: 10.1016/j.nima.2010.04.083.
• Hansson, P; Balbuena, J; Barrera, C; Bolle, Erlend; Borri, M & Boscardin, M [Show all 45 contributors for this article] (2011). 3D silicon pixel sensors: Recent test beam results. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 628(1), p. 216–220. doi: 10.1016/j.nima.2010.06.321.

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• Fackelman, Eric Daniel; Sjobak, Kyrre Ness; Gjersdal, Håvard; Adli, Erik; Thomas, Cyrille & Levinsen, Yngve Inntjore [Show all 7 contributors for this article] (2023). SIMULATION OF THE ESS PROTON BEAM WINDOW SCATTERING. Show summary

  The European Spallation Source produces neutrons used for science by delivering a 5 MW proton beam to a tungsten target. The proton beam parameters must remain within a well-defined range during all phases of facility exploitation. The proton beam parameters are measured and monitored by an instrumentation suite, among which are two beam imaging systems. Parameters such as position and beam current density can be calculated from the images, supporting beam tuning and operation. However, one of the two systems may be affected by beam scattering. In this paper, we will focus on modelling the impact of the scattering on the beam on target distribution. The modelling process, involving simulation codes such as Geant4 and two-dimensional convolution in Matlab, is described. Initially, Geant4 simulates a scattered pencil beam. The resulting distribution is fitted and can be used similarly to an instrument response in image processing to model any possible beam distribution. Finally, we discuss the results of the scattered beam imaging model, showing the range of applications of the model and the impact of scattering on the beam parameters.

• Adli, Erik; Gjersdal, Håvard; Sjobak, Kyrre Ness; Christoforo, Mark Greyson; Fackelman, Eric Daniel & Røhne, Ole Myren [Show all 17 contributors for this article] (2022). PROGRESS OF THE ESS PROTON BEAM IMAGING SYSTEMS. Show summary

  The ESS Target Proton Beam Imaging Systems has the objective to image the 5 MW ESS proton beam as it enters the spallation target. The imaging systems has to operate in a harsh radiation environment, leading to a number of challenges : development of radiation hard photon sources, long and aperture-restricted optical paths and fast electronics required to provide rapid information in case of beam anoma- lies. This paper outlines how main challenges of the imaging systems have been addressed, and the status of deployment as ESS gets closer to beam.

• Gjersdal, Håvard (2014). Test beam track reconstruction and analysis of ATLAS 3D pixel detectors. Det matematisk naturvitenskapelige fakultetet.

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