The Large Hadron Collider (LHC) at CERN in Geneva is the largest particle accelerator in the world. It collides protons at a centre-of-mass energy of 13.6 TeV, probing physics at the highest energy scales ever achieved in collider experiments. The biggest success of the LHC so far was the discovery of the Higgs boson by the ATLAS and CMS experiments in 2012, an elementary particle whose study is crucial for the understanding of the origin of elementary particle masses. Since 2022, the LHC has resumed operations at even higher collision rates, which provides plenty of opportunities to improve precision measurements of elementary particles as well as to extend the reach of searches for new particles beyond the standard model (SM) of particle physics.
The experimental particle physics group at UGent is involved in data analysis with the Compact Muon Solenoid (CMS) detector, covering a wide range of topics including precision measurements of SM processes, new physics searches, and calibration of detectors and reconstruction methods. All data analysis projects make use of the Python programming language and employ specific high-energy-physics software packages. Some basic knowledge of Python (or another programming language) is required, while more advanced programming skills will be taught during the project. After the completion of one of the data analysis projects, the students will have:
Gained insight in the design, technology, and software of one of the most advanced particle detectors in the world;
Improved their programming skills in the field of data analysis and visualization, possibly including machine-learning techniques;
Got experience in taking part in an international environment at the frontier of fundamental research.
We offer the possibility of staying at CERN in Geneva/Switzerland for a summer project to all master students that join the CMS analysis group.
Toponium in four-top production: Searching for bound states at the high-energy frontier
The top quark is the only quark that typically decays before it can hadronize into bound states. However, recent CMS and ATLAS results have identified an excess near the production threshold, providing the first evidence for toponium bound states). While four-top quark production has finally been observed at the LHC, it remains a rare and complex process. Currently, we lack a detailed understanding of how toponium formation manifests within these four-top events, which could serve as a unique laboratory for testing the Standard Model at extreme scales. We will investigate the signature of toponium within the four-top quark production process, specifically targeting multilepton final states (events with two same-sign, three, or four leptons). These channels offer a high signal-to-background ratio, making them the “golden channels” for four-top quark studies. You will analyze CMS Run 3 data to search for the toponium threshold enhancement while accounting for the complex combinatorial background of multiple top decays. This involves using Monte Carlo simulations to model spin correlations and developing dedicated selection criteria to isolate the toponium component from the four-top continuum.
Figure: (left) Graphical representation of a recorded candidate event with four-top quark pair production at CMS. (right) Observation of a pseudoscalar excess near the top quark pair production threshold at CMS.
Skills obtained: advanced data analysis in high-energy physics, proficiency Python-based analysis frameworks, expertise in multilepton event reconstruction, statistical interpretation of LHC data, active engagement within the international CMS collaboration.
Promoter: Prof. Didar Dobur Supervisors: Dr. Kirill Skovpen, Amber Cauwels Contact | Topic 50076 on PLATO
Exploring a unique and brand new dataset: forward physics in proton–oxygen collisions
In 2025, the Large Hadron Collider (LHC) performed a unique series of light-ion collision runs, including proton–oxygen (pO), oxygen–oxygen (OO), and neon–neon (NeNe) collisions. These datasets provide a rare opportunity to study hadronic interactions involving light nuclei at unprecedented energies. Such measurements are not only relevant for collider physics, but also play a crucial role in improving hadronic interaction models used to interpret extensive air showers produced by high-energy cosmic rays in the Earth’s atmosphere. The CMS experiment is particularly well suited for these studies thanks to a set of dedicated forward detectors such as the Forward Shower Counters (FSC), the Zero Degree Calorimeter (ZDC), and the Precision Proton Spectrometer (PPS). Few analyses are able to use these detectors, but thanks to the special configuration of the LHC during data-taking, these important systems were able to be installed. In this master’s thesis project, the student will focus on the analysis of proton–oxygen collision data recorded by CMS. The primary goal will be to study data from the forward detectors to study specific event classes, such as diffractive interactions or nuclear dissociation of the oxygen ion. This would allow the student to investigate how forward activity correlates with central particle production and to compare the measurements with state-of-the-art Monte Carlo models. The thesis will involve modern data analysis techniques used in experimental particle physics, including event selection, efficiency corrections, systematic uncertainty evaluation, and comparison with Monte Carlo simulations. The project offers hands-on experience with real LHC data and special detectors that few people can use for their analysis. This thesis will contribute to an active and brand new physics program within the CMS Collaboration, with high relevance for both collider and cosmic-ray physics communities.
Figure 1: This figure shows the special detectors installed within 220m from CMS that are the main focus of this project with the PPS in light blue, FSC in dark blue and the ZDC in green.Figure 2: Left: FSC during test beam. This detector was specifically installed for the Oxygen runs. Right: An overview of cosmic ray results. As can be seen in the red highlighted area, analyses using different methods and different hadronic models get vastly different results, while we expect them to agree. Results of this master thesis can help us greatly improve this picture in the future.
Figure 1: This figure shows the special detectors installed within 220m from CMS that are the main focus of this project with the PPS in light blue, FSC in dark blue and the ZDC in green. Figure 2: Left: FSC during test beam. This detector was specifically installed for the Oxygen runs. Right: An overview of cosmic ray results. As can be seen in the red highlighted area, analyses using different methods and different hadronic models get vastly different results, while we expect them to agree. Results of this master thesis can help us greatly improve this picture in the future.
Promoter: Prof. Didar Dobur Supervisors: David Marckx Contact | Topic 50077 on PLATO
Top quarks as proton probes: Enhancing PDF determinations with differential cross section measurements
What’s in a name, Julliet once asked. In case of the LHC, it is large hadron collider. This refers to the protons it collides most of the time. One typically thinks of protons as 2 up and 1 down quark, but in reality the proton is more like a sea of many quarks and gluons (collectively called partons) popping up and disappearing continuously. This sea is described with parton density functions or PDFs: distributions of each type of parton inside the proton as a function of fraction of the total proton momentum they carry. They are essential ingredients to predict cross sections in proton collisions, but unfortunately, these PDFs are so far not calculable from first principles. Instead, they have to be determined from experiments. The LHC provides a large dataset of top quarks, which can provide valuable information about the pdfs at high energies.
In this project we will study the production of single top quarks, which is interesting for PDF determinations. We will focus on differential measurements of kinematic quantities in single top quark production, since these are particularly sensitive to the momentum of the initial state partons. The main goal of this project is to study different distributions and how they can contribute to global PDF fits by running the PDF fitting tools ourselves. We will identify the most promising candidates for differential measurements and implement them for data analysis in an ongoing CMS measurement.
Figure: Cross section measurements used to determine the proton PDFs by the NNPDF Collaboration as a function of momentum fraction of the proton and collision energy. From: http://nnpdf.mi.infn.it.
Promoter: Prof. Didar Dobur Supervisors: Maarten de Coen, Dr. Jan van der Linden Contact | Topic 50078 on PLATO
Boosted-Top-Tagging with GloParT: A new window to four-top production
The top quark is the heaviest known elementary particle with a mass of about 173 GeV, consequentially the simultaneous production of four top quarks (tt̄tt̄) is an extremely rare process to occur at the LHC. Still, the UGent CMS analysis group achieved the first observation of tt̄tt̄ production by analysing events with two same-sign, three, or four electrons and/or muons (so-called “multilepton” events) [Phys. Lett. B 847 (2023) 138290]. In this project, we will build upon this great success and attempt to extend the phase-space in which we measure tt̄tt̄. For this we will target events in which the top quarks can be boosted, which means that the decay products are closely collimated and produce a single particle jet, instead of 3 resolved jets. We will explore whether this approach is promising and if it can be used as a complementary approach to the other measurements of tt̄tt̄. This project includes a detailed study of how we can exploit the state-of-the-art jet flavour tagging machine learning algorithms, provided by the CMS experiment. The most recent developed boosted-jet-tagger (Global Particle transformer), aims to tag hadronic and leptonic finals states from the decays of top quarks, W, Z, and H bosons whose decay products are fully clustered into a large-radius jet. Exactly what we need for this analysis, let’s find out if it works!
Figures displaying a boosted top quark (left) and a resolved top quark (right).
Promoter: Prof. Didar Dobur Supervisors: Amber Cauwels, Dr. Jan van der Linden Contact | Topic 50079 on PLATO
How shiny are top quarks: Measuring the interplay between the heaviest particle and the massless photon with the highest-energy LHC data
The production of top quark-antiquark pairs (tt̄) is one of the most common processes at the LHC. Top quark production is so abundant that the LHC is even nicknamed “top quark factory”, and tt̄ measurements are among the most precise cross section measurements ever performed by the CMS Collaboration. To study the electroweak interactions of the top quark, measurements of the production in association with a vector boson are a crucial tool. In this project, the CMS data collected in 2024 will be analysed to identify tt̄ production events that contain one or more additional photons (tt̄+γ). This will include tackling the challenge of accurately reconstructing the tt̄ system in the presence of a photon. The goal is to perform the first cross section measurement of tt̄+γ and tt̄+γγ production at a center-of-mass energy of 13.6 TeV, and to constrain modifications introduced by physics beyond the standard model to the coupling between photons and top quarks.
Fig.1: Feynman diagrams for tt̄+γ production, where the photon originates either from a top quark (left), an incoming quark (middle), or a charged lepton in the top quark decay (right). From: JHEP 05 (2022) 091.
Fig. 2: The distribution of the photon transverse momentum in tt̄+γ events, shown for standard model (SM) couplings between photon and top quark (yellow filled area) and for different scenarios with modified couplings induced by new-physics at a higher energy scale (red and blue lines). From: JHEP 05 (2022) 091.
Promoter: Prof. Didar Dobur Supervisors: Jules Vandenbroeck, Dr. Beatriz Ribeiro Lopes Contact | Topic 55080 on PLATO
Larger jets catch more Higgs bosons: study of the Higgs-charm coupling using large radius jets and Data Scouting techniques
A central part of the LHC physics program is the measurement of the Higgs boson couplings to other particles. Higgs couplings to second generation quarks (e.g., the charm quark) have not yet been experimentally confirmed. The associated production of a Higgs boson with a Z or W boson (collectively VH) provides the most sensitive results to the Higgs-charm coupling so far. While final states with the vector boson decaying to leptons have already been studied, the hadronic final state remains unexplored at the CMS experiment. The main challenge of this final state is the large background from multi-jet production events. Additionally, the standard online selection filters only keep events with very large momentum jets, rejecting most of the potential signal candidates, due to constraints on the maximum event rate. The project will focus on exploring the potential of “Data Scouting” to measure this process. The Data Scouting enables the storage of interesting proton-proton collision events that would otherwise be rejected by the normal online selection filters, for example events with lower jet momentum. The signature of such events consists of two back-to-back jets of particles covering a wide solid angle (large radius jets), each containing the decay products of the Higgs or the vector boson. Preliminary results using a fraction of the data collected during Run 3 will be extracted in this project.
Figure: (left) Couplings of the SM particles to the Higgs boson as a function of particle mass, with a circle indicating the expected coupling of the charm quark, which has yet to be observed. (right) Schematic diagram illustrating the topology of the VH fully hadronic events to be studied.
Promoter: Prof. Didar Dobur Supervisors: David Kavtaradze, Dr. Beatriz Ribeiro Lopes Contact | Topic 50081 on PLATO
Top future: Study of the top quark reconstruction at future-collider experiments at CERN
The study of the properties of the heaviest elementary particle in the Standard Model, the top quark, is a central objective of current experiments at the CERN Large Hadron Collider. Future collider projects aim to significantly improve the precision of these measurements and enhance the sensitivity to possible effects of physics beyond the Standard Model. In this context, the Future Circular Collider (FCC), a proposed next-generation collider at CERN, offers a particularly clean environment through high-energy electron–positron collisions. The goal of this project is to perform an Effective Field Theory (EFT) [1] study of the coupling of the top quark to the Z boson and the photon [2] at the FCC. Such interactions are sensitive probes of new physics and can reveal subtle deviations from Standard Model predictions. To achieve this, the student will investigate how EFT operators modify top-quark pair production in electron–positron collisions. A key component of the project will be the development of a new analysis methodology tailored to the FCC environment. The student will design techniques that improve sensitivity to EFT effects, including top-quark reconstruction optimized for FCC conditions. The student will generate and analyze simulated datasets [3], reconstruct the relevant physics observables, and evaluate the sensitivity of the FCC to anomalous top Z/photon couplings. The analysis will be performed using the ROOT data analysis framework with Python-based tools for data processing, visualization, and statistical interpretation. This work will contribute to assessing the potential of the FCC to probe new physicseffects.
Figure: (left) Measured differential cross section of top quark pair production with a photon at ATLAS. (right) Representative Feynman diagram with the top quark pair production at FCC-ee.
Skills obtained: advanced data analysis in high-energy physics, proficiency Python-based analysis frameworks, expertise in event reconstruction and analysis interpretation.
Promoter: Prof. Didar Dobur Supervisors: Jules Vandenbroeck, Dr. Kirill Skovpen Contact | Topic 50082 on PLATO
Heavy neutrino hunt: Optimizing the Search for Heavy Neutral Leptons in the Minimal Left–Right Symmetric Model
Neutrinos are weakly interacting particles whose masses are not explained in the Standard Model of particle physics. A model that embeds the neutrino masses is the minimal Left–Right Symmetric Model (LRSM). In this model, parity symmetry is restored at high energies by extending the gauge group of the SM and introducing right-handed counterparts to the left-handed weak interactions. Consequently, new gauge bosons such as the heavy right-handed (WR) boson and heavy right-handed neutrinos appear in the spectrum. At the Large Hadron Collider (LHC), these particles could be produced through processes involving the heavy WR boson. A particularly interesting regime arises when the HNL is significantly lighter than the WR, wherethe HNL can be produced with a large Lorentz boost and acquire a macroscopic lifetime. As a result, it may travel a measurable distance before decaying inside the detector, giving rise to displaced signatures. Because the HNL is highly boosted, its decay products can be collimated, leading to a characteristic boosted jet containing a displaced lepton. The goal of this thesis is to study and optimize the search for heavy neutral leptons in the displaced regime within the minimal LRSM framework. To achieve this, reconstruction strategies will be developed to identifydisplaced leptons within boosted jets in simulated LHC events. Attention will be given to optimizing the event selection to maximize the sensitivity to the signal. In addition, the project will investigate data-driven techniques for estimating the relevant backgrounds, especially processes that can produce displaced or non-prompt leptons and therefore mimic the signal signature.
Figure: Representative Feynman diagram with the production of a WR boson and its decay to a heavy neutrino.
Figure: (left) Schematic representation of the heavy neutrino event in the detector. (right) LHC sensitivity to the KS sensitivity to the KS signal in the M(WR) —m(N). Extracted from Nemevšek et al., Phys. Rev. D 97, 115018 (2018).
Promoter: Prof. Didar Dobur Supervisor: Adina Maria Tomaru, Dr. Kirill Skovpen Contact | Topic 50083 on PLATO
SHiP: Searching for the Hidden Universe
The SPS is the second largest accelerator at CERN, beyond feeding the LHC, it will be used to conduct high intensity searches for new physics unattainable at LHC leveraging a beam dump configuration at the Search for Hidden Particles (SHiP) experiment. Starting 2032, it will cover searches for extremely rare events such as interactions of dark sector particles mediators, the origin of neutrinos’ mass, the reasons for baryonic asymmetry as well as signs of extra symmetries of nature lying beyond the reach of any other facility. SHiP will also allow the detailed study of the seldom observed tau neutrino by increasing the available events from up to 26 today to several 10 000s.
The UGent experimental particle physics group is involved in the development and prototyping of innovative new detectors to enable the observation of new physics and tau neutrinos at SHiP, in addition with studies of both signal andbackground needed to ensure the experiment covers its full program, both sides of the program work together to optimise overall experimental performance. The detector work is done in a laboratory using a variety of detector technologies such as photosensors, scintillators or gaseous detectors. Analyses are conducted in either Python or C++ with some basic knowledge of programming required for analysis-focused projects. The completion of a detector project within SHiP will provide the students with:
Experience into advanced particle detection techniques
Expertise with fast readout electronics and data acquisition
Contributions to future detector systems within an international collaboration
The completion of an analysis project within SHiP will benefit the students through:
Insights into new physics modelling and searches
Improved programming skills for data analysis, visualisation and simulation, with possibly machine learning components
Contributions to advanced analysis techniques in future experiments within an international collaboration
SHARP: Development of the SHiP SciFi High Accuracy Reconstruction Planes
The SHiP experiment at CERN will be the flagship experiment for high intensity searches of new physics such as dark matter, portals to hidden sector physics and extra neutrinos. The experiment relies for the reconstruction of neutral final states on a specialised and original calorimeter detector design: the SplitCal. This design comprises a sampling calorimeter which includes a longitudinal split as well as 2-3 high precision layers which allow for the vertexing of neutral final states. These high precision layers are to rely on a novel technology developed in Ghent: Scintillating fibre High Accuracy Reconstruction Planes (SHARP). These detector planes are based on scintillating fibres and readout by silicon photomultipliers (SiPMs). They allow for excellent position and timing resolution to be achieved in a calorimeter setup, allowing the SplitCal to achieve unmatched vertexing resolution among calorimeters. The development of the SHARP technology with an evaluation of precise achieved performance, optimisation of the detector and prototyping. The project will include simulation and detector building as well as analysis of the produced simulated data to determine precise physics reach in different Beyond the Standard Model scenarios. The built prototype is to be evaluated in a test beam at an accelerator facility and the ensuing data is to be analysed to inform simulation studies. Progress and results are to be presented on a regular basis to the broader SHiP Collaboration.
Figure: (left) Illustration of the new particle decay and the corresponding experimental signature in the SHiP calorimeter. (right) Proposed detector design for the SHiP calorimeter high-precision layers (HPL) using scintillator fibers.
Skills obtained: High intensity and energy physics, particle detector development, simulation tools, data acquisition, data analysis, work and engagement in an international research collaboration.
Promoter: Prof. Didar Dobur Supervisor: Dr. Matei Climescu Contact | Topic 50084 on PLATO
Sailing for new physics: Search for feebly interacting particles with the SHiP experiment at CERN
Numerous particle physics experiments around the world have been extensively searching for new particles to construct a more complete theory of nature. The SHiP experiment at CERN aims at filling an important gap in the current phase space of sensitivities probed by various experiments by employing a high-intensity Super Proton Synchrotron (SPS) beam-on-the-target collisions and a large decay volume to search for the decays of new light particles (N), such as heavy neutral leptons, predicted in many beyond the standard model theories. A comprehensive characterization of the dominant production and decay channels of N particles produced on the target is needed to assess the sensitivity of the SHiP experiment. The project will explore the simulation methods to generate N events, calculating expected cross sections and potential backgrounds. A simulation study will employ the hard-level process generation events as well as the fully simulated events inside of the SHiP detector to account for various detector-level effects.
Figure: (left) A schematic illustration of a process with the production of heavy neutral lepton (N) in the target area and its subsequent decay in the hidden sector decay vessel of the SHiP experiment. (right) The expected sensitivity of SHiP to the mass and interaction couplings of N, compared to the latest CMS results at the Large Hadron Collider.
Skills obtained: physics analysis of the CERN SPS data, reconstruction techniques, identification of displaced vertices, new physics models, simulation tools, data analysis methods
Promoter: Prof. Didar Dobur Supervisor: Dr. Kirill Skovpen, Dr. Matei Climescu Contact | Topic 50085 on PLATO
Quenching the noise: Study of electromagnetic background at SHiP
The SHiP experiment at CERN will be the new flagship particle physics experiment for high-intensity accelerator searches for new physics, such as dark matter, portals to hidden sectors and extra neutrinos. The experiment relies, to ensure that all observations are genuine, on having no irreducible background. It employs to this effect a variety of filtering components and background taggers. These components however induce electromagnetic background through rare interactions of surviving muons. Evaluate the intensity of the electromagnetic background in simulation, determine its effects on new physics searches by ascertaining the effects on the SHiP detector systems, whether it mimics signals and determine effective techniques to eliminate or compensate for it. Experimental checks of simulated data should also be performed using test beam data. The project will be led in close coordination with the SHiPbackground taskforce with regular updates as to progress being expected.
Figure: (left) Schematic representation of the background events in the SHiP detectors. (right) Estimated background rate in tracking detector stations of SHiP.
Skills obtained: Physics at high intensity and energy, physics of rare processes, data analysis methods, simulation tools, work and engagement in an international research collaboration.
Promoter: Prof. Didar Dobur Supervisor: Dr. Matei Climescu Contact | Topic 50086 on PLATO
Plastic-fantastic: Calorimeter design using plastic scintillators for the SHiP experiment at CERN
Sampling calorimeters are used in many high-energy physics experiments for the energy measurement. In such calorimeters, plastic scintillators often represent the active material to measure the energy that is released in electromagnetic and hadronic showers created by the incoming particle in the absorber layers. A new sampling calorimeter is currently built at UGent for the Scattering and Neutrino Detector (SND), which is part of the SHiP experiment at CERN. The main building blocks of this calorimeter are plastic scintillator tiles with 2D optical fiber readout based on silicon photomultipliers (SiPMs). Multiple test beam studies for the sampling calorimeter are foreseen at CERN to measure the energy and time resolution of this new detector. For this purpose, a small-scale prototype will be built and commissioned at UGent using plastic scintillator tiles, optical fibers, and SiPMs. A student will be involved in the conceptualization process of the calorimeter design and commissioning of a cosmic muon test bench to measure its main characteristics. This work will be also complemented by simulation studies to derive the expected performance of the calorimeter and to further optimize its design towards the final implementation and integration in SHiP.
Figure: (left) Simulation of an interaction of an energetic electron in a prototype of the sampling calorimeter for SND@SHiP. (right) Plastic scintillator tiles with optical fiber grooves manufactured at UGent.
Skills obtained: particle detector development, data acquisition, simulation tools, data analysis, work in international research collaboration
Promoter: Prof. Didar Dobur Supervisor: Dr. Kirill Skovpen Contact | Topic 50087 on PLATO
High precision calorimetry: SHiP@CERN Calorimeter High-Precision-Layer module development
The SHiP experiment at CERN will be the new flagship particle physics experiment for high-intensity accelerator searches for new physics, such as dark matter, portals to hidden sectors and extra neutrinos. The experiment relies for its particle reconstruction on high precision detector layers located in the calorimeter. These detectors are encapsulated into modules which need to accommodate thousands of ~1mm diameter scintillating optical fibres. The development of a module design and prototyping for usage together with the detector prototype accounting for available manufacturing technologies, cooling requirements and cost. The modules will be built of metal, preferably something light and sturdy such as aluminium and the capability of the module to mechanically support the rest of the detector frame will be studied. The module integration and performance will be simulated in SolidWorks and/or ANSYS whereas the prototype will be manufactured and tested in coordination with the physics team.
Figure: (left) Preliminary design of the High-Precision Layers of the SHiP calorimeter. (right) Scintillating fibers.
Promoter: Prof. Didar Dobur Supervisor: Dr. Matei Climescu Contact | Topic 50089 on PLATO
Detector R&D: Developing the Future of Particle Detection
Advances in experimental physics are driven by the ability to see what was previously invisible. To push the boundaries of the known universe, we must continuously develop new technologies that offer higher precision, faster timing, and greater resilience to radiation. While many of these innovations eventually find their home in large-scale experiments, the core of Detector R&D (Research and Development) happens in the laboratory, where we explore the fundamental limits of sensor technology independent of any single collaboration.
The experimental particle physics group at UGent is a leader in this creative “hardware-to-discovery” process. We work with a diverse portfolio of technologies that form the backbone of modern detection:
Gaseous Detectors (GEMs & RPCs): We develop high-rate Resistive Plate Chambers (RPCs) and Gas Electron Multipliers (GEMs) that can handle the extreme particle fluxes of future colliders.
Scintillators & SiPMs: We innovate with scintillating materials paired with Silicon Photomultipliers (SiPMs) to achieve ultra-fast timing and high-granularity calorimetry.
While our research is often motivated by and applied within the CMS and SHiP experiments at CERN, our R&D program extends beyond these collaborations. We investigate novel materials, optimize readout electronics, and perform characterization studies that contribute to the broader field of instrumentation
A project in Detector R&D will provide the student with:
Technical mastery of laboratory instrumentation, including cleanroom assembly of GEM/RPC prototypes and high-precision characterization of SiPMs;
Experience in the full R&D cycle, from hardware prototyping and test-beam preparation at CERN to the final performance analysis;
Insight into detector physics, learning how to model complex signals and background effects using simulation tools like Geant4 or Garfield++;
A unique skill set that bridges the gap between hardware engineering and high-energy physics analysis, valuable in both academia and high-tech industry.
Looking through the glass: Glass RPC muon telescope for non-destructive material imaging
Non-destructive imaging techniques capable of probing the internal structure of dense or shielded objects are important in fields such as security, archeological studies and materials inspection. Conventional imaging methods (e.g., X-rays) can be limited when large volumes or very dense materials are involved. Cosmic muon tomography provides an alternative approach by exploiting naturally occurring atmospheric muons, which are highly penetrating and can traverse thick materials. The project aims to develop and study Glass Resistive Plate Chambers (GRPCs) operated in sealed mode for muon-based imaging. Several GRPC modules will be assembled into a telescope to detect cosmic muons and reconstruct their trajectories. After studying the detector performance and developing an algorithm to reconstruct muon tracks across multiple layers, the system will be used for muon tomography. The goal is to reconstruct the shape and density of objects placed inside the telescope in order to evaluate the imaging capabilities of GRPC-based systems for non-destructive material inspection.
Figure: Application of the muon tomography fo (left) empty cavity search in pyramids and (right) container screeing at the boarder control.
Skills obtained: design and operation of particle detectors, data acquisition and analysis, track reconstruction and algorithm development, work and engagement in an international research collaboration.
Promoter: Prof. Didar Dobur Supervisor: Karam Kaspar Contact | Topic 50090 on PLATO
Fast analog: High-speed analog front-end design for particle detectors
The initial stage of any particle physics experiment is the analog front-end. Whether detecting scintillation light with Silicon Photomultipliers (SiPMs) or ionization tracks in gaseous detectors, the raw signals are often too weak or too fast for direct digitization. Developing a custom analog chain is critical to suppress electronic noise and prevent signal pile-up in high-luminosity environments, directly determining the detector’s energy and spatial resolution. The student will design and prototype a high-performance analog readout board. The project focuses on the development of a low-noise pre-amplifier and a pulse-shaping stage tailored for the specific discharge characteristics of both SiPMs and gaseous sensors. The performance will be validated through LTSpice simulations and lab measurements using cosmic muons.
Figure: (left) Fast signals produced on a SiPM by incoming photons. (right) An example of the analog circuitry for detector signal amplification and shaping.
Skills obtained: analog circuit simulation (SPICE), PCB layout design for high-frequency signals, signal integrity analysis, and experimental characterization of particle detectors
References:
H. Spieler, Semiconductor Detector Systems, Oxford University Press, 2005.
G. F. Knoll, Radiation Detection and Measurement, 4th Edition, John Wiley & Sons, 2010.
Promoter: Prof. Didar Dobur Supervisor: Dr. Kirill Skovpen Contact | Topic 50091 on PLATO
Fast digital: FPGA-based data acquisition and time measurement
Converting ultra-fast analog pulses in high-energy particle experiments into precise digital timestamps requires sophisticated digital logic. Field Programmable Gate Arrays (FPGAs) are the industry standard for this task, but they require highly optimized firmware to achieve picosecond-level precision without massive power consumption. This project is devoted to the digital side of the readout chain. The student will implement a Time-to-Digital Converter (TDC) on a GateMate FPGA. The work involves developing the logic for high-speed hit detection, data buffering, and transmission protocols. The project will specifically explore the unique architecture of the GateMate FPGA to push the limits of timing resolution for high-rate particle detection.
Figure: (left) Evaluation board for GateMate FPGA developments. (right) Schematic diagram of the time measurement using the clock signal on the FPGA.
Skills obtained: FPGA programming (HDL), implementation of TDCs (tapped delay lines), high-speed digital communication, and hardware-software interfacing for data acquisition (DAQ)
References:
U. Meyer-Baese, Digital Signal Processing with Field Programmable Gate Arrays, 4th Edition, Springer, 2014.
M. J. Kwiatkowski and R. Szplet, “Low-Resource Time-to-Digital Converters for Field Programmable Gate Arrays: A Review,” Electronics, vol. 13, no. 17, 2024.
Promoter: Prof. Didar Dobur Supervisor: Dr. Kirill Skovpen Contact | Topic 50092 on PLATO
Mighty holes: Design of micropattern gaseous detectors
Gaseous detectors are essential for large-scale tracking and muon systems in high-energy physics due to their cost-effectiveness and high spatial resolution. However, traditional designs like Multi-Wire Proportional Chambers (MWPCs) are limited by high occupancy and aging effects under extreme radiation environments. Micro-Pattern Gaseous Detectors (MPGDs), such as ThickGEMs and Micromegas, have emerged as the standard solution to overcome these bottlenecks. The challenge lies in optimizing the detector geometry—such as hole pitch, amplification gap, and induction fields—to ensure high gain, stability against discharges, and excellent timing properties. This project focuses on the design and optimization of ThickGEM and Micromegas detectors through comprehensive simulation studies. Using tools like Garfield++ and Magboltz, the student will model electron transport and gas amplification to determine the ideal geometric parameters. These findings will serve as the baseline for developing a detector prototype. The project aims to bridge the gap between theoretical modeling and physical hardware, to provide a detailed production strategy for a functional MPGD prototype.
Figure: (left) Simulation of an avalanche created by an electron in the gaseous amplification region in a GEM foil. (right) A macro photograph of a fabricated GEM foil.
Skills obtained: simulation of particle-matter interactions, MPGD hardware design, specialized software proficiency (Garfield++/GEANT4), R&D methodology, experience in high-energy physics instrumentation
References:
M. Titov and L. Ropelewski, Micro-pattern gaseous detector technologies and applications, Modern Physics Letters A 28 (2013) 1330002, https://doi.org/10.1142/S0217732313400221.
Y. Giomataris et al., MICROMEGAS: a high-granularity position-sensitive gaseous detector for high particle-flux environments, Nucl. Instrum. Meth. A 376 (1996) 29, https://doi.org/10.1016/0168-9002(96)00175-1.
Promoter: Prof. Didar Dobur Supervisor: Dr. Kirill Skovpen Contact | Topic 50093 on PLATO
Cosmic dew: Measuring soil moisture with cosmic rays
The scarcity of water resources is naturally connected to the process of climate change. The project explores the feasibility of measuring the volumetric water content in soil through application of the innovative technology of cosmic-ray neutron sensing (CRNS) detectors. Cosmic-ray thermal neutron fluxes, which are inversely correlated with the presence of water above the ground, can be measured using radiation detectors capable of thermal neutron identification. A prototype of the soil moisture sensor will be developed to measure cosmic-ray neutrons above the ground with wireless data transmission and powered by solar panels. This probe will be built using plastic scintillators and lithium-6-enriched materials for neutron identification. The performance of the prototype will be compared to the state-of-art sensor that is currently collecting data at Proeftuin campus. The study will also make use of various simulation techniques to model the atmospheric flux of neutrons, their interactions in the soil, and detection efficiencies. The neutron fluxes will be studied as a function of altitude, soil type, and environmental conditions.
Figure: (left) Illustration of the main concept of probing soil moisture through detection of cosmic-ray neutrons. A fraction of thermal neutrons is absorbed by the water present in the soil, while the rest is detected by the cosmic ray neutron sensor (CRNS). (right) A CRNS probe installed at Proeftuin campus.
Skills obtained: particle detector development, design of readout electronics, application of IoT technology, simulation tools, data analysis
References:
S. Gianessi et al., Testing a novel sensor design to jointly measure cosmic-ray neutrons, muons and gamma rays for non-invasive soil moisture estimation, Geosci. Instrum. Method. Data Syst. 13 (2024) 9, https://doi.org/10.5194/gi-13-9-2024.
L. Stevanato et al., A Novel Cosmic-Ray Neutron Sensor for Soil Moisture Estimation over Large Areas, Agriculture. 2019; 9(9):202, https://doi.org/10.3390/agriculture9090202.
Promoter: Prof. Didar Dobur Supervisor: Dr. Kirill Skovpen Contact | Topic 50094 on PLATO
Bike collider: Accelerating particles by cycling
The infinitesimally small scales of particle physics are intrinsically linked to the natural phenomena occurring at vast distances in our universe. In order to recreate the conditions that took place at the very early stages of the Big Bang, the particles are accelerated to the speeds close to that of the light before they collide. High-energy particle collisions are at the heart of the Large Hadron Collider that is currently operating at CERN. A rich physics program and diverse technological challenges of such a major international project require an innovative approach to communicate scientific results and engage the general publiccommunity in fundamental research for the best integration of science in society. Science communication and outreach pave the way for laying out educational foundations and support from society for future research. The project illustrates the concept of a collider by implementing a visual acceleration of particles in the collider rings through actual cycling, for the particle beams to eventually collide and create new massive particles. Two static bikes are placed in front of each other to emulate the acceleration of the two beams in the collider rings. In order to be able to reach high energies, both participants will have to correlate their cycling speeds for the beams to meet at one point and at a given energy, touching upon sociological aspects of working in a tandem. The dynamos of the bikes will be connected to a series of LEDs to indicate the current position of particles in the rings. Electronics for the control system will use low energy consumption modules, such as Arduino. Additionally, a dedicated software running on a RaspberryPi device can be used to project a visualization of the collider on the wall. The installation will be used as part of science fairs and exhibitions in Belgium and at CERN. The project naturally finds its place at the intersection of particle physics, engineering, fitness and exercising, sustainability aspects, science communication, and education.
Figure: (left) A conceptual visualization of a particle collider controlled by two cycling participants. (right) A schematic representation of colliding beams at the Large Hadron Collider at CERN.
Promoter: Prof. Didar Dobur Supervisor: Dr. Kirill Skovpen Contact | Topic 50097 on PLATO
Gravitational waves data analysis topics
Overcoming observational science challenges of the Einstein Telescope
The Einstein Telescope (ET) will have more than ten times the sensitivity of the current LIGO-Virgo-KAGRA detector network. As a result we will see merging black holes which are much farther away (out to the edge of the known universe), as well as heavier black holes, (thousands of times the mass of the sun), which merge at lower frequencies made accessible by the ET. Typical signals observed by the ET will also be much longer – minutes to hours or even longer (as opposed to a fraction of a second for the current detector network). This is exciting. However it brings forth several computational challenges. How will we carry out data analysis for such long signals? Signals will certainly overlap – how will we disentangle them from each other? The ET Collaboration Observational Science Board was recently established to answer such questions.
In this project, you will develop prospective techniques for ET data analysis. In particular you will attempt to bring together traditional methods such as Bayesian Markov Chain Monte Carlo (MCMC) together with more recently developed Convolutional Neural Network (CNN) algorithms with the goal of efficiently analyzing multiple signals present simultaneously in the data.
The work involved will be computational. You will learn about statistical methods and get exposed to state-of-the-art data analysis techniques. You will be involved in a large international collaboration in the forefront field of GW science.
Promoter: Prof. Archisman Ghosh Contact | Topic 44524 on PLATO
Measuring the Hubble constant with LIGO-Virgo-KAGRA data
The fourth observing run (O4) of the LIGO-Virgo-KAGRA (LVK) gravitational-wave (GW) detector network began in May 2023 and is expected to run until December 2024.
After interesting candidate events have been identified and their parameters have been measured, it will be time to obtain science results out of the observations. A central role played by researchers in UGent is in the Cosmology working group of the LVK. A short-term goal of this group is to measure the Hubble constant, H0, the local expansion rate of the universe. One uses the GW distance measurement together with complementary redshift information (from possible electromagnetic counterparts, host galaxies, or galaxy clusters) to infer the cosmological parameters such as H0. Due to a tantalizing discrepancy between the local and early-universe measurements of H0, now dubbed as the “Hubble tension,” such an independent measurement of H0 from the GW sector can prove to be invaluable.
The latest measurement of the Hubble constant by the LIGO-Virgo-KAGRA Collaboration, from B. P. Abbott et al. “Constraints on the cosmic expansion history from GWTC-3,” arXiv: 2111.03604 [astro-ph.CO].
In this project you will work with researchers who have developed the LVK codebase gwcosmo+ for cosmology inference and have put together the upGLADE galaxy catalogue to go along with it. You will be a part of the team that carries out the first cosmology analyses on O4 data. If we are lucky, we may observe a multimessenger signal in O4 and get to analyze the data from it. Until now, we have seen only one such multimessenger signal, namely GW170817.
The work involved will be computational. You will learn about statistical methods and get exposed to state-of-the-art data analysis techniques. You will be involved in a large international collaboration in the forefront field of GW science.
Promoter: Prof. Archisman Ghosh Contact | Topic 44525 on PLATO
Gravitational waves instrumentation topics
The direct detection of gravitational waves (GWs) is a breakthrough discovery of recent years. The several GW detections by the Advanced LIGO and Virgo detectors, since they were first discovered in 2015, have opened up a new window to the observable universe. The current “second generation” detectors are Michelson interferometers with km-scale arms. The principle behind the detector is based on the fact that when a GW passes through, the arms of the interferometer are stretched and squeezed in opposite ways in the two directions.
Effect of a gravitational wave (propagating in the direction perpendicular to the plane of the paper) on the arms of a Michelson interferometer.
The current detectors will eventually be replaced by the next generation of GW detectors of significantly higher sensitivity and distance reach. One of these “third generation” detectors is the Einstein Telescope (ET), which is planned to be built in Europe in the 2030s. Fundamentally new technology will be required to go beyond the limitations of the current detectors. Extensive work and study is required for each of the new techniques to be implemented. ETpathfinder is an R&D facility, located in Maastricht, the Netherlands, with the aim to test these new techniques and to give important inputs for the design and the construction of third generation GW detectors like ET. The ETpathfinder is a Fabry-Perot Michelson interferometer with 10 m arm cavities working at cryogenic temperatures. It will mainly focus on developing prototypes and testing cryogenic temperatures (120 K, 15 K), new mirror material (Silicon), new laser wavelengths (1550 nm, 2090 nm), and advanced quantum noise reduction techniques.
Calibrating GW detectors using scattered light
With the increase of the sensitivity, gravitational-wave detectors will require calibration with better accuracy and precision. Currently, gravitational-wave detectors are calibrated using two independent methods, in order to be able to cross-check the results. The two methods are the Photon Calibrator (PCal) and Newtonian calibration method (NCal) and for both of them the calibration is done inducing a displacement on the mirrors.
A new independent technique which can use scattered light as a signal for the detector calibration was recently proposed [M. Wąs et al., 2021, Class. Quantum Grav.38 075020]. The scattered light is injected in the interferometer from the back of the end mirrors using a scattering element that can be modulated in amplitude. Unlike the other two, this technique does not involve the movement of the mirrors and thus it can be very useful to cross-check the results and be sure that the mirror suspensions do not add any error in the model.
The Ghent Gravity Group, in collaboration with the University of Antwerp, is planning to develop for the Advanced Virgo detector this new calibration technique. This is a very innovative work, since this technique has not yet been used in any other GW detector so far. The work involved will be hands-on instrumentational, with focus on optics and mechanics. The project will be under joint supervision with Dr. Daniela Pascucci (UGent) and Prof. Hans Van Haevermaet (UAntwerpen). For some parts of your research, you may need to work at the lab in UAntwerpen. You will also get a chance to work at the ETpathfinder facility in Maastricht and be a part of the exciting activity in the Belgian-Dutch region centred around the Einstein Telescope.
Layout of Advanced Virgo. The scattered light used for the calibration will come from the Suspended West and North End Benches (SWEB and SNEB) behind the West End (WE) and North End (NE) mirrors.
Promoters: Prof. Archisman Ghosh, Prof. Hans Van Haevermaet (UAntwerpen) Supervisor: Dr. Daniela Pascucci Contact | Topic 44514 on PLATO
Optical characterization of 2μm photodetectors
Next generation GW observatories such as the Einstein Telescope (ET) will use silicon mirrors as test masses to detect low frequency GW with unprecedented sensitivities. This implies the use of new laser wavelengths at 1550nm or 2090nm. The performance of such optics will be first tested at the ETpathfinder facility in Maastricht. To detect the main interferometer signal, coming from the GW strain, photodiodes with a high quantum efficiency (HQE) and a large dynamic range for these new wavelengths are needed. At 1550nm HQE InGaAs sensors exist, however at 2090nm more development is needed and custom made extended InGaAs photodiodes with optimized quantum efficiency, especially for 2090 nm, will need to be acquired and tested. In this project we will contribute to the development of such novel 2090nm HQE photodiodes by performing optical characterizations of available photodiodes.
UGent has recently set up an optical lab for characterization of optical components for 2090nm. You will set up a measurement system at UGent optical lab with existing readout electronics (available in UAntwerpen) to test the sensor for e.g. dark noise, efficiency, and optical power levels. The work involved will be hands-on instrumentational, with focus on optics and mechanics. The project will be under joint supervision with Prof. Hans Van Haevermaet (UAntwerpen). You will also get a chance to work at the ETpathfinder facility in Maastricht and be a part of the exciting activity in the Belgian-Dutch region centred around the Einstein Telescope.
Promoters: Prof. Archisman Ghosh, Prof. Hans Van Haevermaet (UAntwerpen) Supervisor: Dr. Daniela Pascucci Contact | Topic 44519 on PLATO
Optical layout of the ETpathfinder
Ghent University has been involved in the ETpathfinder project since its beginning. The facility in Maastricht is currently still under construction, with the aim to have the interferometer up and running by the end of this year.
Although the layout of ETpathfinder is broadly defined, optical simulations are needed to define position and specifications of all auxiliary optics used to have the proper beam parameters at each step of the path. You will be actively involved in the development of ETpathfinder, working on optical simulations to define the final layout.
You will be a member of the Einstein Telescope Collaboration. You will get involved with the technology and challenges of interferometric detectors in the active field of gravitational-wave science. The project will be done in close coordination with the ETpathfinder community. Travel to Maastricht, where the facility is located, may be required.
Simplified layout of ETpathfinder in its first phase.Picture of the ETpathfinder hall with all the vacuum towers assembled.
Promoter: Prof. Archisman Ghosh Supervisor: Dr. Daniela Pascucci Contact | Topic 44520 on PLATO
Second harmonic generators for 2µm wavelength
Second harmonic generator (SHG), also known as frequency doubling, is a mechanism happening when a light beam passes through a material with non‐linear dielectric coefficient.
Using non-linear crystals as SHG to create green light from an infrared light source has been widely used in the past in a wide range of applications, like display technology, biomedicine, etc. Also in GW instrumentation this technique is not new. In fact, it is used in Advanced Virgo to generate from a 1064nm input source the green light of auxiliary lasers needed for the cavity control system and the squeezing system. However, it has never been used for 2 μm wavelength. Furthermore, since one of the biggest challenges for next generation detectors is the development of high‐efficiency photodetectors, like cameras and photodiodes, and this study can be a first step to develop a method can be used to overcome the problem, changing the wavelength of the laser beam before it reaches the photodetector. Currently the most used materials (from IR to green) are the Periodically-poled Lithium Niobate (LiNbO3 or PPLN) and the Periodically Poled-Potassium Titanyl Phosphate (KTiOPO4 or PPKTP). However, other materials will be studied and taken into account.
The main objective of the proposed research is to study possible SHG materials for 2 μm wavelength, analysing if they are suitable for GW detectors.
Schematic representation of how a non-linear optical medium acts as a second harmonic generator.Periodically-poled Lithium Niobate (LiNbO3 or PPLN).Periodically-poled Potassium Titanyl Phosphate (LiNbO3 or PPKTP).Pictures of two possible materials suitable for 2µm wavelength.
Promoter: Prof. Archisman Ghosh Supervisor: Dr. Daniela Pascucci Contact | Topic 44521 on PLATO
Modelling the effect of Newtonian noise for the Einstein Telescope
Newtonian noise or gravity gradient noise is an effect of the change of the Newtonian gravitational potential due to fluctuations of displacements on the surface of the Earth. Although it is a small effect for current GW detectors, it can become a major nuisance for future detectors such as the ET. Newtonian noise couples to a test mass in a manner very similar to GWs, and it is not possible, even in principle, to remove this noise source (except via active subtraction). It is therefore important to understand and quantify the impact of Newtonian noise. While estimation of Newtonian noise from homogeneous media has been well explored [1], a lot remains to be known in cases of complex, heterogeneous media.
(a) A schematic of Newtonian-noise coupling to the test-mass. (b) Contribution of different fundamental noises to ET’s sensitivity with Newtonian noise dominating the low-frequency contributions.
In this project, you will analyze the generation mechanism of Newtonian noise and simulate scenarios that will best represent the contribution of Newtonian noise to ET’s low-frequency sensitivity. Simulations of elastic waves in a heterogeneous medium will be performed using a spectral finite element solver SPECFEM3D. A software library will be developed to compute the gravitational acceleration on the interferometer’s test-masses, based on the simulated displacement of the medium’s elements. In particular, focus will be given to the understanding of contributions from different parts of the medium like interfaces, and cavern walls that host the vertices of ET.
You will work in collaboration with researchers in the University of Liège, including Dr. Soumen Koley, who is one of the leading experts in modeling Newtonian noise for GW detectors.
Your results may have a significant impact in bringing the ET to Belgium!
Promoter: Prof. Archisman Ghosh Supervisor: Dr. Daniela Pascucci Contact | Topic 44797 on PLATO
Neutrino experiment topics
Towards the neutrino mass measurement with Project 8
Project 8 is a next-generation direct neutrino mass experiment using the tritium endpoint method. To reach the target sensitivity of 40 meV, new technologies are required. Among them is Cyclotron Radiation Emission Spectroscopy (CRES), a new non-destructive technique to measure electron energies via the frequency of their cyclotron radiation. CRES has been successfully demonstrated on a small scale in a waveguide section. To be able to scale to large volumes of tritium gas, we are exploring resonant cavities as detectors. The first demonstrator of CRES in cavities, the Cavity CRES Apparatus, is being commissioned at the University of Washington in Seattle and expected to start data taking in Fall 2025. In this project, you will assist with data taking remotely (such as by monitoring data quality and performing initial reconstructions), refine reconstruction algorithms, and study the electron energy resolution in the cavity. Experience with Python and basic knowledge of C++ is helpful. See https://doi.org/10.5281/zenodo.13385713 for a recent conference presentation.
Promoter: Prof. Juliana Stachurska Contact | Topic 44857 on PLATO
Cavity design for a large-volume demonstrator for the Project 8 neutrino mass experiment
Project 8 is a next-generation direct neutrino mass experiment using the tritium endpoint method. To reach the target sensitivity of 40 meV, new technologies are required. Among them is Cyclotron Radiation Emission Spectroscopy (CRES), a new non-destructive technique to measure electron energies via the frequency of their cyclotron radiation. CRES has been successfully demonstrated on a small scale in a waveguide section. Scaling to large gas volumes requires large, cubic-meter scale detectors. You will work on refining the design of a resonant cavity that can serve as the tritium holding vessel and electron detector and the associated readout probe. Of particular interest is the mode structure and achievable bandwidth. Mode-filtering techniques can be explored to better isolate the readout mode. This is mostly a simulation project employing commercial and custom software. Depending on the features of the best-performing design, the project may culminate with the design of a smaller prototype for testing in an extant setup at the University of Washington.
Project 8 cavity concept with cavity (or- ange), multipole magnet for atom trapping and pinch coils for electron trapping (red) and solenoid magnet to induce cyclotron motion (blue). Electrons couple to the TE011 mode (grey), read out from the center. The electron trapping field is shown on the left. From: PoS (TAUP2023) 229.
Promoter: Prof. Juliana Stachurska Contact | Topic 44858 on PLATO
Triggering on neutrino radio signals with RNO-G
With the discovery of a high-energy astrophysical neutrino flux, IceCube has opened a new window into the Universe. The Radio Neutrino Observatory in Greenland (RNO-G) aims to extend our knowledge of the astrophysical neutrino flux into to higher energies. Consisting of 35 autonomous stations, of which several have already been deployed, RNO-G is the first large-scale radio neutrino observatory. The harsh Greenlandic climate and remote location poses challenges to the stations’ design. The focus of this project lies on a trigger board that has been designed for RNO-G within the Brussels group. We are now working together on the next version of the design to improve the performance.
A single RNO-G station consists of three strings of antennas (Hpol and Vpol) plus surface antennas (LPDAs), as well as three calibration pulsers located both deep in the ice and also at the surface. The string containing the phased array trigger is designated as the power string, while the two additional strings are designated as support strings. From: JINST 16 (2021) 03, P03025.
Promoter: Prof. Juliana Stachurska Contact | Topic 44859 on PLATO
