Degree Projects at FREIA

Bachelor and Master projects in accelerator physics and light generation at the FREIA laboratory

FREIA is a newly built laboratory for advancing accelerator physics. We work on development of various hardware for accelerators, physics of charged particle beams and generation of light by accelerated charges. In particular, at present we are working on characterization of superconducting accelerating cavities; studying of breakdowns in accelerating structures for the Compact Linear Collider; development of efficient microwave sources for driving accelerators; dynamics of vortices in superconductors; generation of single-cycle THz radiation with a field strength in the V/Å range. We offer projects of various complexities from hard-core theoretical studies of the dynamics of vortices in superconductors and generation of single-cycle pulses of THz light to very applied developments in microwave engineering.

Master projects

Electro-magnetic design and analysis of LEnuSTORM magnet system

Superconducting magnets are the backbone of circular accelerator technology, and they are responsible for steering and focusing the particle beams inside an accelerator. In this thesis project, the student will be responsible for performing a parametric study on a unique magnet system especially designed for LEnuSTORM.

LEnuSTORM is a racetrack storage ring which will became a component of the European Spallation Source neutrino Super Beam (ESSνSB) experiment. The racetrack will store muons, and the muon- and electron-neutrinos, that result from muon decays, will be used to create a beam to measure neutrino cross-sections and look for sterile neutrinos.

The strong anisotropy of the storage ring is what makes this racetrack unique. Because LEnuSTORM produces useful neutrinos in its straight sections, the racetrack curves must be as short as possible to minimize muon waste. As a result, LEnuSTORM magnet system, used to store and steer the muon, must be compact and optimized.

The goal of the student will be to model the magnet system of the racetrack using the dedicated software RAT-GUI and to study different electro-magnetic configurations. The student will gain knowledge of superconducting magnet technology throughout the project, and the outcomes will be published in a scientific journal.



The Water Cherenkov Test Experiment at CERN in Geneva

A Water Cherenkov Test Experiment (WCTE ) is being planned at CERN with the purpose of studying in detail the final state particles in the interactions of neutrinos with water in Water Cherenkov Detectors in neutrino-oscillation experiments like T2K in Japan ( ), that planned for Hyper-K in Japan ( ) and that planned for ESSnuSB in Sweden ( ). The final state particles will be detected and identified in a 50 m3 water tank equipped with photomultipliers on its inside walls that will measure the Cherenkov radiation generated by the different kinds of beam-particles in in the water.

The Master Thesis project will consist in taking part in the preparations of test measurements at CERN during the spring and summer 2023 for the final experiment, which will be carried out in 2024. A particular task will be the preparation of the equipment that will be used to mix in and monitor the amount of Gadolinium in the Cherenkov-detector water, which will improve the detection of neutrons. The preparations will be followed during the summer 2023 by measurements of the particle production in the Proton Synchrotron test beam in the CERN experimental hall and the analysis of the collected data and simulation of the operation of the experimental set-up.

Tord Ekelöf tel. 018-4713847 and
Erin O'Sullivan tel. 018-471 3875

The cryo-cooled discharge system

A particle accelerator is a work horse of modern material science and particle physics but also helps to fight cancer or to study art and archeological artefacts. The use of the accelerators is limited to bigger research centers and larger hospitals not due to poor performance or inefficiency but rather due to their often large size and cost. One of the main reasons for the large size is phenomena of vacuum breakdowns. In simple terms a significant increase of the accelerating voltage inside the accelerator will cause an electric discharge which can destroy the machine, thus we keep the accelerator longer and stay at lower voltages.

Uppsala University together with the European Organization for Nuclear Research, CERN, is building a system with large planar electrodes for studies of the fundamental physics of high-fields in vacuum, important for material and surface science, and for development of accelerating technologies. The system will be cooled to cryogenic temperatures and operated in a wide range of temperatures.

In the project the student will work with the system commissioning at the FREIA laboratory.

The tasks include practical work with:

– control system integration

– data collection and analysis

The student will learn about how a cryo-system works. Such system comes with specific challenges for the control and the measurements we want to perform. The student will have to collect measurement data and analyze them. The results from the project will be published in a scientific journal.

Expulsion of magnetic fluxes in type-II superconductors upon the transition from a normal- to superconducting state

If a type-II superconductor is exposed to an external magnetic field upon the transition from a normal- to superconducting state, then the magnetic field gets trapped in the material and the performance of the superconductor degrades. Specifically, the residual resistance of the superconductor, which is a measure of resistance to alternating currents, decreases. In the applications of type-II superconductors such as superconducting accelerating cavities, it is vital to have the residual resistance as low as possible to minimize the heat load produced by  accelerating fields in the cavity. In this project, you will study experimentally and theoretically the novel phenomenon of expulsion of magnetic fluxes by the moving superconducting phase front during fast cool down of superconducting cavities.

Vitaliy Goryashko

Coupling of slow waveguide modes to surface plasmons of a subwavelength wire

We are developing a new technique of testing accelerating cavities, in which a subwavelength wire is used to mimic a beam of charged particles. The accelerating field of the cavity couples to surface plasmons of the wire and the electromagnetic energy is transferred from the cavity to the outside world via the wire resembling the process of particle acceleration. In the project you will perform analytical calculations of plasmonic modes of the subwavelength wire, run computer simulations with the professional software ‘CST Microwave Studio’ to study the coupling of cavity modes to the plasmonic modes and participate in experimental verification of the result in our microwave laboratory.

Vitaliy Goryashko

Diffraction of single-cycle THz pulses

THz radiation is becoming increasingly important in several areas of physics, chemistry and biology because its spectral range corresponds to numerous collective excitations in multiatomic systems such as molecular rotations, DNA dynamics, spin waves, Cooper pairs and so forth. Strong single-cycle THz pulses allow engineering new dynamic states of matter and one of the spectacular examples of using THz radiation for controlling the properties of materials is the THz light-induced superconductivity. If you like mathematical challenges, then this project is for you. We will tackle the problem of diffraction of single-cycle THz pulses in free-space. Specifically, the simulations show that the spatial diffraction "results in the differentiation of the temporal profile" of a single-cycle pulse so that the pulses becomes a quasi-half-cycle. In the project we will look into the math and physics behind this phenomenon.

Vitaliy Goryashko

RF power measurement at FREIA

At the FREIA Laboratory, the general focus is on developing particle accelerator technology that later could be used in large research facilities, such as CERN, European Spallation Source (ESS)... We are presently developing a 10 kW RF power amplifier based on solid state transistors. Each transistor needs a dedicated monitoring. The work consists in developing the RF power measurement, using a SWR meter or VSWR (voltage standing wave ratio) and the Arduino microcontroller.

Dragos Dancila

Electro-acoustic stability of superconducting accelerators

The purpose of an accelerating cavity is to accelerate charged particles when they traverse the cavity. Acceleration is realized through a longitudinal electric field. One can imagine the acceleration of particles as surfers riding on an ocean wave. However, there is number of physical effects that make the cavity operation difficult. One of the negative effects reducing the stability of the excited field is the deformation of cavity walls caused by an electromagnetic pressure, a so-called Lorentz force detuning. Collisions of photons with cavity walls create such pressure determined by the Poynting vector. The project is devoted to studying mechanical oscillations of a superconducting cavity caused by the Lorentz force detuning and methods of its prevention.

Vitaliy Goryashko

RF Breakdown studies for CLIC

After the successful start of the LHC accelerator at CERN, we expect many years of discoveries that could lead to better understanding of the universe. Accelerator physicists however continue to plan for future facilities where more detailed studies of particle physics secrets can be done at higher energies. CLIC, the Compact Linear Collider, is the proposed successor to the LHC. In the CLIC particles are accelerated by a very strong electric field. Unfortunately, large electric fields can lead to vacuum discharges  which in turn can affect the particle beam and lead to reduced performance of the CLIC accelerator. Studies of the physics behind vacuum discharges and its effect on the beam is therefore an important issue we are investigating in Uppsala.

In this project, students will learn how to manage experimental signals in large data sets stored by the logging system. The signals must be synchronized, analysed and correlated in a data analysis program to determine what physical processes occur during the discharge. The results of these measurements will contribute to the development of theory and verification of accelerating structures by providing information about the kinematics of charged particles inside the accelerating structure.

Marek Jacewicz

Other ongoing future projects

If you are interested in discussing other ongoing or future projects, here is a list of contacts.

Solid state amplifier development

Dragos Dancila

Accelerator physics

Vitaliy Goryashko

The CLIC accelerator project

Marek Jacewicz

RF amplification and transmission

Magnus Jobs

Superconducting cavities

Han Li

The Neutrino Super Beam project

Maja Olvegård

FREIA project leader

Roger Ruber

Accelerator physics

Volker Ziemann

Last modified: 2023-03-16