Degree and Student Projects
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.
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.
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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.
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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.
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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.
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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.
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Other Ongoing Projects
If you are interested in discussing other ongoing projects, here is a list of contacts.
Solid state amplifier development and RF amplification and transmission
Accelerator physics
The CLIC accelerator project
The Neutrino Super Beam project
Contact
- Programme Professor
- Hermann Dürr
- Contact information FREIA