The Division of Applied Nuclear Physics is involved in a VR project aimed at commissioning of the NFS neutron facility and studies of neutron-induced fission.

NFS (Neutrons For Science), which is currently being constructed at GANIL, France, will be a unique facility for high-precision experiments in neutron nuclear data for science and technology. The data to be measured (cross sections and angular distributions for fission and light-ion production) are of importance for neutron standards, energy applications, nuclear reaction theory, radiation effects in electronics, spallation neutron sources, crew dosimetry for aviation and spaceflight, and more.

Our group will contribute to the NFS facility with a large nuclear reaction chamber (Medley) equipped with detectors of three different types: parallel plate avalanche counters (PPAC), surface-barrier silicon detectors, and scintillators. The setup and/or its elements may also be employed at other neutron facilities in the future, both in Sweden and abroad.

There are currently a few sub-tasks that can be transformed into master diploma works, in particular:

• Participation in development of new PPACs
• Optimisation of PPAC performance with regard to working gas parameters, electronics, and data acquisition system
• Characterisation of the PPAC and surface-barrier silicon detectors in terms of time and energy resolution as well as of effective area

The study has a potential for publication in a peer-reviewed scientific journal.

We are constantly looking for students who are interested to learn and work “hands-on” in a small group of research scientists and engineers at laboratory environment. Our concepts are “learning by doing” and supervision in the group. It is advantageous for interested students having attended courses in nuclear physics and especially nuclear laboratory courses. The group is international and both English and Swedish languages are spoken.

Interested? Book an interview with us and/or attend one of our exercises at the laboratory.

Start date

Upon agreement

Contact

Diego Tarrío

Background

Ion beam analysis techniques allow for non-destructive studies on near surface hydrogen. Resonant nuclear reaction analysis (NRA), based on the 1H(15N,αγ)12C nuclear reaction, with its cross section exhibiting a narrow resonance (Γ=1.8 keV) at 6.385 MeV, is commonly employed for precise, in-depth, quantification of hydrogen concentrations. The Tandem Laboratory at Uppsala University, employs a resonant-NRA setup that is in regular use. As resonant-NRA relies on the detection of γ-rays emitted from the sample, measurements are subject to the natural background present in any laboratory environment. Fortunately, the high energy of the γ-ray line of interest, separates it well from the majority of lines originating from common radioisotopes. Interference from cosmic-ray muons, however, is still a problem.

Project goal and work plan

The NRA setup at the Tandem Laboratory is currently being upgraded and, as part of this upgrade, the addition of a muon-rejection system is desired to reduce the signal background and improve detection limits. The goal of the project will be to build this system. The project can be divided into the following key tasks:

• build a muon-detection system based on coincident-signal detected in two scintillation detectors;
• combine the system with the NRA station in anti-coincidence to reject muon events registered during measurement;
• quantitively assess the background rejection properties of the system, and the improvement in hydrogen detection-limit it brings;
• further optimise the system based on the results obtained;
• write a report summarizing the results and conclusion of the work.

The position will be based at the Ångström laboratory in Uppsala, within the Ion-physics Group. This project provides an excellent opportunity to become acquainted with the broad range of research being conducted within the Ion-physics group, and to make a long-standing contribution to its operation.

The project can be adjusted to correspond to 15, 30 or 45 ECTS credits and can start during either the autumn 2023, or spring 2024 semesters.

Desired qualifications/experience

The applicant should be enrolled on a physics program at Uppsala University and possess:

• good practical abilities
• a strong interest in experimental work;
• excellent skills in both written and spoken English;
• knowledge/training in Nuclear Physics will be advantageous.

Students seeking diploma-work projects at both Master and Bachelor level are encouraged to apply, as are students seeking project work for courses (but such projects must correspond to at least 15 credits). The possibility of paired or group work can be discussed.

Contact

Robert Frost

Goal

Determine the sensitive area of one or several thin Si-detectors and determine if and in which way this depends on the incoming particle.

Project

At the Department of Applied Nuclear Physics, we conduct several research projects where we study different types of nuclear reactions at international research facilities (for example, GANIL in Caen, France). These nuclear reactions create, among others, light ions and fission products. To register these particles, we use Si detectors. One goal of these studies is to measure reaction cross-sections, i.e., the probabilities of different types of nuclear reactions. The exact size of the sensitive surface of the detector is therefore important to know. This may differ from the nominal value and, for design reasons, would also depend on the particle type.

The active area of the detector can be determined in our lab by using radiation sources and, with the help of radiation shielding, irradiating only a small part of the detector surface. By moving the irradiated part, the entire detector is scanned and the sensitive area can be determined.

As a radiation source, a Cf-252 source is used, which emits both alpha particles and fission products. The latter have a significantly higher mass and the sensitive surface of the detector could therefore differ from that of the relatively light alpha particles. Since the Si detector measures energy of the incoming particles, one can easily distinguish between these different particle types. The measurement takes place in a vacuum chamber located here at Ångström laboratory.

An important part of the project is to build a computer-controlled device that moves the radiation source step by step to irradiate different parts of the detector without having to break a vacuum for each individual measurement.

Thereafter, a series of measurement series will be performed and the collected measurement data will be analyzed to finally determine the detector's response to these different particle types.

Contact

Diego Tarrío

Stephan Pomp

• Investigate a new class of photochromic materials, potentially used in next generation of smart-windows
• Help us to synthetize and characterize – using nuclear physics methods – the materials, building thus the knowledge needed for their potential technological application
• Access and use of a National Research Facility for particle accelerators: The Tandem Laboratory

In this thesis project you will:

• Learn techniques for ultra-thin film growth
• Work with vacuum technology
• Use advanced accelerator based analytical techniques
• Be involved in an academic research environment

Contact

Marcos.Moro@physics.uu.se

Background

Detailed studies are currently being undertaken to assess the risk posed by a potential radioactive release from the European Spallation Source (ESS), a large neutron research facility under construction in Lund, Sweden. The ESS will produce neutrons using a powerful particle accelerator shooting protons on a tungsten target. The nuclear reactions in its target, will also produce many radioactive by-products that, in the event of a severe accident, could be released into the environment.

A new and highly multi-disciplinary project has been created through funding from the Swedish Radiation Safety Authority, which will investigate the potential risk of radionuclides, specific to the ESS, entering the food chain through crops commonly cultivated in the farmlands surrounding the ESS site. The project will be jointly conducted by the Ion-physics group at Uppsala University (Sweden), Medical Radiation Physics Malmö at Lund University (Sweden), the Biotechnical Faculty at the University of Ljubljana (Slovenia), and the Department of Low and Medium Energy Physics at the Jožef Stefan Institute (Slovenia). To support this work, undergraduate and post-graduate projects are to be created.

Project goal and work plan

The goal of the student’s work, will be to participate in the start-up of the broader project, performing baseline measurements, analysis and modelling to support the work that will be performed over the next four years. Projects can be catered to suite those with an interest in either simulation and modelling, or experimental and analytical work.

The position will be based at the Ångström laboratory in Uppsala, within the Ion-physics Group. This project provides an excellent opportunity to become acquainted with the broad range of research being conducted within the Ion-physics group, and to make a long-standing contribution to its operation.

The project can be adjusted to correspond to 15, 30 or 45 ECTS credits and can start during either the autumn 2023, or spring 2024 semesters.

Desired qualifications/experience

The applicant should be enrolled on a program at Uppsala University, with a background in either physics, chemistry or environmental science. It is essential that the applicant has excellent skills in both written and spoken English.

Students seeking diploma-work projects at both Master and Bachelor level are encouraged to apply, as are students seeking project work for courses (but such projects must correspond to at least 15 credits). The possibility of paired or group work can be discussed.

Contact

Robert Frost

Diffusion studies of crystalline solid are important in materials physics. However experimental study of light element diffusion in alloys is a challenging task as most of studies fail to probe light element depth distribution with good depth resolution. To overcome these difficulties, we have developed a coincidence ERDA experimental set up for high resolution depth profiling of light elements in thin foils [1]. Simultaneous depth profiling of two light elements could be performed using this experiment. In this project, light element will be introduced by ion implantation and depth distribution will be studied in self-supporting thin foils by coincidence ERDA at various temperatures (ex-situ, if possible in-situ). This could be useful to understand light element diffusion and impurity-defect interactions in metals. With this method, example studies are, (i) H, He depth distribution in Tungsten: High resolution depth profiling of H and He is important in Tungsten owing to its importance as a nuclear structural material. (ii) C in FeCo alloys: FeCo is a ferro magnetic material and studies of C diffusion is important hence it modifies magnetic properties [2]. Coincidence ERDA experiments can be used for in-situ experiments and we encourage for new ideas and studies from students. Students will involve in preparing thin foil samples, coincidence ERDA experiment, analysis of results and develop in-situ heating if possible.

References

1. In-operando observation of Li depth distribution and Li transport in thin film Li ion batteries featured. Appl. Phys. Lett. 117, 023902 (2020); https://doi.org/10.1063/5.0014761.

2. Influence of ion implantation on the magnetic properties of thin FeCo films. Journal of Applied Physics 97, 073911 (2005); https://doi.org/10.1063/1.1875737.

Contact

Vairavel Mathayan

Background

Model calibration and inverse uncertainty quantification (UQ) is essential in all aspects of science and technology. This project is performed in collaboration with SSM (Strålsäkerhetsmyndigheten). However, the significance is not limited to the area of nuclear technology.

An important part of establishing a safety case in an industry is based on model calculations. In many cases, experiments and measured data can only be used to verify and validate the used models and not be used directly to infer the full information of vital engineering parameters. Hence modeling is paramount. [Hessling17]

The models used are generally calibrated with experiments, and methods are available also to quantify model uncertainties. This is referred to inverse uncertainty quantification (IUQ). IUQ can, in many cases, be computationally heavy, and there is a need to find more efficient methods to determine the uncertainty.

Deterministic sampling (DS) has previously been used for propagation of uncertainties [Hessling13] [Sahlberg16] [Sahlberg18]. DS is significantly more computationally efficient than traditional random sampling. The aim of this work is to explore if deterministic sampling can be used for IUQ, and to compare its performance to other IUQ methods.

Candidate

We are looking for a candidate with an interest in mathematics, statistics, and computational methods. The project will involve programming.

With the growing need for expertise in advanced mathematical modeling and data handling in society, particularly coupled to the onset of Machine Learning and Artificial Intelligence in many fields, we believe that this project will provide the student with a valuable skill set for the future. The project can be completed by one or more students.

References

[Hessling13] P. Hessling, “Deterministic Sampling for Propagating Model Covariance,” SIAM/ASA J. Uncertainty Quantification, vol. 1, no. 1, pp. 297–318, Jan. 2013, doi: 10.1137/120899133.

[Hessling17] P. Hessling, “Kalibrering för bestämning av optimal beräkningsmode,” 2017:23, p. 72, 2017.

[Sahlberg16] A. Sahlberg, “Ensemble for Deterministic Sampling with positive weights,” Master Thesis, Uppsala University, 2016.

[Sahlberg18] A. Sahlberg, C. Hellesen, J. Eriksson, S. Conroy, G. Ericsson, and D. King, “Propagating transport-code input parameter uncertainties with deterministic sampling,” Plasma Phys. Control. Fusion, vol. 60, no. 12, p. 125010, Nov. 2018, doi: 10.1088/1361-6587/aae80b.

Contact

Henrik Sjöstrand

Background

Medium energy ion scattering (MEIS) provides high-depth resolution and sensitivity by employing projectiles with keV energies. MEIS can also be used for the detection of light recoils with extreme depth resolution and sensitivity. Implementing time-of-flight elastic recoil detection in transmission experiments using a pulsed beam of heavy ions (namely Ar and/or Ne) with keV energies allows simultaneous detection of all light constituents. The loading of hydrogen into materials is technologically highly relevant for sensor and energy storage applications as well as for materials ageing when using hydrogen as process gas in decarbonized industrial applications. At the same time, the thermodynamics of hydride formation, in particularly near surfaces of materials needs to be much better understood.

Project goal and work plan

• Investigate the implantation of H in Si crystals
• Help us to create and characterize – using keV ions and recoil detection analytical technique – the implanted crystals
• Access and use of a National Research Facility for particle accelerators: The Tandem Laboratory

In this thesis project you will:

• Learn techniques for in-situ implantation and characterization using keV ions
• Work with vacuum technology
• Use advanced accelerator based analytical techniques
• Be involved in an academic research environment

Desired qualifications/experience

The applicant should be enrolled on a program at Uppsala University and possess:

• Good practical abilities
• Strong interest in experimental work;
• Excellent skills in both written and spoken English.

Students seeking diploma-work projects at both Master and Bachelor level are encouraged to apply, as are students seeking project work for courses (but such projects must correspond to at least 15 credits). The possibility of paired or group work can be discussed.

Contact

Eleni Ntemou

Project and Thesis Topic

• Nanoporous membranes, possessing high filtering efficiency, are a promising approach for addressing critical environmental issues, such as the lack of fresh water supply in many parts of the world and the excessive emission of green-house gases. The membranes also play an important role in chemical processing for cosmetics and pharmaceutical industries. The ideal membranes need to have: (i) a minimal thickness for maximal permeance, (ii) a nanoscale and uniform pore size for high filtering selectivity, (iii) a sufficient mechanical strength under relatively high pressure, and a large enough area for practical applications.
• Recently, we have developed a novel nanoporous membrane by combining sputtering, microfabrication and ion implantation. As shown in Fig. 1, the membrane features high density of the nanoscale pores. Importantly, our approach enables large-scale production of the materials. In the near term, we will continue to investigate the materials in both fundamental and applied aspects. Hence, this project provides a wide variety of subjects for enthusiastic students, from experimental physics to applications and equipment development.

Join this project, you will learn:

• Fabricating the membranes using sputtering, microfabrication and ion implantation.
• Characterizing the membrane using electron microscopy, X-ray diffraction, atomic force microscopy and nanoindentation.
• Fundamental aspects of interactions between energetic ions and materials, and the mechanism of the pore formation.
• Developing equipment for the filtering experiments.

Contact

Tuan Tran

Project and Thesis Topic

• 2-dimensional (2D) materials have been a research area that leads to many discoveries in recent years. The materials are only one or few atomic layer thick, but have fascinating physical, chemical and mechanical properties [1]. At the same time, there is an immense interest in structuring 2D materials at the nanoscale and at the atomic level for added advanced functionalities. Recently, we have developed a versatile approach capable of structuring the 2D lattices at the nanoscale as well as engineering the materials at the atomic level. The approach relies on a broad and uniform beam of energetic ions passing through a suspended nanopatterned membrane [2].
• The nanopattern membrane, acting as a shadow mask, is fabricated using a multi-step nanofabrication process. Characterization of the structured 2D lattices are done using atomic-resolution transmission electron microscopy (TEM) for studying the atomic defects and the impurities.

Join this project, you will learn:

• Fabricating the nanopattern membranes using nano-microfabrication and ion implantation.
• Characterizing the membrane using electron microscopy (SEM and TEM).
• Fundamental aspects of interactions between energetic ions and 2D materials.

References

[1] Geim, A. K. and K. S. Novoselov (2007). "The rise of graphene." Nature Materials 6(3): 183-191
[2 ] Tran, T. T., et al. (2023). "A contactless single-step process for simultaneous nanoscale patterning and cleaning of large-area graphene." 2D Materials 10(2): 025017.

Contact

Tuan Tran

Scope

We are announcing a project work that can be tailored to fit a bachelor work of 15 credits, or a master work of 30 credits.

Objective

This project is a first step to creating a BWR fuel library that will be used in nuclear safeguards research to study the future verification of nuclear fuel before encapsulation and final storage. However, before creating the fuel library, it is necessary to select the prevailing conditions under which the simulations of the fuel irradiation will be performed. The objective of this project is to study the connection between different irradiation circumstances in the reactor and the resulting radionuclide inventory in the irradiated nuclear fuel.

Methodology

The Monte Carlo code Serpent2 will be used to simulate different models of BWR fuel, and different irradiation conditions. Of particular interest is to simulate different BWR geometries (a single-pin models versus a fuel assembly model, and potentially different fuel rod dimensions), and to study to what degree irradiation conditions such as void profile, void level, presence of control rods and burnable absorbers influence the radionuclide inventory at the end of irradiation and at certain cooling times.

Prerequisites

It is good if you have knowledge of nuclear power operation. Experience of Serpent simulations are beneficial but not necessary, as it analyses using Python/Matlab.

Starting time

As soon as possible.

Contact

Erik Branger, erik.branger@physics.uu.se

Sophie Grape, Sophie.grape@physics.uu.se

Background

The production of neutrons by accelerators began in the 1970s with construction of powerful proton accelerators to access neutrons via spallation. At the same time, low-energy driven neutron processes emerged for neutron production using electron accelerators, ion beam accelerators, cyclotrons, and low energy linear accelerators. This wide variety of neutron sources have come to be referred to as Compact Accelerator-driven Neutron Sources (CANS). Due to research reactors within Europe undergoing shutdown, the European Spallation Source user program delayed until 2026 and other large-scale European facilities (ISIS, ILL and PSI) being heavily overbooked, there is currently a serious need for establishing additional neutron sources, especially in Scandinavia. It is believed that a CANS could fulfil this demand.

Project goal and work plan

The goal of the proposed project is to perform preliminary simulation-work that will support the development of a CANS within Sweden. This work will take the form of developing target simulations to constrain possible design parameters, such as target material, beam energy and beam current. The project can be divided into the following key tasks:

• develop a simple CANS-target/moderator design in a Monte Carlo simulation package;
• run simulations for different target materials, primary-ions and beam energies;
• evaluate neutron production in terms of energy and flux;
• evaluate target heating and target damage;
• evaluate gamma-ray production and shielding requirements;
• evaluate possible moderator designs and geometries;
• write a report summarising the results and conclusion of the work.

The position will be based at the Ångström laboratory in Uppsala, within the Ion-physics Group. This project provides an excellent opportunity to become acquainted with the broad range of research being conducted within the Ion-physics group, and to make a long-standing contribution to its operation.

The project can be adjusted to correspond to 15, 30 or 45 ECTS credits and can start during either the autumn 2023, or spring 2024 semesters.

Desired qualifications/experience

The applicant should be enrolled on a physics program at Uppsala University and possess:

• a strong interest in simulation;
• excellent skills in both written and spoken English.
• knowledge/training in Nuclear Physics will be advantageous.

Students seeking diploma-work projects at both Master and Bachelor level are encouraged to apply, as are students seeking project work for courses (but such projects must correspond to at least 15 credits). The possibility of paired or group work can be discussed.

For further information please contact:

Robert Frost rob.frost@physics.uu.se

Project

The verification of hydrogen content is decisive for emerging hydrogen-rich materials in sustainable energy applications, such as hydrogen storage in the hydrogen economy. As hydrogen is the lightest element in the universe, experimental investigation of its distribution at the atomic level encounters difficulties. Ion beams offer nondestructive and distinctive analysis of material composition through elastic and inelastic interactions with the different chemical elements. Resonant nuclear reactions with hydrogen atoms can be induced by high-energy 15N-ion beams employed at the Tandem Laboratory (Ångström), and are utilized for depth-resolved measurement of hydrogen in solid thin films, nanostructures, and on surfaces. To obtain hydrogen depth profiles the incident energy of ions is varied positioning the resonance of the nuclear reaction at varying depths within a target while detecting reaction products (e.g. γ-rays). The experimental excitation curve thus displays the depth distribution of the hydrogen density offering superior depth resolution of only several nanometers. However, the hydrogen signal is convoluted with an effective instrumental function and the nuclear reaction cross-section. The project aims to develop a numerical method to determine real hydrogen concentration profiles from experimental excitation curves by numerical deconvolution.

By joining this project, you will

• learn fundamental aspects of interactions between energetic ions and hydrogen-containing materials;
• learn advanced accelerator-based analytical techniques;
• acquire work experience at a large-scale scientific facility;
• develop a numerical analytical methodology;
• bridge real experimental data with simulations;
• perform benchmark ion beam experiments on ultrathin hydrogen-storing metal films; and simulate hydrogen depth profiles;
• be involved in an academic research environment.

Desired qualifications/experience

• enrolled in a physics program at Uppsala University;
• a strong interest in simulations;
• excellent skills in both written and spoken English;
• some interest in experimental work.

We encourage applications by students seeking diploma-work projects at Master's level.

For further information please contact:

Kristina Komander

HITRAP is a unique facility for high precision experiments with cold highly-charged ions (HCI) of heavy elements currently being constructed at the research facility GSI in Germany. Later HITRAP will become an integrated part of the new international accelerator facility FAIR, one of the largest research projects worldwide.

At HITRAP HCI of all elements and charge states, up to U⁹²⁺, can be delivered by the accelerator complex. These will be decelerated and captured in a Cooling Penning trap and, after cooling to sub-meV energy, the ions will be extracted to the experimental area. One of the first experiments to be constructed is the ARTEMIS Penning trap for measurement of the g-factor of heavy hydrogen like systems like U⁹¹⁺. This measurement will serve as a benchmark of theoretical predictions for g-factors calculated in the framework of bound state quantum electrodynamics (QED). The measurement of the atomic gF factors of two hyperfine structure levels on the ppb level of accuracy will allow the extraction of nuclear magnetic moments without diamagnetic corrections as well as the quantification of diamagnetic shielding effects.

We are constantly looking for students who want to spend time at the research facility working with the development of the setup. There are currently many sub-task that can easily be transformed into suitable diploma works.

Start date

Upon agreement

Contact

Andreas Solders (Supervisor)
Nuclear Reaction Group
Division of Applied Nuclear Physics
018-471 2631

Master work in applied nuclear physics, 20 weeks with 30 credits (also could be a course project with 15 credits in 10 weeks).

Introduction

In order to measure fission yield of neutron-induced fission, we have developed an ion guide in which the fission products are collected. In addition, a GEANT4 model has been constructed to simulate the fission products in the ion guide. Fission products are generated isotopically in neutron-induced fissions. When fission products are thermalized by the helium gas in the ion guide, the charge states of most products are changed to 1+. However, stopping efficiency of the Helium gas is presently not sufficient. One solution to this would be to use a larger stopping volume but this would require static and radio frequent electric fields to guide the fission products. Before adding electric fields in the GEANT4 model, we want to know how the charged particles behave in an electric field and how to design an electric field to confine and drive the ions. A literature study of the GEANT4 manual will be necessary to learn how static and oscillating electric fields are implemented in GEANT4. The second step is to test this in a simple model of the ion guide to optimize the collection and transportation of fission products.

Assignment

Build a simple GEANT4 model including electric fields and investigate ion trajectories in these fields. Design an electric field to guide the ions.

Requirements

Basic knowledge of C++ and nuclear physics. Communication in English.

Start date

As soon as possible, upon agreement.

Contacts

Zhihao Gao, Andreas Solders

Background

Low-energy ions are becoming more frequently employed for near-surface modification of materials, in simulating the effect of the fusion plasma on structural components fusion devices, and in tailoring the electronic properties of 2D materials. The 10 keV ion implanter (LEION) is a new setup at the Tandem Laboratory to initiate studies on the above-mentioned topics. The ion source of LEION is capable of producing a range of ion species, extracted from or gaseous solid media, both light and heavy, and with variable charge state. Implantation can be made in, in principle, any material. The precise limitations of the setup are currently unknown and it is therefore vital that these are tested in a systematic manner.

Project goal and work plan

The project will consist of systematically testing the capabilities of LEION, by implanting a broad range of ions into both thick targets such as silicon, and thin targets such as graphene. The implantations will then be assessed by a range of analysis techniques. The project can be divided into the following key tasks:

• implantation of ions generated from both gases and solids;
• implantation of both light and heavy ions;
• implantation into thick targets and 2D materials;
• implantation under both hot and cold conditions;
• analysis of the implanted materials using, for example, TEM, LEIS and μPIXE;
• propose and implement optimisations to LEION based on the results obtained;
• to write a report summarising the results and conclusions of the work.

The position will be based at the Ångström laboratory in Uppsala, within the Ion-physics Group. This project provides an excellent opportunity to become acquainted with the broad range of research being conducted within the Ion-physics group, and to make a long-standing contribution to its operation.

The project can be adjusted to correspond to 15, 30 or 45 ECTS credits and can start during either the autumn 2023, or spring 2024 semesters.

Desired qualifications/experience

The applicant should be enrolled on a program at Uppsala University and possess:

• good practical abilities
• strong interest in experimental work;
• excellent skills in both written and spoken English;
• knowledge/training in Nuclear Physics will be advantageous.

Students seeking diploma-work projects at both Master and Bachelor level are encouraged to apply, as are students seeking project work for courses (but such projects must correspond to at least 15 credits). The possibility of paired or group work can be discussed.

For further information please contact:

Robert Frost rob.frost@physics.uu.se

Degree and Student Projects

Background

The diffusion of gaseous fission products such as Xe and Kr in nuclear fuel constitute significant performance and safety parameters for reactor operation. The study of diffusion behaviour in nuclear fuels is an experimental challenge however, both due to difficulties in adding gas species to the fuel matrix and in accessing techniques which can and monitor gas concentrations at low-length scales. The majority of diffusion parameters used for UO2 fuel performance analysis, have been derived either: from irradiated material measured in the plenum; or by gas release from the annealing of fuel samples. These methods suffer from the fact that bulk- and grain-boundary thermal and athermal diffusion, as well as radial and axial temperature-variation in the fuel, are highly approximated.

Project goal and work plan

The goal of this project, is to study the thermal-induced diffusion of volatile elements in heavy sample matrices, by medium-energy ion implantation followed by ToF-ERDA (time-of-flight elastic recoil detection analysis). Elemental depth-profiles of the samples are obtained, both as-implanted and post-annealed. The project can be divided into the following key tasks:

• implantation of volatile elements in a range of heavy sample matrices, using the ion-implanter at the Tandem laboratory;
• assessment of the implantations with ToF-ERDA, using the 5 MeV accelerator at the Tandem Laboratory;
• perform sample annealing at a range of temperatures and temperature gradients;
• repeat ToF-ERDA measurements to evaluate the thermally-induced diffusion of the implanted ions;
• write a report summarizing the results and conclusion of the work.

The position will be based at the Ångström laboratory in Uppsala, within the Ion-physics Group. This project provides an excellent opportunity to become acquainted with the broad range of research being conducted within the Ion-physics group, and to make a long-standing contribution to its operation.

The project can be adjusted to correspond to 15, 30 or 45 ECTS credits and can start during either the autumn 2023, or spring 2024 semesters.

Desired qualifications/experience

The applicant should be enrolled on a physics program at Uppsala University and possess:

• good practical abilities
• a strong interest in experimental work;
• excellent skills in both written and spoken English;
• knowledge/training in Nuclear Physics will be advantageous.

Students seeking diploma-work projects at both Master and Bachelor level are encouraged to apply, as are students seeking project work for courses (but such projects must correspond to at least 15 credits). The possibility of paired or group work can be discussed.

Contact

Robert Frost