kth.sePublications
Change search
Link to record
Permanent link

Direct link
Publications (10 of 445) Show all publications
Rubel, M., Primetzhofer, D., Petersson, P., Charisopoulos, S. & Widdowson, A. (2023). Accelerator techniques and nuclear data needs for ion beam analysis of wall materials in controlled fusion devices. EPJ TECHNIQUES AND INSTRUMENTATION, 10(1), Article ID 3.
Open this publication in new window or tab >>Accelerator techniques and nuclear data needs for ion beam analysis of wall materials in controlled fusion devices
Show others...
2023 (English)In: EPJ TECHNIQUES AND INSTRUMENTATION, ISSN 2195-7045, Vol. 10, no 1, article id 3Article, review/survey (Refereed) Published
Abstract [en]

A brief overview of ion beam analysis methods and procedures in studies of materials exposed to fusion plasmas in controlled fusion devices with magnetic confinement is presented. The role of accelerator techniques in the examination and testing of materials for fusion applications is emphasised. Quantitative results are based on robust nuclear data sets, i.e. stopping powers and reaction cross-sections. Therefore, the work has three major strands: (i) assessment of fuel inventory and modification of wall materials by erosion and deposition processes; (ii) equipment development to perform cutting-edge research; (iii) determination of nuclear data for selected ion-target combinations. Advantages and limitations of methods are addressed. A note is also given on research facilities with capabilities of handling radioactive and beryllium-contaminated materials.

Place, publisher, year, edition, pages
Springer Nature, 2023
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-325002 (URN)10.1140/epjti/s40485-023-00092-7 (DOI)000938927400001 ()
Note

QC 20230327

Available from: 2023-03-27 Created: 2023-03-27 Last updated: 2023-03-27Bibliographically approved
López-Rodríguez, D., Crombé, K., Wauters, T., Goriaev, A., Buermans, J., Kovtun, Y., . . . Möller, S. (2023). Characterisation of radio frequency plasmas in the upgraded TOMAS device. In: : . Paper presented at 24th Topical Conference on Radio-frequency Power in Plasmas, Annapolis, United States of America, Sep 26 2022 - Sep 28 2022. American Institute of Physics Inc., Article ID 040006.
Open this publication in new window or tab >>Characterisation of radio frequency plasmas in the upgraded TOMAS device
Show others...
2023 (English)Conference paper, Published paper (Refereed)
Abstract [en]

To complement wall conditioning research in TOMAS, a characterisation of radio-frequency hydrogen plasmas has been performed using a radially movable triple Langmuir probe. Experimental measurements of electron temperature and density radial profiles at different magnetic field on axis strengths and neutral pressures have been performed. First results of simulations of the radial profiles with the code TOMATOR-1D can qualitatively reproduce the measurements of the diagnostic and may be used to understand the behaviour of the waves inside the plasma.

Place, publisher, year, edition, pages
American Institute of Physics Inc., 2023
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-340384 (URN)10.1063/5.0162558 (DOI)2-s2.0-85177075960 (Scopus ID)
Conference
24th Topical Conference on Radio-frequency Power in Plasmas, Annapolis, United States of America, Sep 26 2022 - Sep 28 2022
Note

QC 20231204

Available from: 2023-12-04 Created: 2023-12-04 Last updated: 2023-12-04Bibliographically approved
Goriaev, A., Crombé, K., López-Rodríguez, D., Möller, S., Buermans, J., Verstraeten, M., . . . Kovtun, Y. (2023). First studies of local ion fluxes in radio frequency plasmas for ion cyclotron wall conditioning applications in the TOMAS device. In: AIP Conference Proceedings: . Paper presented at 24th Topical Conference on Radio-frequency Power in Plasmas, Annapolis, United States of America, Sep 26 2022 - Sep 28 2022. American Institute of Physics Inc., Article ID 040007.
Open this publication in new window or tab >>First studies of local ion fluxes in radio frequency plasmas for ion cyclotron wall conditioning applications in the TOMAS device
Show others...
2023 (English)In: AIP Conference Proceedings, American Institute of Physics Inc. , 2023, article id 040007Conference paper, Published paper (Refereed)
Abstract [en]

To measure the local ion energy distribution functions for support of Ion Cyclotron Wall Conditioning (ICWC) application studies in the TOMAS device, a Semion Retarding Field Energy Analyzer (RFEA) by Impedans Ltd. has been installed in the sample load-lock system. The RFEA system has been commissioned in hydrogen Radio-Frequency (RF) plasmas. The first studies have been performed on the influence of the neutral hydrogen pressure, the input power, the magnetic field and the location on the average ion energy and ion flux density.

Place, publisher, year, edition, pages
American Institute of Physics Inc., 2023
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-340386 (URN)10.1063/5.0164706 (DOI)2-s2.0-85177038002 (Scopus ID)
Conference
24th Topical Conference on Radio-frequency Power in Plasmas, Annapolis, United States of America, Sep 26 2022 - Sep 28 2022
Note

QC 20231204

Available from: 2023-12-04 Created: 2023-12-04 Last updated: 2023-12-04Bibliographically approved
Zayachuk, Y., Jepu, I., Zlobinski, M., Porosnicu, C., Catarino, N., Pajuste, E., . . . Widdowson, A. (2023). Fuel desorption from JET-ILW materials: assessment of analytical approach and identification of sources of uncertainty and discrepancy. Nuclear Fusion, 63(9), 096010, Article ID 096010.
Open this publication in new window or tab >>Fuel desorption from JET-ILW materials: assessment of analytical approach and identification of sources of uncertainty and discrepancy
Show others...
2023 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 63, no 9, p. 096010-, article id 096010Article in journal (Refereed) Published
Abstract [en]

This work was carried out to identify sources of errors, uncertainties and discrepancies in studies of fuel retention in wall components from the JET tokamak using methods based on thermal desorption. Parallel aims were to establish good practices in measurements and to unify procedures in data handling. A comprehensive program designed for deuterium quantification comprised the definition and preparation of two types of materials (samples of JET limiter Be tiles and deuterium-containing targets produced in the laboratory by magnetron-assisted deposition), their pre-characterization, quantitative analyses of the desorption products in three different thermal desorption spectroscopy systems and a detailed critical comparison of the results. Tritium levels were also determined by several techniques in samples from JET and in tritiated targets manufactured specifically for this research program. Facilities available for studies of Be- and tritium-contaminated materials from JET are presented. Apparatus development, future research options and challenges are discussed.

Place, publisher, year, edition, pages
IOP Publishing, 2023
Keywords
fuel retention, thermal desorption, dissolution, JET-ILW
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-334754 (URN)10.1088/1741-4326/ace2d2 (DOI)001041325000001 ()2-s2.0-85166957472 (Scopus ID)
Note

QC 20230824

Available from: 2023-08-24 Created: 2023-08-24 Last updated: 2023-08-24Bibliographically approved
Dittrich, L., Petersson, P., Laabadi, H., Pitthan, E., Rubel, M., Widdowson, A., . . . Ciupiński, Ł. (2023). Impact of ion irradiation and film deposition on optical and fuel retention properties of Mo polycrystalline and single crystal mirrors. Nuclear Materials and Energy, 37, Article ID 101548.
Open this publication in new window or tab >>Impact of ion irradiation and film deposition on optical and fuel retention properties of Mo polycrystalline and single crystal mirrors
Show others...
2023 (English)In: Nuclear Materials and Energy, E-ISSN 2352-1791, Vol. 37, article id 101548Article in journal (Refereed) Published
Abstract [en]

Polycrystalline (PC) and single crystal (SC) molybdenum mirrors were irradiated with 98Mo+, 1H+, 4He+, 11B+ and 184W+. Energies were chosen to impact the optically active region (up to 30 nm deep) of Mo mirrors. Some surfaces were coated by magnetron sputtering either with B or W films 4–65 nm thick. The overall objective was to simulate the neutron-induced damage and transmutation (H, He), and the impact of H, He, B, W on the optical performance of test mirrors, and on fuel retention. In parallel, a set of PC Mo mirrors irradiated with 1.6 MeV 98Mo3+ to a damage of 2 dpa and 20 dpa was installed in the JET tokamak for exposure during deuterium-tritium campaigns. Data from spectrophotometric, ion beam and microscopy techniques reveal: (i) the irradiation decreased specular reflectivity, whereby the differences between PC and SC in reflectivity are very small, (ii) He is retained in bubbles within 25–30 nm of the subsurface layer in all irradiated materials, (iii) W, either deposited or implanted, decreases reflectivity, but the strongest reflectivity degradation is caused by B deposition. Laboratory studies show the correlation of damage and H retention. Several cycles of W deposition and its removal from SC-Mo mirrors by plasma-assisted methods were also performed.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Boron, Diagnostic mirrors, Helium, Ion-induced damage, Molybdenum, Reflectivity
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-340976 (URN)10.1016/j.nme.2023.101548 (DOI)001125646100001 ()2-s2.0-85178075778 (Scopus ID)
Note

QC 20231218

Available from: 2023-12-18 Created: 2023-12-18 Last updated: 2024-01-10Bibliographically approved
Kovtun, Y., Wauters, T., Goriaev, A., López-Rodríguez, D., Crombé, K., Dittrich, L., . . . Brezinsek, S. (2023). Measurement of hydrogen plasma parameters of the combined ECR+RF discharge in the TOMAS facility. In: 24TH TOPICAL CONFERENCE ON RADIO-FREQUENCY POWER IN PLASMAS: . Paper presented at 24th Topical Conference on Radio-frequency Power in Plasmas, Annapolis, United States of America, Sep 26 2022 - Sep 28 2022. AIP Publishing, 2984, Article ID 110001.
Open this publication in new window or tab >>Measurement of hydrogen plasma parameters of the combined ECR+RF discharge in the TOMAS facility
Show others...
2023 (English)In: 24TH TOPICAL CONFERENCE ON RADIO-FREQUENCY POWER IN PLASMAS, AIP Publishing , 2023, Vol. 2984, article id 110001Conference paper, Published paper (Refereed)
Abstract [en]

The plasma electron density and temperature were measured in hydrogen electron-cyclotron resonance (ECR) plasma and combined ECR + radio-frequency (RF) discharges in the TOMAS facility. The results of ECR and combined ECR+RF discharges studies are compared. With an addition of RF, it is possible to vary the plasma parameters around the values provided by the ECR discharge. The propagation of slow (SW) and fast (FW) waves in hydrogen plasma is analyzed. Depending on the plasma density and the parallel component of the wave vector three cases are possible: SW propagation only, SW and FW simultaneous propagation, and FW propagation only.

Place, publisher, year, edition, pages
AIP Publishing, 2023
Series
AIP Conference Proceedings, ISSN 0094-243X ; 2984
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-340396 (URN)10.1063/5.0162408 (DOI)2-s2.0-85177094139 (Scopus ID)
Conference
24th Topical Conference on Radio-frequency Power in Plasmas, Annapolis, United States of America, Sep 26 2022 - Sep 28 2022
Note

QC 20231207

Available from: 2023-12-07 Created: 2023-12-07 Last updated: 2023-12-14Bibliographically approved
Kovtun, Y., Goriaev, A., Lopez-Rodriguez, D., Dittrich, L., Petersson, P., Moon, S., . . . Brezinsek, S. (2023). Overview of TOMAS plasma diagnostics. Journal of Instrumentation, 18(2)
Open this publication in new window or tab >>Overview of TOMAS plasma diagnostics
Show others...
2023 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 18, no 2Article in journal (Refereed) Published
Abstract [en]

This paper presents an overview of the TOMAS plasma diagnostics. The Langmuir probe method is employed to measure electron temperature, density and floating potential distributions. Two triple probes (horizontal and vertical distributions) and a single probe (horizontal distribution) are used. The measured plasma parameters by the triple and single probes are compared. The ion and neutral atom flux and energy distribution is respectively characterized with a Residual Field Energy Analyzer and a Time-of-Flight Neutral Particle Ana-lyzer. To determine the elemental/charge content of the plasma, the passive method of time-resolved optical emission spectroscopy is used. The time dependence of the integral flow of plasma emission from the discharge is registered by a photodetector. Using a filter allows the photodetector to measure spectral line intensities. To record a wide variety of plasma events several video diagnostics are used. It includes slow video cameras and one high-speed camera in the visible range including Hα.

Place, publisher, year, edition, pages
IOP Publishing, 2023
Keywords
Plasma diagnostics, - probes, high speed photography, interferometry, spectroscopy and imaging
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-325085 (URN)10.1088/1748-0221/18/02/C02034 (DOI)000937326900013 ()2-s2.0-85148729662 (Scopus ID)
Note

QC 20230329

Available from: 2023-03-29 Created: 2023-03-29 Last updated: 2023-03-29Bibliographically approved
Crombé, K., Buermans, J., Castaño-Bardawil, D., Goriaev, A., López-Rodríguez, D., Verstraeten, M., . . . Wauters, T. (2023). Radio frequency plasma production on the TOMAS device. In: 24th Topical Conference on Radio-Frequency Power in Plasmas: . Paper presented at 24th Topical Conference on Radio-frequency Power in Plasmas, Annapolis, United States of America, Sep 26 2022 - Sep 28 2022. AIP Publishing, 2984, Article ID 040005.
Open this publication in new window or tab >>Radio frequency plasma production on the TOMAS device
Show others...
2023 (English)In: 24th Topical Conference on Radio-Frequency Power in Plasmas, AIP Publishing , 2023, Vol. 2984, article id 040005Conference paper, Published paper (Refereed)
Abstract [en]

The study of discharge initiation by an Ion Cyclotron Range of Frequency (ICRF) antenna is of importance for operational scenarios at low magnetic field in e.g., ITER and Wendelstein 7-X. At low magnetic fields ohmic breakdown is difficult because of relatively short connection lengths and the electron cyclotron (EC) systems cannot assist because of a low-density cut-off. In that case ion cyclotron (IC) start-up, with waves in the Radio Frequency (RF) wavelength range, can be a good alternative solution. To explore in more detail the processes at play during the initial breakdown phase and to test measurement requirements, the diagnostic's capabilities of the TOMAS experimental device are being enlarged to allow for IC breakdown studies. A first set of IC breakdown experiments has been performed and data was taken by a newly installed spectrometer and a horizontal triple Langmuir probe. Limitations were found in pressure, ICRF power, and hydrogen concentration. Further diagnostic's upgrades and extensions of the experimental sessions will allow for a more complete study in support of modelling and experiments on other machines.

Place, publisher, year, edition, pages
AIP Publishing, 2023
Series
AIP Conference Proceedings, ISSN 0094-243X ; 2984
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-340394 (URN)10.1063/5.0162563 (DOI)2-s2.0-85177035886 (Scopus ID)
Conference
24th Topical Conference on Radio-frequency Power in Plasmas, Annapolis, United States of America, Sep 26 2022 - Sep 28 2022
Note

QC 20231207

Available from: 2023-12-07 Created: 2023-12-07 Last updated: 2023-12-14Bibliographically approved
Dittrich, L., Petersson, P., Moon, S., Rubel, M., Tran, T. T., Widdowson, A. & Contribuors, J. E. (2023). Retention of noble and rare isotope gases in plasma-facing components-Experience from the JET tokamak with the ITER-like wall. Fusion engineering and design, 192, Article ID 113620.
Open this publication in new window or tab >>Retention of noble and rare isotope gases in plasma-facing components-Experience from the JET tokamak with the ITER-like wall
Show others...
2023 (English)In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 192, article id 113620Article in journal (Refereed) Published
Abstract [en]

Plasma edge cooling, ion cyclotron wall conditioning and disruption mitigation techniques involve massive gas injection (by puffs or pellets) to the torus. A certain fraction remains in plasma-facing components (PFC) due to co-deposition and implantation. An uncontrolled release/desorption of such retained species affects the stability of plasma operation. The aim of this work was to determine the lateral and depth distribution of noble (3He, 4He, Ne, Ar), seeded (N2, Ne, Ar) and tracer gases (15N, 18O) in PFC retrieved from the JET tokamak with the ITER-Like Wall (JET-ILW) after three experimental campaigns (ILW-1, ILW-2, ILW-3). Results regarding the retention of those gases are shown as well as a comparison to the deuterium retention in the studied areas. Heavy ion elastic recoil detection analysis was used, being the only technique capable of detection and quantitative assessment of all elements, especially low-Z isotopes. Helium was found on the divertor Tile 5, locally up to 44.1015 3He cm-2 and 12.1015 4He cm-2, and on the limiters as well. Neon was found in two positions on the limiters, with up to 10.1015 Ne cm-2 and the 15N tracer on Be limiters exposed to ILW-3. A correlation of N retention with the N seeding rates for each campaign has also been found.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Plasma -wall interactions, Seeded gases, Plasma -facing materials, JET tokamak, ITER-like wall
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-326042 (URN)10.1016/j.fusengdes.2023.113620 (DOI)000956841500001 ()2-s2.0-85150767994 (Scopus ID)
Note

QC 20230424

Available from: 2023-04-24 Created: 2023-04-24 Last updated: 2023-04-24Bibliographically approved
Pitthan, E., Petersson, P., Tran, T. T., Moldarev, D., Kaur, R., Shams-Latifi, J., . . . Primetzhofer, D. (2023). Thin films sputter-deposited from EUROFER97 in argon and deuterium atmosphere: Material properties and deuterium retention. Nuclear Materials and Energy, 34, Article ID 101375.
Open this publication in new window or tab >>Thin films sputter-deposited from EUROFER97 in argon and deuterium atmosphere: Material properties and deuterium retention
Show others...
2023 (English)In: Nuclear Materials and Energy, E-ISSN 2352-1791, Vol. 34, article id 101375Article in journal (Refereed) Published
Abstract [en]

Sputter-deposited thin films (33-1160 nm) from EUROFER97 were obtained on different substrates (C, Si, W, MgO) in argon and a mix of argon and deuterium atmosphere. The composition, microstructure, and mechanical properties of the films were analyzed and compared to those of the bulk material. The films feature lower density (-10%), higher hardness (+79%), and smaller crystallites in comparison to the bulk. Despite such differences, the elemental atomic composition of the films and the bulk was very similar, as determined by ion beam analysis. Deposition in deuterium-containing atmosphere resulted in a low deuterium incorporation (0.28% of atomic content), indicating low retention of hydrogen-isotopes in the deposited material.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Plasma facing components, EUROFER97, Sputtering deposition, Ion beam analysis, Deuterium retention
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-328283 (URN)10.1016/j.nme.2023.101375 (DOI)000990188500001 ()2-s2.0-85147198848 (Scopus ID)
Note

QC 20230607

Available from: 2023-06-07 Created: 2023-06-07 Last updated: 2023-06-07Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9812-9296

Search in DiVA

Show all publications