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Weiszflog, Matthias
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Publications (10 of 64) Show all publications
Haglund, J., Melander, E., Weiszflog, M. & Andersson, S. (2017). University physics students’ ideas of thermal radiation expressed in open laboratory activities using infrared cameras. Research in Science & Technological Education, 35(3), 349-367.
Open this publication in new window or tab >>University physics students’ ideas of thermal radiation expressed in open laboratory activities using infrared cameras
2017 (English)In: Research in Science & Technological Education, ISSN 0263-5143, E-ISSN 1470-1138, Vol. 35, no 3, 349-367 p.Article in journal (Refereed) Published
Abstract [en]

Background

University physics students were engaged in open-ended thermodynamics laboratory activities with a focus on understanding a chosen phenomenon or the principle of laboratory apparatus, such as thermal radiation or a heat pump. Students had access to handheld infrared (IR) cameras for their investigations.

Purpose

The purpose of the research was to explore students’ interactions with reformed thermodynamics laboratory activities. It was guided by the research question: How do university physics students make use of IR cameras in the investigation of the interaction of thermal radiation?

Sample

The study was conducted with a class of first-year university physics students in Sweden. The interaction with the activities of four of the students was selected for analysis. The four students are males.

Design and methods

We used a qualitative, interpretive approach to the study of students’ interaction.  The primary means of data collection was video recording of students’ work with the laboratory activities and their subsequent presentations. The analysis focused on how IR cameras helped students notice phenomena relating to thermal radiation, with comparison to previous research on students’ conceptions of thermal radiation.

Results

When using the IR camera students attended to the reflection of thermal radiation on shiny surfaces, such as polished metals, windows or a white-board, and emissive properties of surfaces of different types. In this way, they went beyond using the technology as a temperature probe. Students were able to discuss merits and shortcomings of IR cameras in comparison with digital thermometers.

Conclusions

With the help of IR cameras, university physics students attend to thermal phenomena that would otherwise easily go unnoticed.

Place, publisher, year, edition, pages
Routledge, 2017
Keyword
Infrared cameras; Thermal radiation; Open laboratory exercises; Physics education
National Category
Physical Sciences
Research subject
Physics with specialization in Physics Education
Identifiers
urn:nbn:se:uu:diva-326285 (URN)10.1080/02635143.2017.1318362 (DOI)000404933100007 ()
Available from: 2017-07-05 Created: 2017-07-05 Last updated: 2017-11-20Bibliographically approved
Melander, E., Haglund, J., Weiszflog, M. & Andersson, S. (2016). More than meets the eye: Infrared cameras in open-ended university thermodynamics labs. Physics Teacher, 54(9), 528-531.
Open this publication in new window or tab >>More than meets the eye: Infrared cameras in open-ended university thermodynamics labs
2016 (English)In: Physics Teacher, ISSN 0031-921X, E-ISSN 1943-4928, Vol. 54, no 9, 528-531 p.Article in journal (Refereed) Published
Abstract [en]

Educational research has found that students have challenges understanding thermal science. Undergraduate physics students have difficulties differentiating basic thermal concepts, such as heat, temperature, and internal energy. Engineering students have been found to have difficulties grasping surface emissivity as a thermal material property. One potential source of students’ challenges with thermal science is the lack of opportunity to visualize energy transfer in intuitive ways with traditional measurement equipment. Thermodynamics laboratories have typically depended on point measures of temperature by use of thermometers (detecting heat conduction) or pyrometers (detecting heat radiation). In contrast, thermal imaging by means of an infrared (IR) camera provides a real-time, holistic image. Here we provide some background on IR cameras and their uses in education, and summarize five qualitative investigations that we have used in our courses.

Keyword
infrared cameras; thermodynamics; physics education research; laboratory
National Category
Didactics Physical Sciences
Research subject
Physics with specialization in Physics Education
Identifiers
urn:nbn:se:uu:diva-306683 (URN)10.1119/1.4967889 (DOI)000388753500005 ()
Available from: 2016-11-02 Created: 2016-11-01 Last updated: 2017-11-29Bibliographically approved
Eriksson, J., Nocente, M., Binda, F., Cazzaniga, C., Conroy, S., Ericsson, G., . . . Weiszflog, M. (2015). Dual sightline measurements of MeV range deuterons with neutron and gamma-ray spectroscopy at JET. Nuclear Fusion, 55(12), Article ID 123026.
Open this publication in new window or tab >>Dual sightline measurements of MeV range deuterons with neutron and gamma-ray spectroscopy at JET
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2015 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 55, no 12, 123026Article in journal (Refereed) Published
Abstract [en]

Observations made in a JET experiment aimed at accelerating deuterons to the MeV range by third harmonic radio-frequency (RF) heating coupled into a deuterium beam are reported. Measurements are based on a set of advanced neutron and gamma-ray spectrometers that, for the first time, observe the plasma simultaneously along vertical and oblique lines of sight. Parameters of the fast ion energy distribution, such as the high energy cut-off of the deuteron distribution function and the RF coupling constant, are determined from data within a uniform analysis framework for neutron and gamma-ray spectroscopy based on a one-dimensional model and by a consistency check among the individual measurement techniques. A systematic difference is seen between the two lines of sight and is interpreted to originate from the sensitivity of the oblique detectors to the pitch-angle structure of the distribution around the resonance, which is not correctly portrayed within the adopted one dimensional model. A framework to calculate neutron and gamma-ray emission from a spatially resolved, two-dimensional deuteron distribution specified by energy/pitch is thus developed and used for a first comparison with predictions from ab initio models of RF heating at multiple harmonics.

The results presented in this paper are of relevance for the development of advanced diagnostic techniques for MeV range ions in high performance fusion plasmas, with applications to the experimental validation of RF heating codes and, more generally, to studies of the energy distribution of ions in the MeV range in high performance deuterium and deuterium-tritium plasmas.

Keyword
fusion, tokamak, fast ions, neutron spectrometry, gamma-ray spectroscopy
National Category
Fusion, Plasma and Space Physics
Research subject
Physics with specialization in Applied Nuclear Physics
Identifiers
urn:nbn:se:uu:diva-247990 (URN)10.1088/0029-5515/55/12/123026 (DOI)000366534500028 ()
Available from: 2015-03-25 Created: 2015-03-25 Last updated: 2017-12-04Bibliographically approved
Hellesen, C., Eriksson, J., Binda, F., Conroy, S., Ericsson, G., Hjalmarsson, A., . . . Weiszflog, M. (2015). Fuel ion ratio determination in NBI heated deuterium tritium fusion plasmas at JET using neutron emission spectrometry. Nuclear Fusion, 55(2), Article ID 023005.
Open this publication in new window or tab >>Fuel ion ratio determination in NBI heated deuterium tritium fusion plasmas at JET using neutron emission spectrometry
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2015 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 55, no 2, 023005Article in journal (Refereed) Published
Abstract [en]

The fuel ion ratio ( n t / n d ) is of central importance for the performance and control of a future burning fusion plasma, and reliable measurements of this quantity are essential for ITER. This paper demonstrates a method to derive the core fuel ion ratio by comparing the thermonuclear and beam-thermal neutron emission intensities, using a neutron spectrometer. The method is applied to NBI heated deuterium tritium (DT) plasmas at JET, using data from the magnetic proton recoil spectrometer. The trend in the results is consistent with Penning trap measurements of the fuel ion ratio at the edge of the plasma, but there is a discrepancy in the absolute values, possibly owing to the fact that the two measurements are weighted towards different parts of the plasma. It is suggested to further validate this method by comparing it to the traditionally proposed method to estimate n t / n d from the ratio of the thermal DD and DT neutron emission components. The spectrometer requirements for measuring n t / n d at ITER are also briefly discussed.

National Category
Fusion, Plasma and Space Physics
Research subject
Physics
Identifiers
urn:nbn:se:uu:diva-244352 (URN)10.1088/0029-5515/55/2/023005 (DOI)000348843100006 ()
Available from: 2015-02-16 Created: 2015-02-16 Last updated: 2017-12-04Bibliographically approved
Romanelli, F., Abhangi, M., Abreu, P., Aftanas, M., Afzal, M., Aggarwal, K. M., . . . Zychor, I. (2015). Overview of the JET results. Paper presented at 25th Fusion Energy Conference (FEC), OCT 13-18, 2014, Govt Russian Federat, St Petersburg, RUSSIA. Nuclear Fusion, 55(10), Article ID 104001.
Open this publication in new window or tab >>Overview of the JET results
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2015 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 55, no 10, 104001Article in journal, Meeting abstract (Refereed) Published
Abstract [en]

Since the installation of an ITER-like wall, the JET programme has focused on the consolidation of ITER design choices and the preparation for ITER operation, with a specific emphasis given to the bulk tungsten melt experiment, which has been crucial for the final decision on the material choice for the day-one tungsten divertor in ITER. Integrated scenarios have been progressed with the re-establishment of long-pulse, high-confinement H-modes by optimizing the magnetic configuration and the use of ICRH to avoid tungsten impurity accumulation. Stationary discharges with detached divertor conditions and small edge localized modes have been demonstrated by nitrogen seeding. The differences in confinement and pedestal behaviour before and after the ITER-like wall installation have been better characterized towards the development of high fusion yield scenarios in DT. Post-mortem analyses of the plasma-facing components have confirmed the previously reported low fuel retention obtained by gas balance and shown that the pattern of deposition within the divertor has changed significantly with respect to the JET carbon wall campaigns due to the absence of thermally activated chemical erosion of beryllium in contrast to carbon. Transport to remote areas is almost absent and two orders of magnitude less material is found in the divertor.

Keyword
JET, tokamaks, magnetic confinement
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-309696 (URN)10.1088/0029-5515/55/10/104001 (DOI)000363762900002 ()
Conference
25th Fusion Energy Conference (FEC), OCT 13-18, 2014, Govt Russian Federat, St Petersburg, RUSSIA
Available from: 2016-12-07 Created: 2016-12-07 Last updated: 2017-11-29Bibliographically approved
Melander, E., Haglund, J., Weiszflog, M. & Andersson, S. (2015). To see the invisible: open-ended university thermodynamics labs with infrared cameras. In: Stefan Pålsson & Björn Victor (Ed.), Proceedings från 5:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar: Technical Report 2016-002. Paper presented at 5:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar (5th Developmental Conference for Sweden's Engineering Education), 18-19 November, 2015, Uppsala (pp. 35-37). Uppsala.
Open this publication in new window or tab >>To see the invisible: open-ended university thermodynamics labs with infrared cameras
2015 (English)In: Proceedings från 5:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar: Technical Report 2016-002 / [ed] Stefan Pålsson & Björn Victor, Uppsala, 2015, 35-37 p.Conference paper, Published paper (Other academic)
Abstract [en]

Thermal imaging with an infrared (IR) camera provides a real-time, holistic image of thermal energy transport. In this workshop, we engage with open-ended laboratory exercises where IR cameras give added value to the understanding of central concepts in second year university thermodynamics courses for physics and engineering students.

Place, publisher, year, edition, pages
Uppsala: , 2015
Keyword
Engineering education; thermal sensors
National Category
Didactics
Identifiers
urn:nbn:se:uu:diva-287549 (URN)
Conference
5:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar (5th Developmental Conference for Sweden's Engineering Education), 18-19 November, 2015, Uppsala
Available from: 2016-04-25 Created: 2016-04-25 Last updated: 2016-04-26Bibliographically approved
Sangaroon, S., Weiszflog, M., Cecconello, M., Conroy, S., Ericsson, G., Wodniak, I., . . . Turnyanskiy, M. (2014). A poloidal section neutron camera for MAST Upgrade. In: Gorini, G; Orsitto, FP; Sozzi, C; Tardocchi, M (Ed.), Fusion Reactor Diagnostics: . Paper presented at International Conference on Fusion Reactor Diagnostics, SEP 09-13, 2013, Varenna, ITALY (pp. 129-132). .
Open this publication in new window or tab >>A poloidal section neutron camera for MAST Upgrade
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2014 (English)In: Fusion Reactor Diagnostics / [ed] Gorini, G; Orsitto, FP; Sozzi, C; Tardocchi, M, 2014, 129-132 p.Conference paper, Published paper (Other academic)
Abstract [en]

The Mega Ampere Spherical Tokamak Upgrade (MAST Upgrade) is intended as a demonstration of the physics viability of the Spherical Tokamak (ST) concept and as a platform for contributing to ITER/DEMO physics. Concerning physics exploitation, MAST Upgrade plasma scenarios can contribute to the ITER Tokamak physics particularly in the field of fast particle behavior and current drive studies. At present, MAST is equipped with a prototype neutron camera (NC). On the basis of the experience and results from previous experimental campaigns using the NC, the conceptual design of a neutron camera upgrade (NC Upgrade) is being developed. As part of the MAST Upgrade, the NC Upgrade is considered a high priority diagnostic since it would allow studies in the field of fast ions and current drive with good temporal and spatial resolution. In this paper, we explore an optional design with the camera array viewing the poloidal section of the plasma from different directions.

Series
AIP Conference Proceedings, ISSN 0094-243X ; 1612
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-221558 (URN)10.1063/1.4894039 (DOI)000343712300024 ()978-0-7354-1248-4 (ISBN)
Conference
International Conference on Fusion Reactor Diagnostics, SEP 09-13, 2013, Varenna, ITALY
Available from: 2014-04-02 Created: 2014-04-01 Last updated: 2014-12-11Bibliographically approved
Weiszflog, M., Sangaroon, S., Cecconello, M., Conroy, S., Ericsson, G., Klimek, I., . . . Turnyanskiy, M. (2014). Conceptual design of a neutron camera for MAST Upgrade. Review of Scientific Instruments, 85(11), 11E121.
Open this publication in new window or tab >>Conceptual design of a neutron camera for MAST Upgrade
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2014 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 85, no 11, 11E121- p.Article in journal (Refereed) Published
Abstract [en]

This paper presents two different conceptual designs of neutron cameras for Mega Ampere Spherical Tokamak (MAST) Upgrade. The first one consists of two horizontal cameras, one equatorial and one vertically down-shifted by 65 cm. The second design, viewing the plasma in a poloidal section, also consists of two cameras, one radial and the other one with a diagonal view. Design parameters for the different cameras were selected on the basis of neutron transport calculations and on a set of target measurement requirements taking into account the predicted neutron emissivities in the different MAST Upgrade operating scenarios. Based on a comparison of the cameras' profile resolving power, the horizontal cameras are suggested as the best option.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-240142 (URN)10.1063/1.4891926 (DOI)000345646000141 ()25430300 (PubMedID)
Available from: 2015-01-07 Created: 2015-01-05 Last updated: 2017-12-05Bibliographically approved
Binda, F., Ericsson, G., Hellesen, C., Hjalmarsson, A., Eriksson, J., Skiba, M., . . . Weiszflog, M. (2014). Monte Carlo Simulation Of The Data Acquisition Chain Of Scintillation Detectors. In: International Conference on Fusion Reactor Diagnostics, SEP 09-13, 2013, Varenna, ITALY: . Paper presented at International Conference on Fusion Reactor Diagnostics, SEP 09-13, 2013, Varenna, ITALY (pp. 101-104). .
Open this publication in new window or tab >>Monte Carlo Simulation Of The Data Acquisition Chain Of Scintillation Detectors
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2014 (English)In: International Conference on Fusion Reactor Diagnostics, SEP 09-13, 2013, Varenna, ITALY, 2014, 101-104 p.Conference paper, Published paper (Refereed)
Abstract [en]

The good performance of a detector can be strongly affected by the instrumentation used to acquire the data. The possibility of anticipating how the acquisition chain will affect the signal can help in finding the best solution among different set-ups. In this work we developed a Monte Carlo code that aims to simulate the effect of the various components of a digital Data Acquisition system (DAQ) applied to scintillation detectors. The components included in the model are: the scintillator, the photomultiplier tube (PMT), the signal cable and the digitizer. We benchmarked the code against real data acquired with a NE213 scintillator, comparing simulated and real signal pulses induced by gamma-ray interaction. Then we studied the dependence of the energy resolution of a pulse height spectrum (PHS) on the sampling frequency and the bit resolution of the digitizer. We found that exceeding some values of the sampling frequency and the bit resolution improves only marginally the performance of the system. The method can be applied for the study of various detector systems relevant for nuclear techniques, such as in fusion diagnostics.

Series
AIP Conference Proceedings, ISSN 0094-243X ; 1612
Keyword
Data acquisition, Scintillators, Photomultiplier tubes, Digitizers, NE213, Gamma-rays, Resolution, Monte Carlo
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-237652 (URN)10.1063/1.4894032 (DOI)000343712300017 ()978-0-7354-1248-4 (ISBN)
Conference
International Conference on Fusion Reactor Diagnostics, SEP 09-13, 2013, Varenna, ITALY
Available from: 2014-12-11 Created: 2014-12-03 Last updated: 2016-05-03Bibliographically approved
Eriksson, J., Binda, F., Conroy, S., Ericsson, G., Hellesen, C., Hjalmarsson, A., . . . Weiszflog, M. (2014). Neutron spectrometry measurements of energetic deuterons in ICRF heated plasmas with the ITER-like wall at JET. In: 41th EPS Conference on Plasma Physics 2014 (EPS 2014): Europhysics Conference Abstracts: . Paper presented at 41st EPS Conference on Plasma Physics, Berlin 2014. .
Open this publication in new window or tab >>Neutron spectrometry measurements of energetic deuterons in ICRF heated plasmas with the ITER-like wall at JET
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2014 (English)In: 41th EPS Conference on Plasma Physics 2014 (EPS 2014): Europhysics Conference Abstracts, 2014Conference paper, Published paper (Other academic)
Abstract [en]

At JET, experiments have been conducted in order to optimize the performance of ion cyclotron radio-frequency (ICRF) heating in the presence of the newly installed ITER-like wall. The ICRF was tuned to the cyclotron frequency of minority hydrogen (H), which is also the 2nd harmonic of the cyclotron frequency of deuterium (D). The relative H concentration was varied from a few percent up to about 25 percent in a series of plasma discharges and the neutron time-of-flight spectrometer TOFOR was used to measure the energy spectrum of neutrons from the D(D,n)3He reaction during these discharges. It could be seen that the signal from ICRF accelerated deuterons depended strongly on H concentration. This observation indicates that the ICRF power absorbed by D at the 2nd harmonic cyclotron resonance increases with decreasing H concentration. This is in qualitative agreement with theoretical expectations obtained from the plasma wave equation solver TOMCAT.

Keyword
neutron spectrometry, radiofrequency heating
National Category
Fusion, Plasma and Space Physics
Research subject
Physics with specialization in Applied Nuclear Physics
Identifiers
urn:nbn:se:uu:diva-234730 (URN)
Conference
41st EPS Conference on Plasma Physics, Berlin 2014
Available from: 2014-10-23 Created: 2014-10-23 Last updated: 2016-01-25
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