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Thungström, Göran
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Publications (10 of 89) Show all publications
Soetedjo, H., Niskanen, I., Rautkari, L., Altgen, M., Hiltunen, E., Thungström, G., . . . Räty, J. (2018). Determining the degree of heat treatment of wood by light polarization technique. European Journal of Wood and Wood Products, 1-4
Open this publication in new window or tab >>Determining the degree of heat treatment of wood by light polarization technique
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2018 (English)In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, p. 1-4Article in journal (Refereed) Published
Abstract [en]

Thermal modification of wood enables the use of non-durable wood species in exterior applications, but quality control methods are required to monitor the product variability. This study tests the potential of a light polarization technique where visible light (400–500 nm) is directed through a linear polarizer to the surface of thermally modified wood to measure the reflectance. Besides an effect of the grain direction, the reflectance decreased with increasing temperature during the thermal modification process. The technique could be used for quality control, but further studies are required to understand its modes of action. 

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-33664 (URN)10.1007/s00107-018-1311-2 (DOI)
Available from: 2018-05-23 Created: 2018-05-23 Last updated: 2018-05-23Bibliographically approved
Niskanen, I., Sutinen, V., Thungström, G. & Räty, J. (2018). Image Information Obtained Using a Charge-Coupled Device (CCD) Camera During an Immersion Liquid Evaporation Process for Measuring the Refractive Index of Solid Particles. Applied Spectroscopy, 72(6), 908-912
Open this publication in new window or tab >>Image Information Obtained Using a Charge-Coupled Device (CCD) Camera During an Immersion Liquid Evaporation Process for Measuring the Refractive Index of Solid Particles
2018 (English)In: Applied Spectroscopy, ISSN 0003-7028, E-ISSN 1943-3530, Vol. 72, no 6, p. 908-912Article in journal (Refereed) Published
Abstract [en]

The refractive index is a fundamental physical property of a medium, which can be used for the identification and purity issues of all media. Here we describe a refractive index measurement technique to determine simultaneously the refractive index of different solid particles by monitoring the transmittance of light from a suspension using a charge-coupled device (CCD) camera. An important feature of the measurement is the liquid evaporation process for the refractive index matching of the solid particle and the immersion liquid; this was realized by using a pair of volatile and non-volatile immersion liquids. In this study, refractive indices of calcium fluoride (CaF2) and barium fluoride (BaF2) were determined using the proposed method.

Keywords
BaF2, barium fluoride, CaF2, calcium fluoride, CCD camera, charge-coupled device camera, evaporation, image immersion liquid method, liquid mixture, Refractive index
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-33666 (URN)10.1177/0003702818756660 (DOI)000434314700010 ()29336586 (PubMedID)
Available from: 2018-05-23 Created: 2018-05-23 Last updated: 2018-07-04Bibliographically approved
Gaynullin, B., Bryzgalov, M., Hummelgård, C., Mattsson, C., Rödjegård, H. & Thungström, G. (2017). Pressure characterization and resolution limits' investigation of high accuracy NDIR Methane sensor for environmental applications. In: : . Paper presented at 14th International Workshop on Advanced Infrared Technology and Applications, AITA 2017, Québec City, Canada, September 27-29, 2017.
Open this publication in new window or tab >>Pressure characterization and resolution limits' investigation of high accuracy NDIR Methane sensor for environmental applications
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2017 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-32634 (URN)
Conference
14th International Workshop on Advanced Infrared Technology and Applications, AITA 2017, Québec City, Canada, September 27-29, 2017
Available from: 2018-01-02 Created: 2018-01-02 Last updated: 2018-01-03Bibliographically approved
Ashraf, S., Mattsson, C. & Thungström, G. (2016). Fabrication of a mid-Ir sensitive thermopile detector. In: Proceedings of IEEE Sensors: . Paper presented at 15th IEEE Sensors Conference, SENSORS 2016; Convention Center at the Caribe Royale HotelOrlando; United States; 30 October 2016 through 2 November 2016. IEEE, Article ID 7808481.
Open this publication in new window or tab >>Fabrication of a mid-Ir sensitive thermopile detector
2016 (English)In: Proceedings of IEEE Sensors, IEEE, 2016, article id 7808481Conference paper, Published paper (Refereed)
Abstract [en]

This paper reports on the integration of a multilayered mid-infrared absorber structure into a SU-8 epoxy membrane-based thermopile detector. The absorber structure was designed and simulated using transfer matrix theory. The fabricated absorber structures were characterized through Fourier transform infrared spectroscopy. The structure shows an absorption of more than 95% in the wavelength range of 3.30pm–5pm for simulations, and 3.2pm–5.47pm for FTIR measurements. The complete fabrication process of a thermopile detector including the integration of a multilayered absorber structure has been presented. A MEMS based infrared emitter was used to characterize the fabricated detector. The serial resistance was measured to 315 kΩ and the responsivity was calculated to 57.5 Vmm2W−1 at a wavelength of 4.26pm. The time constant for the fabricated detector was estimated to around 21ms.

Place, publisher, year, edition, pages
IEEE, 2016
Series
IEEE Sensors, ISSN 1930-0395
Keywords
Detectors, Voltage measurement, Fabrication, Absorption, Electrical resistance measurement, Wavelength measurement, Resistance
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-29547 (URN)10.1109/ICSENS.2016.7808481 (DOI)000399395700076 ()2-s2.0-85011003061 (Scopus ID)STC (Local ID)978-1-4799-8287-5 (ISBN)STC (Archive number)STC (OAI)
Conference
15th IEEE Sensors Conference, SENSORS 2016; Convention Center at the Caribe Royale HotelOrlando; United States; 30 October 2016 through 2 November 2016
Available from: 2017-01-17 Created: 2016-12-13 Last updated: 2017-06-29Bibliographically approved
Fröjdh, C., Krapohl, D. & Thungström, G. (2016). Hard X-ray imaging and particle detection with TIMEPIX3. In: Proceedings of SPIE - The International Society for Optical Engineering: . Paper presented at SPIE Conference on Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XVIII, AUG 29-31, 2016, San Diego, CA. SPIE - International Society for Optical Engineering, 9968, Article ID UNSP 99680T.
Open this publication in new window or tab >>Hard X-ray imaging and particle detection with TIMEPIX3
2016 (English)In: Proceedings of SPIE - The International Society for Optical Engineering, SPIE - International Society for Optical Engineering, 2016, Vol. 9968, article id UNSP 99680TConference paper, Published paper (Refereed)
Abstract [en]

CMOS pixel electronics open up for applications with single photon or particle processing. TIMEPIX3 is a readout chip in the MEDIPIX family with the ability to simultaneously determine energy and time of interaction in the pixel. The device is fully event driven, sending out data on each interaction at a maximum speed of about 40 Mhits/s. The concept allows for off-line processing to correct for charge sharing or to find the interaction point in multi pixel events. The timing resolution of 1.56 ns allows for three dimensional tracking of charged particles in a thick sensor due to the drift time for the charge in the sensor. The experiments in this presentation have been performed with silicon sensors bonded MEDIPIX family chips with special focus on TIMEPIX3. This presentation covers basic performance of the chip, spectral imaging with hard X-rays, detection and imaging with charged particles and neutrons. Cluster identification, centroiding and charge summing is extensively used to determine energy and position of the interaction. For neutron applications a converter layer was placed on top of the sensor.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2016
Series
Proceedings of SPIE, ISSN 0277-786X ; 9968
Keywords
charge sharing, particle identification, Pixel detector, single photon processing
National Category
Physical Sciences
Identifiers
urn:nbn:se:miun:diva-29806 (URN)10.1117/12.2238505 (DOI)000389506700013 ()2-s2.0-85007206718 (Scopus ID)STC (Local ID)978-1-5106-0327-1 (ISBN)978-1-5106-0328-8 (ISBN)STC (Archive number)STC (OAI)
Conference
SPIE Conference on Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XVIII, AUG 29-31, 2016, San Diego, CA
Available from: 2017-01-02 Created: 2017-01-02 Last updated: 2017-06-30Bibliographically approved
Krapohl, D., Schubel, A., Fröjdh, E., Thungström, G. & Fröjdh, C. (2016). Validation of Geant4 Pixel Detector Simulation Framework by Measurements with the Medipix Family Detectors. IEEE Transactions on Nuclear Science, 63(3), 1874-1881, Article ID 7497723.
Open this publication in new window or tab >>Validation of Geant4 Pixel Detector Simulation Framework by Measurements with the Medipix Family Detectors
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2016 (English)In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 63, no 3, p. 1874-1881, article id 7497723Article in journal (Refereed) Published
Abstract [en]

Monte Carlo simulations are an extensively used tool for developingand understanding radiation detector systems. In this work, we usedresults of several chips and readout modes of the Medipix detector family to validatea Geant4 based pixel detector framework, developed in our group, thatis capable of simulating particle tracking, charge transport in thesensor material and different readout schemes. We experimentally verifiedthe simulation with different detector geometries in terms of pixelpitch and size as well as sensor material and sensor thickness. Thesingle pixel mode (SPM) and charge summing mode (CSM) in Medipix3 were evaluated with fluorescenceand synchrotron radiation. The integration of the charge sensitiveamplifier functionality in the simulation framework allowed to simulatethe time-over-threshold mode of the Timepix chip.Simulation and measurement have been compared in terms of spectralresolution using threshold scans in photon counting mode (Medipix3) and time over thresholdmode (Timepix). Furthercomparisons were done using X-ray tube spectra and beta decay to covera broad energy range. Additionally, TCAD simulations are performedas a comparison to a well-established simulation method. The resultsshow good agreement between simulation and measurement.

Keywords
Monte Carlo Simulation, Medipix, Timepix, photon counting detectors, x-ray, alpha-radiation
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:miun:diva-27746 (URN)10.1109/TNS.2016.2555958 (DOI)000382463600021 ()2-s2.0-84978249235 (Scopus ID)STC (Local ID)STC (Archive number)STC (OAI)
Available from: 2016-05-20 Created: 2016-05-20 Last updated: 2017-06-30Bibliographically approved
Gaynullin, B., Hummelgård, C., Mattsson, C., Rödjegård, H. & Thungström, G. (2015). Comparative study of CO2 and CH4 pressure dependence in the HPP NDIR platform. In: : . Paper presented at 2015th FPIRC International Summer Conference.
Open this publication in new window or tab >>Comparative study of CO2 and CH4 pressure dependence in the HPP NDIR platform
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2015 (English)Conference paper, Oral presentation only (Other academic)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-32636 (URN)
Conference
2015th FPIRC International Summer Conference
Available from: 2018-01-02 Created: 2018-01-02 Last updated: 2018-01-05Bibliographically approved
Reza, S., Chang, H., Norlin, B., Fröjdh, C. & Thungström, G. (2015). Detecting Cr Contamination In Water Using X-Ray Fluorescence. In: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference: . Paper presented at 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015; San Diego; United States; 31 October 2015 through 7 November 2015. Institute of Electrical and Electronics Engineers (IEEE), Article ID 7581750.
Open this publication in new window or tab >>Detecting Cr Contamination In Water Using X-Ray Fluorescence
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2015 (English)In: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, Institute of Electrical and Electronics Engineers (IEEE), 2015, article id 7581750Conference paper, Published paper (Other academic)
Abstract [en]

With the rapid growth in population and the overwhelming demand of industrial consumer products around the world, the amount of generated wastes is also increasing. Therefore, the optimal utilization of wastes and the waste management policies are very important in order to protect the environment[1]. The most common way of waste management is to dispose them into city dumps and landfills. These disposal sites may produce toxic and green house gases and also a substantial amount of leachate, which can affect the environment[2]. Leachate is liquid, which, while percolating through wastes in a landfill, extracts soluble and suspended solids. Leachate contains toxic and harmful substances, such as Chromium (Cr), Arsenic, Lead, Mercury, Benzene, Chloroform and Methylene Chloride, and can contaminate surface water and aquifers.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2015
National Category
Engineering and Technology Health Sciences Natural Sciences
Identifiers
urn:nbn:se:miun:diva-26295 (URN)10.1109/NSSMIC.2015.7581750 (DOI)2-s2.0-84994225825 (Scopus ID)STC (Local ID)STC (Archive number)STC (OAI)
Conference
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015; San Diego; United States; 31 October 2015 through 7 November 2015
Available from: 2015-11-24 Created: 2015-11-24 Last updated: 2017-03-02Bibliographically approved
Norlin, B., Reza, S., Krapohl, D., Fröjdh, E. & Thungström, G. (2015). Readout cross-talk for alpha-particle measurements in a pixelated sensor system. Paper presented at 16th International Workshop on Radiation Imaging Detectors (IWORID2014). Journal of Instrumentation, 10, Article ID C05025.
Open this publication in new window or tab >>Readout cross-talk for alpha-particle measurements in a pixelated sensor system
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2015 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 10, article id C05025Article in journal (Refereed) Published
Abstract [en]

Simulations in Medici are performed to quantify crosstalk and charge sharing in a hybrid pixelated silicon detector. Crosstalk and charge sharing degrades the spatial and spectral resolution of single photon processing X-ray imaging systems. For typical medical X-ray imaging applications, the process is dominated by charge sharing between the pixels in the sensor. For heavier particles each impact generates a large amount of charge and the simulation seems to over predict the charge collection efficiency. This indicates that some type of non modelled degradation of the charge transport efficiency exists, like the plasma effect where the plasma might shield the generated charges from the electric field and hence distorts the charge transport process. Based on the simulations it can be reasoned that saturation of the amplifiers in the Timepix system might generate crosstalk that increases the charge spread measured from ion impact on the sensor.

Keywords
Charge transport and multiplication in solid media; Hybrid detectors; X-ray detec- tors; Imaging spectroscopy
National Category
Physical Sciences Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-24977 (URN)10.1088/1748-0221/10/05/C05025 (DOI)000357993300025 ()2-s2.0-84930958451 (Scopus ID)STC (Local ID)STC (Archive number)STC (OAI)
Conference
16th International Workshop on Radiation Imaging Detectors (IWORID2014)
Available from: 2015-05-25 Created: 2015-05-25 Last updated: 2017-12-04Bibliographically approved
Ashraf, S., Mattsson, C., Fondell, M., Lindblad, A. & Thungström, G. (2015). Surface modification of SU-8 for metal/SU-8 adhesion using RF plasma treatment for application in thermopile detectors. Materials Research Express, 2(8), Article ID 086501.
Open this publication in new window or tab >>Surface modification of SU-8 for metal/SU-8 adhesion using RF plasma treatment for application in thermopile detectors
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2015 (English)In: Materials Research Express, ISSN 2053-1591, Vol. 2, no 8, article id 086501Article in journal (Refereed) Published
Abstract [en]

This article reports on plasma treatment of SU-8 epoxy in order to enhance adhesive strength for metals. Its samples were fabricated on standard silicon wafers and treated with (O2 & Ar) RF plasma at a power of 25W at a low pressure of (3×10-3 torr) for different time spans (10 sec – 70 sec). The sample surfaces were characterized in terms of contact angle, surface (roughness and chemistry) and using a tape test. During the contact angle measurement, it was observed that the contact angle was reduced from 73° to 5° (almost wet) and 23° for (O2 & Ar) treated samples, respectively. The RMS surface roughness was significantly increased by 21.5% and 37.2% for (O2 & Ar) treatment, respectively. A pattern of metal squares was formed on the samples using photolithography for a tape test. An adhesive tape was applied to the samples and peeled off at 180o. The maximum adhesion results, more than 90%, were achieved for the O2-treated samples, whereas the Ar-treated samples showed no change. The XPS study shows the formation of new species in the O2-treated sample compared to the Ar-treated samples. The high adhesive results were due to the formation of hydrophilic groups and new O2 species in the O2-treated samples, which were absent in Ar-treated samples.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2015
Keywords
SU-8, contact angle, plasma treatment, surface modification, adhesion, tape test, theromocouples
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:miun:diva-26157 (URN)10.1088/2053-1591/2/8/086501 (DOI)000370037800017 ()2-s2.0-84954539766 (Scopus ID)STC (Local ID)STC (Archive number)STC (OAI)
Available from: 2015-10-28 Created: 2015-10-28 Last updated: 2016-10-17Bibliographically approved
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