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Advanced X-ray Detectors for Industrial and Environmental Applications
Mittuniversitet.
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The new generation of X-ray free electron laser sources are capable of producing light beams with billion times higher peak brilliance than that of the best conventional X-ray sources. This advancement motivates the scientific community to push forward the detector technology to its limit, in order to de-sign photon detectors which can cope with the extreme flux generated by the free electron laser sources. Sophisticated ex-periments like deciphering the atomic details of viruses, filming chemical reactions or investigating the extreme states of matter require detectors with high frame rate, good spatial resolution, high dynamic range and large active sensor area. The PERCI-VAL monolithic active pixel sensor is being developed by an international group of scientists in collaboration to meet the aforementioned detector requirements within the energy rangeof 250 eV to 1 keV, with a quantum efficiency above 90%. In this doctoral research work, Monte Carlo algorithm based Geant4 and finite element method based Synopsys SentaurusTCAD toolkits have been used to simulate, respectively, theX-ray energy deposition and the charge sharing in PERCIVAL. Energydeposition per pixel and charge sharing between adjacent pixels at different energies have been investigated and presented. Novel methods for industrial and environmental applications of some commercially available X-ray detectors have been demonstrated. Quality inspection of paperboards by resolving the layer thicknesses and by investigating orientation of the cellulose fibres have been performed using spectroscopic and phase-contrast X-ray imaging. It was found that, using phase-contrast imaging it is possible to set burn-out like quality index on paperboards non-destructively. X-ray fluoroscopic measurements have been conducted in order to detect Cr inwater. This method can be used to detect Cr and other toxic elements in leachate in landfills and other waste dumping sites.

Place, publisher, year, edition, pages
Sundsvall: Mid Sweden University , 2016. , p. 159
Series
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 253
Keywords [en]
Electrical Engineering, Electronic Engineering, Information Engineering, Elektroteknik och elektronik
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
URN: urn:nbn:se:hig:diva-37240ISBN: 978-91-88025-84-5 (print)OAI: oai:DiVA.org:hig-37240DiVA, id: diva2:1605385
Available from: 2021-10-25 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved
List of papers
1. Readout cross-talk for alpha-particle measurements in a pixelated sensor system
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.

Place, publisher, year, edition, pages
IOP, 2015
Keywords
Charge transport and multiplication in solid media; Hybrid detectors; X-ray detectors; Imaging spectroscopy
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-37248 (URN)10.1088/1748-0221/10/05/C05025 (DOI)
Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved
2. Measurement of the sensitive profile in a solid state silicon detector, irradiated by X-rays
Open this publication in new window or tab >>Measurement of the sensitive profile in a solid state silicon detector, irradiated by X-rays
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2013 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 8, no 4, article id C04004Article in journal (Refereed) Published
Abstract [en]

A newly constructed solid state silicon dose profile detector is characterized concerning its sensitive profile. The use of the MEDIPIX2 sensor system displays an excellent method to align an image of an X-ray slit to a sample under test. The scanning from front to reverse side of the detector, show a decrease in sensitivity of 20%, which indicates a minority charge carrier lifetime of 0.18 ms and a diffusion length of 460 μm. The influence of diced edges results in a volumetric efficiency of 59%, an active volume of 1.2 mm 2 of total 2.1 mm2.

Place, publisher, year, edition, pages
IOP, 2013
Keywords
Computerized Tomography (CT) and Computed Radiography (CR); Dosimetry concepts and apparatus; Solid state detectors; X-ray detectors
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-37253 (URN)10.1088/1748-0221/8/04/C04004 (DOI)
Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved
3. Spectral resolution in pixel detectors with single photon processing
Open this publication in new window or tab >>Spectral resolution in pixel detectors with single photon processing
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2013 (English)In: Proceedings SPIE Optical Engineering + Applications, 2013, SPIE - International Society for Optical Engineering , 2013Conference paper, Published paper (Other academic)
Abstract [en]

Pixel detectors based on photon counting or single photon processing readout are becoming popular for spectral X-ray imaging. The detector is based on deep submicron electronics with functions to determine the energy of each individual photon in every pixel. The system is virtually noiseless when it comes to the number of the detected photons. However noise and variations in system parameters affect the determination of the photon energy. Several factors affect the energy resolution in the system. In the readout electronics the most important factors are the threshold dispersion, the gain variation and the electronic noise. In the sensor contributions come from charge sharing, variations in the charge collection efficiency, leakage current and the statistical nature of the charge generation, as described by the Fano factor. The MEDIPIX technology offers a powerful tool for investigating these effects since energy spectra can be captured in each pixel. In addition the TIMEPIX chip, when operated in Time over Threshold mode, offers an opportunity to analyze individual photon interactions, thus addressing charge sharing and fluorescence. Effects of charge sharing and the properties of charge summing can be investigated using MEDIPIX3RX. Experiments are performed using both Si and CdTe detectors. In this paper we discuss the various contributions to the spectral noise and how they affect detector response. The statements are supported with experimental data from MEDIPIX-type detectors.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2013
Keywords
Pixel detectors, single photon processing, X-ray, Accelerator Physics and Instrumentation, Acceleratorfysik och instrumentering
National Category
Clinical Medicine
Identifiers
urn:nbn:se:hig:diva-37255 (URN)10.1117/12.2023983 (DOI)9780819497024 (ISBN)
Conference
SPIE Optical Engineering + Applications, 2013, San Diego, California, United States
Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved
4. Grating based phase-contrast X-ray imaging technique
Open this publication in new window or tab >>Grating based phase-contrast X-ray imaging technique
2015 (English)In: Radiation Detectors for Medical Imaging, CRC Press , 2015Chapter in book (Other academic)
Place, publisher, year, edition, pages
CRC Press, 2015
Keywords
Physical Sciences, Fysik, Engineering and Technology, Teknik och teknologier
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-37247 (URN)9781498704359 (ISBN)
Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved
5. Characterisation of a PERCIVAL monolithic active pixel prototype using synchrotron radiation
Open this publication in new window or tab >>Characterisation of a PERCIVAL monolithic active pixel prototype using synchrotron radiation
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2016 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 11, no 2, article id C02090Article in journal (Refereed) Published
Abstract [en]

PERCIVAL (""Pixelated Energy Resolving CMOS Imager, Versatile And Large"") is a monolithic active pixel sensor (MAPS) based on CMOS technology. Is being developed by DESY, RAL/STFC, Elettra, DLS, and PAL to address the various requirements of detectors at synchrotron radiation sources and Free Electron Lasers (FELs) in the soft X-ray regime. These requirements include high frame rates and FELs base-rate compatibility, large dynamic range, single-photon counting capability with low probability of false positives, high quantum efficiency (QE), and (multi-)megapixel arrangements with good spatial resolution. Small-scale back-side-illuminated (BSI) prototype systems are undergoing detailed testing with X-rays and optical photons, in preparation of submission of a larger sensor. A first BSI processed prototype was tested in 2014 and a preliminary result—first detection of 350eV photons with some pixel types of PERCIVAL—reported at this meeting a year ago. Subsequent more detailed analysis revealed a very low QE and pointed to contamination as a possible cause. In the past year, BSI-processed chips on two more wafers were tested and their response to soft X-ray evaluated. We report here the improved charge collection efficiency (CCE) of different PERCIVAL pixel types for 400eV soft X-rays together with Airy patterns, response to a flat field, and noise performance for such a newly BSI-processed prototype sensor.

Place, publisher, year, edition, pages
IOP, 2016
Keywords
X-ray detectors, Instrumentation for FEL, Solid state detectors
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-37241 (URN)10.1088/1748-0221/11/02/C02090 (DOI)
Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved
6. Experimental characterization of the PERCIVAL soft X-ray detector
Open this publication in new window or tab >>Experimental characterization of the PERCIVAL soft X-ray detector
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2016 (English)In: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), Institute of Electrical and Electronics Engineers (IEEE) , 2016Conference paper, Published paper (Refereed)
Abstract [en]

Considerable interest has been manifested for the use of high-brilliance X-ray synchrotron sources and X-ray Free-Electron Lasers for the investigation of samples.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2016
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-37243 (URN)10.1109/NSSMIC.2015.7581940 (DOI)9781467398626 (ISBN)
Conference
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, San Diego
Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved
7. Non-Destructive Method to Resolve the Core and the Coating on Paperboard by Spectroscopic X-ray Imaging
Open this publication in new window or tab >>Non-Destructive Method to Resolve the Core and the Coating on Paperboard by Spectroscopic X-ray Imaging
2013 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 28, no 3, p. 439-442Article in journal (Refereed) Published
Abstract [en]

Quality control is an important issue in the paperboard industry. A typical sheet of paperboard contains a core of cellulose fibers [C6H10O5], coated on one or both sides with layers of calcium carbonate [CaCO3] or Kaolin [Al2Si2O5(OH)4]. One of the major properties of a good quality paperboard is the consistency of the expected ratio between the thickness of the core and the coating layers. A measurement system to obtain this ratio could assist the paperboard industry to monitor the quality of their products in an automatic manner. In this work, the thicknesses of the core and the coating layers on a paperboard with coating layer on only one side were measured using an X-ray imaging technique. However, the limited spectral and spatial resolution offered by the measurement system being used led to the measured thicknesses of the layers being lower than their actual thicknesses in the paperboard sample. Suggestions have been made in relation to overcoming these limitations and to enhance the performance of the method. A Monte Carlo N-particle code simulation has been used in order to verify the suggested method.

Keywords
Spectroscopic X-ray imaging, Thickness measurement of layers in paperboard, Paperboard quality, Paper, Pulp and Fiber Technology, Pappers-, massa- och fiberteknik, Electrical Engineering, Electronic Engineering, Information Engineering, Elektroteknik och elektronik
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-37254 (URN)
Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved
8. Investigation on the directional dark-field signals from paperboards using a grating interferometer
Open this publication in new window or tab >>Investigation on the directional dark-field signals from paperboards using a grating interferometer
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2014 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 9, article id C04032Article in journal (Refereed) Published
Abstract [en]

Recent advancements in the grating interferometer based Phase Contrast X-ray Imag- ing (PCXI) technique enables high quality dark-field images to be obtained using conventional X-ray tubes. The dark-field images map the scattering inhomogeneities inside objects. Since, the dark-field image is constructed by considering only those photons which are scattered while pass- ing through the objects, it can reveal useful information about the object inner structures, such as, the fibre structures inside paperboards. The end-use performance of paperboards, such as the printing quality and the stiffness de-pends on the uniformity in the thickness and the structures of the coating layer of the paperboards. The uniformity in the coating layer is determined by the coating techniques, the coating materials and the topography of the base sheet. In this article, the dark-field signals from four paperboard samples with different quality indices are analysed. The isotropic and the anisotropic scattering coefficients for all of the samples have been calculated. Based on the correlation between the isotropic coefficients and the quality indices of the paperboards, a new method for paperboard quality measurement has been suggested.

Place, publisher, year, edition, pages
IOP, 2014
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-37251 (URN)10.1088/1748-0221/9/04/C04032 (DOI)
Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved
9. Detecting Cr Contamination In Water Using X-Ray Fluorescence
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 (NSS/MIC), Institute of Electrical and Electronics Engineers (IEEE) , 2015Conference paper, Published paper (Refereed)
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
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-37246 (URN)10.1109/NSSMIC.2015.7581750 (DOI)978-1-4673-9862-6 (ISBN)
Conference
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, San Diego
Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2021-10-25Bibliographically approved

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Reza, Salim

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