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Advanced X-ray Detectors for Industrial and Environmental Applications
Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The new generation of X-ray free electron laser sources arecapable of producing light beams with billion times higherpeak brilliance than that of the best conventional X-ray sources.This advancement motivates the scientific community to pushforward the detector technology to its limit, in order to de-sign photon detectors which can cope with the extreme fluxgenerated by the free electron laser sources. Sophisticated ex-periments like deciphering the atomic details of viruses, filmingchemical reactions or investigating the extreme states of matterrequire 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 aninternational group of scientists in collaboration to meet theaforementioned detector requirements within the energy rangeof 250 eV to 1 keV, with a quantum efficiency above 90%.In this doctoral researchwork, Monte Carlo algorithm basedGeant4 and finite element method based Synopsys SentaurusTCADtoolkits have been used to simulate, respectively, theX-rayenergy deposition and the charge sharing in PERCIVAL. Energydeposition per pixel and charge sharing between adjacent pixelsat different energies have been investigated and presented.Novel methods for industrial and environmental applica-tions of some commercially available X-ray detectors have beendemonstrated. Quality inspection of paperboards by resolv-ing the layer thicknesses and by investigating orientation ofthe cellulose fibres have been performed using spectroscopicand phase-contrast X-ray imaging. It was found that, usingphase-contrast imaging it is possible to set burn-out like qualityindex on paperboards non-destructively. X-ray fluoroscopicmeasurements have been conducted in order to detect Cr inwater. This method can be used to detect Cr and other toxicelements in leachate in landfills and other waste dumping sites.

Abstract [sv]

Acceleratorbaserade röntgenkällor utvecklas ständigt, dessakan producera röntgenstrålning med miljarder gånger så högeffekttäthet som de starkaste konventionella röntgenkällorna.Därför finns en vetenskaplig utmaning att utveckla röntgende-tektorer som inte förstörs i de extrema flöden som genereras avdessa röntgenkällor. De visioner som finns för de nya källornaär t.ex.; att avbilda detaljer av virus ner på atomnivå, att filmakemiska reaktioner eller att undersöka extrema tillstånd hos ma-teria. Dessa typer av experiment kräver röntgendetektorer medhög bildhastighet, hög spatial upplösning och stort intensitets-omfång och stor aktiv sensoryta. Detektorsystemet PERCIVALsom bygger på aktiva pixlar med energiupplösning utvecklasinom ett internationellt vetenskapligt samarbetsprojekt. Må-let är att uppfylla detektorspecifikationerna för de nämndaexperimenten inom energiområdet 250 eV till 1 keV, med enkvantverkningsgrad över 90 %.I föreliggande vetenskapliga avhandlingsarbete har simule-ringar av energideponering i PERCIVAL-detektorn genomförtsbaserat på Monte Carlo-algoritmer och simuleringar av ladd-ningsdelning mellan pixlar har simulerats med hjälp av finitaelementmetoden. Därmed har energideponeringen per pixeloch laddningsdelningen mellan närliggande pixlar vid olikaenergier kunnat utredas och presenteras.I avhandlingen demonstreras nya lovande metoder för in-dustriella applikationer och miljöövervakning,därkommersiellttillgängliga röntgendetektorer kan användas. Kvalitetsövervak-ning av kartongtillverkning genom att mäta bestrykningstjock-lek och fiberorientering kan realiseras med energiupplöstaröntgenbilder eller faskontrastbilder i röntgenområdet. Det kankonstateras att med icke-förstörande provning, genom faskon-trastbilder, kan kvalitetsindexvärlden erhållas på samma sättsom kvalitetsindex kan erhållas från ”burn-out”-mätningar.Spektroskopiska mätningar av röntgenflourescens har genom-förts för att detektera krom (Cr) i vatten. Metodik för att detek-tera krom och andra giftiga metaller i lakvatten från deponioch annan lagring för giftigt avfall har utarbetats.

Place, publisher, year, edition, pages
Sundsvall: Mid Sweden University , 2016. , 159 p.
Series
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 253
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
URN: urn:nbn:se:miun:diva-29264ISBN: 978-91-88025-84-5OAI: oai:DiVA.org:miun-29264DiVA: diva2:1045610
Public defence
2016-12-01, M108, Sundsvall, 10:15 (English)
Opponent
Supervisors
Available from: 2016-11-10 Created: 2016-11-10 Last updated: 2016-11-10Bibliographically 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, Vol. 10, 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.

Keyword
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 (ScopusID)
Conference
16th International Workshop on Radiation Imaging Detectors (IWORID2014)
Available from: 2015-05-25 Created: 2015-05-25 Last updated: 2016-11-10Bibliographically 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, Art. no. C04004- p.Article 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.

Keyword
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:miun:diva-18741 (URN)10.1088/1748-0221/8/04/C04004 (DOI)000317462400004 ()2-s2.0-84877780840 (ScopusID)STC (Local ID)STC (Archive number)STC (OAI)
Conference
14th International Workshop on Radiation Imaging Detectors; 1-5 July 2012; Figueira da Foz, PORTUGAL
Available from: 2013-04-12 Created: 2013-04-12 Last updated: 2016-11-10Bibliographically 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 of SPIE - The International Society for Optical Engineering, SPIE - International Society for Optical Engineering, 2013, Art. no. 88520O- p.Conference 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
Series
, Proceedings of SPIE, ISSN 0277-786X ; 8852
Keyword
Pixel detectors, single photon processing, X-ray
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:miun:diva-21069 (URN)10.1117/12.2023983 (DOI)000326643800014 ()2-s2.0-84886996985 (ScopusID)STC (Local ID)978-081949702-4 (ISBN)STC (Archive number)STC (OAI)
Conference
SPIE Conference on Hard X-Ray, Gamma-Ray and Neutron Detector Physics XV; San Diego, CA; United States; 26 August 2013 through 28 August 2013; Code 100563
Available from: 2014-01-16 Created: 2014-01-16 Last updated: 2016-11-10Bibliographically 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 / [ed] Jan S. Iwanczyk and Krzysztof Iniewski, CRC Press, 2015Chapter in book (Refereed)
Place, publisher, year, edition, pages
CRC Press, 2015
National Category
Physical Sciences Engineering and Technology
Identifiers
urn:nbn:se:miun:diva-21021 (URN)9781498704359 (ISBN)
Available from: 2014-01-13 Created: 2014-01-13 Last updated: 2016-11-10Bibliographically 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 1748-0221Article 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.

Keyword
X-ray detectors, Instrumentation for FEL, Solid state detectors
National Category
Natural Sciences Engineering and Technology
Identifiers
urn:nbn:se:miun:diva-27220 (URN)10.1088/1748-0221/11/02/C02090 (DOI)000371479800090 ()
Conference
17th International Workshop on Radiation Imaging Detectors
Available from: 2016-03-08 Created: 2016-03-08 Last updated: 2016-11-10Bibliographically 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 2015, Institute of Electrical and Electronics Engineers (IEEE), 2016, 7581940Conference paper (Other academic)
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
Engineering and Technology
Identifiers
urn:nbn:se:miun:diva-26298 (URN)10.1109/NSSMIC.2015.7581940 (DOI)2-s2.0-84994107250 (ScopusID)978-146739862-6 (ISBN)
Conference
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference / Symposium on Room-Temperature Semiconductor X-Ray and Gamma-Ray Detectors, October 31 - November 7, San Diego, California, USA
Available from: 2015-11-24 Created: 2015-11-24 Last updated: 2016-12-02Bibliographically 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, 439-442 p.Article 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.

Keyword
Spectroscopic X-ray imaging, Thickness measurement of layers in paperboard, Paperboard quality
National Category
Paper, Pulp and Fiber Technology Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-18400 (URN)000325145900014 ()2-s2.0-84883036103 (ScopusID)STC (Local ID)STC (Archive number)STC (OAI)
Available from: 2013-01-31 Created: 2013-01-31 Last updated: 2016-11-10Bibliographically 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, Vol. 9, Art. no. C04032- p.Article 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.

Keyword
Data processing methods, Inspection with x-rays, Interferometry, X-ray detectors
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-21822 (URN)10.1088/1748-0221/9/04/C04032 (DOI)000336123800032 ()2-s2.0-84899557220 (ScopusID)
Available from: 2014-04-24 Created: 2014-04-24 Last updated: 2016-11-10Bibliographically 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, Institute of Electrical and Electronics Engineers (IEEE), 2015, 7581750Conference 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 (ScopusID)978-146739862-6 (ISBN)
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: 2016-12-02Bibliographically approved

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