| fullrecord |
[{"key": "dc.contributor.advisor", "value": "Kataja, Markku", "language": "", "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.advisor", "value": "Parkkonen, Joni", "language": "", "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.author", "value": "Yliharju, Janne", "language": "", "element": "contributor", "qualifier": "author", "schema": "dc"}, {"key": "dc.date.accessioned", "value": "2019-06-25T10:13:12Z", "language": null, "element": "date", "qualifier": "accessioned", "schema": "dc"}, {"key": "dc.date.available", "value": "2019-06-25T10:13:12Z", "language": null, "element": "date", "qualifier": "available", "schema": "dc"}, {"key": "dc.date.issued", "value": "2019", "language": "", "element": "date", "qualifier": "issued", "schema": "dc"}, {"key": "dc.identifier.uri", "value": "https://jyx.jyu.fi/handle/123456789/64839", "language": null, "element": "identifier", "qualifier": "uri", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Tutkielman aiheina ovat energiasensitiiviset fotoninlaskentailmaisimet ja r\u00f6ntgenkuvien kontrastin parantaminen. Tutkielma koostuu kirjallisuuskatsauksesta ja kokeellisesta osuudesta. Kirjallisuuskatsauksen t\u00e4rkeimpin\u00e4 tavoitteina oli selvitt\u00e4\u00e4, millaisia energiasensitiivisi\u00e4 fotoninlaskentailmaisimia on kehitetty ja millaisissa sovelluksissa niit\u00e4 on k\u00e4ytetty. Teoriaosuudessa esitell\u00e4\u00e4n my\u00f6s energian integroivia ilmaisimia. Erilaisiin mittausperiaatteisiin perustuvia ilmaisimia on vertailtu sek\u00e4 teoriassa ett\u00e4 k\u00e4yt\u00e4nn\u00f6ss\u00e4. Advacam MiniPIX on energiasensitiivinen fotoninlaskentailmaisin, jota k\u00e4ytettiin kokeissa. Kokeellisen osan t\u00e4rkeimp\u00e4n\u00e4 tavoitteena oli testata, pystyt\u00e4\u00e4nk\u00f6 koko spektrill\u00e4 kuvattaessa vaikeasti eroteltavien materiaalien kontrastia parantamaan k\u00e4ytt\u00e4m\u00e4ll\u00e4 kuvan muodostuksessa tiettyj\u00e4 energia-alueita.\nT\u00e4t\u00e4 testattiin kuvaamalla erilaisia muoveja sek\u00e4 Nb- ja Rh-kalvoja. Muovien tapauksessa kontrastissa ei havaittu merkitt\u00e4vi\u00e4 muutoksia, vaikka kuvaukset tehtiin erilaisilla energia-alueilla. Oletettavasti t\u00e4m\u00e4 johtuu muovien koostumuksen samankaltaisuudesta. Selvin havainto oli kontrastin huonontuminen, kun kuvan muodostukseen k\u00e4ytettiin spektrin suurimpia energian arvoja. Lis\u00e4ksi fotonien laskenta paransi hieman kontrastia verrattuna energian integrointiin, kun kuvauksessa k\u00e4ytettiin k\u00e4yt\u00e4nn\u00f6ss\u00e4 samaa energia-aluetta. Nb ja Rh ovat alkuaineita, joiden vaimennuskertoimien K-reunat ovat ilmaisimen toiminta-alueella. Mittausten perusteella kontrastin merkitt\u00e4v\u00e4 parannus on mahdollista hy\u00f6dynt\u00e4m\u00e4ll\u00e4 K-reunoja.", "language": "fi", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.abstract", "value": "The subjects of thesis are energy sensitive photon-counting detectors and contrast enhancement of x-ray images. The thesis comprises a literature review and an experimental part. The most important aims of the literature review were to find out what kind of energy sensitive photon-counting detectors have been developed and in what kind of applications they have been used. In addition, energy-integrating detectors are discussed in the theory section. Detectors based on different measurement principles have been compared in theory and in practice. Advacam MiniPIX is an energy sensitive photon-counting detector which was used in the experiments. The most important aim of the experimental part was to find out whether it is possible to enhance the contrast of materials which are hard to differentiate from each other when the whole energy spectrum is used by using some specific energy intervals in the image formation. This was tested by imaging different types of plastics and also Nb and Rh foils. In the case of plastics remarkable changes in contrast were not observed although imaging was done by using different energy intervals. Presumably this was caused by similarity of the composition of the plastics. The most evident observation was deterioration of the contrast when imaging was done by using the largest values of the spectrum. Furthermore, the contrast was slightly improved by using a photon-counting detector instead of an energy-integrating detector, when practically the same energy interval was used in both cases. Nb and Rh are elements which have their K-edges of the absorption coefficients in the energy range of the detector. Based on the measurements remarkable enhancement of the contrast is possible by utilizing K-edges.", "language": "en", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Submitted by Miia Hakanen (mihakane@jyu.fi) on 2019-06-25T10:13:12Z\nNo. of bitstreams: 0", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Made available in DSpace on 2019-06-25T10:13:12Z (GMT). No. of bitstreams: 0\n Previous issue date: 2019", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.format.extent", "value": "146", "language": "", "element": "format", "qualifier": "extent", "schema": "dc"}, {"key": "dc.format.mimetype", "value": "application/pdf", "language": null, "element": "format", "qualifier": "mimetype", "schema": "dc"}, {"key": "dc.language.iso", "value": "fin", "language": null, "element": "language", "qualifier": "iso", "schema": "dc"}, {"key": "dc.rights", "value": "In Copyright", "language": "en", "element": "rights", "qualifier": null, "schema": "dc"}, {"key": "dc.subject.other", "value": "r\u00f6ntgenkuvantaminen", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "r\u00f6ntgenilmaisimet", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "heterogeeninen materiaali", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "energiariippuvuus", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "fotonien laskenta", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.title", "value": "Energiasensitiiviset fotoninlaskentailmaisimet ja niiden k\u00e4ytt\u00f6 r\u00f6ntgenkuvien kontrastin parantamisessa", "language": "", "element": "title", "qualifier": null, "schema": "dc"}, {"key": "dc.type", "value": "master thesis", "language": null, "element": "type", "qualifier": null, "schema": "dc"}, {"key": "dc.identifier.urn", "value": "URN:NBN:fi:jyu-201906253425", "language": "", "element": "identifier", "qualifier": "urn", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Pro gradu -tutkielma", "language": "fi", "element": "type", "qualifier": "ontasot", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Master\u2019s thesis", "language": "en", "element": "type", "qualifier": "ontasot", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Matemaattis-luonnontieteellinen tiedekunta", "language": "fi", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Faculty of Sciences", "language": "en", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Fysiikan laitos", "language": "fi", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Department of Physics", "language": "en", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "Jyv\u00e4skyl\u00e4n yliopisto", "language": "fi", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "University of Jyv\u00e4skyl\u00e4", "language": "en", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Fysiikka", "language": "fi", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Physics", "language": "en", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "yvv.contractresearch.funding", "value": "0", "language": "", "element": "contractresearch", "qualifier": "funding", "schema": "yvv"}, {"key": "dc.type.coar", "value": "http://purl.org/coar/resource_type/c_bdcc", "language": null, "element": "type", "qualifier": "coar", "schema": "dc"}, {"key": "dc.rights.accesslevel", "value": "openAccess", "language": null, "element": "rights", "qualifier": "accesslevel", "schema": "dc"}, {"key": "dc.type.publication", "value": "masterThesis", "language": null, "element": "type", "qualifier": "publication", "schema": "dc"}, {"key": "dc.subject.oppiainekoodi", "value": "4021", "language": "", "element": "subject", "qualifier": "oppiainekoodi", "schema": "dc"}, {"key": "dc.subject.yso", "value": "fotonit", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "energia", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "kontrasti", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.format.content", "value": "fulltext", "language": null, "element": "format", "qualifier": "content", "schema": "dc"}, {"key": "dc.rights.url", "value": "https://rightsstatements.org/page/InC/1.0/", "language": null, "element": "rights", "qualifier": "url", "schema": "dc"}, {"key": "dc.type.okm", "value": "G2", "language": null, "element": "type", "qualifier": "okm", "schema": "dc"}]
|