| dc.contributor.advisor | Salditt, Tim Prof. Dr. | |
| dc.contributor.author | Müller, Matthias | |
| dc.date.accessioned | 2019-01-24T09:22:20Z | |
| dc.date.available | 2019-01-24T09:22:20Z | |
| dc.date.issued | 2019-01-24 | |
| dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-002E-E566-6 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-7183 | |
| dc.language.iso | deu | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 530 | de |
| dc.title | Hochauflösende Bildgebung und NEXAFS-Spektroskopie mit weicher Röntgenstrahlung aus laserinduzierten Plasmen | de |
| dc.type | doctoralThesis | de |
| dc.title.translated | Soft X-ray high-resolution imaging and NEXAFS spectroscopy using a laser-induced plasma | de |
| dc.contributor.referee | Salditt, Tim Prof. Dr. | |
| dc.date.examination | 2018-10-20 | |
| dc.subject.gok | Physik (PPN621336750) | de |
| dc.description.abstracteng | Soft x-ray microscopy and absorption spectroscopy are extremely useful
tools for high-resolution imaging and chemical analysis of samples in
various scientific fields. However, due to the required high photon flux
of soft x-ray radiation, up to now, both methods are almost exclusively
performed at synchrotron sources. To overcome this limitation there
have been successful efforts to employ laboratory-scale sources based
on gas discharge or laser-produced plasmas using liquid and solid laser
targets. A serious drawback of these sources is the almost unavoidable
generation of debris particles, which can damage optical elements close
to the plasma. The operation of liquid jet targets requires also great
experimental and technical effort. Thus, there is still the need for further
optimization and simplification of lab-scale soft x-ray sources to pave
the way for their wider dissemination.
Here, the development of a laser-produced plasma source from a
pulsed gas jet is presented, enabling the construction of a clean, compact
and long-term stable soft x-ray source. As its photon yield is smaller
due to the lower particle density within the laser focus, several ways
to increase the source brilliance have been examined in detail. In particular,
it was investigated how higher gas pressures, shorter laser pulses
and smaller emission angles affect the plasma properties. Based on this
source a compact transmission x-ray microscope operating in the "water
window" ( = 2.3 – 4.4nm) was built, characterized and applied for imaging
of various test and biological objects. The resolving power of the
microscope is about 50 to 60 nm. In addition, an advanced laboratoryscale
NEXAFS spectrometer has been established, allowing for the reliable
analysis of different absorption edges at photon energies between
250 to 1250 eV. So far, NEXAFS experiments with the table-top spectrometer
have been performed in a high vacuum system, excluding a
number of interesting samples from spectroscopic investigations. To
extend the application possibilities of the spectrometer, the setup was
modified to measure samples also under atmospheric conditions using
two silicon nitride membranes as vacuum windows. Finally, different
schemes have been suggested to merge the soft x-ray microscope and
the NEXAFS spectrometer to a combined laboratory-scale spectromicroscope,
which shall enable spatially resolved elemental mapping in the
future. It has already been shown that a test object can be imaged at two
wavelengths below and above the titanium L-edge. | de |
| dc.contributor.coReferee | Mann, Klaus Dr. | |
| dc.contributor.thirdReferee | Egner, Alexander Prof. Dr. | |
| dc.contributor.thirdReferee | Quadt, Arnulf Prof. Dr. | |
| dc.contributor.thirdReferee | Niemeyer, Jürgen PD Dr. | |
| dc.contributor.thirdReferee | Ropers, Claus Prof. Dr. | |
| dc.subject.ger | Röntgenstrahlung | de |
| dc.subject.ger | laserinduziertes Plasma | de |
| dc.subject.ger | NEXAFS-Spektroskopie | de |
| dc.subject.ger | Mikroskopie | de |
| dc.subject.ger | Laborquelle | de |
| dc.subject.eng | X-rays | de |
| dc.subject.eng | laser-induced plasma | de |
| dc.subject.eng | microscopy | de |
| dc.subject.eng | NEXAFS spectroscopy | de |
| dc.subject.eng | laboratory-scale source | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-11858/00-1735-0000-002E-E566-6-0 | |
| dc.affiliation.institute | Fakultät für Physik | de |
| dc.identifier.ppn | 104735652X | |