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A 9 keV electron-impact liquid-gallium-jet x-ray source
KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.ORCID-id: 0000-0002-4394-0591
KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.ORCID-id: 0000-0003-2723-6622
2008 (engelsk)Inngår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 79, nr 1, s. 016102-Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We demonstrate a high-brightness compact 9 keV electron-impact microfocus x-ray source based on a liquid-gallium-jet anode. A similar to 30 W, 50 kV electron gun is focused onto the similar to 20 m/s, 30 mu m diameter liquid-gallium-jet anode to produce an similar to 10 mu m full width at half maximum x-ray spot. The peak spectral brightness is >2 x 10(10) photons/(s mm(2) mrad(2) x 0.1% BW). Calculation and experiments show potential for increasing this brightness by approximately three orders of magnitude, making the source suitable for laboratory-scale x-ray crystallography and hard x-ray microscopy.

sted, utgiver, år, opplag, sider
2008. Vol. 79, nr 1, s. 016102-
Emneord [en]
Electron guns, Gallium, Luminance, Microscopic examination, Photons, X ray crystallography, Electron impact, Hard x-ray microscopy, Peak spectral brightness, X-ray spot
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-8666DOI: 10.1063/1.2833838ISI: 000252821800060Scopus ID: 2-s2.0-38849143134OAI: oai:DiVA.org:kth-8666DiVA, id: diva2:14047
Merknad
QC 20100915Tilgjengelig fra: 2008-06-04 Laget: 2008-06-04 Sist oppdatert: 2017-12-14bibliografisk kontrollert
Inngår i avhandling
1. A Compact High-Brightness Liquid-Metal-Jet X-Ray Source
Åpne denne publikasjonen i ny fane eller vindu >>A Compact High-Brightness Liquid-Metal-Jet X-Ray Source
2006 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This thesis describes the development and characterization of a compact high-brightness liquid-metal-jet anode x-ray source. Initial calculations show that a source based on this concept could potentially lead to a >100-fold increase of the brightness compared to current state-of-the-art rotating-anode x-ray sources. This improvement is due to an increased thermal load capacity of the anode.

A low-power proof-of-principle source has been built, and experiments show that the liquid-metal-jet anode can be operated at more than an order of magnitude higher power densities than modern solid-metal anodes. This brightness enhancement has been utilized to acquire in-line phase-contrast images of weakly absorbing objects with substantially shorter exposure times than previously reported. To be able to target different application areas different liquid-jet-anode materials have been tested. The Sn-jet anode could potentially be used in mammography examinations, whereas the Ga-jet could be utilized for, e.g., protein-structure determination with x-ray diffraction.

Scaling to higher power and brightness levels is discussed and seems conceivable. A potential obstacle for further development of this source concept, the generation of a microscopic high-speed liquid-metal jet in vacuum, is investigated and is proven to be feasible. Dynamic-similarity experiments using water jets to simulate 30-μm, ~500-m/s tin and gallium jets show good coherence and directional stability of the jet. Other potential difficulties in the further source development, such as excessive debris emission and instabilities of the x-ray emission spot, are also investigated in some detail.

sted, utgiver, år, opplag, sider
Stockholm: KTH, 2006. s. xii, 61
Serie
Trita-FYS, ISSN 0280-316X ; 2006:36
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-4005 (URN)91-7178-371-7 (ISBN)
Disputas
2006-06-09, Sal D3, Lindstedtsvägen 5, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Merknad
QC 20100915Tilgjengelig fra: 2006-05-30 Laget: 2006-05-30 Sist oppdatert: 2010-09-15bibliografisk kontrollert
2. Liquid-Jet-Target Microfocus X-Ray Sources: Electron Guns, Optics and Phase-Contrast Imaging
Åpne denne publikasjonen i ny fane eller vindu >>Liquid-Jet-Target Microfocus X-Ray Sources: Electron Guns, Optics and Phase-Contrast Imaging
2008 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This Thesis describes the development of an electron-impact microfocus x-ray source and its application for phase-contrast imaging. The source is based on a novel, liquid-jet target concept. Stable and continuous operation can be achieved at substantially higher electron-beam power densities than conventional solid target based systems. The maximum x-ray brightness can potentially be increased by a factor of 10-1000, which would provide significantly improved performance in applications such as imaging. In order to reach the high x-ray brightness, comparable performance from the electron gun is needed. A LaB6-cathode-based electron gun is analyzed in terms of achievable e-beam brightness and beam quality and is found capable to deliver power densities in the 10-100 MW/mm2 range using optimized electro-optics. A proof-of-principle microfocus source has been developed. Experiments show that the liquid-metal-jet target can be operated at more than an order of magnitude higher e-beam power densities than modern solid-metal targets. This brightness enhancement has been utilized to acquire in-line phase-contrast images of weakly absorbing objects. The source potentially enables the application of high-resolution phase-contrast x-ray imaging with short exposure times in clinics and laboratories.

Different liquid-jet-target materials have been tested. The Sn-jet (Ka=25.3 keV) could be suitable for mammography, whereas the Ga-jet ((Ka=9.2 keV) may be utilized for x-ray diffraction studies. In addition, a non-metallic methanol jet has been the demonstrated in stable x-ray operation. All materials and compounds found in liquid form can, thus, potentially be used for electron-impact liquid-jet-target x-ray generation.

Scaling to higher e-beam power density and x-ray brightness levels is discussed and is determined to be feasible. Potential difficulties, such as debris emission and instabilities of the x-ray emission spot, are investigated in some detail. Larger and/or faster jets could overcome the present limitations because of their inherently higher heat load capacities. Dynamic-similarity experiments show that liquid jets can in principle be operated in a stable manner at much higher speeds than previously shown.

sted, utgiver, år, opplag, sider
Stockholm: KTH, 2008. s. x, 91
Serie
Trita-FYS, ISSN 0280-316X ; 2008:12
Emneord
electron-impact, x-ray, brightness, liquid-jet-target, phase-contrast imaging
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-4802 (URN)978-91-7415-004-9 (ISBN)
Disputas
2008-06-13, FR4, Albanova, Roslagstullsbacken 21, Stockholm, 14:00 (engelsk)
Opponent
Veileder
Merknad
QC 20100915Tilgjengelig fra: 2008-06-04 Laget: 2008-06-04 Sist oppdatert: 2010-09-15bibliografisk kontrollert

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