Vacuum UV actinometry. Ion current measurements with enclosed light sources

AbstractDuring the past decade the intensive development of novel incoherent xenon excimer light sources emitting in the vacuum-UV region of the electromagnetic spectrum at λmax of 172 nm led to a renaissance of investigations that deal with the direct photolysis of water. Upon 172 nm excitation water molecules homolyze with formation of hydroxyl radicals and hydrogen atoms. In the presence of organic substrates and dissolved molecular oxygen a complex series of interrelated radical reactions is initiated leading to the oxidative degradation of the organic compounds and finally to their complete mineralization, i.e. to the diminution of the total organic carbon (TOC) content of the solution. This advanced oxidation process (AOP) is usually designated as H

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Development of Electron Guns for Excimer Light Sources in the Vacuum UV

IEEE Transactions on Electron Devices ◽

10.1109/ted.2005.845860 ◽

2005 ◽

Vol 52 (5) ◽

pp. 884-888 ◽

Cited By ~ 4

Author(s):

R. Steinhuebl ◽

K. Besenthal ◽

N. Koch ◽

G. Kornfeld

Keyword(s):

Light Sources ◽

Electron Guns ◽

Vacuum Uv

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Apparatus for spectroenergetic studies of plasma light sources in the vacuum UV

Journal of Optical Technology ◽

10.1364/jot.73.000117 ◽

2006 ◽

Vol 73 (2) ◽

pp. 117

Author(s):

A. G. Bedrin ◽

A. N. Zhilin ◽

V. K. El'ts ◽

G. G. Vorypaev ◽

E. M. Golybev

Keyword(s):

Light Sources ◽

Vacuum Uv

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Vacuum Ultraviolet Irradiation of Polymers

MRS Proceedings ◽

10.1557/proc-544-109 ◽

1998 ◽

Vol 544 ◽

Cited By ~ 4

Author(s):

A. C. Fozza ◽

A. Bergeron ◽

J. E. Klemberg-Sapieha ◽

M. R. Wertheimer

Keyword(s):

Quartz Crystal Microbalance ◽

Spectroscopic Ellipsometry ◽

Ultraviolet Irradiation ◽

Quartz Crystal ◽

Vacuum Ultraviolet ◽

Ex Situ ◽

Light Sources ◽

Argon Mixture ◽

Vacuum Uv

AbstractThe interest in incoherent sources for wavelength selective photochemistry has increased lately, but little is still known about the behavior of polymers when exposed to far UV and vacuum UV (VUV) radiation, for example that emitted from low-pressure plasmas. In order to study VUV-UV effects on several polymers (polyethylene - PE, polystyrene - PS, hexatriacontane - HTC, polymethylmethacrylate - PMMA and polycarbonate - PC), we used the wellcharacterized emissions from hydrogen and hydrogen/argon mixture plasmas as light sources. Mass changes were measured in-situ using a quartz crystal microbalance (QCM); irradiated samples were analyzed ex-situ by XPS, spectroscopic ellipsometry, and AFM.

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Quantitative Measurements on the Ion Etching of TMV

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072125 ◽

1973 ◽

Vol 31 ◽

pp. 336-337

Author(s):

Irwin Bendet ◽

Nabil Rizk

Keyword(s):

Electron Microscope ◽

Tobacco Mosaic Virus ◽

Mosaic Virus ◽

Ion Current ◽

Beam Diameter ◽

Ion Etching ◽

Preliminary Results ◽

Quantitative Measurements ◽

Monitoring Devices

Preliminary results reported last year on the ion etching of tobacco mosaic virus indicated that the diameter of the virus decreased more rapidly at 10KV than at 5KV, perhaps reaching a constant value before disappearing completely.In order to follow the effects of ion etching on TMV more quantitatively we have designed and built a second apparatus (Fig. 1), which incorporates monitoring devices for measuring ion current and vacuum as well as accelerating voltage. In addition, the beam diameter has been increased to approximately 1 cm., so that ten electron microscope grids can be exposed to the beam simultaneously.

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Spatially Resolved Photoelectron Spectroscopy: Recent Progress and Future Plans

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010013554x ◽

1990 ◽

Vol 48 (2) ◽

pp. 388-389

Author(s):

A. M. Bradshaw

Keyword(s):

Photoelectron Spectroscopy ◽

Chemical Reactivity ◽

Target Material ◽

Orbital Energy ◽

Light Sources ◽

Analytical Technique ◽

Hartree Fock ◽

Spatially Resolved ◽

Koopmans Theorem ◽

Surface Analytical Technique

X-ray photoelectron spectroscopy (XPS or ESCA) was not developed by Siegbahn and co-workers as a surface analytical technique, but rather as a general probe of electronic structure and chemical reactivity. The method is based on the phenomenon of photoionisation: The absorption of monochromatic radiation in the target material (free atoms, molecules, solids or liquids) causes electrons to be injected into the vacuum continuum. Pseudo-monochromatic laboratory light sources (e.g. AlKα) have mostly been used hitherto for this excitation; in recent years synchrotron radiation has become increasingly important. A kinetic energy analysis of the so-called photoelectrons gives rise to a spectrum which consists of a series of lines corresponding to each discrete core and valence level of the system. The measured binding energy, EB, given by EB = hv−EK, where EK is the kineticenergy relative to the vacuum level, may be equated with the orbital energy derived from a Hartree-Fock SCF calculation of the system under consideration (Koopmans theorem).

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Ultrastructural Features of Normal and Diseased Hair Revealed by Ion Beam Etching and Freeze Fracture

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115419 ◽

1975 ◽

Vol 33 ◽

pp. 358-359

Author(s):

M. Spector ◽

A. C. Brown

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Ectodermal Dysplasia ◽

Ion Beam ◽

Freeze Fracture ◽

Ion Current ◽

Ion Beam Etching ◽

Pili Torti ◽

Argon Ion ◽

Scanning Electron

Ion beam etching and freeze fracture techniques were utilized in conjunction with scanning electron microscopy to study the ultrastructure of normal and diseased human hair. Topographical differences in the cuticular scale of normal and diseased hair were demonstrated in previous scanning electron microscope studies. In the present study, ion beam etching and freeze fracture techniques were utilized to reveal subsurface ultrastructural features of the cuticle and cortex.Samples of normal and diseased hair including monilethrix, pili torti, pili annulati, and hidrotic ectodermal dysplasia were cut from areas near the base of the hair. In preparation for ion beam etching, untreated hairs were mounted on conducting tape on a conducting silicon substrate. The hairs were ion beam etched by an 18 ky argon ion beam (5μA ion current) from an ETEC ion beam etching device. The ion beam was oriented perpendicular to the substrate. The specimen remained stationary in the beam for exposures of 6 to 8 minutes.

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Tandem scanning confocal light microscopy as compared with x-ray diffraction for characterizing the behavior of clays in fluid-saturated petroleum reservoir rock

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152719 ◽

1989 ◽

Vol 47 ◽

pp. 148-149

Author(s):

C.J. Stuart ◽

B.E. Viani ◽

J. Walker ◽

T.H. Levesque

Keyword(s):

Light Microscopy ◽

Image Plane ◽

Reservoir Rock ◽

Depth Of Field ◽

Objective Lens ◽

Scanning System ◽

Light Sources ◽

Petroleum Reservoir ◽

Image Recording ◽

Scan Speed

Many techniques of imaging used to characterize petroleum reservoir rocks are applied to dehydrated specimens. In order to directly study behavior of fines in reservoir rock at conditions similar to those found in-situ these materials need to be characterized in a fluid saturated state.Standard light microscopy can be used on wet specimens but depth of field and focus cannot be obtained; by using the Tandem Scanning Confocal Microscope (TSM) images can be produced from thin focused layers with high contrast and resolution. Optical sectioning and extended focus images are then produced with the microscope. The TSM uses reflected light, bulk specimens, and wet samples as opposed to thin section analysis used in standard light microscopy. The TSM also has additional advantages: the high scan speed, the ability to use a variety of light sources to produce real color images, and the simple, small size scanning system. The TSM has frame rates in excess of normal TV rates with many more lines of resolution. This is accomplished by incorporating a method of parallel image scanning and detection. The parallel scanning in the TSM is accomplished by means of multiple apertures in a disk which is positioned in the intermediate image plane of the objective lens. Thousands of apertures are distributed in an annulus, so that as the disk is spun, the specimen is illuminated simultaneously by a large number of scanning beams with uniform illumination. The high frame speeds greatly simplify the task of image recording since any of the normally used devices such as photographic cameras, normal or low light TV cameras, VCR or optical disks can be used without modification. Any frame store device compatible with a standard TV camera may be used to digitize TSM images.

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