Excimer Lamp Research Articles

306 真空紫外線で励起したアンモニアによる無触媒脱硝法の開発(大気環境保全・改善技術(2))

To broaden and lower the temperature window of the selective non catalytic reduction (SNCR) of nitric oxide (NO), the use of activated ammonia as the reduction agent was examined. A xenon excimer lamp emitting a wavelength of 172 nm (i.e., vacuum ultraviolet; VUV) was employed as the excitation source for molecular ammonia The effects of reaction temperatures, oxygen concentrations, and length between an excimer lamp and a reactor on NO removal were investigated in a lab-scale plug flow reactor.

当教室におけるターゲット型エキシマランプによる円形脱毛症の治療経験

エキシマランプとは，塩化キセノンガスを媒体とした308nmの波長を発する光線治療器であり，尋常性乾癬，掌蹠膿疱症，尋常性白斑において高い有効性が示されている。当教室では，ターゲット型エキシマランプである米国Photo Medex社製のVTRACを使用して，種々疾患の治療を行っている。今回は円形脱毛症に対する発毛効果の検討につき報告する。単発性6例，多発性3例，汎発性4例の計13例に，ターゲット型エキシマランプを週1～2回照射した。治療効果は発毛までの治療回数，発毛範囲，患者評価の3項目で評価した。単発性においては6例中5例に脱毛面積75％以上の範囲に毛髪の新生を認め，うち3例は照射開始後半年以内に治癒した。また，従来の一般的な治療に抵抗性を示した症例でも，3～8回の照射で毛髪の新生を認め，比較的早期に効果が発現した。多発性3例中1例においても，4ヵ月後には治癒した。汎発性4例では2例に産毛の新生は認めたものの著効は得られなかった。2010年に作成された本邦における円形脱毛症診療ガイドラインに記載されているPUVA療法と比較して，ターゲット型エキシマランプは，健常部への不要な照射を避けることができ，しかも簡便に照射できる利点がある。以上より，ターゲット型エキシマランプを用いた光線療法は単発性円形脱毛症に特に有用であり，新たな標準治療の一つになり得ると思われる。

Surface Modification of Polyethylene Terephthalate (PET) by 172-nm Excimer Lamp

We studied the effects of 172 nm Xe2* excimer lamp irradiation on polyethylene terephthalate (PET) surfaces. Two kinds of techniques were applied: vacuum ultraviolet (VUV) light irradiation and VUV irradiation in the presence of oxygen gas (VUV/O3). The modified PET surfaces were investigated by using contact angle measurements which enabled the surface free energy to be calculated, X-ray photoelectron spectroscopy (XPS), nano-thermal analysis (nano-TA), and atomic force microscopy (AFM). The surface free energy increased significantly after the treatments. The results of XPS analysis showed that the elemental ratio of oxygen on the surface increased, whereas that of carbon decreased. From the deconvoluted C1s and O1s spectra, it was revealed that new oxidized functional groups such as alcoholic and carboxyl groups were generated. The nano-TA results showed that a low melting temperature (Tm) layer had formed on the VUV and VUV/O3 treated PET surfaces. The results of AFM measurements showed there were no remarkable changes after the treatments compared with untreated PET. In summary, the VUV and VUV/O3 treatments using a Xe2* excimer lamp not only change the surface functionalities but also reduce the Tm of the PET surfaces without significantly affecting the surface morphologies.

Ultraviolet-based therapy for vitiligo: What′s new?

Vitiligo is an ancient disease in which depigmented and hypopigmented macules appear on the skin. It is a disfiguring condition that may lead to severe psychological trauma. Among the many treatment modalities available for use in vitiligo, those using light therapy, and in particular ultraviolet (UV) light, are some of the most effective treatments. UV-based therapy includes phototherapy (narrowband UVB), photochemotherapy (psoralens with UVA), and targeted phototherapy (excimer laser and excimer lamp). It is important for any practitioner of UV-based therapy to understand the efficacy of each treatment type, as well as their respective adverse effects. In order to take full advantage of UV-based therapy, location, dosing, and photoadaptation must also be taken into account. This review discusses the various UV-based therapeutic options, adjuvant therapies, optimal dosing guidelines, appropriate patient selection, future treatment options, and recommendations based upon the current evidence and the authors' experience with vitiligo.

Photo-oxidized Coating on the Optical Materials for High Power Laser Resistance and Waterproof

ABSTRACTA photo-oxidized thin film, which transformed the organic silicone oil into inorganic glass, was coated on optical materials surface by using Xe2 excimer lamp at room temperature. This technique has enabled an optical thin coating capable of transmitting ultraviolet rays [UV] of wavelengths under 200 nm and possessing the characteristics of hardness, strain-free, resistance to high power laser, and resistance to water. UV and IR spectroscopic analysis was carried out for investigation of the oxidized silicone oil. The results revealed that the absorption peak of the CH3 group at 2900 cm-1 decreased as the irradiation time of the excimer lamp increased, and the transmittance of the light in the 172 nm wavelengths conversely became high. The UV transmittance of the silicone oil was 29.2 % before the lamp irradiation; and it improved to 90.6 % after the irradiation for 120 minutes. Moreover, in order to evaluate for resistance to laser damage [J/cm2/10 ns], the films were further irradiated with the Nd: YAG laser of ω [1.06 μm] or 2ω [0.503 μm]. The silica glass substrate had almost same laser tolerance in ω and 2ω, 112 J/cm2 and 113 J/cm2, respectively. The laser damage threshold of the photo-oxidized 100 nm thick film formed on the fused silica substrate was 72 J/cm2 in ω and 107 J/cm2 in 2ω.

Low Temperature Growth of CaTiO3: Pr Phosphor Thin Film on Flexible Substrate by Photo- induced Chemical Solution Process

ABSTRACTPreparation of the CaTiO3:Pr (CTO:Pr) phosphor thin film on PET substrate was investigated by using the excimer laser-assisted metal organic decomposition(ELAMOD) and photo reaction of nano-particles (PRNP) process. The effects of the substrate material, starting materials, and UV sources on photoluminescence (PL) were investigated. By using the BaTiO3(BTO) nano-particles buffer layer and the CTO: Pr nano-particles as a starting material, CTO: Pr thin film on the PET substrate was successfully obtained by using the KrF laser and excimer lamp irradiation at 25°C. It was found that excimer lamp irradiation is effective for improving the PL of the films.

Evaluation of the clinical safety and efficacy of a newly developed 308‐nm excimer lamp for vitiligo vulgaris

Evaluation of the clinical safety and efficacy of a newly developed 308‐nm excimer lamp for vitiligo vulgaris

Influence of gas discharge parameters on emissions from a dielectric barrier discharge excited argon excimer lamp

A dielectric barrier discharge excited neutral argon (Ar I) excimer lamp has been developed and characterised. The aim of this study was to develop an excimer lamp operating at atmospheric pressure that can replace mercury lamps and vacuum equipment used in the sterilisation of medical equipment and in the food industry. The effects of discharge gas pressure, flow rate, excitation frequency and pulse width on the intensity of the Ar I vacuum ultraviolet (VUV) emission at 126 nm and near infrared (NIR) lines at 750.4 nm and 811.5 nm have been investigated. These three lines were chosen as they represent emissions resulting from de-excitation of excimer states that emit energetic photons with an energy of 9.8 eV. We observed that the intensity of the VUV Ar 2 * excimer emission at 126 nm increased with increasing gas pressure, but decreased with increasing excitation pulse frequency and pulse width. In contrast, the intensities of the NIR lines decreased with increasing gas pressure and increased with increasing pulse frequency and pulse width. We have demonstrated that energetic VUV photons of 9.8 eV can be efficiently generated in a dielectric barrier discharge in Ar.

Photodegradation of congo red using XeBr, KrCl and Cl2 barrier discharge excilamps: A kinetics study

Different physical, biological and chemical methods have been used to remove congo red mainly from textile industry effluents. All of these treatments usually transfer the contamination from one phase to another. In this work the oxidation of congo red using a combined advanced oxidation treatment based on photodegradation with UV radiation generated by KrCl, XeBr and Cl2 excimer lamps in the presence of H2O2 has been studied. Experiments suggest that high congo red conversion values (>90%) were only reached with KrCl excilamp in the absence of H2O2. In the presence of a molar ratio H2O2/congo red of 12.5/1 KrCl excilamp totally removed congo red in 120min whereas XeBr needed a molar ratio H2O2/congo red of 25/1 to attain total removal in the same time. Due to its low radiation intensity compared to the other two excilamps, Cl2 excilamp never reached total removal of congo red in the experimental range assayed. Based on the experimental data, a pseudo-first order kinetic model for the three excilamps was proposed. A good correlation between experimental and calculated data was obtained.

Removal of nitric oxide by activated ammonia generated by vacuum ultraviolet radiation

To broaden and lower the narrow temperature window of the selective non-catalytic reduction (SNCR) of nitric oxide (NO), the use of activated ammonia as the reduction agent was examined. A 172nm VUV (vacuum ultraviolet) excimer lamp was employed as the excitation source for molecular ammonia. Activated ammonia generated by VUV radiation in a photochemical reactor was injected into a model flue gas (NO/O2/N2) at room temperature. The effects of reaction temperatures, oxygen concentrations, and NH3/NO molar ratios (MRs) on NO removal were investigated in a lab-scale plug flow reactor. Temperatures ranged from 500°C to 850°C. A temperature window enlargement of 150°C was achieved at the lower boundary of the temperature window. The results are the first clear observations of low temperature SNCR by activated ammonia. Above 600°C, NO removal was affected by injection of activated ammonia, while around 750°C, conventional SNCR by injection of molecular ammonia was effective. An approximate 80% NO removal was attained at 700°C with an MR=2.0 and 8.3% O2. Although the chemical compositions of activated ammonia remained unknown during the present study, the results suggested that effective chemical species for NO removal such as NH2 and H2 were produced from activated ammonia above 600°C. The number of photons emitted per mole of molecular ammonia, Np, was proposed to evaluate the effects of NH3 concentrations and residence times of NH3 gas in the photochemical reactor. The optimum Np range was found to be the point at which maximum NO removal was attained.

Cell Patterning Using a Template of Microstructured Organosilane Layer Fabricated by Vacuum Ultraviolet Light Lithography

Micropatterning techniques have become increasingly important in cellular biology. Cell patterning is achieved by various methods. Photolithography is one of the most popular methods, and several light sources (e.g., excimer lasers and mercury lamps) are used for that purpose. Vacuum ultraviolet (VUV) light that can be produced by an excimer lamp is advantageous for fabricating material patterns, since it can decompose organic materials directly and efficiently without photoresist or photosensitive materials. Despite the advantages, applications of VUV light to pattern biological materials are few. We have investigated cell patterning by using a template of a microstructured organosilane layer fabricated by VUV lithography. We first made a template of a microstructured organosilane layer by VUV lithography. Cell adhesive materials (poly(d-lysine) and polyethyleneimine) were chemically immobilized on the organosilane template, producing a cell adhesive material pattern. Primary rat cardiac and neuronal cells were successfully patterned by culturing them on the pattern substrate. Long-term culturing was attained for up to two weeks for cardiac cells and two months for cortex cells. We have discussed the reproducibility of cell patterning and made suggestions to improve it.

An Argon Excimer Lamp as a Source of Vacuum Ultraviolet Light for Inducing Mutations that Lead to Morphological Changes in Plants

An Argon Excimer Lamp as a Source of Vacuum Ultraviolet Light for Inducing Mutations that Lead to Morphological Changes in Plants

Effects of irradiation with vacuum ultraviolet xenon excimer lamp at 172 nm on water vapor transport through poly(lactic acid) membranes

The diffusivity, solubility, and permeability of water vapor and nitrogen were systematically investigated for Vacuum Ultraviolet (VUV)-irradiated poly(lactic acid) (PLA) membranes by a xenon excimer lamp at 172nm. The photon was completely absorbed in the surface membrane, and the VUV irradiation did not depend on the color center and bulk structure of the PLA membrane. Additionally, surface hydrophilicity increased in the irradiation time range of 0–10min and settled at a steady state in the irradiation time range of 30–100min. We discovered the surface photo-oxidation, scission reaction, and crystallization of PLA membranes by VUV irradiation. The PLA chemical structure changed as chain cleavage and formation of CC double bonds and hydroperoxide OH at newly formed chain terminals through a Norrish II mechanism. The water vapor permeability of VUV-irradiated PLA membrane for 60min was equal to that of unirradiated PLA membranes because the water vapor diffusivity reduction for surface crystallization counteracted the solubility enlargement for surface hydrophilicity. The temperature dependence on water vapor permeability of VUV-irradiated PLA membrane at low relative feed pressure showed that diffusivity-controlled behavior and that, at high relative feed pressure, diffusivity- and solubility-controlled behavior.

Study of the influence of the sulfide and ultraviolet treatment of the n-i-GaAs surface on the parameters of ohmic contacts

The possibility of improving the parameters of AuGe/Ni- and Ge/Cu-based ohmic contacts to n-i-GaAs by modifying the preliminarily oxidized GaAs surface in a sulfide-containing solution, as well as via the effect of ultraviolet radiation generated with a KrCl excimer lamp on a chalcogenated surface, is studied. It is shown that preliminary oxidation of the n-i-GaAs surface with subsequent chalcogenation makes it possible to decrease the density of the surface states, to increase the reproducibility of the passivation of the surface, and to decrease the reduced contact resistance of the AuGe/Ni ohmic contacts by a factor of 1.5. The treatment of the chalcogenated surface of n-i-GaAs with an ultraviolet radiation with wavelength λ = 222 nm and emission power density W = 12 mW cm−2 performed in vacuum before the deposition of metal layers of the Ge/Cu ohmic contacts makes it possible to decrease the reduced contact resistance by 25–50% andimprove the morphological characteristics of the surface of the contact area.

12th International Symposium on High Pressure, Low Temperature Plasma Chemistry (HAKONE XII)

The 11th International Symposium on High Pressure, Low Temperature Plasma Chemistry (HAKONE XI) was held on Oleron Island, France, from September 7th to 12th, 2008, organized by the LAPLACE laboratory of the University of Toulouse. This specialized biannual conference derives its name from the small resort area Hakone in Japan where it was first organized in 1987. It is purposely kept small with no parallel sessions and preferentially meets in remote locations to stimulate scientific discussion. This year we had 117 contributions and 130 participants from 26 countries. The next meeting, HAKONE XII, will be organized in 2010 in the High Tatra Mountains in Slovakia. Since the first conference, which was mainly devoted to ozone generation and NOx formation in corona discharges (CDs) and in dielectric barrier discharges (DBDs) a number of new applications have evolved: DBD excited CO2 lasers, excimer lamps emitting UV and VUV radiation and fluorescent lamps based on excimer radiation, flat plasma display panels, pollution control, surface modification and thin film deposition. This symposium showed again that the field is still very active. New results were presented on a better under- standing, the numerical modeling and the control of various discharge mechanisms: filamentary, regularly patterned or homogeneous DBDs, streamer formation and propagation. Various discharge types are investigated: special co-planar DBD arrangements, microplasma devices, pulsed coronas, gliding arc discharges, atmospheric-pressure plasma jets and electron beam generated plasmas.

Oxide Nanoparticle Thin Films Created Using Molecular Templates

We present a new generic method to synthesize nanostructured metal(II) oxide films on a substrate such as silicon. Vacuum ultraviolet (VUV) excimer lamps rupture metal organic precursors, creating volatile organic fragments, while the metal species at the surface form oxides. X-ray photoemission spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) confirm that 172 nm VUV irradiation of manganese and copper phthalocyanines yields manganese(II) and copper(II) oxides, respectively. The morphology of the precursor film provides a template from which metal oxide nanoparticles are formed, which we demonstrate for particles with dimensions 40 x 40 x 10 nm(3). Our procedure is both simple and flexible, with low thermal budget and potential for patterning.

One-Dimensional Modeling of a Dielectric Barrier Discharge in NeXe Mixture, Application to Excimer Lamps

The dielectric barriers discharges or silent discharges had knew these last years a great progress, particularly in the area of ultraviolet light production, which produced by Xe2* excimer molecules. This new application led to the realization of the nonpolluting excimer lamps. In this work we develop a one-dimensional model of sheath coupled to a kinetic model in NeXe mixture. Calculations were done for sixteen chemicals species in xenon concentration of 10% and under pressure of 400 torr. The results illustrate the spatiotemporal evolution of the charged particles and neutral species as well as the variations of the electric parameters of the lamp during the first pulse discharge.

Modeling of a Ne-Xe-HCl DC Discharge for Excimer Lamp

A mathematical model was developed to describe a DC discharge of a Ne-Xe-HCl for excilamp. To achieve our aims we used a one-dimensional model of the cathode sheath coupled to a zero dimensional model of plasma with the external circuit. The spatial profiles of the electron density, ion density and the electric field were shown to exhibit distinct structures of glow discharge. A current in DC discharge increase in monotonous way until reaching 52 A at 225 ns. The breakdown delay times have been calculated, the plasma breakdown is occurring at 160.75ns. The orders of the values of the electric field (105 V/cm) are a condition of the good operation of the excimer lamp. This model permits us to have a good resolution of the sheath region, and to provide a quantitative analysis of the time evolution of the electrical and chemical discharge properties.

Optical characteristics of cylindrical exciplex and excimer lamps excited by microwave radiation

The object of investigation is the optical characteristics of Br2, Cl2, XeBr, and XeCl excilamps excited by microwave radiation. The power of the microwave discharge is determined from a pressure jump in the bulb of the lamp. Conditions for the effective generation of XeCl* and XeBr* exciplexes in cylindrical lamps are found. The efficiency of generation of these exciplexes equals 7.2 and 7.8%, respectively.

Degradation of phenolic pollutants using KrCl and XeBr excilamps in the presence of dye: A comparative study

Phenolic compounds removal in colourless and non turbid water systems has been widely studied. In this work, the oxidation of phenol and 4-chlorophenol in the presence of the dye methyl green has been studied using a combined advanced treatment based on photodegradation with UV radiation generated by KrCl and XeBr excimer lamps in the presence of H 2O 2. Experiments suggest that pollutants removal is practically independent of the presence of the dye in the reaction matrix. The KrCl excilamp was found to require a shorter treatment period than the XeBr to totally degrade the phenolics. Increasing phenol or 4-chlorophenol concentrations has a negative influence on methyl green degradation, whereby maximum dye degradation rate is achieved when there are no phenolic compounds in the aqueous matrix. It was also evident in the experimental range tested, that the H 2O 2:phenolic compound molar ratio does not significantly influence the removal of phenol and 4-chlorophenol using both excimer lamps. Nevertheless, the removal of methyl green is improved with high molar ratios. Based on the experimental data, a pseudo-first order kinetic model for the KrCl excilamp and a pseudo-second order for the XeBr were proposed. A good correlation between experimental and calculated data was obtained.