A laboratory demonstrator of the optoelectronic sensor employing cavity enhanced spectroscopy has been designed to detect the trace amounts of carbon monoxide. High sensitivity of this sensor is provided by the use of optical cavity consisted of dielectric mirrors with extremely high reflectance. The instrument concept was taking into consideration the latest achievement of optoelectronic technology as a part of the ‘EDEN’ project, funded by the Polish National Centre for Research and Development. Preliminary tests using the sensor concept have shown that detection of carbon monoxide is possible using the developed devices. In this configuration, the sensor is characterized by high linear sensitivity in the concentration range of 10 ppb to 2.5 ppm.
Gradient structures are very important for sensors, laser and wave-guide techniques, telecommunications and other
techniques which employ radiation propagation and conversion. By varying admixture concentration, the stress occurring
in the structure may increase or reduce, which is vital for charge carrier movement velocity. We discusse two kind of
gradient structures of thin TiNx layer with a total thickness of approximately 22 nm deposited on the Si(100) substrate
and multi-layer structures with a Si-Pd and Si-Mg bi-layer periods. The gradient structures were deposited using a laser
ablation of target-compound materials. A Lambda Physics excimer laser (model LPX 305i; t ~ 15 ns, λ = 193 nm) with
f = 5 Hz operating frequency was used for layer depositing. The analyses confirmed the presence of the gradient
distribution of deposited materials. The gradient structures proved highly sensitive to both thermal effects and strong
adsorption of ambient gases. The usefulness of titanium-containing structures for gas, especially hydrogen and oxygen,
sensors was confirmed. Due to the strong gas adsorption, the gradient structures used in radiation conversion or waveguide
technology should be adequately protected against ambient conditions.
Koichi Kasuya, S. Ozawa, T. Norimatsu, H. Azechi, K. Mima, S. Nakai, S. Suzuki, B. Budner, W. Mroz, N. Kasuya, W. Kasuya, Kei. Kasuya, Y. Izawa, H. Furukawa, Y. Shimada, T. Yamanaka, M. Nakai, K. Nagai, K. Yokoyama, K. Ezato, M. Enoeda, M. Akiba, A. Prokopiuk
The most recent fundamental research results to investigate surface erosions of nuclear fusion candidate
chamber materials are described in short. We used a commercial surface profiler with a red semiconductor
laser. Various material surfaces ablated and eroded by a rather short pulse electron beam and a short pulse
ArF laser light were measured with this surface profiler and the associated three-dimensional analysis
software. Threshold input levels for various sample surface erosions with electron and laser beams were
clearly decided for the first time with our new method in this article. After the above fundamental results were
gathered, the methods to inspect inner surface conditions of nuclear fusion reactor chambers were newly
proposed with various kinds of laser displacement sensors. The first one is the erosion monitor with the above
profiler, and the second one is the laser induced ultrasonic wave detection method to inspect deeper surface
layers than the first one.
Ti-Si material compositions with layered structures are very interesting for sensors and optoelectronics applications. The ultra-thin multilayered Ti/Si films were prepared by pulsed excimer laser ablation (PLA) at wavelength of 193 nm from the Ti and Si targets. Two samples S1 and S2 with multilayered structures of four bilayer period of ~20 nm and five bilayer period of ~1 nm thickness of the Ti-Si layers on Si(100) substrates, respectively were deposited. Samples were post-deposition heated at 600°C in argon atmosphere for 10 min by rapid thermal process (RTP). The composition structures were investigated by transmission electron microscopy (TEM), secondary ion mass spectrometry (SIMS), grazing X-Ray reflectance (XRR), and X-ray diffraction (XRD) methods. The results show that intermixing of the Ti- and Si-based films appears even in the as deposited layers. The multilayered structure of the S2 sample after post-deposition annealing indicates the formation of the titanium silicide layer. The domination of interfacial and surface energies leads to the formation of metastable phase with a low interfacial energy.
Hydroxyapatite layers (Ca10(PO4)6(OH)2) were deposited by means of laser ablation method using an ArF excimer laser
(193 nm). The influence of substrate temperature on the structure of deposited layers was studied. The layers were
deposited on Ti6Al4V titanium alloy which temperature varied from 250 °C to 700 °C. The characteristics of the
hydroxyapatite coatings were determined by means of Fourier Transform Infrared spectroscopy (FTIR). The obtained
spectra reveal that the presence and abundance of the PO4 absorption bands depend on the substrate temperature. The
topography of the deposited layers were analyzed with the use of an Atomic Force Microscope.
Two kinds of experiments were performed to observe the ablation characteristics with a pulsed intense UV laser beam. The former was ArF laser ablation experiment to gather data, which were useful for the near future design of the nuclear fusion reactor chambers. The latter was the same laser ablation experiment to get various materials, which were useful in the material sciences including the bio and industrial engineering. Our interests for the uses of this laser beam arise from the modeling of the similar ablation processes for the future applications.
Effects of process parameters on pulsed laser deposition of hydroxyapatite (Ca10(PO4)6(OH)2) were studied. Process parameters like laser energy and ambient atmosphere influence both the expansion dynamics of a laser ablated plasma plume and topography of deposited layers. The plume created using 193 nm, 20 ns pulses from ArF laser was analysed
by means of space and time resolved optical emission spectroscopy. The velocity of the plasma plume at several distances from the target in different ambient conditions was determined. The deposited hydroxyapatite layers were analyzed by means of atomic force microscopy and X-ray diffractometry in order to determine the film topography, its structure and mechanical and physical properties. The results show that the plume expansion velocity as well as the topography of deposited films depend on the sort of ambient gas and its pressure.
It is necessary to know the ablation rates of various material surfaces under the irradiation of intense UV laser lights, as one of the ablating beams, when we design the future inertial fusion reacotrs driven by big lasers. So that, we irradiated various materials with a UV laser light. The laser wavelength, the pulse width and the maximum repetition rate were 193 nm, 20 ns, and 50 Hz. Irradiated materials were LiPb, Pb as the wet wall candidates of the inertial fusion reactors, while W, C, Al2O3, SiC and SiC-Si composite material as the dry wall candidates were also irradiated. The changes of teh irradiated surface conditions under different irradiation conditions were observed with three different kinds of optical diagnostic tools. The structures of the produced craters were investigated precisely. We could know how strong the tungsten was against such laser ablations, compared with LiPb or Pb etc..
Two kinds of laser ablation experiments were performed with two types of lasers. The first one was a possibility-search for an IR laser ablation which can be applied to plasma sources of pulsed ion diodes, and the second one was an inter-metallic layer deposition with KrF laser ablations. The both results are shown briefly in this paper.
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