The Experts below are selected from a list of 29703 Experts worldwide ranked by ideXlab platform
S S Hong - One of the best experts on this subject based on the ideXlab platform.
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residual gas survey of stainless steel 304 extreme high Vacuum Chamber with hot cathode ionization gauge
Measurement, 2008Co-Authors: S S Hong, Y.-h. ShinAbstract:Abstract The residual gas in a high Vacuum Chamber comes from a continuous outgassing which is a main obstacle in achieving the extreme high Vacuum (XHV). To decrease the outgassing of hydrogen is the most prominent and persistent challenge to achieve the XHV. Another source of outgassing is from the hot cathode ionization gauge (HCIG) which has been used as a reference gauge for XHV. As the Vacuum Chamber of stainless steel is baked up to 320 °C, the gas species of outgassing are analyzed by QMS (quadrupole mass spectrometer). After reached at a high Vacuum of ∼2 × 10 −9 Pa, the outgassing from the hot cathode ionization gauge is mainly from the residual hydrogen molecules, which is compared with other gas species such as H 2 O, CH 4 , CO, C, and CO 2 .
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generation of extremely high Vacuum by ordinary procedures with a sus304 Vacuum Chamber and total and partial pressure measurements by hot cathode ionization gauges and a quadrupole mass spectrometer
Measurement Science and Technology, 2006Co-Authors: S S Hong, K H Chung, Yonghyeon Shin, Ichiro ArakawaAbstract:The present study generated an extremely high Vacuum of 10−10 Pa by very common methods such as using SUS304 Chamber material, electropolishing surface treatment and turbomolecular pumping technology. We examined the gas phase and electron-stimulated desorption ions of the ion gauges, the effect of ambient temperature, total pressure and H2 partial pressure. One of the results showed that, as is well known, most of the residual gas in the extremely high Vacuum Chamber was H2 but there was also a little F, which is not so well known.
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investigation of gas species in a stainless steel ultrahigh Vacuum Chamber with hot cathode ionization gauges
Measurement Science and Technology, 2004Co-Authors: S S Hong, Y.-h. Shin, Ichiro ArakawaAbstract:A residual gas analyser was used to study the gas species evolved during degassing of a stainless steel 304 ultrahigh Vacuum Chamber before and during bake-out of the Chamber at temperatures up to 235 °C with two different types of hot cathode ionization gauge. In both cases, when the ionization gauges were turned on and degassed the dominant outgassing species were H2 and H2O. During bake-out of the Chamber the main gas species detected were H2, CO (mass 28), and H2O. When the Chamber was finally baked out the main gas species detected were H2 and CO, even at room temperature. These results should help to solve the problem of evolution of degassing species, which affect the achievement of ultra and extreme high Vacuum. By baking the system most species are removed; the others have to be removed by alternative means.
R Cimino - One of the best experts on this subject based on the ideXlab platform.
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colddiag a cold Vacuum Chamber for diagnostics
IEEE Transactions on Applied Superconductivity, 2011Co-Authors: Sara Casalbuoni, C Boffo, G Sikler, V Baglin, Stefan Gerstl, Michael Hagelstein, Tilo Baumbach, G Grau, David Saez De Jauregui, R CiminoAbstract:One of the still open issues for the development of superconducting insertion devices is the understanding of the heat load induced by the beam passage. With the aim of measuring the beam heat load to a cold bore and in order to gain a deeper understanding in the beam heat load mechanisms, a cold Vacuum Chamber for diagnostics is under construction. We plan to have access with the same set-up to a number of different diagnostics, so we are implementing: i) retarding field analysers to measure the electron flux, ii) temperature sensors to measure the total heat load, iii) pressure gauges, iv) and mass spectrometers to measure the gas content. The inner Vacuum Chamber will be removable in order to test different geometries and materials. COLDDIAG is built to fit in a short straight section at ANKA, but we are proposing its installation in different synchrotron light sources with different energies and beam characteristics. A first installation in DIAMOND is planned in June 2011. Here we describe the technical design report of this device and the planned measurements with beam.
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Vacuum Chamber surface electronic properties influencing electron cloud phenomena
Applied Surface Science, 2004Co-Authors: R Cimino, I R CollinsAbstract:Abstract In the Vacuum science community, it is now commonly accepted that, for the present and next generation of accelerators, the surface electronic properties of the Vacuum Chamber material have to be studied in detail. Moreover, such studies are of valuable help to define the cleaning procedures of the chosen materials and to identify the most efficient Vacuum commissioning. In the case of the large hadron collider (LHC) the proton beam stability, in the presence of an electron cloud, is analysed using beam induced electron multipacting (BIEM) simulations requiring a number of surface related properties, such as photon reflectivity, electron and photon induced electron emission, heat load, etc. and their modification during machine commissioning and operation. Such simulation codes base their validity on the completeness and reliability of the aforementioned input data. In this work we describe how a surface science approach has been applied to measure, total electron yield (SEY) as well as energy distribution curves excited by a very low-energy electron beam (0–320 eV), from the industrially prepared Cu co-laminated material, the adopted LHC beam-screen material, held at cryogenic temperatures (about 9 K). The data show that the SEY converges to unity at zero primary electron energy and that the ratio of reflected to secondary electrons increases for decreasing energy below about 70 eV, and becomes dominant below electron energies of about 20 eV. These observations lead to the notion of long-lived low-energy electrons in the accelerator Vacuum Chamber, which could be an issue for the LHC, damping rings and future accelerators.
S Bamford - One of the best experts on this subject based on the ideXlab platform.
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a portable micro x ray fluorescence spectrometer with polycapillary optics and Vacuum Chamber for archaeometric and other applications
Spectrochimica Acta Part B: Atomic Spectroscopy, 2007Co-Authors: Gunter Buzanich, P. Wobrauschek, C Streli, A Markowicz, D Wegrzynek, E Chineacano, S BamfordAbstract:Abstract A portable focused-beam XRF spectrometer was designed, constructed, and manufactured. The spectrometer allows to detect and perform analysis of chemical elements from Na upwards. The system is equipped with a compact Vacuum Chamber to reduce absorption of both the excitation and the fluorescence radiation in air. A low power Pd-anode tube operated up to 50 kV and 1 mA with a point focus of 400 μm is used as excitation source. A polycapillary lens with a spot size of about 160 μm, or a collimator with a 1 mm inner diameter can be used alternatively for either focusing or collimating the primary beam. The fluorescence radiation is collected by an Si drift detector with an active area of 10 mm2 and equipped with an 8 μm Be entrance window. A compact Vacuum Chamber was designed to house the X-ray beam optics and the detector snout. The Chamber is attached to the X-ray tube and can be pumped down to 0.1 mbar. A Kapton™ window of 7.5 μm thickness allows to locate the investigated spot at about 1–2 mm distance outside of the Chamber, thus minimizing absorption losses in the excitation and X-ray fluorescence radiation paths. Two lasers pointers are mounted inside the Chamber. The laser beams cross at a point outside the Chamber in front of the entrance window and coincide with the focal spot of the polycapillary. This paper reports some preliminary results obtained from an in situ analysis of bronze samples as well as a comparison of these data with those given by other laboratory spectrometers and the reference values provided by the Italian bronze foundry Venturi Arte Bologna, Italy.
A Markowicz - One of the best experts on this subject based on the ideXlab platform.
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a portable micro x ray fluorescence spectrometer with polycapillary optics and Vacuum Chamber for archaeometric and other applications
Spectrochimica Acta Part B: Atomic Spectroscopy, 2007Co-Authors: Gunter Buzanich, P. Wobrauschek, C Streli, A Markowicz, D Wegrzynek, E Chineacano, S BamfordAbstract:Abstract A portable focused-beam XRF spectrometer was designed, constructed, and manufactured. The spectrometer allows to detect and perform analysis of chemical elements from Na upwards. The system is equipped with a compact Vacuum Chamber to reduce absorption of both the excitation and the fluorescence radiation in air. A low power Pd-anode tube operated up to 50 kV and 1 mA with a point focus of 400 μm is used as excitation source. A polycapillary lens with a spot size of about 160 μm, or a collimator with a 1 mm inner diameter can be used alternatively for either focusing or collimating the primary beam. The fluorescence radiation is collected by an Si drift detector with an active area of 10 mm2 and equipped with an 8 μm Be entrance window. A compact Vacuum Chamber was designed to house the X-ray beam optics and the detector snout. The Chamber is attached to the X-ray tube and can be pumped down to 0.1 mbar. A Kapton™ window of 7.5 μm thickness allows to locate the investigated spot at about 1–2 mm distance outside of the Chamber, thus minimizing absorption losses in the excitation and X-ray fluorescence radiation paths. Two lasers pointers are mounted inside the Chamber. The laser beams cross at a point outside the Chamber in front of the entrance window and coincide with the focal spot of the polycapillary. This paper reports some preliminary results obtained from an in situ analysis of bronze samples as well as a comparison of these data with those given by other laboratory spectrometers and the reference values provided by the Italian bronze foundry Venturi Arte Bologna, Italy.
D Wegrzynek - One of the best experts on this subject based on the ideXlab platform.
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a portable micro x ray fluorescence spectrometer with polycapillary optics and Vacuum Chamber for archaeometric and other applications
Spectrochimica Acta Part B: Atomic Spectroscopy, 2007Co-Authors: Gunter Buzanich, P. Wobrauschek, C Streli, A Markowicz, D Wegrzynek, E Chineacano, S BamfordAbstract:Abstract A portable focused-beam XRF spectrometer was designed, constructed, and manufactured. The spectrometer allows to detect and perform analysis of chemical elements from Na upwards. The system is equipped with a compact Vacuum Chamber to reduce absorption of both the excitation and the fluorescence radiation in air. A low power Pd-anode tube operated up to 50 kV and 1 mA with a point focus of 400 μm is used as excitation source. A polycapillary lens with a spot size of about 160 μm, or a collimator with a 1 mm inner diameter can be used alternatively for either focusing or collimating the primary beam. The fluorescence radiation is collected by an Si drift detector with an active area of 10 mm2 and equipped with an 8 μm Be entrance window. A compact Vacuum Chamber was designed to house the X-ray beam optics and the detector snout. The Chamber is attached to the X-ray tube and can be pumped down to 0.1 mbar. A Kapton™ window of 7.5 μm thickness allows to locate the investigated spot at about 1–2 mm distance outside of the Chamber, thus minimizing absorption losses in the excitation and X-ray fluorescence radiation paths. Two lasers pointers are mounted inside the Chamber. The laser beams cross at a point outside the Chamber in front of the entrance window and coincide with the focal spot of the polycapillary. This paper reports some preliminary results obtained from an in situ analysis of bronze samples as well as a comparison of these data with those given by other laboratory spectrometers and the reference values provided by the Italian bronze foundry Venturi Arte Bologna, Italy.
