351 research outputs found
Stark spectroscopy at Balmer-αline of atomic hydrogen for measuring sheath electric field in a hydrogen plasma
No full textThis paper reports a diode laser based system which is applicable to the measurement of electric field in the sheath region of a hydrogen plasma. The electric field is deduced from the Stark spectrum of the Balmer-α line of atomic hydrogen. Saturation spectroscopy with a Doppler-free spectral resolution is adopted to detect the Stark effects of the low energy states. We have demonstrated a detection limit of 10 V cm−1, which is a sufficient sensitivity for investigating the structures of the sheath electric fields in low-temperature plasmas. We have discussed the detection limit, the measurement ambiguity, the spatial resolution, and the limitation of the developed method
オオガタ ヘリカル ソウチ LHD ニ オケル スイソ オヨビ ヘリウム ノ プラズマ ブンコウ ケンキュウ
No full text京都大学0048新制・論文博士博士(工学)乙第11314号論工博第3754号新制||工||1295(附属図書館)UT51-2003-T319(主査)教授 藤本 孝, 教授 斧 髙一, 教授 立花 明知学位規則第4条第2項該当Doctor of EngineeringKyoto UniversityDA
Spontaneous rupture of renal cell carcinoma: a case report
No full textA 74-year-old man with severe right flank pain and hypochondralgia, was admitted to a hospital where he was found to have an abnormality of the right kidney on computed tomographic (CT) scan. He was referred to our department for further examination and treatment on the next day. Spontaneous rupture of the right renal cell carcinoma was mostly suspected from preoperative clinical findings obtained by ultrasonography. CT scan and angiography. Extravasation was not recognized on angiography. We chose emergent transcatheter arterial embolization prior to radical nephrectomy. The surgical specimen contained a solid and yellowish mass invading into the renal pelvis. Subcapsular rupture was identified. Histopathological diagnosis was renal cell carcinoma consisting of invasive growth of highly atypical epithelial cells with a sarcomatous pattern, and the tumor cells were present in the renal pelvis. He died of lung cancer 26 months after the operation
Performance of sheath electric field measurement by saturation spectroscopy in Balmer-α line of atomic hydrogen
No full textWe developed a diode laser-based system for measuring the sheath electric fields in low-temperature plasmas. The Stark spectrum of the Balmer-α line of atomic hydrogen was measured by saturation spectroscopy with a fine spectral resolution. The spectrum observed experimentally was consistent with the theoretical Stark spectrum, and we succeeded in evaluating the electric field strength on the basis of the experimental Stark spectrum. A sensitive detection limit of 10 V/cm was achieved by the developed system
Polarization of Lyman-α Line Due to the Anisotropy of Electron Collisions in a Plasma
No full textAjournal articl
Simultaneous Measurement of Electron and Ion Temperatures with Helium-like Argon X-Ray Spectrum
No full textHelium-like argon spectra are measured for plasmas in the Large Helical Device (LHD). The electron temperature Te derived from the intensity ratio of a dielectronic satellite line (1 s2 2p 2P1/2 - 1s2p2 2D3/2) to the resonance line (1 s2 1S0 - 1s2p 1P1) is consistent with the central Te measured with the Thomson scattering method when the electron density ne has a peaked profile. The ion temperature Ti is simultaneously determined from the Doppler broadening width of the resonance line and an establishment of thermal equilibrium between electrons and ions, i.e., Ti = Te, due to increase of ne is experimentally confirmed. The density ratio of lithium-like ion to helium-like ion is determined from fitting of the entire spectrum.journal articl
Ionization Balance in the Rotating Radiation Belt Accompanying Complete Divertor Detachment in LHD
No full textA spectroscopic measurement is performed for a plasma in a rotating radiation belt, which accompanies the complete divertor detachment recently realized in the Large Helical Device (LHD) [J. Miyazawa et al., Nucl. Fusion 46, 532 (2006)]. The population distribution over the exited levels is experimentally determined from the Balmer series line intensities and is compared with the result of the collisional-radiative model calculation to determine the electron temperature Te and density ne. No reasonable pair of Te and ne is found when either the ionizing plasma or the recombining plasma is assumed. A good fitting is obtained under an assumption of the ionization balance plasma with Te = 1.8 eV and ne = 2 × 1020 m-3. These parameters are confirmed through analysis of a high-wavelength-resolution measurement for the Balmer series lines which clearly exhibit the Stark broadening effect.journal articl
Ionization Balance in the Rotating Radiation Belt Accompanying Complete Divertor Detachment in LHD
No full textX-ray crystal spectrometer with a charge-coupled-device detector for ion temperature measurements in the Large Helical Device
No full textBranching ratio between resonant and non-resonant ionization of xenon evaluated from photoelectron angular distributions [Elektronisk resurs]
No full textPhotoelectron imaging of xenon gases ionized with a femtosecond 388 nm pulse reveals three ionization processes: resonant and non-resonant multi-photon ionization and autoionization. The relative yield of the first two was evaluated from the deconvolution of their angular distribution for the specific electron energy, which includes the electron production via the 3hv–5p5(2P° 1/2)6s resonance. The non-resonant process gains in importance with increasing laser intensity and accounts for 50% of the ionization yield at 30TWcm−2
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