タイトル | Thermal and electron-beam irradiation effects on the surfaces of niobium for RF cavity production |
その他のタイトル | RF空洞生産のためのニオブ表面に対する熱および電子ビーム照射効果 |
著者(日) | Ma, Qing; Rosenberg, Richard A. |
著者(英) | Ma, Qing; Rosenberg, Richard A. |
著者所属(日) | Argonne National Laboratory; Argonne National Laboratory |
著者所属(英) | Argonne National Laboratory; Argonne National Laboratory |
発行日 | 2003-06 |
刊行物名 | Proceedings of the 10th Workshop on RF Superconductivity, SRF2001 Proceedings of the 10th Workshop on RF Superconductivity, SRF2001 |
開始ページ | 368 |
終了ページ | 372 |
刊行年月日 | 2003-06 |
言語 | eng |
抄録 | Results of a study of thermal and electron-beam irradiation effects on the surfaces of Nb are presented. The samples were prepared by chemical etching methods used in superconducting rf cavity production. For such prepared samples, a layer of Nb2O5 covered the surface with some Nb2O interfacing the Nb metal. Some hydrocarbon species were also found on the surface. Oxidation in air at room temperature will be discussed. Heating the samples at temperatures from 100 to 300 C caused reduction of the surface oxide. The reduction rate increased with temperature. Near 100 C, some Nb2O5 reduced and some NbO(x) (x less than 2.5) formed. Near 170 C, only a little Nb2O5 remained after longer than 70 h. Substantial amounts of NbO(x) (1 less than or equal to x less than 2.5) formed. Heating at these temperatures also caused hydrocarbon decomposition, leaving graphitic carbon on the surface, but had no effect on Nb2O at the interface. At temperatures higher than 210 C, Nb2O5 disappeared. Only Nb2O remained on the surface that exhibited a metallic character. In addition, more than half of the surface carbon reacted with Nb and formed metal carbide. Reaction kinetics will be discussed. Under 1-keV electron beam irradiation, surface damage occurred. Changes in the secondary electron yield (SEY) were observed and identified to be due to two causes: surface chemical changes and defect creation in the oxide. There was a slope change in the SEY-vs-dose relationship that led to two cross-section values of 4.8 x 10(exp -18) cm(sup 2) and 2.3 x 10(exp -19) cm(sup 2) for the electron/matter interaction. The larger value primarily results from changes in surface chemistry and the smaller one from defect creation. |
キーワード | electron beam irradiation; temperature effect; superconducting cavity resonator; XPS; SEY; Nb cavity surface; chemical etching method; surface damage; oxidation; research and development; binding energy; reaction kinetics; 電子ビーム照射; 温度効果; 超伝導空洞共振器; XPS; SEY; ニオブ空洞表面; 化学エッチング法; 表面損傷; 酸化; 研究開発; 結合エネルギー; 反応速度論 |
資料種別 | Conference Paper |
SHI-NO | AA0046174065 |
レポートNO | KEK-Proceedings-2003-2 |
URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/46353 |