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Title | Oxygen-Free Titanium Thin Film as a New Nonevaporable Getter with an Activation Temperature as Low as 185 °C | |
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Abstract | Although nonevaporable getter (NEG) pumps are widely used in synchrotron radiation facilities, pure metal Titanium (Ti) has not been used as a NEG because the activation temperature of a Ti thin film deposited by DC magnetron sputtering was reported to be 350-400 °C*. Recently Miyazawa et al. found that high-purity Ti deposited under ultra-high vacuum (UHV) followed by N₂ introduction works as a NEG with an activation temperature of 185 °C**,***. Since the concentration of impurities such as O, C, and N in the Ti thin film prepared by this method is 0.05% or less, we named this as oxygen-free Ti. In this study, we evaluated the pumping properties of oxygen-free Ti thin films after high-purity N₂ introduction by total and partial pressure measurements. A vacuum vessel with oxygen-free Ti deposited on the inner walls was found to pump H₂, H₂O, O₂, CO and CO₂ even after 30 cycles of high purity N₂ introduction, air exposure, pumping, and baking at 185 °C. Furthermore, we analyzed the oxygen-free Ti thin films after high-purity N₂ or air introduction by synchrotron radiation X-ray photoelectron spectroscopy. The results show that more TiN was formed when high-purity N₂ was introduced after oxygen-free Ti deposition. High purity of the Ti thin film and TiN formation on the surface seem to be responsible for the reduced activation temperature as low as 185 °C. | |
Footnotes & References | *C. Benvenuti et al., J. Vac. Sci. Technol. A 16, 148 (1998). **T. Miyazawa et al., Vac. Surf. Sci. 61, 227 (2018). ***KEK, patent pending, WO2018097325 (Nov. 28, 2017). |
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Funding | This work was partly supported by JSPS KAKENHI (17K05067, 19K05280) and TIA-Kakehashi (TK19-035, TK20-026). The XPS measurements were performed under the Photon Factory proposal (2018S2-005). | |
Paper | download TUPA01.PDF [1.495 MB / 4 pages] | |
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Conference | MEDSI2020 | |
Series | Mechanical Engineering Design of Synchrotron Radiation Equipment and Instrumentation (11th) | |
Location | Chicago, IL, USA | |
Date | 24-29 July 2021 | |
Publisher | JACoW Publishing, Geneva, Switzerland | |
Editorial Board | Yifei Jaski (ANL, Lemont, IL, USA); Patric Den Hartog (ANL, Lemont, IL, USA); Kelly Jaje (ANL, Lemont, IL, USA); Volker R.W. Schaa (GSI, Darmstadt, Germany) | |
Online ISBN | 978-3-95450-229-5 | |
Online ISSN | 2673-5520 | |
Received | 30 July 2021 | |
Accepted | 14 October 2021 | |
Issue Date | 01 November 2021 | |
DOI | doi:10.18429/JACoW-MEDSI2020-TUPA01 | |
Pages | 119-122 | |
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