台灣光子源超高真空抽氣分析及真空計量測

Measurement of Vacuum Gauge and Pumping Analysis in Ultrahigh Vacuum for the Taiwan Photon Source

鄭家沐(C. M. Cheng) ； 熊高鈺(G. Y. Hsiung) ； 陳俊榮(J. R. Chen)

《真空科技》 25卷2期 (2012/06) Pp. 21-25

https://doi.org/10.29808/JVSROC.201206.0004

摘要

台灣光子源同步加速器之電子儲存環為一超高真空系統，以維持電子束流低發散度光源特性與長時間穩定運轉壽命。真空幫浦採用特殊設計較小尺寸的離子幫浦配合非蒸發式結拖（NEG）幫浦安裝於磁鐵之間且靠近主要釋氣光吸收器元件以達到最高的有效抽氣速率。真空計安裝於離子幫浦側，所測量真空氣壓應為系統最低局部氣壓約在10^(-11) Torr之超高真空度。本實驗組裝一組模擬儲存環真空腔，安裝離子幫浦、NEG幫浦及不同類型之超高真空計，同時進行超高真空幫浦抽氣分析以及評估真空計測量性能。真空系統經過抽氣烘烤及NEG活化後，最低氣壓達到6×10^(-12) Torr，主要殘留氣體為氫氣、一氧化碳、二氧化碳；將系統與渦輪分子幫浦隔離並關閉離子幫浦，真空腔內僅有NEG幫浦抽氣，此時系統內氣壓約3×10^(-11)Torr，殘留釋氣以甲烷為主。再啟動離子幫浦時氣壓可回復到6×10^(-12) Torr，可見離子幫浦的抽氣作用；而僅有Extractor真空計及ATG真空計可測量在10^(-12) Torr 範圍的氣壓。

關鍵字

台灣光子源 ； 離子幫浦 ； 超高真空 ； 真空計

並列摘要

The electron storage ring in the Taiwan Light Source synchrotron accelerator is required to be an ultrahigh vacuum system for maintaining the lower emittance characteristics of light source as well as the longer life time and high stability of beam operation. The combination of smaller size sputtering ion pump and the non-evaporable getter (NEG) pump assembly was designed to fit in the spaces between the magnets and locate closed to the major outgassing sources from the various photon absorbers to achieve the highest effective pumping speed. The vacuum gauges can only be installed near the pumps in which will measure the local pressure as low as 10^(-11) Torr. The experiment in this paper assembles a vacuum system similar with that in the electron storage ring which contains the ion pump, NEG pump, and various kinds of vacuum gauges for pumping analysis and evaluation of the performance of gauge measurements in ultrahigh vacuum degree. After evacuation of the system and baking degas as well as NEG activations, the ultimate pressure reaches to 6×10^(-12) Torr with the major residual gases contain the hydrogen, carbon monoxide, and carbon dioxide. When the system is isolated the turbo-molecular pump and shut off the ion pump, the ultimate pressure was increased to 3×10^(-11) Torr with the residual outgas of only methane while the NEG pump is active. The pressure was recovered to 6×10^(-12) Torr when the ion pump had switched on which reveals the active pumping of ion pump at 10^(-12) Torr regime, in which only the extractor gauge and the axial transmission gauge was awaken to measure the pressure.

並列關鍵字

Taiwan Light Source ； Ion pump ； Ultrahigh Vacuum ； Gauge