Korean Journal of Materials Research (한국재료학회지)

Materials Research Society of Korea (한국재료학회)
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Effects on Addition of Metal Oxides with Low Workfunctions on the Ca-Sr-Ba Oxide Cathodes for VUV Ionizers

VUV 이오나이저용 Ca-Sr-Ba계 산화물 캐소드에 낮은 일함수를 갖는 금속산화물 첨가의 영향

  • Park, Seung-Kyu (Department of Advanced Materials and Chemical Engineering, Hannam University) ;
  • Lee, Jonghyuk (Department of Advanced Materials and Chemical Engineering, Hannam University) ;
  • Kim, Ran Hee (Department of Advanced Materials and Chemical Engineering, Hannam University) ;
  • Jung, Juhyoung (Department of Advanced Materials and Chemical Engineering, Hannam University) ;
  • Han, Wan Gyu (Department of Advanced Materials and Chemical Engineering, Hannam University) ;
  • Lee, Soo Huan (Department of Advanced Materials and Chemical Engineering, Hannam University) ;
  • Jeon, Sung Woo (Department of Advanced Materials and Chemical Engineering, Hannam University) ;
  • Kim, Dae Jun (VSI Co. Ltd.) ;
  • Kim, Do-Yun (VSI Co. Ltd.) ;
  • Lee, Kwang-Sup (Department of Advanced Materials and Chemical Engineering, Hannam University)
  • 박승규 (한남대학교 화공신소재공학과) ;
  • 이종혁 (한남대학교 화공신소재공학과) ;
  • 김란희 (한남대학교 화공신소재공학과) ;
  • 정주형 (한남대학교 화공신소재공학과) ;
  • 한완규 (한남대학교 화공신소재공학과) ;
  • 이수현 (한남대학교 화공신소재공학과) ;
  • 전성우 (한남대학교 화공신소재공학과) ;
  • 김대준 ((주)브이에스아이) ;
  • 김도윤 ((주)브이에스아이) ;
  • 이광섭 (한남대학교 화공신소재공학과)
  • Received : 2018.12.13
  • Accepted : 2019.04.02
  • Published : 2019.04.27
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Abstract

There are several manufacturing techniques for developing thermionic cathodes for vacuum ultraviolet(VUV) ionizers. The triple alkaline earth metal emitters(Ca-Sr-Ba) are formulated as efficient and reliable thermo-electron sources with a great many different compositions for the ionizing devices. We prepare two basic suspensions with different compositions: calcium, strontium and barium. After evaluating the electron-emitting performance for europium, gadolinium, and yttrium-based cathodes mixed with these suspensions, we selected the yttrium for its better performance. Next, another transition metal indium and a lanthanide metal neodymium salt is introduced to two base emitters. These final composite metal emitters are coated on the tungsten filament and then activated to the oxide cathodes by an intentionally programmed calcination process under an ultra-high vacuum(${\sim}10^{-6}torr$). The performance of electron emission of the cathodes is characterized by their anode currents with respect to the addition of each element, In and Nd, and their concentration of cathodes. Compared to both the base cathodes, the electron emission performance of the cathodes containing indium and neodymium decreases. The anode current of the Nd cathode is more markedly degraded than that with In.

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References

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