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2019 Vol.29, Issue 4 Preview Page
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

Seung-Kyu Park1
,
Jonghyuk Lee1
,
Ran Hee Kim1
,
Juhyoung Jung1
,
Wan Gyu Han1
,
Soo Huan Lee1
,
Sung Woo Jeon1
,
Dae Jun Kim2
,
Do-Yun Kim2
,
Kwang-Sup Lee1†
박 승규1
,
이 종혁1
,
김 란희1
,
정 주형1
,
한 완규1
,
이 수현1
,
전 성우1
,
김 대준2
,
김 도윤2
,
이 광섭1†
1Department of Advanced Materials and Chemical Engineering, Hannam University, 1646 Yuseongdae-ro, Yuseong-Ku, Daejeon 34054, Republic of Korea
2VSI Co. Ltd., 151-33 Namsuk-ro, Cheongju, Chungcheongbuk-do 28182, Republic of Korea
1한남대학교 화공신소재공학과
2㈜브이에스아이
†Corresponding author E-Mail : kslee@hnu.kr (K.-S. Lee, Hannam Univ.)
April 2019. pp. 241-251
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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(~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.

Keywords
ionizer
thermionic cathode
vacuum ultraviolet
metal oxides
work function
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Information
  • Publisher :Materials Research Society of Korea
  • Publisher(Ko) :한국재료학회
  • Journal Title :Korean Journal of Materials Research
  • Journal Title(Ko) :한국재료학회지
  • Volume : 29
  • No :4
  • Pages :241-251
  • Received Date : 2018-12-13
  • Revised Date : 2019-04-01
  • Accepted Date : 2019-04-02
  • DOI :https://doi.org/10.3740/MRSK.2019.29.4.241
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