Loss of Ba atom from the electrode of fluorescent lamp operating under AC and DC discharges

Ahmed Samir, Go Yamashita, Yuichi Egashira, Shozaburo Shimada, Yukihiko Yamagata, Kiichiro Uchino, Yoshio Manabe, Takashi Ueda

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Low work function is a vital life-determining characteristic of fluorescent lamp electrodes. The work function of a fluorescent lamp electrode increases due to the loss of Ba atom from the electrode. Hence the rate of Ba atom loss controls the lifetime of the lamp. However the loss mechanism and the optimum discharge condition has not been well understood yet. In the study, the loss of Ba atom from a fluorescent lamp electrode using a laser-induced fluorescence (LIF) technique is investigated. The lamp was operated at both AC 60 Hz and DC discharge modes with different discharge currents. In addition, the electrode of fluorescent lamp was connected through an external DC current source to control the electrode temperature. The effects of both the discharge current and the electrode temperature on the emission of Ba atom were investigated. For the lamp operation at 60 Hz, the physical behavior of the emission of Ba atom from the anode and the cathode were found to be different. The most of the loss of Ba atom was observed in an anode half-cycle, while this loss was lower in a cathode half-cycle. In the case of DC discharge, with increase in the discharge current, the loss of Ba atom was increased at the anode while it was decreased at the cathode. At the cathode the decrease in temperature was due to the electron emission from the cathode, which is called as "electron cooling" and it played an important role for the suppression of the Ba atom loss. Additionally, the sputtering of Ba atom due to ion bombardment was also considered to be an important factor for the loss of Ba atom from the cathode at a low discharge current.

Original languageEnglish
JournalIEEJ Transactions on Fundamentals and Materials
Volume127
Issue number9
DOIs
Publication statusPublished - Sep 25 2007

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Fluorescent lamps
Atoms
Electrodes
Cathodes
Electric lamps
Anodes
Electron emission
Ion bombardment
Temperature
Sputtering
Fluorescence
Cooling

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

Cite this

Loss of Ba atom from the electrode of fluorescent lamp operating under AC and DC discharges. / Samir, Ahmed; Yamashita, Go; Egashira, Yuichi; Shimada, Shozaburo; Yamagata, Yukihiko; Uchino, Kiichiro; Manabe, Yoshio; Ueda, Takashi.

In: IEEJ Transactions on Fundamentals and Materials, Vol. 127, No. 9, 25.09.2007.

Research output: Contribution to journalArticle

Samir, Ahmed ; Yamashita, Go ; Egashira, Yuichi ; Shimada, Shozaburo ; Yamagata, Yukihiko ; Uchino, Kiichiro ; Manabe, Yoshio ; Ueda, Takashi. / Loss of Ba atom from the electrode of fluorescent lamp operating under AC and DC discharges. In: IEEJ Transactions on Fundamentals and Materials. 2007 ; Vol. 127, No. 9.
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