Beam characteristics of positively and negatively charged droplets generated by vacuum electrospray of an ionic liquid

Yukio Fujiwara, Naoaki Saito, Hidehiko Nonaka, Shingo Ichimura

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

To develop a vacuum-electrospray beam source for secondary ion mass spectrometry (SIMS), beam characteristics of charged droplets electrosprayed in vacuum were investigated in the negative-ion mode as well as the positive-ion mode. A quaternary ammonium ionic liquid was tested. Experimental results showed that there are differences as well as similarities between the positive-ion mode and the negative-ion mode. Beam current changed greatly with capillary voltage and the flow rate of the ionic liquid. Transient response analysis showed that the vacuum electrospray generated a mixed beam consisting of charged particles of smaller m=z values (m=z ∼ 10 3) and charged droplets of larger m=z values (m=z ∼ 10 5 to 10 6). It turned out that the m=z values of the charged droplets diminished with increasing capillary voltage. Using a threedimensional positioning stage, the capillary position dependence on the beam characteristics was measured. It proved to be of great importance to align the central axis of a capillary with those of apertures in order to maximize the current component of the charged droplets of the larger m=z values and minimize the ratio of the current component of the smaller m=z values. A high alignment accuracy proved to be required at small gap lengths between a capillary tip and a counter electrode.

Original languageEnglish
Article number036701
JournalJapanese Journal of Applied Physics
Volume51
Issue number3 PART 1
DOIs
Publication statusPublished - 2012 Mar 1
Externally publishedYes

Fingerprint

Ionic liquids
Vacuum
vacuum
liquids
Negative ions
positive ions
negative ions
Positive ions
Electric potential
Charged particles
Secondary ion mass spectrometry
Transient analysis
transient response
electric potential
beam currents
secondary ion mass spectrometry
Flow rate
positioning
charged particles
counters

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Beam characteristics of positively and negatively charged droplets generated by vacuum electrospray of an ionic liquid. / Fujiwara, Yukio; Saito, Naoaki; Nonaka, Hidehiko; Ichimura, Shingo.

In: Japanese Journal of Applied Physics, Vol. 51, No. 3 PART 1, 036701, 01.03.2012.

Research output: Contribution to journalArticle

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