22P037-P
Mass Spectrometry of the Atmospheric Pressure Plasma Jet
大気圧プラズマジェットの質量分析
Shuichiro Tsunoda1, Hajime Sakakita1,2, Satoru Kiyama2, Shengwei Chang2 and Jiro Kasahara1
角田 秀一郎1，榊田 創1,2，木山 學2，常 勝威2，笠原 次郎1
1

University of Tsukuba
1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, JAPAN筑波大学 〒305-8573 茨城県つくば市天王台1-1-1
2

National Institute of Advanced Industrial Science and Technology (AIST),
Tsukuba central2, 1-1-1 Umezono, Tsukuba 305-8568, JAPAN
産業技術総合研究所 〒305-8568 茨城県つくば市梅園1-1-1 中央第2Plasma phenomena which are produced under the atmospheric pressre region have been studied. Tomeasure the particle components and the ion energy spectrum, mass analyzer with energy filter wasprepared, and which was installed in the original three sets of differential pumping system. It was observedthat measured ion energy specrums and the number of counted particles strongly depend on the electric
potential differences between orifices which are installed in each pumping stage. Moreover, it wasobviously observed that the pressure in the first pumping stage decreases in the case with the plasma jet.
This possible cause will be presented at the meeting by showing the Schlieren high-speed imaging.

1. Introduction
It was obviously found that the pressure
decreases in the case with the plasma. This cause
will be presented at the meeting by showing theSchlieren high-speed imaging.
The plasma production under atmospheric pressure
has been studied for the purpose of applying to new
medical instruments [1], combustion improvement[2], material surface processing, and so forth. To
understand the discharge phenomena underatmospheric pressure plasma, it is very important tomeasure the components such as neutral particles,
excited particles, ions. However, the components of
the atmospheric pressure plasma were not studied indetail, because the components immediatelychanges due to the interaction with high pressure
ambient gases. Under this background, we have
tried to measure mass species and the energy ofeach particle, usually which is not easy under theatmospheric pressure region.
In the present study, we have prepared an original
differential pumping system to guide the plasmacomponents from the atmospheric pressure region
to a mass analyzer under high vacuume region
through three set of orifices. Voltage biasing effects
on these orifices are studied during inhaling theplasma jet components.

Differential pumping＆Analyzer (PPM422)
Pressure gauge

PCHePlasma source

Power source②①③Controller

Vacuum pumpFig.1. Mass spectrometry system.

① 2nd Stage
1st Stage

3rd Stage

PlasmaandOther gas
Orifice1

Analyzer (PPM422)

Orifice2
Orifice3①②③

Fig.2. Differential pumping system.

2. Mass spectrometry system
Fig. 1 shows the mass spectrometry system. The
main components of this system are composed of aplasma source and a mass analyzer (Pfeiffer:
PPM422) which is installed in three-staged ofdifferential pumping system. In the present
experiments, we have measured helium (He) gas
plasma and argon (Ar) gas plasma which areproduced by the dielectric barrier discharge.

Fig. 2 shows the schematic diagram of thedifferential pumping system. This system is divided
into three regions by three orifices (orifice 1;φ=0.1or1.0mm, orifice 2; φ =0.4mm, orifice 3; φ=0.1or1.0mm). The material of those orifices isstainless steel. First stage (①) are evacuated using ascroll pump, and second and third stages (② and③ ) are evacuated using a rotary pump andturbo-molecular pump. Here, the orifice 3 installed
between second and third stages is the entrance
aperture of the analyzer tube. PPM422 can beoperated under the lower pressure range than 10-2
Pa. Therefore, the atmospheric pressure plasma isintroduced into the analyzer region through the eachpressure of ① 101, ② 10-3, and ③ 10-6 Pa. In
addition, it is possible to apply voltages to eachorifice independently. It is possible for PPM422 tomeasure the energy spectrum of each particle using
an electrostatic energy filter.
3. Results and discussion
Fig. 3 and Fig. 4 show the energy distribution of
the argon ion in Ar gas plasma. In theseexperimental series, following conditions are set.
For Fig. 3 case, Vb1 (bias voltage of the orifice 1) is
set from -10 to -50 V, Vb2 (bias voltage of theorifice 2) is set to 10 V, and Vb3 (bias voltage of theorifice 3) is set to -10V. For Fig. 4 case, Vb1 is set toa floating potential, Vb2 is set to from 0 to 20V, andVb3 is set to 0V. As shown in Fig.3, it was observedthat there were two peaks around the energy regionof 0 and 10 eV. The peak value located around 10eV increases, when the value of the Vb1 becomes
negatively large. Fig. 4 indicated that the amplitudeof Vb2 affected on the peak position of the ion
energy distribution. Moreover, the maximum counts
at the peak increased when the electric potential
difference between orifice 1 and orifice 2 becomeslarge. This result suggests that particles in 1st stage
are ionized by electrons and accelerated.
Fig.5 shows the dependency of 1st stage pressure
on the distance between the nozzle of plasma device
and orifice 1 with or without the plasma jet. It was
obviously found that the pressure decreases in thecase with the plasma. This possible cause will bepresented at the meeting by showing the Schlieren
high-speed imaging.
References[1] E. Stoffels, Y. Aranda Gonzalvo, T. D. Whitmore,
D. L. Seymour and J. A. Rees: Plasma Sources Sci.
Technol. 15 (2006) 501-506.
[2] K. Takita and Y. Ju: Jounal of the Combustion Sci. ofJapan Vol.50 No.151 (2008) 45-50.

410Vb1:-50V
Vb1:-30V
Vb1:-20V
Vb1:-10V

310210110010-505101520+

Ar Energy [eV]+Fig.3. Ar energy spectrums Ⅰ410

Vb2:20V

3

10

Vb2:10V2

Vb2:0V101

10010-5051015202530+

Ar energy [eV]+Fig.4. Ar energy spectrums Ⅱ60
55

plasma-off
plasma-on

5045403530

810121416182022
Distance between orifice1 and plasma source [mm]Fig.5. Dependency of 1st stage pressure on thedistance between the nozzle of plasma device andorifice1 with or without helium plasma jet.