CONCLUSIONSDEDICATION

EXPERIMENT

INTRODUCTION

Lorentzian width

electron densityGaussian width

gas temperature

Spatial and temporal distribution of excited Cl atomsin a linear dielectric barrier discharge

M. Miclea, K. Kunze, J. Franzke, C. Vadla*, K. Niemax

Institute of Spectrochemistry and Applied Spectroscopy (ISAS), Dortmund, Germany*Institute of Physics, Zagreb, Croatia

0

8

10

12

14

16

18

20

22

24

26

21P

23P

21S

23S

11S

4D

o

7/24P

5/2

2P

o

3/2

1P

1

3P

2

1S

0

He

Cl

Ar

Energ

y[e

V]

0 20 40 60 80 100 120 140

0,0

0,5

1,0

1,5

-15 -10 -5 0 5 10 15 20

0,0

0,5

1,0

Kr(�

�)

tB

tA

(pm)��

�� = + 5 pm

�� = + 2.5 pm

�� = 0 tB

tA

Kr(

t)

t (�s)

0 10 20 30 40 500

1

2

3

4

10

1

0.1

1016

1015

1014

320000K

80000K

20000K

10000K

Ne(cm

-3

)

wL

Sta

rk(p

m)

wL

Sta

rk[p

m]

time [µs]

�

�

�

�

optical investigation of a dielectric barrier discharge (DBD) usingdiode laser absorption spectroscopy performed by a high spatialresolution arrangement

study of the distribution of excited Cl atoms on the P metastable

level in Ar or He with 150 ppm CCl F

results on the plasma parameters (electron density and gastemperature) temporally resolved

improvement of the detection limit of halogenated hydrocarbons

4

5 / 2

2 2

4 - 5 cm

Al electrode50 - 100 µm thick0.7 - 1 mm width

glass type dielectric10 - 20 µm thick

= 6 -13�r

1 mm

+/-

10 - 100 mbar,50 - 500 ml/min0.7 - 1 kVp p

5 - 20 kHz

0 10 20 30 120 1400

1

2

3

4

300 K

950 K

wG

[pm

]

time [µs]

This paper is dedicated to the 70 birthday of Dr. Geavit Musa andhis significant contribution to the field of plasma physics and

technology in the last 40 years.

t h

SPATIAL RESOLUTION 50 µm

TEMPORAL RESOLUTION 100 ns

�

�

Cl ( P D )

837.824 nm

4 4 o

5/2 7/2�

Hitachi HL8325G

Ar 1s 2p

800.838 nmSharp LTO16MDO

res

4 6�

Different spatial position of maxima

different electron mean free path ( > )� � �e e

He Ar

�

�

�

spatial (~50 µm) and temporal (~100 ns)evolution of excited Cl atoms

different excitation processes in He and Arproved by the behaviour of the excited Clatoms

improvement of the detection of CCl F by Cl

absorption measurements in the volumecontaining the maximum excited atoms density

2 2

lensf = 10 cm

photomultiplier

l = 1 m

h = 1 mm

plasma

screen withpinholed = 500 µm

beam-splitter

mirrorwavemeter

PLASMAPARAMETERS

SPATIALTEMPORAL

DISTRIBUTION

0 50 100 150 200

-0,2

-0,1

0,0

0,1

0,2

0,3

0

200

400

600

8001000ln

(Io/I(t

))

positio

n[µ

m]

time [µs]

0 50 100 150 200

-0,2

-0,1

0,0

0,1

0,2

0,3

0

200

400

600

8001000ln

(Io/I(t

))

positio

n[µ

m]

time [µs]

0 50 100 150 200

-0,1

0,0

0,1

0

200

400

600

8001000

ln(I

o/I(t

))

positio

n[µ

m]

time [µs]

0 50 100 150 200-0,1

0,0

0,1

0

200

400

600

8001000

ln(I

o/I(t

))

positio

n[µ

m]

time [µs]

Higher population density in Arthan in He

�

�

different electron density(n < n )

collisional transfer betweenbuffer gas and Cl excitedatoms is more efficient in Ar

e e

He Ar

100 mbar

20 mbarHelium Argon

60 mbar

30 mbar

CALIBRATIONCURVE

10-3

10-2

10-1

100

101

102

10-3

10-2

10-1

100

101

102

3�

Discharge conditionsAr at 50 mbar and 500 ml/min700V

ppf=11.5 kHz

spatia

l reso

lution

/ 100µm

from

K

nosp

atial r

esolutio

n

Ab

so

rptio

nsig

na

l[%

]

CCl2F

2concentration [ppm]