Characterization and Optimization of an Electron

Cyclotron Resonance Ion Source

J.Rabinder Henry

External: Dr. Stefhan Facsko(FZR Rossendorf)

Dip-Ing. Gerald Staats

Professor: Prof. Dr.-Ing. Christian Schäffer

Outlook

• Introduction

Electron Cyclotron Resonance Ion Source (ECRIS)

FZR 14.5 GHz source

• Characterization and Optimization

Plasma –X-ray Spectroscopy

Results

• Beam Emittance

Results

• Summary and outlook

RFcemeB ωω == /

Principle of ECRIS

●Electron Cyclotron Resonance Heating

●Electron impact ionization

●Magnetic confinement

Magnetic Field

FZR 14.5 GHz Supernanogan

RF Power

3

RF Power

ECR Zone

Gas Inlet

ECR Source Working PrincipleExtraction Electrode

Electron Cyclotron Emission

FC2

Microwave source

BL1

BL2

Target Chamber

BPM2

SL2

FZR 14.5 GHz ECR Source

and Beam Line

4

ECRISSL1BPM1FC1

MD

EL1

EBIT

Multielectrode

extraction

MS1

SL2

RF Power (x)

Pressure (y)

Biased disc (z)

I extracted (Iex)ECRIS

Characterization and Optimization

Max f (Iex) = min (x, y, z)

5

Gas mixing (a)

Plasma Characterization

X-ray Spectroscopy

Ion beam quality

Emittance

Electron Distribution

Charge State Distribution }Source Parameters

x, y, z, a

X-ray Spectroscopy

Electron –Bremsstrahlung Measurement

Ion charge state –Characteristics X-ray Measurement

Germanium Detector Attenuation of Radiation

Be window

Air column

Collimation

Extraction Voltage

6

Analyzing

Magnet

HPGe Detector

ECRIS

Faraday Cup

Beryllium

Window

4000

6000

Electronic Peak

Counts

No collimation

With collimation 1mm

2000

4000

Counts

US= 25KV

US=0V

Bremsstrahlung Measurement

Collimation Extraction Voltage

7

0 50 100 150 2000

2000

Energy (keV)

0 50 100 150 2000

2000

E (keV)

0 50 100 150 200

0

2000

4000

6000

8000

10000

25W

50W 75W

100W 125W

175W 200W

250W

Counts

E(keV)

0 50 100 150 2000

1000

2000

3000

0V

-100V

-200v

-300V

-400V

-600V

Coun

ts

E ( keV)

Photon Distribution Analysis

Power Bias

80 50 100 150 200

0

2000

4000

6000

8000

1x10-5mbar

2.5x10-5mbar

5X10-5mbar

4.210-5mbar

7.5x10-5mbar

1x10-4mbar

Counts

E (keV)

0 50 100 150 2000

2000

4000

6000

8000

Counts

E (keV)

Argon+Oxygen

Argon

Photon Distribution Analysis

PressureGas mixing

Bremsstrahlung Spectra for Varying Power

6000

8000

10000

25W 50W

75W

100W

125W

175W

200W

250W

Counts

Xenon Plasma

Pressure 9.8x10-5mbar

Bias voltage -200 V

9

0 50 100 150 200

0

2000

4000

Counts

E(keV)

4000

6000

8000

1x10-5mbar

2.5x10-5mbar

5X10-5mbar

4.210-5mbar

7.5x10-5mbar

1x10-4mbar

Counts

Bremsstrahlung Spectra for Varying Pressure

Argon Plasma

Power 100 W

Bias voltage -164 V

10

0 50 100 150 2000

2000

4000 1x10 mbar

Counts

E (keV)

2000

3000

0V

-100V

-200v

-300V

-400V

-600V

Co

un

ts

Bremsstrahlung Spectra for Varying Bias

Xenon Plasma

Pressure 9.8x10-5mbar

Power 100 W

11

0 50 100 150 2000

1000

Co

un

ts

E ( keV)

4000

6000

8000

Co

un

ts

Argon+Oxygen

Argon

Bremsstrahlung Spectra for Gas Mixing

Power 50 W

Pressure 3.9x 10-5 mbar

Bias voltage of -200V

12

0 50 100 150 2000

2000

4000Co

un

ts

E (keV)

0 50 100 150 2000

1

2

3

4

5

6

7

F(E

) (R

ea

ltiv

e C

ou

nts

)

Energy

50W

100W

200W

40 50 60 70 80 90 100 110 1200,0

0,2

0,4

0,6

0,8

1,0

F(E

) R

ela

tiv

e C

ou

nts

Energy (keV)

-200V

-300V

-400V

-500V

-600V

Electron Distribution Analysis

PowerBias

130 50 100 150 200 2500,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

F(E

) (R

ela

tive

Co

un

ts)

Energy (keV)

1x10-4

mbar

5x10-5

mbar

1X10-5

mbar

50 100 150 2000

1

2

F(E

) R

ela

tive

Co

un

ts

Energy (kev)

Argon

Argon+Oxygen

Electron Distribution Analysis

PressureGas mixing

10000

15000

20000

1 8

054ev

1 7

061ev

1 6

401ev

Xe L

α1 4

104ev

Counts

Characteristics X-ray Measurements

Xenon

Power 120 W

Pressure 9.7 x 10-5 mbar

Bias -200V

14

0 5000 10000 15000 20000 25000 30000 35000 400000

5000

Xe K

β1 3

3384ev

Xe K

α1 2

9779ev

Cu K

β1 8

904ev

Cu K

α1 8

054ev

Fe K

β1 7

061ev

Fe K

α1 6

401ev

Counts

E (eV)

0 10000 20000 30000 40000

0

5000

10000

15000

20000

60W

200W

20W

60W

80W

100W

120W

140W

160W

180W

200W

Co

un

ts

0 10000 20000 30000 400000

2000

4000

6000

8000

10000

12000

14000

2.7x10-6

mbar

1.03X-4

mbar

Ks

eri

es

Ls

eri

es

1.03x10-4

mbar

6.5x10-5

mbar

4.5x10-5

mbar

3.9x10-5

mbar

2.4x10-5

mbar

1.5x10-5

mbar

4.1x10-6

mbar

9.8x10-6

mbar

2.7x10-6

mbar

Co

un

ts

X-ray Spectra

Power Pressure

15

0 10000 20000 30000 40000

E (eV)

0 10000 20000 30000 40000

E(eV)

0 20 40 60 80 100 120 140 160 180 200

0,02

0,04

0,06

0,08

0,10

Inte

nsity R

atio

RF-Power(watts)0,0 2,0x10

-54,0x10

-56,0x10

-58,0x10

-51,0x10

-41,2x10

-40,00

0,01

0,02

0,03

0,04

0,05

0,06

Ik/IL Inte

nsity r

atio

Pressure mbar

10000

15000

20000

60W

200W

20W

60W

80W

100W

120W

140W

160W

180W

200W

Co

un

ts

X-ray Spectra For Varying Power

Xenon plasma

Pressure1.03 x 10-4 mbar

Bias voltage -200 V

16

0 10000 20000 30000 40000

0

5000

10000

Co

un

ts

E (eV)

8000

10000

12000

14000

Lse

ries

1.03x10-4

mbar

6.5x10-5

mbar

4.5x10-5

mbar

3.9x10-5

mbar

2.4x10-5

mbar

1.5x10-5

mbar

4.1x10-6

mbar

9.8x10-6

mbar

2.7x10-6

mbar

Co

un

ts

X-ray Spectra For Varying Pressure

Xenon plasma

Power 100 W

Bias voltage -200 V

17

0 10000 20000 30000 400000

2000

4000

60002.7x10

-6mbar

1.03X-4

mbar

Kse

ries

2.7x10 mbar

Co

un

ts

E(eV)

6000

8000

10000

Xe

L S

eri

es

Co

un

ts

-50V

-250V

-400V

-600V 2000

Fe K

α

Cu K

α 1

,2

Xe L

α 1

,2

Counts

Xe 27% /O 20%

Xe 27% /O 21.50%

Xe 27% /O 25.20%

X-ray Spectra

Bias Gas mixing

18

0 10000 20000 30000 400000

2000

4000X

e K

Se

rie

s

Co

un

ts

E(eV)0 10000 20000 30000 40000

0

1000

Xe K

β

Cu K

β

Fe K

β

Xe

Lβ

Counts

E (eV)

X-ray Spectra For Varying Bias

60 0 0

80 0 0

1 00 0 0

Xe L

Series

Counts

-50V

-250V

-400V

-600V

Xenon plasma

Pressure1.03 x 10-4 mbar

Power 100 W

19

0 10 0 00 20 0 00 30 00 0 4 0 00 00

20 0 0

40 0 0

Xe K

Series

Counts

E (e V )

2 0 0 0

Fe K

α

Cu K

α 1

,2

β

Xe L

α 1

,2

Counts

X e 2 7 % /O 2 0 %

X e 2 7 % /O 2 1 .5 0 %

X e 2 7 % /O 2 5 .2 0 %

X-ray Spectra For Gas Mixing

Xenon and Oxygen

Pressure 1.6x 10-6 mbar

Power 100 W

Bias voltage -200 V

20

0 1 0 0 0 0 2 0 0 0 0 3 0 0 0 0 4 0 0 0 00

1 0 0 0

Xe K

β

Cu K

β

Fe K

β

Xe L

β

Counts

E (e V )

60

80

Ar

2+

Ar

3+

Ar

4+

I e

xtr

acte

d u

A

40W

60W

80W

100W

Mass Spectra For Varying Power

Argon

Pressure 1x 10-4 mbar

Bias voltage -400 V

21

200 250 300 350 400 450 500

0

20

40

Ar

9+

Ar

8+

Ar

7+

Ar

5+

Ar

6+

I e

xtr

acte

d u

A

B mT

200 250 300 350 400 450 500

0

20

40

60

80

Ar 9+

Ar 8+

Ar 7+

Ar 6+

Ar 5+

Ar 4+

Ar 3+ Ar 2+

I extracted uA

B mT

1x10-5

mbar

1x10-4

mbar

5x10-5

mbarMass Spectra For Varying Pressure

Argon

Power 100 W

Bias voltage -400 V

22

B mT

2 3 4 5 6 7 8 9

0

20

40

60

80

I uA

Charge State

1x10-5

mbar

5x10-5

mbar

1x10-4

mbar

Charge State Distribution

200 250 300 350 400 450 500

0

10

20

30

40

50

60

70

80

Ar 2+

Ar 3+

Ar 4+

Ar 5+

Ar 6+

Ar 7+

Ar 8+

Ar 9+

I extracted uA

0V

-400V

-200V

Mass Spectra For Varying Bias

Argon

Power 100 W

Pressure 1x 10-4 mbar

23

B mT

1 2 3 4 5 6 7 8 9 100

10

20

30

40

50

60

70

80

I uA

Charge State

Ar

0V

-200V

-400V

Charge State Distribution

α

σ

z

y

x

Current

Profile

d

Emittance calculation

πε /xxA=

ασε .2 xx =

( )d/tan 1 σα −=

24

FC1

SL1ECRIS

z

d

Pin hole

Einzel lens

Steerer

Measurement Setup

0 2 4 6 80,0

0,2

0,4

0,6

0,8

1,0

1,2

FC

Curr

ent m

A

Slit Position mm

Slit +X

Slit -X

Slit +Y

Slit -Y

-x+x

Z

+y

-y

Emittance Measurement

250 2 4 6 8 10 12 14 16

0,00

0,05

0,10

0,15

0,20

0,25

Peak3

Peak 2

Peak1

M1S1

dI/dx

Current Profile

σ =0.24149

σ =0.40832

σ =0.35993

σ =0.4551

Re

lati

ve

In

ten

sit

y m

A

Slit position mm

Pea

ks

Peak width

2σ mm

Peak half width

σ mm

Divergenc

e Angle α

Phase

space

area

2σ* α

mmrad

1 0.72 0.36 0.147 0.001

2 0.92 0.46 0.188 0.003

3 0.80 0.40 0.163 0.002

Mea

n = 0.81 = 0.40

=0.166

0.002

Summary

Plasma

Two different population of electrons below 30 keV and 100 keV

Stable plasma at nominal power

Unstable plasma at very low pressure

Charge state distribution

Enhanced with bias voltage but no change in plasma characteristics

Ion current extracted depends on gas mixing ratio

Emittance

26

Emittance

Ion beam emittance depends on extraction and beam line elements

Outlook

Longmuir probe measurements

Better emittance with pin hole and CCD camera

Thank you !

27