1 laser background

eXenhXe 32 1 Laser Background

2 Apparatus Overview

3 Ion Beam PropertiesA Energy Spread

B Spatial Spread

4 Xe+ & Xe2+ In Laser

5 Z-Scan of Laser Focus

6 Summary

eXenhXe 242 eXenhXe 352 eXenhXe 462 eXenhXe 572

Multiple Charged Ions Production From Xe+ & Xe2+ In Intense Laser Field

BY M.SURESH

Femtosecond Lasers

Ti: Sapphire at 800 nm (1.6 eV)

Chirped Pulse Amplification

Terrawatt (1012 W) LasersASTRA ~10 mJ in ~10 fs

High field physics > 1016 Wcm-2

1 au = 3 x 1016 Wcm-2

Repetition rate 10 Hz

Apparatus Overview

Laser AlignmentLaser Alignment

ShadowExit Window Entrance

Window

Two Wire Crosses

Laser Beam

AnalyzerAnalyzer

Analyzer Plate Scan for Multiply Charged Ions of

andXe+

1.15E -1

0.00E +0

2.42E -2

4.58E -2

7.33E -2

8.92E -2

5.00E -6

0.00E +0

2.00E -7

4.00E -7

6.00E -7

8.00E -7

1.00E -6

1.20E -6

1.40E -6

1.60E -6

1.80E -6

2.00E -6

2.20E -6

2.40E -6

2.60E -6

2.80E -6

3.00E -6

3.20E -6

3.40E -6

3.60E -6

3.80E -6

4.00E -6

4.20E -6

4.40E -6

4.60E -6

4.80E -6

190 2 4 6 8 10 12 14 16 18

Voltage (V)

Xe2+

Voltage (V)

Tim

e of

Fli

ght

Tim

e of

Fli

ght

Spatial Spread Measurement

1 mm Aperture

0.5 mm Aperture0.13 mm Slit

ION BEAM CHARACTERIZATION

0 10 20 30 40 50

0

50

100

150

200

250

300

Spatial Spread Scan of He+ Ion Beam

Spatial Spread of He+ and Ar+ at Different Ion Beam Energies

Type of Ion Energy (KeV) Spatial Spread(mm)

1 1.27

He+ 2 1.07

3 0.97

1 1.35

Ar+ 2 1.2

3 1.03Spatial Spread Depends On Energy Spatial Spread Depends On Energy And Mass Of The BeamAnd Mass Of The Beam

Spatial Spread Scan of He+ Ion Beam Selected by 1mm & 2mm Apertures

Current Decreases From 300nA To 120nACurrent Decreases From 300nA To 120nA

2 mm Aperture2 mm Aperture

1 mm Aperture1 mm Aperture

Ion

bea

m C

urr

ent

(nA

)

Slit Position (mm)

Spatial Spread of He+ and Ar+ (3keV) With 1mm & 2mm Apertures

Spatial Spread Depends on Aperture Size

Type of Ion

2mm Aperture

1mm Aperture

He+ 0.97 0.56

Ar+ 1.03 0.66

Spatial Spread of HeSpatial Spread of He++ Ion Beam Ion Beam at Different Focusing at Different Focusing

ConditionsConditionsEnergyEnergy Without Without

FocusingFocusing Focused Focused Through Through 0.5mmApertur0.5mmAperturee

1keV1keV 1.27mm1.27mm 0.41mm0.41mm

3keV3keV 0.97mm0.97mm 0.34mm0.34mm

Energy spread

Energy Spread

1mm Aperture 2mm Aperture

1kV Energy 2kV Energy

Different DischargeConstant Pressure

Different PressureConstant Discharge

Energy Spread of 1keV and 2keV Ar+ - 2 mm Aperture

Nergy Spread(eV)

1000 1200 1400 1600 1800 2000

10

20

30

40

50

60

70

Discharge Voltage (V)

En

erg

y S

pre

ad

(e

V)

1KeV

2KeV

ISS Z-Scan

2

0

20

2

2),(

1

2exp

1Z

Z

r

Z

Z

II

o

ozr

200 zDf 20

6.0E-9

-1.0E-9

0.0E+0

1.0E-9

2.0E-9

3.0E-9

4.0E-9

5.0E-9

20.00000.0000 5.0000 10.0000 15.0000

Z-scan of Xe3+ from Xe2+ Z -scan of Xe4+ from Xe2+

1.1E-8

-1.0E-9

0.0E+0

1.0E-9

2.0E-9

3.0E-9

4.0E-9

5.0E-9

6.0E-9

7.0E-9

8.0E-9

9.0E-9

1.0E-8

25.00000.0000 5.0000 10.000015.000020.0000

Sig

nal

Z-Position (mm)

Z-scan of XeZ-scan of Xe6+6+ from Xe from Xe2+2+ Z-scan of XeZ-scan of Xe7+7+ from Xe from Xe2+2+

Z-Position (mm)

Sig

nal

2.5E-9

-5.0E-10

-2.5E-10

0.0E+0

2.5E-10

5.0E-10

7.5E-10

1.0E-9

1.3E-9

1.5E-9

1.7E-9

2.0E-9

2.3E-9

25.00000.0000 5.0000 10.0000 15.0000 20.0000

0.0E+0

-1.4E-9

-1.2E-9

-1.0E-9

-8.0E-10

-6.0E-10

-4.0E-10

-2.0E-10

6.00000.0000 1.0000 2.0000 3.0000 4.0000 5.0000

SummarySummary

First experimental results First experimental results onon XeXe22++ in in intenseintense laser laser fieldfield

Less Than 2% Energy spread

0.34mm Spatial Spread

Up to Xe7+ from both Xe+ and Xe2+