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+