17 th HAPL Meeting Washington, DC October 30, 2007 Naval Research Laboratory Plasma Physics Division...
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Transcript of 17 th HAPL Meeting Washington, DC October 30, 2007 Naval Research Laboratory Plasma Physics Division...
17th HAPL MeetingWashington, DCOctober 30, 2007
Naval Research LaboratoryPlasma Physics Division
Washington, DC
Work supported by DOE/NNSA/DP
Optical System and staging of the Electra KrF laser facility
NRL M. Wolford
M. MyersJ. SethianJ. Giuliani
Commonwealth Tech
F. Hegeler
RSIP. Burns
SAIC R. Jaynes
LPX 305 i
Input 0.5 J10 cm x 10 cm
Cylindrical lens Pair
Telescope
1 cm x 3 cm
3 cm x 3 cm
OutputInput
BG 28
LA Vision
Improved Near Field Measurements since last HAPL Meeting
80% Ar, 0.3% F2
0.0
5.0
10.0
15.0
20.0
25.0
30.0
8 12 16 20Pressure (psi)
Las
er O
utp
ut
(J)
Orestes 0.5 J Input
Measured Input ~0.5 J
Orestes 0.7 J Input
Measured Input 0.6 J
Single Beam Electra Pre-Amplifier Yield
Voltage
OutputInput
64.8 ns
-50
0
50
100
150
200
250
300
350
-40 -20 0 20 40 60 80 100 120 140
Time (ns)
Vo
ltag
e (k
eV)
Po
wer
(10
0 M
W)
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Inte
nsi
ty (
arb
.)
Diode VoltageDiode PowerOutputInput
Single Beam Timing Between Laser Input, Laser Output and Electron Beam (10 J)
-1
0
1
2
3
4
5
6
0 20 40 60 80 100 120 140
Time (ns)
Inte
ns
ity (
arb
.)
1 (-36.3 ns) 3.8 J
2 (1.3 ns) 10.0 J
3 (21.5 ns) 15.7 J
4 (40.7 ns) 20.0 J
5 (64.8 ns) 10.0 J
6 (88.0 ns) 2.9 J
Power (10 GW)
1
2
3
4
5
6
-40 -20 0 20 40 60 80 100 120 140
1 2 3 4 56
Input
Output
Single Beam Output Time Dependent Intensity
0
5
10
15
20
25
-50 0 50 100 150Input Time (ns)
En
erg
y (J
)
80% Ar, 0.3% F2@ 16 psi80%Ar, 0.3% F2@ 18 psiOrestes 16 psi
Orestes 18 psi
-30 -10 10 30 50 70 90Time (ns)
Cause of Discrepancy
Single Beam Pre-Amplifier Yield Function of Input Timing
LPX
PLCC
Cylindrical Optics6 m Nike Lens
BeamsplitterCalorimeter
Photodiode Combo
770 mJ Laser Input Laser Beam separation ~26 ns
00.10.20.30.40.50.60.70.80.9
1
-5.0E-08 0.0E+00 5.0E-08 1.0E-07 1.5E-07Time (s)
Vo
lts
Beam 1 ~ 373 mJBeam 2 ~ 397 mJ
PD 2PD1
Two Beam Angularly Multiplex Preamplifier
Calorimeter Data
-1
0
1
2
3
4
5
6
7
0 25 50 75 100
Time (ns)
Inte
ns
ity
25 J Laser Output
300 mJ Laser Input Laser Beam separation ~26 ns
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 20 40 60 80 100Time (ns)
Vo
lts
Beam 1 Beam 2
8.1 cm 7.6 cm
9.0 cm 9.7 cm
25 J Output of Two Beam Angularly Multiplex Preamplifier
Dimensions
LPX
Pre-AMPMain AMP
Electra Laser System
Calorimeter
Photodiode (PDM)
Photodiode (PDTarget)
42 m
-0.5
0
0.5
1
1.5
2
2.5
3
600 650 700 750 800 850
Time (ns)
Inte
nsi
ty (
arb
.)
PDM (452 J)
Pdtarget (452 J)
PDM1 2
3 4
5 6
Pdtarget
0
100
200
300
400
500
-1 0 1 2 3 4 5 6
Time (s)E
ner
gy
(J)
Big Calorimeter33 x 33 cm2 Calorimeter
Nike Calorimeters18 x 18 cm2 Calorimeters
Sum
Full Laser System 452 J Single Shot Yield
Full Laser System Laser Yield Depends on Timing Between LPX, Pre Amplifier and Main Amplifier
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 50 100 150 200 250Time (ns)
Inte
nsi
ty (
arb
.)
452 J (PDM)237 J (PDM)
The Difference if one or both beams are amplified in Pre-amplifier
Timing Discrepancy Between Amplifiers
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
-50 0 50 100 150 200Time (ns)
Inte
ns
ity
(a
rb.)
Shot 1 (PDM)Shot 2 (PDM)Shot 3 (PDM)Shot 4 (PDM)Shot 5 (PDM)
0
0.2
0.4
0.6
0.8
1
1.2
0 50 100 150 200 250 300
Time (ns)
Inte
nsi
ty (
arb
.)
Shot 1 (406 J)
Shot 2 (365 J)
Shot 3 (412 J)
Shot 4 (268 J)
Shot 5 (134 J)
PDM1 2
3 4
5 6
PDTarget
Full Laser System Yield 1.585 kJ in One Second 5 Hz Burst
Single Pass Double Pass
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
-50 0 50 100 150 200Time (ns)
Inte
ns
ity
(a
rb.)
Shot 1 (PDM)Shot 2 (PDM)Shot 3 (PDM)Shot 4 (PDM)Shot 5 (PDM)
0
0.2
0.4
0.6
0.8
1
1.2
0 50 100 150 200 250 300
Time (ns)
Inte
nsi
ty (
arb
.)
Shot 1 (406 J)
Shot 2 (365 J)
Shot 3 (412 J)
Shot 4 (268 J)
Shot 5 (134 J)
Single Pass Double Pass
Why laser Yield is Decreasing with Shot #?
Observation: Larger Percentage Laser Intensity Decrease was observed after one pass than double pass
Probable Cause: A declining input laser intensity into the main amplifier
Single Shot 5 shot Rep-Rate Burst
Cross Hairs for Scale
Near Field (7m) Beam ProfileSuggests increase in Phase Aberration is the cause for the drop in laser energy for
the Electra Laser System
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
-20 0 20 40 60 80 100
time (ns)
ampl
itude
(ar
b. u
nits
)
1st shot
5th shot
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 50 100 150 200 250
time (ns)
ph
oto
dio
de
amp
litu
de
(V) shot 1
shot 100
shot 200
shot 300
shot 400
shot 500
500 shots @ 5 Hz
5 shots @ 5 Hz
Pre-amp without gas recirculator
Main-amp with gas
recirculator
Pre-amplifier Needs Recirculator For Rep-Rate Operation
0
500
1000
1500
2000
2500
3000
-2 0 2 4 6 8 10 12Time (seconds)
To
tal L
aser
Yie
ld (
J)Electra Laser System 2.5 kJ 2 second burst @ 5 Hz
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 50 100 150 200 250
Time (ns)
Inte
ns
ity
(a
rb.)
PDM_1PDM_2PDM_3PDM_4PDM_5PDM_6PDM_7PDM_8PDM_9PDM_10
All Components 5 Hz operational for longer bursts
Again, Low Yield for later shots due to Pre-AmpPhase Aberrations, will be corrected with Recirculator
Calorimeter Response
1)Pre-Amp Recirculator (Design Complete) (For Beam Quality, Consistent Rep-Rate Output)
2)Improved Coupling from Pre-Amp to Main Amp
3)Improved timing control, Reduced Jitter (improvement already made)
4)Increase and Improve Diagnostics for KrF Code Comparison
5)Strip Cathode for Pre-Amp (Increased Energy Deposition in laser gas by ~25%)
On Going Improvements in Laser System Since Measurements were made