Transcript Status of Equatorial CXRS System Development

Status of Equatorial CXRS
System Development
S. Tugarinov, Yu. Kaschuck, A. Krasilnikov,
V. Serov
SRC RF TRINITI, Troitsk, Moscow reg, Russia.
E-mail: [email protected]
Main directions of the CXRS diagnostic
development in RF
• 1. Collection optical system design and
integration into the equatorial port plug # 3.
• 2. Numerical simulation.
• 3. Data analysis development.
• 4. Measurement methodology development.
• 5. Specific spectroscopic instruments
development.
General scheme of CXRS for ITER
-Distribution of the
CXRS
periscopes
looking at the DNB.
-Russia responsible
for two periscopes
at the E-port # 3 for
plasma
edge
measurements.
Five mirrors optical system integration into E-port #3
r/a=1
r/a=0.5
Version September 2005
1. Collection optical system design and
integration in to port plug
• Optical system design and imaging
properties optimization was carried out by
ZEMAX software.
• Imaging scale is 10 : 1.
• Collection optical system has agree with
spectral instrument light throughput.
• Individual spectrometer will be used for
each view chord.
Five mirrors optical system focusing properties
• Five view chords distributed from r = a to r = a/2
• Color of spot correspond to Hα, He II and CVI wavelength
m
r/a=1
r/a=0.5
m
m
m
Focal plane
m
At the RF - EU Workshop devoted to ITER CXRS
diagnostic development that took place in
TRINITI (14–16 September, 2005) was suggested:
• Extend equatorial port observation system
up to r = 0.3a for deep overlap of edge and
core measurement systems and extend the
plasma region where poloidal and toroidal
plasma rotation could be separate.
• Achieve the best possible spatial resolution
at the plasma periphery for edge physics
studies.
Version December 2005
r/a=1
r/a=0.5
r/a=0.3
• Only flat and spherical mirrors was used for
design to make optical system more simple
in alignment and practically feasible.
Four mirrors optical system focusing properties
m
r/a=1
r/a=0.5
r/a=0.3
m
m
Focal plane
2. Numerical simulation
• Involve all physical processes analysis
that be the result of CXR reaction
inside beam volume.
• Allow estimate measured signals value
and SNR value.
• In general, allow estimate abilities and
efficiency of CXRS diagnostic for ITER
application.
Experimental scheme for numerical simulation
5
4
3
2
1
6
7
8
r/a=0.3
r/a=1
Plasma parameters for numerical simulation
•
•
•
•
Electron density 1  1020 m-3 with a flat profile.
Center temperature ~20 keV with parabolic shape.
Equal electron and ion temperature.
Uniform impurity composition along radius :
D and T = 77%, C = 1.2%, Be = 2%, He = 4% with
respect to ne ( that correspond Zeff = 1.7 ).
• Integration time  = 0.1 sec .
• The simulation was carried out for He II 468.6 nm;
BeIV 465.8 nm and C VI 529.1 nm lines.
DNB’s parameters for numerical simulation
"Negative Ion" Beam
( 100 keV/amu)
"Positive Ion" Beam
(80 keV/amu)
100 H0
160 D0
70
183, 23, 29
E, E/2, E/3
Beam 1/e – radius
(m)
0.1
0.042, 0.056, 0.07
stop (10-20 m2)
2.28
2.63, 4.16, 5.32
Voltage (kV)
Current density
in focal position
(mA/cm2)
• “Negative Ion” beam – this is a beam which created with negative
ion source use.
• “Positive Ion” beam – this is a beam which created with positive
ion source use.
We have create original software for CXRS
numerical modeling, instead of DINA code
simulation.
Atomic data for cross section <σ> and rate
coefficients <σv> was simulated using ADAS
code.
(We are very appreciate to Dr. M. von Hellermann
for help with atomic data)
DNB’s profiles
•
“Negative” DNB
“Positive” DNB
DNB’s attenuation in plasma column
• “Negative” DNB
“Positive” DNB
Radial distribution of active CX He II line (white) and
background (red) intensity along view chord
integrated
• “Negative” DNB
“Positive” DNB
Radial distribution of active CX CVI line (white) and
background (red) intensity along view chord
integrated
• “Negative” DNB
“Positive” DNB
- With DNB modulation the signal-to-noise ratio
(SNR) is calculated for the case of continuum
radiation fluctuations as the main noise source.
- Thus, the SNR value calculated as:
I cx 
SNR 
2 I ff  I cx
• I’cx – signal from CX lines [ 1/s ]
• I’cx – signal from continuum radiation [ 1/s ]
•  - integration time [ s ]
Signal-noise ratio value radial distribution for
uniform 2.5 A0 (red) and variable 2.5 - 0.5 A0 (white)
spectral resolution for He II line
• “Negative” DNB
“Positive” DNB
Signal-noise ratio value for uniform 2.5 A0 (red)
and variable 2.5 - 0.5 A0 (white) spectral
resolution for CVI line
• “Negative” DNB
“Positive” DNB
• Comparison of "negative" and "positive"
DNB show advantageous of "positive" DNB
application for edge CXRS and acceptability
for core CXRS measurements.
• "Negative" DNB with 100 keV/amu energy
have less attenuation coefficient and
penetrate further into the plasma core,
therefore gives advantageous for core
measurements.
5. Specific spectroscopic instruments
development
• For the CXRS diagnostic, high resolution,
high light throughput spectrometer (HRS)
based on echelle grating was design.
• Spectral range: 200 – 900 nm.
• F-number = 3.
• Stigmatic image.
• Max. spectral resolution:  0.1 A0.
• Average linear dispersion: 2.5 - 3 A0/mm.
• Dispersion range: 2 – 20 A0/mm.
Optical scheme of new HRS design
•
•
•
•
1 – Entrance slit
2 – Flat mirror
3 – Spherical mirror
4 – Flat mirror with
hole
• 5 – Correction
element
• 6 – Echelle grating
• 7 – Image plane
New design of HRS
• 1. Entrance slit.
• 6. Echelle grating.
3. Spherical mirror.
7. Detector box.
5. Correction element
New design of HRS
•
•
•
1. Entrance slit.
3. Spherical mirror.
4. Flat mirror with hole.
5. Correction element.
6. Echelle grating (400 mm length).
Conclusion
• We plan continue activity in all directions of
the CXRS diagnostic development :
• 1. Collection optical system design and
integration into the port plug # 3.
• 2. Numerical simulation.
• 3. Data analysis development.
• 4. Measurement methodology development.
• 5. Specific spectroscopic instruments
development.