HT-7 Soft x-ray PHA diagnostics in the HT-7 and the EAST Z.Y.Chen, Y.J.Shi,B.Lv,B.N.Wan, L.Q.Hu, S.Y.Lin Q.S.Hu, S.X.Liu, Institute of Plasma Physics,Chinese.

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Soft x-ray PHA diagnostics in the HT-7 and the EAST

Z.Y.Chen, Y.J.Shi,B.Lv,B.N.Wan, L.Q.Hu, S.Y.Lin Q.S.Hu, S.X.Liu,

Institute of Plasma Physics,Chinese Academy of Sciences P.O.Box 1126, Hefei,Anhui, 230031 P.R.China

Email:[email protected]

ASIPP

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Content

• Aims of PHA and qualifications of its detector• Virtues of Silicon Drift Detector (SDD) • Layout of PHA in the HT-7 • Preliminary experimental results• PHA diagnostics for EAST• Summary

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PHA diagnostic aims in the HT-7• Te profile with high spatial resolution

• High time resolution of Te

• Investigating the concentration of heavy impurities

1. Compact assembly

Spatial multi-channel configuration

2. High input count rate

Considerable time resolution

3. High energy resolution

Impurities concentration measurement

Qualifications of soft x-ray PHA detector

Qualifications of detector

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HT-7Virtues of SDD detector for PHA

• High count rate count rate up to 200kHZ (0.5 sec shaping time)

• High energy resolution FWHM<160eV (@5.9keV, -10 ºC)

• High quantum efficiency suitable for soft X-ray detecting in range of 1~20keV

• Integrated FET lower noise, high SNR, no microphony

• Compact setup work at -10 ~ -20 ºC, cooled by peltier element

SDD very suitable spatial multi-channel PHA setup in tokamaks

active surface: 5mm² 280µm thick Silicon crystal

with 8m Be foil in the entrance

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High detecting efficiency with 8m Be foil in the energy range of 1~20keV

Performance of SDD

Calibration spectra of SDD

The energy resolution is about [email protected](0.5 sec shaping time, -10 ºC )

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HT-7Layout of SDD_PHA in HT-7 tokamak

Vertical 15-channel (V-PHA)

Measuring range: + 21 cm

Spatial resolution : 3 cm

Horizontal 6 channels (H-PHA)

Measuring range: 0~+24 cm

Spatial resolution : 4.8 cm

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HT-7SDD for PHA in HT-7

Isolated SDD

With preamplifier, shaper,

and peltier cooler in a housing

Five preamplifiers were not operational in last experiment, now they work.

15-channel SDD linear array

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Arrangement of vertical SDD_PHA

Interchangeable Be foils

for each sight line

Interchangeable pinholes

and Be foils in the focus

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Vertical PHA Setup Horizontal PHA Setup

Unfortunately, the SDD measured 24cm was not operational in last experiment

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Experimental Results from H-PHA(1)

Ip=120 kA

ne0 =1.43×1019m-3

Central Te with 100ms time resolution

X-ray spectra obtained along five chords

With horizontal PHA (350~450ms)

Te profile of ohmic discharge,

it is close to the parabola form of :

0.91×(1-(r/a)2)2.3

Waveforms of OH discharge

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HT-7Experimental Results from H-PHA(2)

Ip=120kAne0=1.35×1019m-3 LHW~400kW (0.1 s to 5 s )IBW~200kW(0.2 s to 5.1 s )

Central Te with 250ms time resolution

Waveforms of high performance long-pulse discharge

•Te increased considerably in half plasma minor radius during wave heated phase

•Profile was much flat in central region and had a large gradient at 0.52a, showing an ITB-like structure

Profile at 2.75s in wave heated long pulse discharge by 250ms collecting time

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Experimental Results from V-PHA

Waveforms of LHCD discharge

Ip=154kAne0=1.1 ×1019m-3

LHW: ~275kW

The concentration of iron in core plasma range is about 0.08%

The blue curve is OH phase, the red curve is wave heated phase

X-ray spectra from V-PHA

200ms collecting time

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PHA diagnostics for EAST

Arrangement of PHA in the EAST

Vertical 15-channel PHA for full section measurement

Horizontal 6-channel PHA for upper half section measurement

Spatial resolution: 6cm

Time resolution: <100ms

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Summary

1. The use of SDD has allowed the design of compact spatial multi-channel soft x-ray PHA

2. The level of count rate improved the time resolution in Te measurement

3. The high energy resolution is suitable for investigating heavy impurities

4. The experimental results from SDD_PHA are satisfying

5. Further study on the metallic impurities by SDD_PHA is the next target

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Thank you

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Appendix

The redesign of horizontal PHA

sketch map:

pinholes Be foils

Arrangement ofdetector

Gate valve