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ASIPP. 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:czy1003@ipp.ac.cn. Content.
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ASIPP 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:czy1003@ipp.ac.cn
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
PHA diagnostic aims in the HT-7 Qualifications of detector • Te profile with high spatial resolution • High time resolution of Te • Investigating the concentration of heavy impurities Qualifications of soft x-ray PHA detector • 1. Compact assembly Spatial multi-channel configuration • 2. High input count rate Considerable time resolution • 3. High energy resolution Impurities concentration measurement
Virtues 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
Performance of SDD High detecting efficiency with 8m Be foil in the energy range of 1~20keV Calibration spectra of SDD The energy resolution is about 160eV@5.9keV (0.5 sec shaping time, -10 ºC )
Layout 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
SDD for PHA in HT-7 • 15-channel SDD linear array • Isolated SDD With preamplifier, shaper, and peltier cooler in a housing Five preamplifiers were not operational in last experiment, now they work.
Arrangement of vertical SDD_PHA Interchangeable Be foils for each sight line Interchangeable pinholes and Be foils in the focus
Vertical PHASetup Horizontal PHA Setup Unfortunately, the SDD measured 24cm was not operational in last experiment
Experimental Results from H-PHA(1) Waveforms of OH discharge Ip=120 kA ne0 =1.43×1019m-3 Central Te with 100ms time resolution Te profile of ohmic discharge, it is close to the parabola form of : 0.91×(1-(r/a)2)2.3 X-ray spectra obtained along five chords With horizontal PHA (350~450ms)
Experimental Results from H-PHA(2) Profile at 2.75s in wave heated long pulse discharge by 250ms collecting time Waveforms of high performance long-pulse discharge Central Te with 250ms time resolution • 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 Ip=120kA ne0=1.35×1019m-3 LHW~400kW (0.1 s to 5 s ) IBW~200kW(0.2 s to 5.1 s )
Experimental Results from V-PHA Waveforms of LHCD discharge X-ray spectra from V-PHA 200ms collecting time Ip=154kA ne0=1.1 ×1019m-3 LHW: ~275kW The blue curve is OH phase, the red curve is wave heated phase The concentration of iron in core plasma range is about 0.08%
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
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
Appendix The redesign of horizontal PHA sketch map: Gate valve Arrangement of detector Be foils pinholes