1. 1 B. C. Stratton, S. von Goeler, and R. Feder PPPL J. Lowrance, V. Mastrocola, and G. Renda Princeton Scientific Instruments NSTX Physics Meeting June 7, 2004 Initial Operation of the NSTX Fast Tangential Soft X-Ray Camera

2. 2 Goal Implement fast, tangentially-viewing soft x-ray camera on NSTX for MHD studies

3. 3 System Overview Pinhole camera with wide-angle tangential view of plasma Based on Princeton Scientific Instruments PSI5 CCD camera –64 X 64 pixel image –Pixel light-sensitive area: 202  m X 62  m –Frame rates up to 500 kHz for 300 frames –Pre- and post-triggering possible Soft x-rays (~1-5 keV) converted to visible light by fast P47 phosphor deposited on fiber-optic faceplate Electrostatic image intensifier demagnifies image by 6:1 Image is lens-coupled to CCD Remotely selectable pinholes (1-5 mm diameter) allow tradeoff of spatial resolution and signal level Remotely selectable beryllium foils allow low-energy cutoff to be varied

4. 4 Camera and Data Acquisition Schematic

5. 5 Camera Layout

6. 6 System Installed on NSTX CCD camera Image intensifier inside magnetic shield Pinholes and Be foils NSTX bay K port

7. 7 Horizontal Field of View of Camera Optical axis inclined at 7º downward angle with respect to midplane

8. 8 Initial Operation of Camera System installed on NSTX in December 2003-February 2004 First operation on February 27, 2004 Have operated camera at frame rates of 1-500 kHz Good signals at frame rates up to 200 kHz Time evolutions of camera signals agree with soft x-ray diode signals

9. 9 Data Examples Will show several movies of MHD events at frame rates in the 50-200 kHz range 3 mm pinhole 7.6  m Be foil; ~1 keV low-energy cutoff

10. 10 Shot 112824: Image at 50 kHz Frame Rate Wires in front of scintillator produce H-shaped shadow

11. 11 Shot 112824: Sawtooth Crash at 385.6 ms SXR diode data shows sawtooth crash with precursor (1,1) mode

12. 12 SXR Camera Data Shows Precursor Mode and Sawtooth Crash Camera frame rate: 50 kHz

13. 13 Shot 113052: IRE at 286.7 ms SXR diode data shows crash with no precursor or postcursor modes

14. 14 SXR Camera Data Shows Drop in SXR Emission at IRE Camera frame rate: 100 kHz

15. 15 Shot 113090: Fishbones SXR diode data shows fishbones at ~10 kHz

16. 16 Shot 113090: SXR Camera Data Shows Fishbones Camera frame rate: 200 kHz

17. 17 Shot 113212: Growth of Tearing Mode SXR diode data shows (1,1) mode at ~2 kHz

18. 18 Shot 113212: SXR Camera Data Shows Tearing Mode Camera frame rate: 50 kHz

19. 19 Plans Implement sawtooth trigger system Perform flat field and pincushion distortion calibrations of camera using x-ray source Do experiment to observe sawtooth crash at high frame rate –Will likely require Argon or Neon puffing to increase soft x-ray emission Further study of tearing modes Thanks to D. Stutman and K. Tritz for SXR diode data, E. Fredrickson for MHD mode identification, and S. Zweben for the MPEG movie maker