TJ-II:Fast camera

TJ-II disposes of different fast camera systems for plasma imaging ^[1] ^[2] ^[3]. The main system is located in sector B8, port B8TANG, viewing tangentially the poloidal limiter in sector C3.

Camera

The newest fast camera employed at TJ-II is a Photron SA1 camera. Sampling speed (measured in frames per second, fps) and image size can be selected, but there is a trade-off:

5000 fps with 1024 x 1024 pixels(full frame)
10000 fps with 512 x 512 pixels
200000 fps (maximum ever employed so far) with 182x80 pixels

The dynamic range of the sensor is 8 bits, and the memory size is 8 GB.

Image intensifier

A Hamamatsu C9548-03BL series image intensifier is used. This is a two stage intensifier, including a first GEN II stage with a fast phosphor (P-46) and gain adjustable via the voltage at the MCP, and a second GEN I one (booster) with a fixed gain of 50 and somewhat slower phosphor screen (P-24). Both stages are optically coupled by a Fiber Optic Plate (FOP) which transfers the output signal from the first to the second.

Schematic diagram of the TJ-II fast camera installation

Videos

References

↑ J.A. Alonso et al, Impact of different confinement regimes on the two-dimensional structure of edge turbulence, Plasma Phys. Control. Fusion 48 (2006) B465-B473
↑ D. Carralero et al, Turbulence studies by fast camera imaging experiments in the TJII stellarator, Journal of Nuclear Materials 390-391 (2009) 457-460
↑ E. de la Cal et al, Visible intensified cameras for plasma imaging in the TJ-II stellarator, Rev. Sci. Instrum. (2009)

[1] J.A. Alonso et al, Impact of different confinement regimes on the two-dimensional structure of edge turbulence, Plasma Phys. Control. Fusion 48 (2006) B465-B473

[2] D. Carralero et al, Turbulence studies by fast camera imaging experiments in the TJII stellarator, Journal of Nuclear Materials 390-391 (2009) 457-460

[3] E. de la Cal et al, Visible intensified cameras for plasma imaging in the TJ-II stellarator, Rev. Sci. Instrum. (2009)

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