TJ-II:Fast camera: Difference between revisions

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== Image intensifier ==
== Image intensifier ==
Incoming photons are converted into electrons on a photocathode.
The emitted electrons are multiplied in a Micro Channel Plates (MCP) element.
These electrons impact on a phosphor screen, stimulating line emission.
The phosphor material is specially selected for its short decay time (which is the main limitation for high speed operation).


A [http://sales.hamamatsu.com/en/home.php Hamamatsu] C9548-03BL series image intensifier is used.
A [http://sales.hamamatsu.com/en/home.php Hamamatsu] C9548-03BL series image intensifier is used.

Revision as of 16:27, 3 March 2011

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