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TJ-II:Fast camera: Difference between revisions
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<ref name="delaCal">[http://onlinelibrary.wiley.com/doi/10.1002/ctpp.201000039/pdf E. de la Cal et al, ''The visible intensified cameras for plasma imaging in the TJ-II stellarator'', Contrib. Plasma Phys. (2010)]</ref>. | <ref name="delaCal">[http://onlinelibrary.wiley.com/doi/10.1002/ctpp.201000039/pdf E. de la Cal et al, ''The visible intensified cameras for plasma imaging in the TJ-II stellarator'', Contrib. Plasma Phys. (2010)]</ref>. | ||
The main system is located in [[TJ-II:Sectors|sector]] B8, [[TJ-II:Ports|port]] B8TANG, viewing the [[TJ-II:Limiter|poloidal limiter]] in sector C3 tangentially. | The main system is located in [[TJ-II:Sectors|sector]] B8, [[TJ-II:Ports|port]] B8TANG, viewing the [[TJ-II:Limiter|poloidal limiter]] in sector C3 tangentially. | ||
== Cameras == | == Cameras == | ||
The newest fast camera employed at TJ-II is a [http://www.photron.com/ Photron] SA1 camera. | The newest fast camera employed at TJ-II is a [http://www.photron.com/ Photron] SA1 camera. | ||
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The dynamic range of the sensor is 8 bits, and the memory size is 8 GB. | The dynamic range of the sensor is 8 bits, and the memory size is 8 GB. | ||
== Image Intensifier for Fast Camera== | == Image Intensifier for Fast Camera== | ||
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. | ||
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. | 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. | ||
[[File:TJ-II_Fast_camera_diagram.jpg|800px|thumb|center|Schematic diagram of the TJ-II fast camera installation]] | [[File:TJ-II_Fast_camera_diagram.jpg|800px|thumb|center|Schematic diagram of the TJ-II fast camera installation]] | ||
== Videos == | == Videos == | ||
Below are some examples of movies recorded with the fast camera system of TJ-II. | Below are some examples of movies recorded with the fast camera system of TJ-II. Click on the images to see the corresponding movie. | ||
Click on the images to see the corresponding movie. | |||
=== Double imaging to visualize the fine structure of Blobs=== | |||
[[File:25623wComm_Photo000001.jpg|300px|link=http://www-fusion.ciemat.es/fileshare/doc_exchange/camaras/video_DOUBLE_IMAGING.mp4 | |||
A visible fast camera coupled with an image intensifier was employed to view turbulent coherent plasma structures (Blobs) at the gas plume being puffed through a poloidal limiter. The image intensifier amplifies the light intensity thereby allowing the imaging system to be operated at ultra-short exposure times down to 100 ns. | |||
To distinguish real physical signal from noise we get two simultaneous images with the same view and compare them. We call this Double Imaging technique and it allowed us to validate the detected blob shape to scales down to a few millimetres, limited by our optical resolution. | |||
=== Double Imaging of two He I lines #25623=== | === Double Imaging of two He I lines #25623=== | ||