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TJ-II:Fast camera: Difference between revisions
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In the framework of EUROFUSION program, the group has leaded the installation and operation of the KL8 Wide Angle Visible Fast Camera in '''JET Tokamak''' (UK). | In the framework of EUROFUSION program, the group has leaded the installation and operation of the KL8 Wide Angle Visible Fast Camera in '''JET Tokamak''' (UK). | ||
The latest upgrade and experiments with the ITER like Wall (ILW) are described elsewhere <ref name="delacal5">[http://ocs.ciemat.es/ | The latest upgrade and experiments with the ITER like Wall (ILW) are described elsewhere <ref name="delacal5">[http://ocs.ciemat.es/epsicpp2012pap/pdf/P5.041.pdf E. de la Cal et al et al, ''The Visible Intensified Fast Camera with Wide-angle view of JET ILW experiment'', 39th EPS Conference & 16th Int. Congress on Plasma Physics P5.041]</ref>. | ||
== Cameras == | == Cameras == | ||
Three Photron Fast Cameras (APX-RS and SA1) are employed at TJ-II [http://www.photron.com/ Photron]. | |||
Sampling speed (measured in frames per second, fps) and image size can be selected, but there is a trade-off: | Sampling speed (measured in frames per second, fps) and image size can be selected depending on active area of the MOS sensor, but there is a trade-off: | ||
5000 fps with 1024 x 1024 pixels(full frame) and up to 200000 fps (maximum ever employed so far) with 182 x 80 pixels | 5000 fps with 1024 x 1024 pixels(full frame) and up to 200000 fps (maximum ever employed so far) with 182 x 80 pixels | ||
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== | ||
The coupling of an image intensifier to a High-speed camera is not trivial, since relatively high light intensity fluxes, sufficient for short exposure times down to the µs range, are captured continuously for a long time period, typically of up to some seconds. As is well known, imageintensifiers (as photomultipliers) are vulnerable to this combination and if not operated correctly, they can be damaged. Moreover, not only the amplification factor is important, but also the image quality and the responselinearity. | |||
Two Hamamatsu image intensifiers C9548-03BL [http://www.hamamatsu.com/resources/pdf/etd/GateII_TII0006E.pdf] were tested and are successfully operated. | |||
They are 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. Both stages are optically coupled by a Fiber Optic Plate (FOP) which transfers the output signal from the first to the second. Their linear response is guaranteed up to 200000 fps speed. | |||
[[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]] | ||