TJ-II:Fast camera - Revision history

Admin at 15:47, 29 January 2023

2023-01-29T15:47:42Z

← Older revision		Revision as of 17:47, 29 January 2023
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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/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>.		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>.

E.delacal at 10:11, 7 May 2015

2015-05-07T10:11:52Z

← Older revision		Revision as of 12:11, 7 May 2015
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	=== Dust Visualisation <ref name="delaCal3"> </ref>===		=== Dust Visualisation <ref name="delaCal3"> </ref>===

			[[File:Dust.png\|700px\|link=http://www-fusion.ciemat.es/fileshare/doc_exchange/camaras/delaCal_dust.mp4]]

	Dust is observed in the TJ-II stellarator with a fast camera equipped with a bifurcated coherent fibre-bundle system that allows different set-ups such as dual filtering of atomic lines or a stereoscopic view to obtain tangential and perpendicular (to the magnetic field) observations simultaneously. The camera looks to a poloidal limiter that can be biased and it is observed that when a negative voltage is applied, dust from the limiter is ejected intensely once a certain threshold voltage is exceeded.		Dust is observed in the TJ-II stellarator with a fast camera equipped with a bifurcated coherent fibre-bundle system that allows different set-ups such as dual filtering of atomic lines or a stereoscopic view to obtain tangential and perpendicular (to the magnetic field) observations simultaneously. The camera looks to a poloidal limiter that can be biased and it is observed that when a negative voltage is applied, dust from the limiter is ejected intensely once a certain threshold voltage is exceeded.


			[[File:Polvo1b.jpg\|300px\|link=media:Polvo1b.gif\|Dust movie]]


	First insertion of the poloidal limiter after a lithiation of the vacuum vessel. Tangential observation, 15 kHz sampling rate. The ejection of lithium flakes from the carbon surface can be seen clearly at the beginning of the discharge. At the end of the video, as the plasma becomes colder, the flakes penetrate deeper into it until they float freely in the collapsing discharge.		First insertion of the poloidal limiter after a lithiation of the vacuum vessel. Tangential observation, 15 kHz sampling rate. The ejection of lithium flakes from the carbon surface can be seen clearly at the beginning of the discharge. At the end of the video, as the plasma becomes colder, the flakes penetrate deeper into it until they float freely in the collapsing discharge.

	~~[[File:Polvo1b.jpg\|300px\|link=media:Polvo1b.gif\|Dust movie]]~~

E.delacal at 11:40, 24 April 2015

2015-04-24T11:40:01Z

← Older revision		Revision as of 13:40, 24 April 2015
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	~~[[File:Dust.png\|500px\|link=http://www-fusion.ciemat.es/quixplorer/delaCal_dust.wmv]~~

E.delacal at 11:38, 24 April 2015

2015-04-24T11:38:17Z

← Older revision		Revision as of 13:38, 24 April 2015
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	=== Two-dimensional imaging of n<sub>e</sub> and T<sub>e</sub> showing ELM-like Edge Bursts<ref name="delaCal4"> </ref>===		=== Two-dimensional imaging of n<sub>e</sub> and T<sub>e</sub> showing ELM-like Edge Bursts<ref name="delaCal4"> </ref>===

	[[File:25623wComm_Photo000001.jpg\|700px\|link=http://www-fusion.ciemat.es/fileshare/doc_exchange/camaras/HeliumRatio_ELMs.m4v)]		[[File:25623wComm_Photo000001.jpg\|700px\|link=http://www-fusion.ciemat.es/fileshare/doc_exchange/camaras/HeliumRatio_ELMs.m4v]]

	An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n<sub>e</sub> and T<sub>e</sub>.		An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n<sub>e</sub> and T<sub>e</sub>.

E.delacal at 11:37, 24 April 2015

2015-04-24T11:37:27Z

← Older revision		Revision as of 13:37, 24 April 2015
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	=== Two-dimensional imaging of n<sub>e</sub> and T<sub>e</sub> showing ELM-like Edge Bursts<ref name="delaCal4"> </ref>===		=== Two-dimensional imaging of n<sub>e</sub> and T<sub>e</sub> showing ELM-like Edge Bursts<ref name="delaCal4"> </ref>===

	[[File:25623wComm_Photo000001.jpg\|700px\|link=http://www-fusion.ciemat.es/fileshare/doc_exchange/camaras/HeliumRatio_ELMs.m4v]		[[File:25623wComm_Photo000001.jpg\|700px\|link=http://www-fusion.ciemat.es/fileshare/doc_exchange/camaras/HeliumRatio_ELMs.m4v)]

	An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n<sub>e</sub> and T<sub>e</sub>.		An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n<sub>e</sub> and T<sub>e</sub>.

E.delacal at 11:36, 24 April 2015

2015-04-24T11:36:37Z

← Older revision		Revision as of 13:36, 24 April 2015
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	=== Two-dimensional imaging of n<sub>e</sub> and T<sub>e</sub> showing ELM-like Edge Bursts<ref name="delaCal4"> </ref>===		=== Two-dimensional imaging of n<sub>e</sub> and T<sub>e</sub> showing ELM-like Edge Bursts<ref name="delaCal4"> </ref>===

	[[File:25623wComm_Photo000001.jpg\|700px\|link=http://www-fusion.ciemat.es/camaras/~~25623wComm~~.~~avi\|Limiter recycling movie]~~]		[[File:25623wComm_Photo000001.jpg\|700px\|link=http://www-fusion.ciemat.es/fileshare/doc_exchange/camaras/HeliumRatio_ELMs.m4v]

	An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n<sub>e</sub> and T<sub>e</sub>.		An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n<sub>e</sub> and T<sub>e</sub>.

E.delacal at 12:33, 22 April 2015

2015-04-22T12:33:32Z

← Older revision		Revision as of 14:33, 22 April 2015
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	[[File:Polvo1b.jpg\|300px\|link=media:Polvo1b.gif\|Dust movie]]		[[File:Polvo1b.jpg\|300px\|link=media:Polvo1b.gif\|Dust movie]]



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	=== The Visible Intensified Fast Camera with Wide-angle view of JET ILW experiment <ref name="delaCal5"> </ref>===		=== The Visible Intensified Fast Camera with Wide-angle view of JET ILW experiment <ref name="delaCal5"> </ref>===

	[[File:Jet.png\|~~700px~~\|link=http://www-fusion.ciemat.es/camaras/JETselection.mp4]]
			[[File:Jet.png\|500px\|link=http://www-fusion.ciemat.es/camaras/JETselection.mp4]]


	The JET wide-angle view Fast Camera has been upgraded with an image intensifier for light amplification and a filter wheel. The objective was to track fast events down to the microsecond range without filtering and to image atomic emission at a speed so as to resolve Edge Localised Modes (ELM), disruptions, pellet injection or plasma breakdown.		The JET wide-angle view Fast Camera has been upgraded with an image intensifier for light amplification and a filter wheel. The objective was to track fast events down to the microsecond range without filtering and to image atomic emission at a speed so as to resolve Edge Localised Modes (ELM), disruptions, pellet injection or plasma breakdown.

E.delacal at 12:23, 22 April 2015

2015-04-22T12:23:49Z

← Older revision		Revision as of 14:23, 22 April 2015
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	=== The Visible Intensified Fast Camera with Wide-angle view of JET ILW experiment <ref name="delaCal5"> </ref>===		=== The Visible Intensified Fast Camera with Wide-angle view of JET ILW experiment <ref name="delaCal5"> </ref>===

	[[File:~~25623wComm_Photo000001~~.~~jpg~~\|700px\|link=http://www-fusion.ciemat.es/camaras/JETselection.mp4]]		[[File:Jet.png\|700px\|link=http://www-fusion.ciemat.es/camaras/JETselection.mp4]]

	The JET wide-angle view Fast Camera has been upgraded with an image intensifier for light amplification and a filter wheel. The objective was to track fast events down to the microsecond range without filtering and to image atomic emission at a speed so as to resolve Edge Localised Modes (ELM), disruptions, pellet injection or plasma breakdown.		The JET wide-angle view Fast Camera has been upgraded with an image intensifier for light amplification and a filter wheel. The objective was to track fast events down to the microsecond range without filtering and to image atomic emission at a speed so as to resolve Edge Localised Modes (ELM), disruptions, pellet injection or plasma breakdown.

E.delacal at 12:00, 22 April 2015

2015-04-22T12:00:19Z

← Older revision		Revision as of 14:00, 22 April 2015
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	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>.		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 ==
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	[[File:camaras1.png]]		[[File:camaras1.png]]
	[[File:camaras2.png\|500px\|]]		[[File:camaras2.png\|500px\|]]




	== 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.		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 and C10880) [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.		Two Hamamatsu image intensifiers (C9548-03BL and C10880) [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]]



	== Videos ==		== Videos ==
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	Below are some examples of movies recorded with the fast camera system of TJ-II. Click on the images to see the corresponding movie.		Below are some examples of movies recorded with the fast camera system of TJ-II. Click on the images to see the corresponding movie.
	Some of them contain Audio.		Some of them contain Audio.



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	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.		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.		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.



	=== Two-dimensional imaging of n<sub>e</sub> and T<sub>e</sub> showing ELM-like Edge Bursts<ref name="delaCal4"> </ref>===		=== Two-dimensional imaging of n<sub>e</sub> and T<sub>e</sub> showing ELM-like Edge Bursts<ref name="delaCal4"> </ref>===
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	[[File:Polvo1b.jpg\|300px\|link=media:Polvo1b.gif\|Dust movie]]		[[File:Polvo1b.jpg\|300px\|link=media:Polvo1b.gif\|Dust movie]]



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	The JET wide-angle view Fast Camera has been upgraded with an image intensifier for light amplification and a filter wheel. The objective was to track fast events down to the microsecond range without filtering and to image atomic emission at a speed so as to resolve Edge Localised Modes (ELM), disruptions, pellet injection or plasma breakdown.		The JET wide-angle view Fast Camera has been upgraded with an image intensifier for light amplification and a filter wheel. The objective was to track fast events down to the microsecond range without filtering and to image atomic emission at a speed so as to resolve Edge Localised Modes (ELM), disruptions, pellet injection or plasma breakdown.



	== References ==		== References ==

	<references />		<references />

E.delacal: /* Videos */

2015-04-22T11:58:50Z

Videos

← Older revision		Revision as of 13:58, 22 April 2015
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	Below are some examples of movies recorded with the fast camera system of TJ-II. Click on the images to see the corresponding movie.		Below are some examples of movies recorded with the fast camera system of TJ-II. Click on the images to see the corresponding movie.
			Some of them contain Audio.



	=== Double imaging to visualize the fine structure of Blobs at ultra-short exposure time of 100 ns<ref name="delaCal2"> </ref>===		=== Double imaging to visualize the fine structure of Blobs at ultra-short exposure time of 100 ns<ref name="delaCal2"> </ref>===
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	The JET wide-angle view Fast Camera has been upgraded with an image intensifier for light amplification and a filter wheel. The objective was to track fast events down to the microsecond range without filtering and to image atomic emission at a speed so as to resolve Edge Localised Modes (ELM), disruptions, pellet injection or plasma breakdown.		The JET wide-angle view Fast Camera has been upgraded with an image intensifier for light amplification and a filter wheel. The objective was to track fast events down to the microsecond range without filtering and to image atomic emission at a speed so as to resolve Edge Localised Modes (ELM), disruptions, pellet injection or plasma breakdown.




	== References ==		== References ==
	<references />		<references />