... regions

Figures 2-4, and 6-8 are only available in electronic form at http://www.edpsciences.org

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... key-project

The observation of the key-project were made in 6 runs between December 1992 and March 1994, before a re-adjustment of the panel frames in July 1997.

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... observations

Figures 2 to 4 are only available in electronic form at http://www.edpsciences.org

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... beam

Figures 6 to 8 are only available in electronic form at http://www.edpsciences.org

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