A polarization imaging diagnostic called IMSE (Imaging Motional Stark Effect) was developed in 2013 for the ASDEX Upgrade experimental fusion reactor. Initial results were promising but poor signal/noise ratio and temporal resolution limited the capability of the system. It was decided to upgrade the imaging camera and from several commercially available options, the ZYLA-4.2-CL10 sCMOS (scientific CMOS) camera from Andor Technology was chosen.

Inside the ASDEX Upgrade experiment hall, the camera is exposed to a very harsh environment:

• Strong vibrations
• Strong and rapidly varying magnetic field: B > 50mT
• High gamma-ray and neutron radiation fluxes: > 107 cm^-2 s-1 14 MeV and 2.45 MeV neutrons
• EM interference from nearby high power sources (e.g. 6 MW RF heating at > 30 MHz)

LOT-QuantumDesign provided a Zyla example camera for magnetic field testing before purchase. In the ASDEX Upgrade hall, the camera was able to operate up to 40 mT field and above this operation was possible with a small iron shield. The EM interference and violent vibrations had no detectable effect. The camera saw significant radiation noise but an acceptable level of permanent damage, which manifests as an increase in the dark current of some pixels. This was slightly worse than the previous camera but not significantly. The camera offers an extensive, although complex, range of exposure and triggering modes which give a flexibility very useful to the IMSE experiments. Extremely fast frame rates can be achieved for small regions of the image (2560 x 64 pixels at > 3000 fps).

The camera performed well and gave a significant improvement in both image quality and temporal resolution.

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