Radiation-tolerant APS camera survives battering by high-energy particles

DECEMBER 20--Tests by independent organizations have recently confirmed the extremely high-radiation tolerance of Sira (Chislehurst, Kent, UK; www.sira.co.uk) APS250 video camera.

DECEMBER 20--Tests by independent organizations have recently confirmed the extremely high-radiation tolerance of Sira (Chislehurst, Kent, UK; www.sira.co.uk) APS250 video camera. The camera had previously been successfully tested with a 5-Mrad dose of gamma rays, but has now survived high-radiation doses exceeding 6 Mrad from beams of high-energy particles with similar performance.

The APS250 camera uses a STAR250 CMOS image sensor with a protective epilayer, developed and manufactured by Fillfactory NV, a Cypress semiconductor company (Mechelen, Belgium) for the European Space Agency, supported with radiation-hard electronics developed by Sira using its experience with design of satellite-borne imagers. One test was performed at the Medical Research Council Laboratory of Molecular Biology (MRC-LMB; Cambridge, UK).

The camera was subjected to a dose in excess of 10 million 300-keV electrons/pixel with only a 15% reduction in sensitivity. MRC-LMB is investigating the possibility of using radiation-hard cameras for direct imaging of biological samples in electron microscopes to avoid the need for the complexity of a phosphor/fiberoptic or lens coupling.

Another test was performed by CERN in Geneva, Switzerland, to assess the suitability of the STAR250 sensor for monitoring applications. The imager received a dose of 253 million 60-MeV protons/pixel, a total radiation dose of 6 Mrad at a fluence of 400 krad/hour, and was still operational, although with reduced contrast. The agency has ordered five APS250 video cameras, two of which will be installed as target monitors for the CERN Neutrinos to Grand Sasso project in 2005; the others will be used in beam dump monitoring for the Large Hadron Collider, Sira spokesperson Jon Holmes said.

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