Radiation-tolerant camera survives onslaught of energetic particles

December 21, 2004, Chislehurst, England--Two tests by independent organizations have confirmed the high radiation tolerance of a video camera manufactured by Sira. The camera has now survived radiation doses exceeding 6 Mrad from beams of high-energy particles. Sira designs and produces optoelectronic instruments and systems, including optical diffractometers, stereo imagers, space-qualified spectrometers and photometers, and laser satellite links.

Sira's APS250 camera uses a CMOS image sensor with a protective epilayer, developed and manufactured by Fillfactory N.V., a Cypress semiconductor company (Mechelen, Belgium), for the European Space Agency; the sensor is supported with radiation-hard electronics developed by Sira using its experience in the design of satellite-borne imagers.

One of the radiation tests was performed at the Medical Research Council Laboratory of Molecular Biology (MRCLMB; Cambridge, England). The camera was subjected to a dose in excess of 10 million 300-keV electrons per pixel with only a 15% reduction in sensitivity. MRCLMB 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 radiation test was performed by CERN (Geneva, Switzerland) to assess the suitability of the camera's CMOS sensor for monitoring applications. The imager received a dose of 253 million 60-MeV protons per pixel--a total radiation dose of 6 Mrad at a fluence of 400 krad/hour--and was still operational, although with reduced contrast. Researchers at CERN have ordered five APS250 video cameras, two of which will be installed as target monitors for the CERN Neutrinos to Grand Sasso project in 2005 (in which neutrinos generated at CERN will be detected in Italy's Grand Sasso tunnel); the other three will be used in beam-dump monitoring for CERN's Large Hadron Collider.

"We are finding lots of applications for the APS250, ranging from monitoring in nuclear plants, particle accelerators, and fusion reactors, to scientific research where ionizing radiation is a problem for conventional detectors," said Sira spokesperson Jon Holmes.