Tritium autoradiography with thinned and back-side illuminated monolithic active pixel sensor device

The first autoradiographic results of the tritium (3H) marked source obtained with monolithic active pixel sensors are presented. The detector is a high-resolution, back-side illuminated imager, developed within the SUCIMA collaboration for low-energy (<30 keV) electrons detection. The sensitivity to these energies is obtained by thinning the detector, originally fabricated in the form of a standard VLSI chip, down to the thickness of the epitaxial layer. The detector used is the 1×106 pixel, thinned MIMOSA V chip. The low noise performance and thin (∼160 nm) entrance window provide the sensitivity of the device to energies as low as ∼4 keV. A polymer tritium source was parked directly atop the detector in open-air conditions. A real-time image of the source was obtained.