SOI image sensor for ion flight time measurement using thermal noise suppressing sample hold circuit

Abstract

In the biotechnology / medical field, simultaneous measurement technology of spatial distribution for each mass of various substances has been expected to be applied to rapid pathological diagnosis. In imaging mass spectrometry, it is important to develop a time of flight sensor that can simultaneously detect ion position with high spatial resolution and high temporal resolution at high framerate. In this research, we develop a pixel that acquires the voltage level according to the ion arrival time using ramp signal. In this circuit, holding of thermal noise becomes a problem. Therefore, we propose a method for suppressing thermal noise by interlocking the ramp signal with the soft reset mechanism. The proposed pixel circuit size was 20 μm x 20 μm.