Application of a CMOS differential and amplified dosimeter with Field Oxide n-channel MOSFETs to Diagnosis X-Ray beams

We present in this paper a new circuit embedded sensor for ionizing radiation based on MOSFET dosimeters. The circuit presents differential sensing and inherent amplification, making it much more sensitive than standard MOS dosimeters. An n-channel Field Oxide transistor pair is used as the sensitive module of the circuit. The circuit was tested against γ-radiation and showed a non-linear responsivity and a maximum 58× amplification, corresponding to a sensitivity of 25.6 V/Gy. Then the circuit was tested against X-Ray beams and the response was corrected using the previous characterization, showing to be linear with the beam charge and dependent with the energy of the beam. These results indicate that the proposed circuit is suitable for X-Ray dosimetry.