Effects of capacitance ratio on the image linearity of capacitive division image readout

Capacitive division readout anode has the advantages of simple manufacture technology and high spatial resolution. Linearity of the restored image is limited by the relationship between the values of C (charge divide capacitor), Cs (parasitic capacitor), Cd (capacitor introduced by diagonal electrode) and Cp (perimeter capacitor). This paper describes a discrete capacitance matrix to investigate the dependence of image linearity on capacitor ratios, including C/Cs, C/C d and(N-1)C/C p (N is the number of nodes in each row of the capacitance matrix). Results presents that image nonlinearity varies monotonically with C/Cs, C/C d and(N-1)C/Cp. The effect of these capacitors on the linearity of image can be negligible when C/Cs is greater than 100, C/Cd is greater than 10 and (N-1)C/Cp is smaller than 0.1. The reliability of the simulation results is verified by experiments. The RMS nonlinearity of capacitive anode is expected to less than 0.71%.