Modeling small diameter straw tubes in terms of their high frequency electrical characteristics

As a part of the effort to design a prototype of a low mass tracking detector, the authors have developed an empirical model of the high frequency behavior of small diameter proportional straw tubes. The equivalent circuit is a distributed network of RLC-clusters, where the value of the discrete components is directly related to measurable characteristics of the em straws. The model is an approximation of the straw as a low loss transmission line, and yields very good agreement with measurements of transmission and reflection coefficients. Measurements and simulations of input impedance in frequency domain also agree well at frequencies below 120 MHz, when termination is close to Zo, the characteristic impedance