A permanent magnet has a grain structure that includes a main phase and a grain boundary phase that is primarily composed of a first metal. A radiation jammer circuit in accordance with the present invention, including an RC differentiator and a depletion mode MOS circuit, when inserted at the output of a logic cell, significantly reduces the propagation of transient glitches. Each mode of operation utilizes the same predictive algorithm for estimating the temperature of the subject before the thermometer reaches full equilibrium.