© 1999 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999

4.6.5 Spatial Thermal Gradients

Two (200-400 nm)³ thermal sensors located at either end of a 1-micron nanorobot can detect temperature changes as small as 10⁶ K per micron, a ~1 kelvin/m spatial gradient. The maximum detectable gradient in nanomedical systems would involve adjacent measurements differing by ~100°C, a peak spatial gradient of ~10⁸ kelvins/m. The detection event must be completed before the two sensors can thermally equilibrate, e.g., t_meas < t_EQ = L² C_V / K_t (Eqn. 10.24). If the material between the sensors is mostly diamondoid, then t_EQ ~ 10^-9 sec; if mostly water, then t_EQ ~ 10^-5 sec, for L = 1 micron.

Last updated on 17 February 2003