  GaN high electron mobility transistors (HEMT) have gained some foothold in
the power electronics industry due to wide frequency bandwidth and power
handling. The material offers a wide bandgap and higher critical field strength
compared to most wide bandgap semiconductors, resulting in better radiation
resistance and theoretically higher speeds as the devices dimensions could be
reduced without suffering voltage breakdown. This work consists of the
underlying simulation work intended to examine the response of the GaN HEMTs
preamlifying circuits for high resolution high energy radiation detectors. The
simulation and experimental results illustrate the superior performance of the
GaN HEMT in an amplifying circuit. Using a spice model for a commercially
available GaN HEMT non distorted output to an input signal of 200 ps was
displayed. Real world measurements underscore the fast response of the GaN HEMT
with its measured slew rate at approximately 3000 V /{\mu}s a result only 17%
lower than the result obtained from the simulation.
