Micro Proton Accelerators
Proton accelerators possess the difficulty of being unusually large and energy intensive; the large HADRON collider in the CERN facility is over 27 kilometers in circumference, or essentially 27 kilometers long. It uses an enermous amount of power to, to power the extensive array of computers and super magnets designed to accelerate and focus the array of hadrons accelerated by the device, or protons in a general sense.
To accelerate protons to high velocities, you must first utilize extensive power; to accelerate a kilogram of matter to 90% the speed of light, it would require roughly 90 billion joules, Not compensating for massive inefficiencies, an entire 10 billion dollar facility is required just to accelerate protons to these levels.