  The temporary resistance triggered by phase slip will result in the switching
of superconductor nanowire to a permanent normal state, decreasing the
switching current. In this letter, we propose an improved impedance matching
circuit that releases the transition triggered by phase slips to the load
resistor through the RF port of a bias tee. The transportation properties with
different load resistors indicate that the switching current decreases due to
the reflection caused by impedance mismatching, and is maximized by optimized
impedance matching. Compared to the same setup without impedance matching
circuit, the switching current was increased from 8.0 micro A to 12.2 micro A
in a niobium nitride nanowire after releasing the temporary transition
triggered by phase slips. The leakage process with impedance matching outputs a
voltage pulse which enables the user to directly register the transition
triggered by phase slips. The technique for maximizing the switching current
has potential practical application in superconductor devices, and the
technique for counting phase slips may be applied to explore the quantum
behavior of phase slips.
