A cryoablation system has a gas source which provides a working gas at room temperature and at a constant set pressure. The system also includes a liquid generator which is coupled to the gas source to receive the working gas, and which then generates a working cryogen fluid in a liquid phase that operates at a temperature and pressure that lies on its Joule-Thomson Inversion Curve, with the Joule-Thomson coefficient maintained within the range 0.00±0.08 degrees F./Atmosphere. The system also includes a catheter coupled to the liquid generator for receiving the working cryogen, the catheter having a distal section which delivers the working cryogen to a treatment location.
