The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory comprises vacuum systems that range in pressure from 10(-4) to 10(-11) Torr. For cost savings associated with commonality, it is desirable to use one ultrahigh vacuum (UHV)-compatible high vacuum gauge throughout the accelerator. Work was done with radioactive isotopes to enhance ignition of inverted magnetron gauges at very low pressures (i.e., < 10(-10) Torr). Tests were initially conducted using cobalt-coated copper washers with a nickel flash to prevent oxidation. Solid nickel washers were also activated and tested. Problems with these sources will be discussed. Finally, an americium source was tested. The UHV-compatible americium sources yielded average ignition times of about 10 min at 4x10(-11) Ton : The addition of the americium source produced a gauge suitable for operation at UHV pressures, and as a consequence for all of the RHIC.