Four ionization beam profile monitors (IPM’s) are in RHIC to measure vertical and horizontal profiles in the two rings. Each IPM collects and measures the distribution of electrons in the beamline resulting from residual gas ionization during bunch passage. The ionized electron signal provides an accurate beam profile and the detectors are capable of measuring individual gold bunches. However the detectors are extremely sensitive and their performance has been limited by backgrounds from radiation spray, rf coupling to the beam, and secondary electrons. In 2002 two IPM’s were rebuilt using design changes which greatly reduced the backgrounds. During the summer 2003 shutdown another rebuild will increase the sweep electric field, make the electric field more uniform, and add a calibration system. The improvements in the electric field will increase the sensitivity to beam without increasing backgrounds and the calibration system will allow channel‐channel gain variations to be removed. These improvements should increase the detectors sensitivity to a level where the IPM can be considered as a beam halo monitor. © 2003 American Institute of Physics