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Four ionization profile monitors (IPMs) in RHIC measure vertical and horizontal beam profiles in the two rings (yellow and blue). These work by measuring the distribution of electrons produced by beam ionization of residual gas. In 2007 a prototype of a new design was installed in the yellow ring. During the 2007-2008 run it proved to be almost completely free from backgrounds from rf coupling, electron clouds and x-rays from upstream beam loss. In 2009 four new IPMs were built based on the prototype. During the 2009 shutdown two of these IPMs were installed. This paper describes the new IPMs and shows data from the 2010 beam run. The new IPMs have been extremely important in the commissioning of the RHIC stochastic cooling system.

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While RHIC is filled with beam, bunches are stored for up to several minutes at the injection energy before acceleration starts. In gold operation, the RHIC injection energy is below transition. A bunch length increase, and correspondingly an increase in the longitudinal emittance, can lead to particle loss during transition crossing and rebucketing into the storage buckets. The longitudinal growth of gold beams in RHIC at injection is dominated by intra-beam scattering. Measurements of longitudinal growth times are presented and compared with computations.