  The Polarized Atomic Hydrogen Gas Jet Target polarimeter is employed by the
Relativistic Heavy Ion Collider (RHIC) to measure the absolute polarization of
each colliding proton beam. Polarimeter detectors and data acquisition were
upgraded in 2015 to increase solid angle, energy range and energy resolution.
These upgrades and advanced systematic error analysis along with improved beam
intensity and polarization in RHIC runs 2015
($E_\textrm{beam}=100\,\text{GeV}$) and 2017 ($255\,\text{GeV}$) allowed us to
greatly reduce the statistical and systematic uncertainties for elastic spin
asymmetries, $A_N(t)$ and $A_NN(t)$, in the Coulomb-nuclear interference
momentum transfer range $0.0013<-t<0.018\,\text{GeV}^2$. For the first time
hadronic single spin-flip $r_5$ and double spin-flip $r_2$ amplitude parameters
were reliably isolated at these energies and momentum transfers. Measurements
at two beam energies enable a separation of Pomeron and Regge pole
contributions to $r_5(s)$ and $r_2(s)$, indicating that the spin component may
persist at high energies.
