Progress on a Polarimeter for the Deuteron EDM Search

The design of the storage ring for the deuteron electric dipole moment (EDM) search uses crossed {\bf E} and {\bf B} fields to nearly stop the magnetic moment precession of the deuteron in the ring bending magnets. This allows time for the EDM (whose predession is based on $E=\gamma{\bf v}\times{\bf B}$) to generate a detectable vertical polarization component [1]. A polarimeter for the EDM ring must monitor continuously and with high statistical precision. Recent tests at COSY-J\"ulich have demonstrated high efficiency ($\sim 1.5\%$) using a thick-walled carbon tube target that also determines the ring aperture. Extraction onto the target was tested using beam position ramping and beam heating with a cluster jet target or a white-noise electric field. Systematic errors were investigated. Continuous monitoring demonstration measurements were made using an RF solenoid whose frequency was ramped through the $1-G\gamma$ depolarizing resonance.\break [1] F.J. Farley {\it et al}, Phys.\ Rev.\ Lett.\ {\bf 93}. 052001 (2004).