Plan for focal plane polarimeter for Grand Raiden

Grand Raiden, a large-size spectrograph with world's highest performance, is currently being produced to be used with a large-scale cyclotron with a proton acceleration energy of 400 MeV under construction at RCNP. The focal plane polarimeter (FPP) is intended to measure the polarization degree of the spin of particles coming into the focal plane of the spectrograph. It comprises a dipole for spin rotation (DSR), focal plane position detector and polarimeter. DSR causes particles to spin in a direction that permits easy measurement by the polarimeter. The present report describes the background against the development of the FPP, significance of the observable of spin, effectiveness of the combination of the Grand Raiden with a FPP, different focal plane polarimeters used in the world, and physical studies expected to be carried out in the future using a focal plane polarimeter. For the FPP for Grand Raiden, the report describes the features of the FPP, structure of the FPP for Grand Raiden, structure of the trigger system, required performance of the FPP, and estimation of the cost required for the production of the FPP (calculated at approximately 100 million yen). (N.K.)