Better-resolution measurement of vertical scattering angle in a new ion-optical mode of spectrometer "Grand Raiden"

Demand for near-zero-degree measurements using a magnetic spectrometer is i ncreasing with the growing interest in the study of L = 0 nuclear excitatio n modes. For the precise determination of scattering angles near 0 degrees, both horizontal and vertical scattering angle components have to be measur ed with good accuracy. It is, however, not easy to realize a good vertical angle resolution using modern high-resolution magnetic spectrometers with s mall vertical angle magnifications, like "Grand Raiden" at RCNP or "K600" a t IUCF. A new ion-optical mode which enables the precise determination of vertical components of scattering angles from vertical position measurements in the focal plane has been developed for these spectrometers. For the wide range of spatial as well as momentum acceptances, vertical angle resolution bette r than 8 mrad is realized for Grand Raiden at RCNP. (C) 2001 Elsevier Scien ce B.V. All rights reserved.