A beamline zero-degree spectrometer for measurements of projectile fragment distributions.

A technique for using a section of a beamline as a zero-degree spectrometer is described. The beamline magnets of the K1200 cyclotron at NSCL were operated as a zero-degree medium acceptance spectrometer to measure projectile fragment distributions. Projectile fragments were produced in a fragmentation target at the exit of the cyclotron and detected at the end of the beamline with a detector array consisting of two position-sensitive detectors and a ΔE-E telescope. Energy loss, position and angle at the focal plane and time of flight were measured for the isotopes produced. A procedure was developed to calculate the reaction angle and the momentum of the isotopes from the measured quantities. Typical examples of momentum and angular distributions of projectile fragments from a 14N beam at 75 MeV/u with Al and Ta targets at and near 0° are shown. [ABSTRACT FROM AUTHOR]