Transport efficiency in large acceptance spectrometers

A general technique to study the transmission efficiency of charged particles through a large acceptance magnetic device is presented. This basically involves the measurement of the impact positions and angles of the particles in any plane normal to the optical axis and the use of a powerful algorithm for the reconstruction of the trajectories. This latter is designed to perform the calculations of highly non-linear transport functions and is essential when high-order aberrations are not negligible. The technique is applied to study the transport efficiency of the heavy ions produced in different nuclear reactions and analyzed by the MAGNEX large acceptance spectrometer. Both the angular integral and differential efficiency have been deduced with overall accuracy of about ±1.5% and ±5%, respectively.