A superconducting spectrometer magnet system for the detection of heavy isotopes

摘要

LASSY is a proposed large angle gas filled spectrometer for detecting and analyzing heavy nuclei generated when a heavy ion beam (such as fully stripped argon) collides with an actinide thin film target (such as curium). With luck, superheavy nuclei, up to atomic number 114 to 116, produced at the target. In order to improve acceptance and resolution of the shortest lived nuclei, the length of the magnet system must be as short as possible. The LASSY spectrometer consists of a 4 to 6 T superconducting magnet that produces 2.5 Tm of bending (bend radius induction product) with a bend angle of 135 degrees or more. Particles generated at the target (and there decay products) must be focused on an electronic detector less than 3 meters from the target, The resulting spectrometer magnet is quite complex with sections that focus as well as bend the particles from the target. This report presents two possible designs for a large superconducting bending magnet that is a pure bending magnet in the center with defocusing bending sections at the ends of the magnet. This paper shows how one might build bending magnet that is in sections, with each section having a tunable quadrupole and sextupole field in addition to the dipole field.