Performance of a QDDD spectrograph

Abstract A new type magnetic spectrograph for charged-particle nuclear-reaction studies has been put into operation in conjuction with the Heidelberg MP-Tandem Van de Graaff accelerator. The main elements of the spectrograph are a quadrupole magnet and three dipoles (deflecting magnets). It is therefore called the QDDD or Q3D spectrograph. The instrument has an acceptance solid angle of 13 msr, a range E max / E min = 1.21 and a resolving power of the order of p / Δp = 10 4 . Other features of the instrument include a multipole used for magnetic correction of kinematic broadening and other aberrations and an electrostatic deflector for separation of particles according to their specific mass m / q .