Recoil Mass Spectrometers in Low-Energy Nuclear Physics

Multinucleon transfer processes in heavy-ion reactions

“…This expression shows clearly that the matrix element derives from the product of an overlap term (the two bases used to write the transition amplitude (28) are in fact non-orthogonal) times the matrix element of the one-particle transfer. If several shell model pairs (a 1 a 2 ) contribute to the wavefunctions of initial and final states the form factor becomes a sum over many two-particle form factors arising from the various initial and final state two-nucleon configurations, i.e.…”

“…Recoil mass spectrometers [28] employ a combination of magnetic and electric elements to provide directly mass identification, and have been designed to separate ions with different electric rigidities (compound nuclei and beam-like particles). Even if not originally constructed for quasi-elastic reactions, these devices have been used in some cases for studies at sub-barrier energies detecting the (higher mass) target recoils at angles close to θ lab = 0 • (i.e.…”

“…Of course it was immediately recognized the necessity of a microscopic calculation which includes the coordinates of the individual nucleons. For the case of a pair of nucleons in the states a 1 and a 2 in the projectile that are transferred in the states a 1 and a 2 of the target the transition amplitude may be written as (+) α ( r α ) (28) and the form factor may be reduced in the form:…”

“…This inadequacy prevented the use of these reactions (at least with heavy ions) to gain direct information on pair correlation in nuclei. Bayman pioneered the discussion of this problem, not only developing a Monte Carlo method for the calculation of the transfer amplitude where the recoil term was exactly taken into account, but pointing out that the amplitude (28) represents just the simultaneous contribution to the transfer process [69]. The successive mechanism is in fact missing in the above expression.…”

Nuclei at the Limits of Particle Stability

“…The limits of particle stability have been mapped by exploiting all of the above-mentioned production and separation techniques, and it appears that all will continue to contribute into the foreseeable fu ture. Various authors have reviewed the production and separation tech niques in general (2) and, more specifically, the ISOL (8), recoil mass spectrometer (9), and fragmentation techniques (lO, 11).…”