TwinSol is a dual in-line superconducting solenoid system used for the production of low-energy radioactive ion beams at the University of Notre Dame (UND) Nuclear Science Laboratory. Each solenoid possesses a 30 cm bore, is liquid-helium cooled, and is capable of producing fields up to about 6 Tesla in strength. A primary beam bombards a production target to produce the nuclei of interest. The recoils are then collected, separated from contaminants, transported and focused onto the secondary target position. The primary beams are produced by the 10MV UND FN-Tandem accelerator, which is capable of achieving production beam intensities of up to 1012 particles per second and energies between 1 and 10 MeV/u. For more information about TwinSol see the University of Michigan Twinsol homepage.
TwinSol was the first device dedicated to production of exotic beams in the United States. Since the separator was dedicated in 1998, at least 90 publications have reported data from its use including 7 in Physical Review Letters and 1 in Physics Letters. Several of these have over 100 citations with one now over 200 citations. Hundreds of collaborators from tens of different institutions spanning approximately 10 countries have participated in experiments with TwinSol during the last 15 years. Graduate student training and mentorship has always been a priority, and numerous dissertations and student research projects have resulted from use of the device. To continue this track record of cutting-edge science, several improvements are planned or have been performed for the device.
First, a multi-production-target capability has been implemented allowing for quick change overs between gas cell failures and better distribution of the heat-load via rastering of the targets. This allows for greater primary beam intensities on target. The reaction chamber and second solenoid were moved approximately a meter downstream for greater flexibility in experimental usage with smaller beam spot sizes on target. A switching magnet is being installed after TwinSol to allow the construction of an ion trap on one beamline while continuing radioactive beam experiments on a second line. Finally, a third solenoid has been procured to refocus radioactive beams after the switching magnet.
|Beams||Rate on Target|
|3H, 6He, 8Li, 15O||106-107 ions/s|
|7Be, 8B, 10Be, 10C, 12B, 12N, 13N, 17F, 19Ne, 29P||105-106 ions/s|
|14O,18Ne, 21Na, 33Cl||103-104 ions/s|