Production Techniques and Detection Challenges for Nuclei around 132Sn
- David Perez-Loureiro, GANIL
Monday, May 20, 11:00 AM - Special Seminar
NSCL Lecture Hall
Medium-mass neutron-rich nuclei belong to one of the most exciting regions of the nuclear landscape. The presence of shell closures at large neutron excess in the vicinity of the r-process provides an excellent region for investigating nuclear structure and the origin of the nuclei heavier than iron in the universe. Although the fission of actinides has proven to be the most efficient mechanism for producing nuclei in this region of the nuclear chart, the fragmentation of post-accelerated fission residues offers one method for producing rare-isotope beams in the vicinity of 132Sn. The feasibility of this technique has been studied experimentally at GSI . However, producing secondary beams of the most neutron-rich nuclei poses significant challenges and only low-intensity beams (< 104 pps) can be achieved in the foreseeable future.
Due to the fact that production of the most neutron-rich nuclei will remain limited for most conventional reaction studies, the use of a gas-filled active target and time projection chamber (ACTAR TPC) will make it possible to access nuclear structure information at relatively low beam intensities. The ACTAR TPC detection system is a detector development project that will use a large gas volume as both a sensitive detector and as the target itself. This offers significant advantages over traditional experiments due to its intrinsic high detection efficiency, low detection threshold, excellent angular and position resolution, and the ability to reconstruct the kinematics of every event in three dimensions. Furthermore, the use of a gas allows the use of thicker targets enhancing the probability for a nuclear reaction to occur and compensating the limited intensities of the secondary beams. During the R&D phase of the ACTAR TPC project, a GEANT4/ROOT based simulation package has been developed and was recently applied to the detector response of micro-pattern gaseous detectors like MICROMEGAS or GEMs in measurements with an alpha source and a small prototype of the final detector .
The seminar will summarize the different techniques available for the producing medium-mass neutron-rich nuclei and give the present status of the detector project including a description of the simulation package. Simulated results will be compared to experimental source data and the potential of active targets will be demonstrated for single nucleon transfer reactions.
 D. P´erez-Loureiro et al. Phys. Lett. B703 (2011) 552
 J. Pancin and D. P´erez-Loureiro et al., submitted to Nucl. Instr. and Meth. A.