Speaker
Description
Direct reaction experiments in inverse kinematics are one of the best suited tools to probe a broad range of nuclear properties, providing great insight into the nuclear structure of exotic nuclei. However, the inverse kinematics approach impose constraints in the experimental detection systems: charged-particles are emitted over a large angular range, hence large solid angular coverage is required. In addition, beam intensity limitations for most exotic beams are often compensated with the use of thicker targets at the expense of the excitation energy resolution derived from charged-particles. Measuring gamma-rays in coincidence will much improve the excitation energy resolution, enabling direct reaction studies for nuclei where the level density is too high to distinguish excited states with charged-particles alone.
A large amount of effort was devoted at the Center for Exotic Nuclear Studies (CENS) to develop nuclear detection instruments especially intended for experiments with direct reactions in inverse kinematics at RAON. With the aforementioned constraints in mind, SCIGA (Silicon-CsI-GAGG Array) was designed as a large solid angle array of Silicon-CsI telescopes for charged-particle detection and an array of GAGG scintillator crystals for highly efficient observation of gamma-rays in coincidence. The GAGG crystals provide better resolution than NaI crystals while offering higher intrinsic efficiency than HPGe detectors and more flexibility due to the lack of cooling. SCIGA modular design allows to be used with self-supporting targets or gas cell targets.
This contribution will present SCIGA detailed specifications, performance and current status, including preliminary in-beam commissioning results. Ongoing development efforts and upcoming SCIGA experiments will also be discussed.