Overview of the CAGRA Collaboration*

The collaboration, Clover Array Gamma-Ray Spectrometer at RCNP/RBIF for Advanced Research (CAGRA), was first conceived as a collaboration between institutions in the U.S. and Japan to build a gamma-ray detector array for use at accelerator facilities in Japan.  The concept was to utilize funding from the Department of Energy (DOE) to build a digital data acquisition system, a LN-fill system, and support structure to instrument sixteen Compton-suppressed Ge Clover detectors where the inventory of detectors would come from both U.S. and Japanese institutions.  In the first campaign at RCNP, detectors from the U.S., Japan and China were used in experiments on the EN-course. Six experiments were performed with three of the six experiments utilizing radioactive beams developed using the in-flight technique. In the second campaign, CAGRA was coupled to the high-resolution spectrometer Grand Raiden.  Physics topics addressed included:  (i) characterization of the Pygmy Dipole Resonance (PDR) as a function of Z and N with both proton and alpha probes, (ii) measurement of the GT response function using the (⁶Li,⁶Li’ + g) reaction and (iii) search for rare decay and shapes in ²⁸Si and ⁴⁰Ca using light-ion scattering. While the collaboration initially included only U.S. and Japanese institutions, the number of participating countries has grown and the collaboration in now international in scope. Future campaigns are being considered at RCNP, JAEA, and RBIF. In this talk, I will give a brief history of the collaboration, update on the current status, and discuss possible future directions.