The performance of the Gamma-Ray Energy Tracking In-beam Nuclear Array GRETINA

The Gamma-Ray Energy Tracking In-beam Nuclear Array (GRETINA) is a new generation high-resolution γ-rayγ-ray spectrometer consisting of electrically segmented high-purity germanium crystals. GRETINA is capable of reconstructing the energy and position of each γ-rayγ-ray interaction point inside the crystal with high resolution. This enables γ-rayγ-ray energy tracking which in turn provides an array with large photopeak efficiency, high resolution and good peak-to-total ratio. GRETINA is used for nuclear structure studies with demanding γ-rayγ-ray detection requirements and it is suitable for experiments with radioactive-ion beams with high recoil velocities. The GRETINA array has a 1π1π solid angle coverage and constitutes the first stage towards the full 4π4π array GRETA. We present in this paper the main parts and the performance of the GRETINA system.