The Gamma-Ray Energy Tracking Array (GRETA), a powerful new detector for studying atomic nuclei, has completed its primary construction phase.\u00a0<\/p>\n
A collaborative team led by the US Department of Energy\u2019s (DOE) Lawrence Berkeley National Laboratory has finished building the key components, which are multiple germanium detector modules, the electronics system, the instrument\u2019s mechanical frame and infrastructure, and the computing systems..<\/p>\n
Once running, GRETA\u2019s expected to be 10 to 100 times more sensitive than previous detectors, allowing scientists to study the core of atoms in greater detail than ever before.<\/p>\n
\u201cOur goal was to make the best high-resolution, high-efficiency gamma-ray detector we possibly could,\u201d said Paul Fallon, GRETA\u2019s project director from Berkeley Lab.<\/p>\n
Using a particle beam<\/p>\n
To see inside a nucleus, researchers will use a particle beam to hit a target placed at the center of GRETA. This collision creates unstable, energetic nuclei<\/a>. As these nuclei return to a more stable state, they release energy as gamma rays. GRETA\u2019s spherical array of detectors is designed to track the path and energy of these gamma rays.<\/p>\n \u201cThe excited states and gamma rays are a fingerprint for each isotope,\u201d explained Heather Crawford, a scientist at Berkeley Lab. \u201cGRETA is the world\u2019s most powerful microscope to examine these fingerprints.\u201d<\/p>\n This \u201cfingerprint\u201d data will help scientists answer several fundamental questions. For instance, it\u2019ll provide insights into how elements heavier than iron are created in stars and what the limits are for how many protons and neutrons can be held together in a nucleus. The research will also help explore why the universe is made of matter instead of antimatter.<\/p>\n Providing maximum sensitivity<\/p>\n GRETA is an expansion of an earlier detector, GRETINA. It\u2019ll eventually combine GRETINA\u2019s 12 detector modules with 18 new ones, for a total of 30 modules that form a complete sphere. Each module contains four crystals of ultra-pure germanium cooled to approximately -300\u00b0F for maximum sensitivity.<\/p>\n Argonne National Laboratory played a key role by designing the detector\u2019s trigger system<\/a>, which is essential for sorting through the enormous amount of data and identifying important events.\u00a0<\/p>\n The research team is also applying artificial intelligence (AI) to improve the software that reconstructs the gamma-ray paths, making the instrument even more powerful.\u00a0<\/p>\n