High Performance Algorithm for Signal Decomposition in Gamma Ray Detectors

76060-The GRETINA detector (a forerunner of the GRETA detector, the gamma ray energy tracking array, under development at Lawrence Berkeley National Laboratory) is used to detect gamma rays in nuclear physics experiments. GRETINA consists of Ge crystal diodes that produce currents upon impact of the gamma rays. The decomposition of these currents into combinations of known signals determines the number, location, and energies of the gamma ray interactions. This decomposition must be done in real time as the experiment is running, requiring fast and efficient algorithms. This project will develop prototype software with more efficient data structures and explore new algorithms for the purpose of signal decomposition. In Phase I, a software framework will be created in which the sampling of crystal response conforms to the geometry of the GRETINA crystals. For signal decomposition, the use of advanced linear solver algorithms, such as singular value decomposition, will be explored. Also, hybrid methods, which combine advanced solver algorithms with traditional search algorithms, will be examined. Commercial Applications and Other Benefits as described by the awardee: With the new software, two dimensionally segmented Ge crystals should be able to provide gamma ray detectors greater spatial resolution and efficiency than currently available. Such improved detectors should have uses not only in nuclear physics but also in astrophysics and nuclear medicine.