GRETINA status and recent progress: The effect of neutron damage on energy and position resolution of the GRETINA detector

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 241; no. 1-4; pp. 931 - 934
• Main Authors: Descovich, M., Lee, I.Y., Cromaz, M., Clark, R.M., Deleplanque, M.A., Diamond, R.M., Fallon, P., Macchiavelli, A.O., Rodriguez-Vieitez, E., Stephens, F.S., Ward, D.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2005
• Subjects: Gamma-ray tracking; Position resolution; Pulse shape analysis; Position resolution; 29.40.Gx; Pulse shape analysis; Gamma-ray tracking
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2005.07.150

GRETINA is a high precision gamma-ray detector for nuclear spectroscopy experiments, which is currently being developed. It consists of a number of highly segmented coaxial germanium detectors arranged in a close-packed configuration. GRETINA uses digital signal processing electronics and pulse shape analysis to determine the energy and position of each individual interaction resulting from the gamma-ray absorption. Gamma-ray tracking is then used to reconstruct the gamma-ray scattering sequence. This results in high efficiency, peak-to-total ratio and position resolution. Particularly, the capability of reconstructing the position of the interaction with resolution at the level of a few millimeters is a fundamental requirement and is important to understand and quantify limiting factors of position resolution. This paper reports on the effects of neutron damage on pulse shape and on its impact on position resolution. Simulation results show that even a relatively heavily damaged detector maintains high position resolution. Only for neutron flux >6×109 neutron/cm2, the position resolution becomes worse than 1mm, which is the achievable limit.