Light-Sharing Interface for dMiCE Detectors Using Sub-Surface Laser Engraving.
We have previously reported on dMiCE, a method of resolving depth or interaction (DOI) in a pair of discrete crystals by encoding light sharing properties as a function of depth in the interface of a crystal-element pair. A challenge for this method is the cost and repeatability of interface treatment for each crystal pair. In this work, we report our preliminary results on using sub-surface laser engraving (SSLE) as a means of forming this depth-dependent interface in a dMiCE detector. A surplus first-generation SSLE system was used to create a partially reflective layer 100-microns thick at the boundary between two halves of a 1.4-by-2.9-by-20 mm3LYSO crystal. The boundary of these paired crystal elements was positioned between two 3-mm wide Silicon photomultiplier arrays. The responses of these two photodetectors were acquired for an ensemble of 511-keV photons collimated to interact at a fixed depth in just one crystal element. Interaction position was then varied to measure detector response as a function of depth, which was then used to maximum-likelihood positions. Despite use of sub-optimal SSLE processing we found an average DOI resolution of 3.4 mm for front-sided readout and 3.9 mm for back-sided readout while obtaining energy resolutions on the order of 10%. We expect DOI resolution can be improved significantly by optimizing the SSLE process and pattern.
Department of Radiology, University of Washington, Seattle, WA 98195 USA.
William C J
WC
Hunter
Department of Radiology, University of Washington, Seattle, WA 98195 USA.
Robert S
RS
Miyaoka
Department of Radiology, University of Washington, Seattle, WA 98195 USA.
Lawrence
L
MacDonald
Department of Radiology, University of Washington, Seattle, WA 98195 USA.
Wendy
W
McDougald
Departments of Radiology and Electrical Engineering, University of Washington, Seattle, WA 98195 USA.
Thomas K
TK
Lewellen
Depth of interaction; PET detectors; laser etching; nuclear medicine detectors; radiation detectors; scintillators