Speaker
Description
Compton imaging is a promising gamma-ray imaging method that can visualize a radioactive source without any mechanical collimators based on the Compton scattering kinematics. Challenges of the conventional Compton imaging method are an artifact in a reconstructed image and the low signal-to-background ratio, which are caused by drawing multiple Compton cones with a calculated scattered angle. A promising approach to overcome this limitation is the measurement of recoil electron tracks in the scatterer, which can estimate the source position from on a conical surface to on an arc surface.
We have developed fine-pitch hybrid pixel silicon detectors consisting of 18 µm pixel silicon PIN sensor (HORIBA Ltd.) with 450 µm thickness and 18 µm pixel ASIC (5 mm x 5 mm) fabricated by TSMC 250 nm CMOS technology in order to measure recoil electron tracks in a scatterer. The sensor was combined with the ASIC using micro-bumps. Each pixel of the ASIC can generate digital triggers when an energy deposition in the pixel is bigger than a threshold; therefore, only pixels of an electron track can be readout. The triggers are also useful to synchronize the scatterer with an absorber of Compton cameras. We will present the detail of the detector and report on its basic performance.
