Mendicino Roberto, Dalla Betta Gian-Franco
Center for Sensing Solutions, Eurac Research, Via A. Volta 13A, 39100 Bolzano, Italy.
Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123 Trento, Italy.
Micromachines (Basel). 2023 Apr 27;14(5):952. doi: 10.3390/mi14050952.
A monolithic pixel sensor with high spatial granularity (35 × 40 μm) is presented, aiming at thermal neutron detection and imaging. The device is made using the CMOS SOIPIX technology, with Deep Reactive-Ion Etching post-processing on the backside to obtain high aspect-ratio cavities that will be filled with neutron converters. This is the first monolithic 3D sensor ever reported. Owing to the microstructured backside, a neutron detection efficiency up to 30% can be achieved with a B converter, as estimated by the Geant4 simulations. Each pixel includes circuitry that allows a large dynamic range and energy discrimination and charge-sharing information between neighboring pixels, with a power dissipation of 10 µW per pixel at 1.8 V power supply. The initial results from the experimental characterization of a first test-chip prototype (array of 25 × 25 pixels) in the laboratory are also reported, dealing with functional tests using alpha particles with energy compatible with the reaction products of neutrons with the converter materials, which validate the device design.
本文介绍了一种具有高空间粒度（35×40μm）的单片像素传感器，旨在用于热中子探测和成像。该器件采用CMOS SOIPIX技术制造，并在背面进行深反应离子刻蚀后处理，以获得将填充中子转换器的高纵横比腔体。这是有史以来报道的首个单片3D传感器。根据Geant4模拟估计，由于背面具有微结构，使用硼转换器时可实现高达30%的中子探测效率。每个像素都包含允许大动态范围、能量鉴别以及相邻像素间电荷共享信息的电路，在1.8V电源下每个像素的功耗为10μW。还报告了实验室中首个测试芯片原型（25×25像素阵列）实验表征的初步结果，该结果涉及使用与中子和转换器材料反应产物能量兼容的α粒子进行功能测试，验证了器件设计。
