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Abstract: The ATLAS Tile Calorimeter is a sampling detector composed by cells made of iron-scintillator tiles. The calorimeter cell signals are digitized in the front-end electronics and transmitted to the Read-Out Drivers (RODs) at the first level trigger rate. The ROD receives triggered data from up to 9856 channels and provides the energy, phase and quality factor of the signals to the second level trigger. The back-end electronics is divided into four partitions containing eight RODs each. Therefore, a total of 32 RODs are used to process and transmit the data of the TileCal detector. In order to emulate the detector signals in the production and commissioning of ROD modules a board called ROD Injector and Multiplexer Board (RIMBO) was designed. In this paper, the RIMBO main functional blocks, PCB design and the different operation modes are described. It is described the crucial role of the board within the TileCal ROD test-bench in order to emulate the front-end electronics during the validation of ROD boards as well as during the evaluation of the ROD signal reconstruction algorithms. Finally, qualification and performance results for the injection operation mode obtained during the Tile Calorimeter ROD production tests are presented. [ABSTRACT FROM AUTHOR]

Silicon photomultipliers (SiPMs) are considered among the most promising sensors for positron emission tomography (PET) applications. To fully utilize the fast response of SiPMs, a 1-to-1 coupling configuration for scintillators and sensors is applied in SiPM-based detectors, leading to a vast number of channels to process. Previously, we have proposed a multi-voltage threshold (MVT) sampling method that can digitize scintillation pulses by means of simplified circuits. The feasibility of implementing MVT digitizers with only field programmable gate arrays (FPGAs) was proven, and hence, a digital PET detector module based on SiPMs was developed. In this work, we report the performance of our upgraded detector modules based on an evaluation of a fully functional demonstrator system. The system has the form of a 12-sided ring with a 108 mm diameter and a 25 mm axial length composed of 6 detector modules. Our measurements show an energy resolution of 18.9% at 511 keV and a coincidence timing resolution of 354 ps. With an energy window of 450–650 keV, the absolute sensitivity at the center of the scanner is 1.11%. The spatial resolutions are 2.08, 2.19 and 2.24 mm in the radial, tangential and axial directions, respectively. Since inter-crystal scatter (ICS) can cause count loss in the system, a recovery scheme is employed for the same data. As a result, the sensitivity and signal-to-noise ratio in the uniform region for an image quality phantom increase by 83% and 19%, respectively. However, we observe a compromised time resolution of 419 ps and a deterioration of 7–12% in spatial resolution. [ABSTRACT FROM AUTHOR]