The Clear-PEM Electronics System

Abstract

The Clear-PEM detector system is a compact positron emission mammography scanner with about 12000 channels aiming at high sensitivity and good spatial resolution. Front-end, Trigger, and Data Acquisition electronics are crucial components of this system. The on-detector front-end is implemented as a data-driven synchronous system that identifies and selects the analog signals whose energy is above a predefined threshold. The off-detector trigger logic uses digitized front-end data streams to compute pulse amplitudes and timing. Based on this information it generates a coincidence trigger signal that is used to initiate the conditioning and transfer of the relevant data to the data acquisition computer. To minimize dead-time, the data acquisition electronics makes extensive use of pipeline processing structures and derandomizer memories with multievent capacity. The system operates at 100-MHz clock frequency, and is capable of sustaining a data acquisition rate of 1 million events per second with an efficiency above 95%, at a total single photon background rate of 10 MHz. The basic component of the front-end system is a low-noise amplifier-multiplexer chip presently under development. The off-detector system is designed around a dual-bus crate backplane for fast intercommunication between the system boards. The trigger and data acquisition logic is implemented in large FPGAs with 4 million gates. Monte Carlo simulation results evaluating the trigger performance, as well as results of hardware simulations are presented, showing the correctness of the design and the implementation approach.

PET System Synchronization and Timing Resolution Using High-Speed Data Links

“…Research of systems with fully digital trigger, where trigger signals such as the last dynode output from PMTs undergo a minimal shaping stage before analog-to-digital conversion, is increasingly common [1]- [3]. Additionally, many PET systems are shifting from discrete implementation of the analog processing stages to integrated analog front-end architectures with higher performance [4]- [6], in order to increase spatial and time resolution. This has the added benefit of reducing board size requirements for front-end electronics.…”

“…In a usual PET system electronics setup, as shown in Fig. 1 (left), DAQ boards and higher-level digital processors are integrated with a common backplane, and thus physically separated from the detectors and front-end electronics [6]- [8]. However, the described trends naturally carry a tendency to integrate the increasingly simplified analog front-end, ADCs and first stages of digital processing together on the same circuit board.…”

Automatic adjustment of a medical imaging data acquisition system to unknown delays in the input communication channels

“…1) is justified. It is mainly constituted by a scanner (SA), a DAE (DAP) and a PC [1][2][3][4][5][6]. As highlighted in Fig.…”

“…Meaningful data must be time-coherent or coherent data. In order to guarantee data coherence along the entire acquisition and processing flow, generated data is, usually, tagged with a temporal mark, TimeTag [5][6][7][8]. This temporal mark accompanies data along the entire acquisition and data processing (in the DAP).…”

“…The synchronization procedure takes place when a data acquisition process starts, or asynchronously, by user's requirement. The synchronization strategy is demonstrated in the DAE [4][5][6] used as case study in this article.…”