Moses W W, Buckley S, Vu C, Peng Q, Pavlov N, Choong W-S, Wu J, Jackson C
Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA.
IEEE Trans Nucl Sci. 2009 Oct 24;2009:3491-3495. doi: 10.1109/NSSMIC.2009.5401797.
We present the design for OpenPET, an electronics readout system designed for prototype radiotracer imaging instruments. The critical requirements are that it has sufficient performance, channel count, channel density, and power consumption to service a complete camera, and yet be simple, flexible, and customizable enough to be used with almost any detector or camera design. An important feature of this system is that each analog input is processed independently. Each input can be configured to accept signals of either polarity as well as either differential or ground referenced signals. Each signal is digitized by a continuously sampled ADC, which is processed by an FPGA to extract pulse height information. A leading edge discriminator creates a timing edge that is "time stamped" by a TDC implemented inside the FPGA. This digital information from each channel is sent to an FPGA that services 16 analog channels, and information from multiple channels is processed by this FPGA to perform logic for crystal lookup, DOI calculation, calibration, etc. As all of this processing is controlled by firmware and software, it can be modified / customized easily. The system is open source, meaning that all technical data (specifications, schematics and board layout files, source code, and instructions) will be publicly available.
我们展示了OpenPET的设计，它是一种为放射性示踪剂成像仪器原型设计的电子读出系统。关键要求是它要有足够的性能、通道数、通道密度和功耗来服务于一台完整的相机，同时又要足够简单、灵活和可定制，以便能与几乎任何探测器或相机设计配合使用。该系统的一个重要特性是每个模拟输入都独立处理。每个输入可配置为接受任何极性的信号以及差分或接地参考信号。每个信号由一个连续采样的ADC进行数字化，该ADC由一个FPGA处理以提取脉冲高度信息。一个前沿鉴别器产生一个定时沿，该定时沿由FPGA内部实现的TDC进行“时间标记”。来自每个通道的这种数字信息被发送到一个服务16个模拟通道的FPGA，来自多个通道的信息由该FPGA处理以执行晶体查找、DOI计算、校准等逻辑操作。由于所有这些处理都由固件和软件控制，所以可以很容易地进行修改/定制。该系统是开源的，这意味着所有技术数据（规格、原理图和电路板布局文件、源代码及说明）都将公开可用。
