Readout Firmware of the Vertex Locator for LHCb Run 3 and Beyond
Readout Firmware of the Vertex Locator for LHCb Run 3 and Beyond
复制标题
LHCb Run 3 及更高版本的顶点定位器读出固件
DOI：
10.1109/tns.2021.3085018
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发表时间：
2021
影响因子：
1.8
通讯作者：
Hennessy K
中科院分区：
文献类型：
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作者：
Hennessy K
用于LHCb的新的LHCb顶点探测器（VELO），包括一个新的像素探测器和读出电子设备，将于2021年安装，用于LHC运行3的数据采集。电子设备以前端的“VeloPix”ASIC为中心，以40 MHz的无干扰读出操作。一个自定义串行化器，称为千兆有线传输器（GWT），和相关的自定义协议已设计的VeloPix。GWT数据以5.12 Gb/s的线速率从VeloPix的串行器发送，对于完整的VELO检测器，达到2-3 Tb/s的总数据速率。数据通过300米光纤链路发送到控制和读出电子卡，以便在英特尔Arria 10 FPGA中进行数字化和处理。由于采用了VeloPix无缓存设计，相邻数据报之间的延迟差异可达12。因此，在向前传播之前，必须在固件中缓冲和同步数据，否则将遭受巨大的CPU处理损失。本文将详细描述读出固件的体系结构，重点是烧灼机制和烧灼技术。在读出调试过程中发现的问题，并缩放资源利用率，沿着与他们的解决方案，将被说明。可以提供固件数据处理链的最新结果以及模拟中采用的验证程序。下一代探测器的挑战也将提出读出处理解决方案的想法。
The new LHCb Vertex Locator (VELO) for LHCb, comprising a new pixel detector and readout electronics, will be installed in 2021 for data taking in Run 3 at the LHC. The electronics centers around the “VeloPix” ASIC at the front-end operating in a trigger-less readout at 40MHz. A custom serializer, called gigabit wireline transmitter (GWT), and associated custom protocol have been designed for the VeloPix. The GWT data are sent from the serializers of the VeloPix at a line rate of 5.12 Gb/s, reaching a total data rate of 2–3 Tb/s for the full VELO detector. Data are sent over 300-m optic-fiber links to the control and readout electronics cards for deserialization and processing in Intel Arria 10 FPGAs. Because of the VeloPix trigger-less design, latency variances up to 12can occur between adjacent datagrams. It is therefore essential to buffer and synchronize the data in firmware prior to onward propagation or suffer a huge CPU-processing penalty. This article will describe the architecture of the readout firmware in detail with focus given to the resynchronization mechanism and techniques for cauterization. Issues found during readout commissioning, and scaling resource utilization, along with the their solutions, will be illustrated. The latest results of the firmware data-processing chain can be presented as well as the verification procedures employed in simulation. Challenges for the next generation of the detector will also be presented with ideas for a readout processing solution.