Network Time Synchronization of the Readout Electronics for a New Radioactive Gas Detection System

Abstract

In systems with multiple radiation detectors, time synchronization of the data collected from different detectors is essential to reconstruct multi-detector events such as scattering and coincidences. In cases where the number of detectors exceeds the readout channels in a single data acquisition electronics module, multiple modules have to be synchronized, which is traditionally accomplished by distributing clocks and triggers via dedicated connections.To eliminate this added cabling complexity in the case of a new radioactive gas detection system prototype under development at the French Atomic Energy Commission, we implemented time synchronization between multiple XIA Pixie-Net detector readout modules through the existing Ethernet network, based on the IEEE 1588 precision time protocol. The detector system is dedicated to the measurement of radioactive gases at low activity and consists of eight large silicon pixels and two NaI(Tl) detectors, instrumented with a total of three 4-channel Pixie-Net modules. Detecting NaI(Tl)/silicon coincidences will make it possible to identify each radioisotope present in the sample. To allow these identifications at low activities, the Pixie-Net modules must be synchronized to a precision well below the targeted coincidence window of 500-1000 ns. Being equipped with an Ethernet PHY compatible with IEEE 1588 and synchronous Ethernet that outputs a locally generated but system-wide synchronized clock, the Pixie-Net can operate its analog to digital converters and digital processing circuitry with that clock and match time stamps for captured data across the three modules. Depending on the network configuration and synchronization method, the implementation is capable to achieve timing precisions between 300 ns and 200 ps. Index Terms-Radioxenon, network time synchronization, precision time protocol, coincidence detection. W. Hennig (whennig@xia.com) and S. Hoover are with XIA LLC, Hayward, CA 94544 USA. V. Thomas and O. Delaune are with CEA, DAM,

PoE-Enabled Visible Light Positioning Network With Low Bandwidth Requirement and High Precision Pulse Reconstruction

“…In order to tackle the synchronization transmission, the SyncE and the PTP are exploited to realize the reference clock frequency synchronization and the clock synchronization requirement among the LED-based transmitter APs, respectively [18]. Fig.…”

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White Rabbit Time Synchronization for Radiation Detector Readout Electronics

“…ZeroMQ's PUB and SUB socket types, built on a foundation of automatic connection management, allow us to program in a decoupled publish/subscribe style while still leaning on the inherent properties of TCP transport for flow control and reliable ordered messaged delivery. We first tested the ZeroMQ library and benchmarked binaries on the earlier Pixie-Net electronics [6] and a variety of virtual and bare metal machines. Using the Pixie-Net as a server and a Ubuntu x86_64 virtual machine as a client exchanging 10,000 10-byte messages over a nondedicated LAN, we observed one-way latencies ranging from 161-211 microseconds.…”

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“…More recently, time synchronization through data networks has been developed, such as the IEEE 1588 precision time protocol [10] (PTP) and in particular its "high accuracy profile" also known as White Rabbit [11]. Since detector readout electronics is usually connected to a data network in any case for readout to storage, these methods can be used as an alternative [6]. The challenge for the use of such network synchronization techniques in detector readout electronics is to integrate the synchronization with the data capture from analog to digital converters (ADC) and the processing of digitized detector signals in a field programmable gate array (FPGA).…”