Data Acquisition for the New Muon $g$-$2$ Experiment at Fermilab

TL;DR

The paper describes the design and implementation of a high-speed, deadtime-free data acquisition system for the Fermilab muon g-2 experiment, aiming to improve measurement precision of the muon's magnetic moment.

Contribution

It introduces a novel data acquisition system capable of handling 18 GB/s data rates with 700 μs deadtime-free recording for the muon g-2 experiment at Fermilab.

Findings

System handles 18 GB/s data rate.

Achieves 140 ppb measurement precision.

Operational system ready before 2017.

Abstract

A new measurement of the anomalous magnetic moment of the muon, $a_{\mu} \equiv (g-2)/2$, will be performed at the Fermi National Accelerator Laboratory. The most recent measurement, performed at Brookhaven National Laboratory and completed in 2001, shows a 3.3-3.6 standard deviation discrepancy with the Standard Model predictions for $a_\mu$. The new measurement will accumulate 21 times those statistics, measuring $a_\mu$ to 140 ppb and reducing the uncertainty by a factor of 4. The data acquisition system for this experiment must have the ability to record deadtime-free records from 700 $\mu$s muon spills at a raw data rate of 18 GB per second. Data will be collected using 1296 channels of $\mu$TCA-based 800 MSPS, 12 bit waveform digitizers and processed in a layered array of networked commodity processors with 24 GPUs working in parallel to perform a fast recording and processing of detector signals during the spill. The system will be controlled using the MIDAS data acquisition software package. The described data acquisition system is currently being constructed, and will be fully operational before the start of the experiment in 2017.