Broadband, Dead-Time-Free Spectrometer Using RFSoC for WISP Dark Matter Searches

TL;DR

This paper introduces a broadband, dead-time-free spectrometer based on RFSoC technology, significantly enhancing search efficiency for ultra-light dark matter candidates by enabling wide bandwidth and high resolution in a compact, resource-efficient design.

Contribution

The study presents a novel RFSoC-based spectrometer with optimized FPGA firmware that achieves 4 GHz bandwidth and 16 kHz resolution, doubling search efficiency for dark matter detection.

Findings

Achieves over 99.6% time efficiency in spectrometry.

Demonstrates accurate performance validation results.

Enables wide bandwidth and high resolution in a compact device.

Abstract

Ultra-light dark matter candidates, such as axions and dark photons, particularly within the mass range of $\mu$eV to meV, have garnered significant research interest. However, the effectiveness of existing experiments is often hindered by the narrow bandwidths of conventional spectrometers. This study presents a novel spectrometer solution based on a RFSoC, which integrates a high-speed data converter, field programmable gate array (FPGA), and a CPU within a single chip. The spectrometer's programmable logic implements an optimized fast Fourier transform (FFT) that minimizes memory usage, enabling an instantaneous bandwidth of 4 GHz with a frequency resolution of 16 kHz. This configuration achieves more than 99.6% time efficiency, effectively doubling search efficiency, compared with traditional approaches. This paper provides a comprehensive description of the hardware architecture, FPGA firmware, and software implementation, with a focus on the resource-efficient pipelined FFT algorithm. Performance validation results are also presented, demonstrating the accuracy and time efficiency of the developed spectrometer, highlighting its potential for advancing dark matter search.