arXiv subjects

Emma Ellingwood

Publications and source records attributed to Emma Ellingwood.

3 recordsLinked to original sources

arXiv2026

The Darkside-20k Data Acquisition System

DarkSide-20k is a WIMP search experiment using liquid argon as a target, designed to perform a background-free search for dark matter with unprecedented sensitivity, and is currently under construction at INFN Laboratori Nazionali del Gran Sasso, Italy. The detector comprises a dual-phase Time Projection Chamber complemented with external veto systems and is equipped with a total of 2720 SiPM-based readout channels. This work presents the DAQ system designed for DarkSide-20k. The system is capable of continuous, triggerless digitisation of the waveforms with high single-photoelectron detection efficiency and online processing, ensuring data reduction for long-term storage. The DarkSide-20k DAQ system employs commercial CAEN VX2745 digitisers with custom FPGA firmware implementation. Timing and synchronisation across all 48 digitisers are provided by custom Global and Crate Data Manager boards distributing a phase-aligned clock derived from a disciplined rubidium standard. Waveform segments are processed in real time by Front End Processor machines. Data are organised into collections containing whole detector information and distributed across a farm of Time Slice Processors for event reconstruction, classification, and further reduction before storage and offline analysis. A full "Quadrant" of the system, corresponding to one quarter of the final DAQ, has been assembled and validated at TRIUMF laboratory in Canada. The Quadrant has been stress-tested with simultaneous pulses and demonstrated sustained digitizer readout exceeding expected physics rates and stable long-term performance.

physics.ins-det↗

arXiv2025

G4CASCADE: A data-driven implementation of (n, $γ$) cascades in Geant4

De-excitation $γ$ cascades from neutron captures form a dominant background to MeV-scale signals. The Geant4 Monte Carlo simulation toolkit is widely used to model backgrounds in nuclear and particle physics experiments. While its current modules for simulating (n, $γ$) signals, G4NDL and G4PhotoEvaporation, are excellent for many applications, they do not reproduce known gamma-ray lines and correlations relevant at 2-15 MeV. G4CASCADE is a new data-driven Geant4 module that simulates (n, $γ$) de-excitation pathways, with options for how to handle shortcomings in nuclear data. Benchmark comparisons to measured gamma-ray lines and level structures in the ENSDF database show significant improvements, with decreased residuals and full energy conservation. This manuscript describes the underlying calculations performed by G4CASCADE, its various usage options, and benchmark comparisons. G4CASCADE for Geant4-10 is available on GitHub at https://github.com/UCRDarkMatter/CASCADE

physics.comp-ph↗

arXiv2024

Temperature-Dependent Photoluminescence of PEDOT:PSS for use as Transparent Electrodes in the DarkSide-20k Time Projection Chamber

Dual-phase time-projection chambers (TPCs) filled with noble elements are used for particle detection, with many focusing on rare-event searches. These detectors measure two signals: one from scintillation light, and another from drifting ionized electrons. The DarkSide-20k design uses a transparent vessel with external photodetectors. Electrodes, used to drift the electrons, are located between the active medium and the photodetectors, requiring them to be transparent to allow scintillation light to transmit through them. The transparent electrode coating for DarkSide-20k is poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT:PSS) or Clevios. For rare-event search detectors, the fluorescence of materials that are between the active volume and the photodetectors may lead to backgrounds in the data. Since Clevios is a new material for TPC electrodes, its fluorescent properties need to be characterized to understand their potential impact on backgrounds. Previous studies have indicated that Clevios can fluoresce, with maximal fluorescence produced using UV-excitation. Our study analyzes the fluorescence of Clevios, under UV-excitation, using both time-resolved and spectral techniques between 4 K and 300 K. We find that the fluorescence of Clevios is negligible when compared to the fluorescence of common fluorescent materials used in TPCs, such as 1,1,4,4-tetraphenyl-1,3-butadiene (TPB).

physics.ins-det↗