Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

The Direct Search Experiment for Light Dark Matter (DELight): Overview and Perspectives

Melih Solmaz

TL;DR

The paper proposes DELight, a direct-detection experiment for light dark matter using a superfluid $^4$He target coupled to large-area microcalorimeters (LAMCALs) to detect low-energy nuclear recoils. It exploits multiple detection channels—heat via quasiparticles, scintillation photons, and quantum evaporation amplification at the liquid-vacuum interface—to achieve sub-keV energy thresholds, with a pancake cell design and film-burner to maximize signal gain. Phase I–II plans include a 1 L target with a $20$ eV threshold and 1 kg·day exposure, expanding to 10 L with a $10$ eV threshold and 100 kg·day exposure to reach front-running light DM limits, all supported by Geant4-based simulations and background modelling. An R&D DELight Demonstrator tests key technologies (level sensing, quasiparticle response, and sensor integration) at ~15 mK, validating the practicality of the approach for scalable future runs. Success would yield competitive sub-GeV DM limits and establish a novel cryogenic detection paradigm for light dark matter.

Abstract

Driven by the null results in the searches for dark matter, the field of direct dark matter detection is constantly evolving to push new frontiers. Ultimately, a vast parameter space for dark matter masses below a few GeV is yet to be explored. That said, low mass dark matter candidates necessitate novel detector designs with lower thresholds and alternative target materials. The Direct search Experiment for Light dark matter (DELight) will deploy a target of superfluid $^4$He instrumented with large area microcalorimeters (LAMCALs) based on magnetic microcalorimeter (MMC) technology in a setup optimized for low mass dark matter searches. This paper presents an overview of this novel upcoming experiment, including detection technology, sensitivity goals and R&D studies.

The Direct Search Experiment for Light Dark Matter (DELight): Overview and Perspectives

TL;DR

The paper proposes DELight, a direct-detection experiment for light dark matter using a superfluid He target coupled to large-area microcalorimeters (LAMCALs) to detect low-energy nuclear recoils. It exploits multiple detection channels—heat via quasiparticles, scintillation photons, and quantum evaporation amplification at the liquid-vacuum interface—to achieve sub-keV energy thresholds, with a pancake cell design and film-burner to maximize signal gain. Phase I–II plans include a 1 L target with a eV threshold and 1 kg·day exposure, expanding to 10 L with a eV threshold and 100 kg·day exposure to reach front-running light DM limits, all supported by Geant4-based simulations and background modelling. An R&D DELight Demonstrator tests key technologies (level sensing, quasiparticle response, and sensor integration) at ~15 mK, validating the practicality of the approach for scalable future runs. Success would yield competitive sub-GeV DM limits and establish a novel cryogenic detection paradigm for light dark matter.

Abstract

Driven by the null results in the searches for dark matter, the field of direct dark matter detection is constantly evolving to push new frontiers. Ultimately, a vast parameter space for dark matter masses below a few GeV is yet to be explored. That said, low mass dark matter candidates necessitate novel detector designs with lower thresholds and alternative target materials. The Direct search Experiment for Light dark matter (DELight) will deploy a target of superfluid He instrumented with large area microcalorimeters (LAMCALs) based on magnetic microcalorimeter (MMC) technology in a setup optimized for low mass dark matter searches. This paper presents an overview of this novel upcoming experiment, including detection technology, sensitivity goals and R&D studies.

Paper Structure

This paper contains 5 sections, 3 figures.

Table of Contents

  1. Motivation
  2. DELight Detector
  3. From Foundation to Expansion: DELight Phase I-II
  4. DELight Demonstrator
  5. Conclusion

Figures (3)

  • Figure 1: Sketch of the DELight Phase-I detector. Left: Pancake geometry of the helium cell with top and bottom LAMCAL array. Right: Schematic of a large area microcalorimeter (LAMCAL).
  • Figure 2: (Left) DELight background goals for phase-I/II (solid lines). The dashed dark(light) blue line is the phase-I(II) ER goal background after a rudimentary ER/NR discrimination cut, drawn for instructive purposes. (Right) Sensitivity projections at 90% CL for DELight phase-I/II at the goal background-levels without ER/NR discrimination.
  • Figure 3: (Left) Interior of the DELight Demonstrator cell filled with $\sim$300 ml helium (purple). (Right) Picture of the DELight Demonstrator attached to the dilution refrigerator. Image credit: Florian Freundt.