Calorimetric approach to paleo-detection of dark matter

TL;DR

This paper introduces a calorimetric paleo-detector method for dark matter detection, combining vacancy counts and track length analysis to improve sensitivity and background discrimination.

Contribution

It presents the first sensitivity analysis using calorimetric readout in paleo-detectors, demonstrating comparable performance to existing track-based methods.

Findings

Vacancy-only readout achieves sensitivity similar to track-only analyses.

Combining observables enhances discrimination of nuclear recoil species.

Sensitivity reaches $10^{-48}\,\mathrm{cm}^2$ for WIMP masses of tens of GeV.

Abstract

We present the first paleo-detector dark matter sensitivity analysis based on a calorimetric readout, in which the number of stable lattice vacancies produced by each nuclear recoil is used as a per-event observable complementary to the track length. Using full-cascade SRIM simulations in olivine, we compute the expected sensitivity for a 100 gGyr exposure. We find that a vacancy-only readout reaches a sensitivity envelope very similar to that of state-of-the-art track-only analyses. The combination of the two observables provides an event-by-event proxy for |dE/dx| and hence for the recoiling nuclear species. Since the neutron-nucleus cross section is approximately flat in nuclear mass while the dark-matter--nucleus cross section scales as $A^2$, this discrimination suppresses the dominant neutron background by more than an order of magnitude at moderate dark matter masses. The combined-analysis sensitivity reaches spin-independent dark-matter--nucleon cross sections of order $10^{-48}\,\mathrm{cm}^2$ at WIMP masses of a few tens of GeV, comparable to future direct detection experiments. A two-stage readout combining selective-plane illumination microscopy with scanning electron microscopy is identified as a path to making a 100 g-scale analysis plausible.