New Dark Matter Detector using Nanoscale Explosives

TL;DR

This paper proposes a novel dark matter detector using nanoscale explosives, specifically nanothermites, which can detect WIMP interactions through explosive chain reactions, offering high background rejection and sensitivity to low-energy events.

Contribution

The paper introduces nanoscale explosive detectors based on nanothermites for dark matter detection, demonstrating their potential for high sensitivity and background discrimination at room and cryogenic temperatures.

Findings

Detects WIMPs above 100 GeV at room temperature

Achieves sensitivity to 0.5 keV energy deposits at cryogenic temperatures

Offers excellent background rejection due to nanoscale granularity

Abstract

We present nanoscale explosives as a novel type of dark matter detector and study the ignition properties. When a Weakly Interacting Massive Particle WIMP from the Galactic Halo elastically scatters off of a nucleus in the detector, the small amount of energy deposited can trigger an explosion. For specificity, this paper focuses on a type of two-component explosive known as a nanothermite, consisting of a metal and an oxide in close proximity. When the two components interact they undergo a rapid exothermic reaction --- an explosion. As a specific example, we consider metal nanoparticles of 5 nm radius embedded in an oxide. One cell contains more than a few million nanoparticles, and a large number of cells adds up to a total of 1 kg detector mass. A WIMP interacts with a metal nucleus of the nanoparticles, depositing enough energy to initiate a reaction at the interface between the two layers. When one nanoparticle explodes it initiates a chain reaction throughout the cell. A number of possible thermite materials are studied. Excellent background rejection can be achieved because of the nanoscale granularity of the detector: whereas a WIMP will cause a single cell to explode, backgrounds will instead set off multiple cells. If the detector operates at room temperature, we find that WIMPs with masses above 100 GeV (or for some materials above 1 TeV) could be detected; they deposit enough energy ($>$10 keV) to cause an explosion. When operating cryogenically at liquid nitrogen or liquid helium temperatures, the nano explosive WIMP detector can detect energy deposits as low as 0.5 keV, making the nano explosive detector more sensitive to very light $<$10 GeV WIMPs, better than other dark matter detectors.