New Dark Matter Detectors using Nanoscale Explosives

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 specic 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 o multiple cells. If the detector operates at room temperature, we nd 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.