DNA Dark Matter Detector Proposed
Performing a DNA test to identify dark matter may seem like something only a seriously mixed-up scientist would do, but a cross-disciplinary group of scientists from the USA say in the very near future that is just what physicists probing the mysteries of the cosmos could be doing. The reason for this is that last week they proposed a new detector for WIMPs (Weakly Interacting Massive Particles), which relies on the properties of DNA. WIMPs are thought to make up the bulk of the mysterious dark mass, needed to explain (among other things) galactic rotation curves and thought to account for 23% of the Universe’s mass-energy (with 72% coming from the equally mysterious dark energy, with visible matter only accounting for the remaining 5%).
The design of the detector is fairly simple: from a very thin sheet of gold foil (approximately 10 atoms thick) are hung evenly-spaced strands of DNA (up to 0.7 micrometers long), with each strand molecularly labeled and placed about 10 nanometers apart. Occasionally a WIMP will hit one of the gold nuclei in the foil, knocking it out of the foil, causing it to smash through the DNA and breaking the strands of DNA. The broken strands are collected on a plate below and techniques from molecular genetics are used to identify where exactly the nucleus severed the DNA strands. The experiment consists of several detectors stacked on top of each other and from this the direction and speed of the WIMP can be worked out.
The main advantage of the novel dark matter detector is its ability to detect the direction of the incoming WIMP, which is important as it helps to distinguish WIMPs from other particles such as cosmic ray photons. Another advantage of the new experiment is that it is much smaller (coming in at only ~1kg) than conventional WIMP detection experiments, which are usually very large and often need to be housed deep underground. The experiment should also be able to probe lower energies than current WIMP detectors are able to. John Davis
ArXiv blog: http://www.technologyreview.com/view/428391/revolutionary-dna-tracking-chamber-could-detect/
Original paper: http://arxiv.org/abs/1206.6809