January 9, 2012
A paper detailing how a SLAC-led research team turned a Fermi Gamma-ray Space Telescope instrument into an electron-positron detector has garnered the cover of Physical Review Letters, a highly-respected journal published by the American Physical Society. The paper was also called out in Physics, an online journal published by the APS that "highlights a few important papers from the family of Physical Review journals."
The scientists found a clever way to use Fermi’s main instrument, the SLAC-built-and-managed Large Area Telescope, to distinguish positive particles from negative particles, even though the instrument is not equipped with a magnet. The cover is an illustration from their paper, entitled "Measurement of Separate Cosmic-Ray Electron and Positron Spectra with the Fermi Large Area Telescope.” The journal’s caption explains:
"Using the Earth’s magnetic field to distinguish positrons (blue) from electrons (red) arriving at the Fermi Large Area Telescope. The solid trajectories are forbidden because they lie in the Earth’s shadow. Selected for an Editors' Suggestion and a Synopsis in Physics. [M. Ackermann et al. (Fermi LAT Collaboration), Phys. Rev. Lett. 108, 011103 (2012)]"
- "Fermi Gamma-ray Space Telescope Confirms Puzzling Preponderance of Positrons," SLAC Today, Sep. 12, 2011
- "One Promising Puzzle Piece for Confirming Dark Matter Now Seems Unlikely Fit, Researchers Find," The Kavli Foundation Science Spotlights, Fall 2011
- "Cosmic Antimatter Excess Confirmed," Science Now, Nov. 2011