Double Penning Trap System (image) Johannes Gutenberg Universitaet Mainz Share Print E-Mail Caption Double Penning trap system for measuring the g-factor of the proton: the gold-plated cylindrical trap electrodes are isolated using sapphire rings. The approximately 20 centimeters tall structure is located within a superconducting magnet in an ultrahigh vacuum near absolute zero. Credit photo/©: Georg Schneider Usage Restrictions This image may only be used in connection with the press release "New proton record: Researchers measure magnetic moment with greatest possible precision", issued by Johannes Gutenberg University Mainz on November 27, 2017. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.