How Stiff Is the Proton? (IMAGE) DOE/US Department of Energy Caption Compton scattering setup at the High Intensity Gamma Ray Source. The central cylinder is the liquid hydrogen target. High energy gamma rays are scattered from the liquid hydrogen into eight large detectors that measure the gamma rays’ energy. Credit Image courtesy of Mohammad Ahmed, North Carolina Central University and Triangle Universities Nuclear Laboratory Usage Restrictions Image courtesy of Mohammad Ahmed, North Carolina Central University and Triangle Universities Nuclear Laboratory License Original content 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.