Calcium 52 Image (IMAGE) DOE/Oak Ridge National Laboratory Caption The image above shows the chain of the studied calcium isotopes. The "doubly magic" isotopes with mass numbers 40 (Ca-40) and 48 (Ca-48) exhibit equal charge radii. The first measurement of the charge radius in Ca-52 yielded an unexpectedly large result. Credit Image credit: COLLAPS Collaboration/Ronald Fernando Garcia Ruiz. Usage Restrictions Credit Ronald/organization License Licensed 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.