"The ion source used for hydrogen and deuterium ions in the variable energy cyclotron at the University of Rochester is of the hooded arc type. For the past year it has been operating with a new feature which has greatly improved its performance. The new feature is a magnetic mirror built into the upper end of the arc hood by a simple insertion of a steel bearing ball 1/8" in diameter. The magnetic field gradient near the ball provides a magnetic mirror action on electrons moving up the arc channel toward the ball, reflecting may of them."

From abstract: "The objective of this program is to make a compilation of neutron capture gamma ray spectra of the naturally occurring elements, covering both the low and high energy region, using Na I(TI) scintillation detectors...During this phase of the program a detection system, together with its associated shielding was constructed and tested."