A Direct Determination of the Energy of theHe3Nucleus from the D - D Reaction

The energy of the ${\mathrm{He}}^3$ nuclei emitted at 90° to the incident deuteron beam in the D - D reaction has been measured directly by deflecting them through a 90°, 15-cm radius, cylindrical electrostatic analyzer. The ${\mathrm{He}}^3$ ions were detected by allowing them to eject secondary electrons from the first plate of a 12-element electron multiplier tube. Thus the ions were not required to traverse any foil or window material between the heavy ice target and the point of their detection.