Magnetic Compton spectrometer free of second-order aberration

Improvements to an earlier concept for a magnetic, Compton, gamma-ray spectrometer make it possible to remove both the second-order radial aberrations which depend upon the position of the point of initiation of the Compton recoil in the converter, while at the same time retaining coincidence of the axial focus with the second radial focus. The improved performance is possible over a wide range of source to converter distances, including the case in which the incident gamma-rays form a parallel beam. The relationship of the new concept to the proposals of Daniel and of Bosi is discussed. (Auth.)