Formation of Bremsstrahlung Focal Spots in Betatrons Using Small-Size Targets

The main patterns of formation of focal spots of bremsstrahlung radiation during interaction of a betatron electron beam with various small-sized targets are investigated on the basis of a model previously determined in experimental and model studies of the method of measuring focal spots of bremsstrahlung radiation of betatrons with flat targets. The sizes of the focal spots depend on the ratio between the size of the target along the axis of the electron beam and the size of the target normal to the beam axis. Parallelepiped-shaped targets with appropriate size ratios form circular focal spots. The latest version of the method using a slit collimator determines the size of focal spots of small targets as the width of the distributions at half the height of normal approximations of the real distributions of quanta in the focal spots. The output of bremsstrahlung from a focal spot of a small target is much greater than the output from a secondary focal spot component of the same size when collimating bremsstrahlung emerging from a flat target.