Improvement of beam uniformity for radiation effect test on electronic devices for space applications at KOMAC

Low flux proton beam irradiation has become increasingly important and demanding in space applications of electronic devices where the device failure can be fatal. Large beam area with a good beam uniformity is also demanding as more number of electronic components can be tested at once so that the test time can be reduced significantly. We have a low flux proton beamline at KOMAC. The beamline has two octupole magnets which fold the Gaussian beam into flat-top uniform beam profile. If a beam center is misaligned against the magnetic center of octupole magnets, the uniform beam profile on the target is asymmetrically deformed and it becomes difficult to get a good beam uniformity. In order to understand the effects of the beam center deviations on the flatness of the a beam profile, we performed the beam characterization and error analysis of the magnets in the beamline. We also experimentally apply x beam center deviations by the last bending magnet in the beamline, right before the octupole magnets. From this experiment, the slopes of the beam profile are measured to show the effect of the beam center deviations. The experimental results are compared with the particle simulation studies. To improve the beam uniformity at the target in the beamline, we suggest that the bending magnet can be used in compensating the beam center deviation in the horizontal direction without installing any additional instruments. This can be further applied to expand an irradiation area larger still satisfying the beam uniformity requirement.