MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, Dionne, Gerald F., Crocker, Phillip S., Smith, James F., MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, Dionne, Gerald F., Crocker, Phillip S., and Smith, James F.
A new ferrimagnetic single-crystal sphere orientation device has been developed for use with a variety of sphere sizes and compositions. Similar to other instruments which operate on a magnetic principle, this orienter provides (110) axes alignments. However, with one small electromagnet, it is considerably simpler than previously reported instruments of this type. From theoretical considerations, it is concluded that high alignment sensitivity will be obtained for polished spheres of low mass density, small radius, high magnetocrystalline anisotropy, and low coefficient of friction between sphere and support. It is also concluded that the sphere should be supported in cavities of conical geometry, with the cone angle as small as possible. The results of both x-ray analysis and microscope visual observation with a number of typical spheres indicate that the combination of accuracy and reliability of the instrument is superior to that of the other devices and suggests that the factors controlling the alignment sensitivity as derived from theory are at least qualitatively correct.