| 摘要 |
995,450. Photo-electric polarimeters. BODENSEEWERK PERKIN-ELMER & CO. G.m.b.H. June 13, 1962 [June 13, 1961], No. 22721/62. Heading G1A. The invention relates to a polarimeter which includes a polarizer, a further polarizer acting as an analyzer, and a radiation detector behind the analyzer wherein an optically active sample is inserted between the polarizer and the analyzer, and the polarizer is excited into rotary oscillations about its beam axis by magnetic means, the output signal of the detector is fed to phase sensitive balancing means causing a follow-up rotation of the analyzer with the rotation of the polarization plane due to the sample, characterized in that the polarizer is connected to a magnet rotor pivotally supported in the air gap of an A.C. excited electromagnet. In the embodiment shown light from a source S such as a mercury vapour lamp is fed through an oscillating polarizer P oscillating at 50 c/s, and from there through a sample PR to an analyzer A behind which is a photo-electric cell E which may be a photomultiplier connected through an amplifier V to a Ferraris motor M which controls the position of the analyzer A. With no sample in position and the polarization planes of the polarizer P and the analyzer A previously aligned at rest, the output signal of the photoelectric cell E will have twice the frequency of the oscillation of the polarizer P and will cause no rotation of the motor M since its exciting winding is fed from the same 50 c/s supply as the electromagnet (Figs. 1-5 not shown) oscillating the magnetic rotor connected to the polarizer P. With a rotation of the polarization plane due to a sample PR the detector signal obtains a Fourier component of the frequency of the polarizer oscillations (Figs. 7 and 8 not shown) which causes the motor to rotate to the right or left according to the direction of rotation of the polarization plane and through suitable gearing the analyzer is rotated until balancing is effected, the angle of rotation being indicated by a digital meter 2 driven with the analyzer. A filter wheel (Figs. 1 and 2 not shown) having several spectral filters of different transmission ranges any one of which may be inserted in the ray path of the apparatus, may be provided. Specification 875,278 is referred to. |
