Reflector Dimensions Research Articles

Radiation fields inside an elliptical photoreflector with a source of finite spatial dimensions

AbstractUsing the Extense Source Formulation (Irazoqui et al., 1973a), a radiation distribution model for the tubular lamp‐elliptical reflector system was developed for predicting energy density profiles inside the elliptical cavity of the system.It introduces a significant improvement over the linear‐lamp models since it avoids any form of singularities in the prediction of radiation energy density profiles at the focal points of the elliptical reflector. Also, all lamp and reflector dimensions are parameters of the model.Calculated results agree well with published experimental data for a similar lamp reflector set up.One of the most important conclusions is the absence of uniform irradiation from all radial directions at the reactor location.

The Formation of Uniform Beams from Long and Thin Radiators

The coupling of long and thin radiators with nonaxisymmetric reflectors is considered for the production of generally rectangular beams with very good uniformity and attractive collection efficiencies. Reflector profiles are derived analytically, and cases of practical interest are discussed. Numerical results show that medium size beams (0.2-1 sr) may be obtained with collection efficiencies of 40% to 70%. Such beams are perfectly uniform over one angle while over the other they have nonuniformities generally lower than +/-10%. Limitations of the reflector dimensions and the effects of the radiator thickness are evaluated both analytically and by experimental observation.

Angular Spectra of Optic Cavities*†

The resonant modes of optic interferometer cavities are investigated in the angular spectrum domain. The investigation is based on an integral equation (governing the relation between the normal modes and cavity geometry) which is derived by using the self-consistent Rayleigh formulation for solving diffraction problems. For plane-parallel cavities this integral equation can be solved by means of a series expansion of orthogonal functions characteristic of the cavity geometry without making any assumption about the relative magnitudes of end reflector dimensions and separation. The solution also provides, in addition to a comparison with the solutions of the approximated Huygens’ integral equation as found by other investigators, a direct way for obtaining the angular plane-wave spectrum (or the radiation pattern) of the beam emerging from the cavity. The particular cases of plane-parallel cavities with infinite-strip and circular end reflectors are considered in this paper.

Transducer Beam Control with Plane and Conical Reflectors

It is well known that a large plane reflector directly above and normal to the axis of a cylindrical transducer can have a rather drastic effect on the beam patterns of such a transducer. The degree of such an effect is, of course, dependent on size and material of the reflector, distance above the active face of the transducer, and the size of the active face of the transducer in wavelengths. Experimental data will be presented indicating some of the precautions one must take to guard against such effects or to use these effects to one's advantage if desired. Information will be presented, for both plane and conical reflectors, as to the beam depression, beam width, effective hydrophone sensitivity, and minor-lobe structure as a function of reflector dimensions and for various distances of the reflectors above the active face. (This work is supported by the Bureau of Ships.)