Absolute Spectral Sensitivity Research Articles

Das Farbensehen bei Schielamblyopie

Colour vision in squint amblyopia depends on the fixation modus. In eyes with foveolar or unsteady foveolar from fixation the 3 primary colour vision mechanisms (CVMs) gave normal foveolar CVM patterns. The absolute spectral retinal sensitivity was somewhat, but not significantly lowered. The spectral sensitivity for hue discrimination was either normal, or slightly reduced in the short wavelength side, or slightly reduced over the whole visible spectrum. The spectral sensitivity for saturation discrimination showed normal curves. -- In amblyopic eyes with parafoveal to perifoveal fixation mode the absolute spectral retinal sensitivity is lowered for about 0.45--0.60 log units in comparison to an approximately corresponding excentric retinal area in a normal eye. In eyes with parafoveolar to perifoveal fixation mode measurements of CVMs and of hue discrimination gave better results than could be expected with regard to the position of the fixating area as determined by visuscope. The values correspond to those obtained in retinal areas at least as close to the foveola as the amblyopic fixation point, but usually of an even more central position. The sensitivity for saturation discrimination showed no significant disturbance.

Detectors for the Extreme Ultraviolet I: Photomultipliers Used in the dc Output Current Mode

An investigation has been made of voltage-sensitivity characteristics, absolute spectral response, dark current and output current limitations of seven photomultipliers suitable for detection of extreme uv radiation. These photomultipliers are windowless types, utilizing cathode surfaces blind to visible and near uv radiation; they include a microminiature continuous channel multiplier. For measurements of absolute spectral sensitivity, they were compared to a conventional 1P21, coated with sodium salicylate which, in turn, had been calibrated at 1216 A with a nitric oxide ionization chamber. The spectral response measurements cover the spectral region from 1500 A to 584 A. The photomultipliers were used in a dc output currrent mode and were excited with radiation from both pulsed and dc gas discharge sources. A discussion of the suitability of the detectors for use with each type of source is given.

Absolute spectral sensitivity of phototubes and the application to the measurement of the absolute quantum yields of chemiluminescence and bioluminescence.

Abstract— Methods for the absolute measurement of the spectral sensitivity of phototubes are reviewed in detail. Several experimental arrangements are described for the independent determination of these values to insure the elimination of systematic error. On the basis of these measurements a rapid, simple technique is described for measuring the average absolute spectral sensitivity of a phototube over a defined emission spectrum, thus obviating the original tedious point‐by‐point methods and allowing frequent re‐Standardization. The application of these standardized phototubes to the measurement of the absolute quantum yields of the chemiluminescence of luminol and the bioluminescence of luminous bacteria and the firefly is described. An absolute low‐level light emission standard in the form of the luminol chemiluminescence reaction, either in aqueous or in the non‐aqueous solvent dimethylsulfoxide is proposed for general use and the conditions for its use are described in detail. It should therefore be possible for any researcher to obtain an absolute calibration, in his own experimental geometry, in the blue region of the spectrum.

Absolute Calibration of a Light Detector

A method is described for the determination of the absolute spectral sensitivity of a photomultiplier in the wavelength range from 2200 A to cutoff. The standard of radiation is thermal radiation from a tungsten strip lamp and the dispersing instrument is an arrangement of two conventional grating monochromators in tandem. The major portions of the calibration are the determinations of the monochromator transmissions and then of the relative and finally absolute spectral sensitivity of the photomultiplier. As an example of the use of this detector, the determination of the absolute spectral output of two lamps is described.