Changes In Spectral Response Research Articles

Incorporation of lithium into gallium phosphide electrodes from lithium salt electrolytes in the presence of crown ethers

Anodic stripping analysis of cathodically polarized n- and p-type Gap electrodes has revealed that incorporation of lithium into a surface region of the electrodes takes place in aqueous electrolytes containing lithium salts and crown ethers such as 15-crown-5. Changes in spectral response of p-type electrodes caused by cathodic polarization in such electrolytes give support to the lithium incorporation. The redox potential for the incorporation reaction was estimated to lie somewhere between −1.95 and −0.91 V vs. SCE. The roles of crown ethers in the incorporation reaction are discussed.

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Spectral characteristics of bulk extrinsic photo-conductive detectors have been measured under conditions that only partially illuminated the photo-sensitive areas. The data presented were obtained at background photon flux levels of 10" to 10" photons/sec-cm'. The geometry of the detectors was such that the applied electric field was perpendicular to the incident radiation. Substantial changes in spectral responsivity have have been measured. These changes are dependent upon which portion of the detector's sensitive area is illuminated.

Low Energy Proton Damage to Solar Cells

Various types of silicon solar cells have been irradiated with 4.6 - 4.8 Mev protons in two separate experiments. In the first experiment, variations included the bulk material, impurity concentration, and oxygen concentration; the second experiment involved the cells of various manufacturers. Changes in diffusion length, spectral response, and efficiency under sun-like illumination are presented. Annealing effects in terms of the aforermentioned parameters are given. Comparison of the effects of this damage to that of 1 Mev electrons is made. Some preliminary results on the effects of proton damage to GaAs photovoltaic cells are also mentioned.

Temperature Effects in Photomultipliers.

view Abstract Citations (2) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Temperature Effects in Photomultipliers. Young, Andrew T. Abstract The effect of temperature changes on the spectral response curves of RCA 1P21, EMI 6256 and 9558, and Farnsworth FW-1 18 photomultipliers has been measured for two tubes of each type. The cathodes are respectively S-4 (Sb-Cs), S-13 (Sb-Cs), S-20 (Sb-Na-K-Cs), and S-1 (Ag-O-Cs). All but the FW-1 18 have Sb-Cs dynode surfaces. Cooling from room temperature to dry-ice temperature causes changes in relative spectral response of the order of 10% or less for the Sb-Cs cathodes for A~5000 A, for the S-20 cathode for x~6250, and for the S-1 cathode over at least the range from 6250 to 10 000 A. At A=7300, the S-20 cathode loses about 30% of its normal sensitivity when it is refrigerated. The data are consistent with a temperature coefficient of -0.04%/0C per stage for the Sb-Cs dynodes. The Sb-Cs cathodes lose a large fraction of their sensitivity for A> 5000 A when they are refrigerated. This loss is more than enough to account for the discrepancy between observed B - V colors of stars and colors computed from stellar atmosphere theory. The coefficient of the temperature effect between 5000 and 6000A is 1.12x10-5 mag./0Q/A. This typically requires a temperature stabilization of one or two degrees if a 1P21 is required to carry a color zero point in this part of the spectrum with an accuracy of 1%. Publication: The Astronomical Journal Pub Date: June 1962 DOI: 10.1086/108726 Bibcode: 1962AJ.....67..286Y full text sources ADS |

Surface States of Cadmium Sulfide

Photoconductive and phosphorescent properties of cadmium Sulfide are modified by adsorbed molecules. Change in spectral response of photoconductivity and the phosphorescence efficiency when crystals are exposed to vapors suggest that surface states due to adsorbed molecules aid in recombination. Photovoltaic behavior of rectifying contacts lends credence to the hypothesis that infrared releases otherwise immobile holes.