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The purpose of this paper is to report changes in the optical transmission spectrum (solarization) of commercial low-iron cerium containing glass (CG). UV absorption by CG has been shown to reduce yellowing rates of EVA polymeric pottants in PV modules resulting from UV radiation. Absorption and fluorescence spectra of CG change with exposure to UV light in the glass matrix. Solarization of CG could cause changes in the glass transmission that may result in changes in the UV protection and the efficiency of the module. The authors are studying the solarization of glasses in a variety of accelerated light exposure chambers at intensities ranging from 1 to more than 1000 Suns. Measurements made at various stages of the accelerated exposure tests are presented.

An apparatus which has been employed for the measurement of the optical transmission and mass changes in metal films is described. The stoichiometry of the metal film is inferred from measurements carried out with an automated bakeable vacuum microbalance. The optical transmission of the film is measured for monochromatic light from 4000 to 8000 A. The experimental difficulties encountered in this study are discussed in detail.

The design of a microbalance vacuum system for obtaining a particular ultimate pressure in the sample region is examined in quantitative detail. The system considered includes the sample container, the hangdown tubes, balance housing, tubulation, and valves that lead to the pump. Since the ultimate pressure is simply the steady state between the gas influx into the system and the pumping speed, the basic equations for calculating the pressure and the effective pumping speed are considered. Then, the sources of total gas influx, such as outgassing of the chamber walls, permeation of gases through the walls, sample outgassing, desorption or outgassing, leaks, and any related temperature effects are considered for baked and unbaked Pyrex glass, quartz, and stainless steel systems. The equations for calculating the effective pumping speed at any point in a vacuum system with different sizes of tubulation and valves are considered. A working system is described to illustrate how the design considerations can be used to obtain the desired performance in a microbalance vacuum system. Finally, the ultimate pressure calculated for various gas loads is compared with the actual performance of the working system.

Mass analyzed thermal desorption spectra for coadsorbed complexes of oxygen and CO evolving from a silver surface are discussed. The products of the desorption process are CO, CO2 and oxygen. The CO and CO2 evolution is partly due to direct desorption from the silver surface while the remainder of evolution is from internal parts of the vacuum system by replacement chemisorption. The replacement chemisorption of CO and CO2 is caused by the oxygen desorbing from the dissociating surface complexes. The replacement chemisorption process involves a considerable fraction of the desorbing oxygen, rendering this oxygen component undetectable.

An etched OFHC copper foil has been depth profiled with ion scattering spectrometry for its compositional analysis for typical contamination and cleaning treatments. For contamination by fingerprints the effectiveness of cleaning was found to be: etched in HNO3 > rinsed in trichloroethylene, acetone, methanol and distilled water > wiped with acetone. The depth of sodium chloride on the contaminated surface was estimated to be about 100 A.

A stainless‐steel UHV system which includes a bakable automated vacuum ultramicrobalance and a quadrupole residual gas analyzer, has been designed to permit loading samples onto the balance from a controlled environment. The 20‐g load capability of the ultramicrobalance permits using rugged hangdown suspensions. The line‐of‐sight positioning and high sensitivity of the mass filter allows direct analysis of the outgassing products and permits eliminating the complications of secondary surface reactions. A linear motion feedthrough with a bellows assembly is used to uncouple and raise part of the sample hangdown suspension from the furnace region to an access port above the furnace region. After backfilling the vacuum system with an inert gas, the access port is opened into the controlled atmosphere of a dry box. The unloading and taring of the balance is accomplished by operating a micromanipulator with rubber gloves. A vacuum bakeout oven is used for processing samples prior to storage in the dry box. Representative data concerned with water vapor adsorption and outgassing by a solder sealing glass are presented and discussed.

A questionnaire addressed to the physics department chairmen at 92 colleges and universities with accredited engineering programs in the U. S. generated 77 responses. These responses have provided hard data concerning the physics lecture and laboratory requirements at engineering schools. Most schools offer from eight to 12 credit hours of physics, which includes one or two credit hours of laboratory work. In the last four years, there has been no significant decrease or increase in these requirements.

A simple device for welding metals with high electrical and thermal conductivity is described. The use of the device, which was adapted from a commercially available carbon deposition unit, for welding 0.0127 and 0.0507‐cm‐diam Ag, Au, and Pt wires is discussed.

An UHV system has been constructed for use in conjunction with a Rodder ultramicrobalance for gravimetric studies of metal–gas reactions. Though intended specifically for the study of the early stages of uranium oxidation, the apparatus and techniques are readily adaptable to other metal–gas systems. The system is pumped by sorption, titanium sublimation, and noble‐ion pumps which avoid the need for oil diffusion pumping, thus eliminating the possibility of sample contamination by oil vapor. Provisions for in situ sputter cleaning of samples, as well as electron beam heating and infrared thermometry, have been built into the system. Gas compositions are monitored with a residual gas analyzer.

The redeposition of sputtered Au, Ag, and Cu onto glass surfaces, which are in the same plane as bombarded metal foils, has been established by ion scattering spectrometry. Sites near the sputtering center were analyzed with sensitivities of 0.0008–0.001 monolayers after neon bombardment of the foils for up to 2 h. From the data, the redeposition coverage is estimated to be from 0.0094 to 0.042 monolayers after 2 h of Ne bombardment at 1500 eV. The electric field of the incident ion beam, acting on low‐energy sputtered ions, is a likely cause of the redeposited material.

The thermal desorption of carbon dioxide from an oxygen-covered silver powder was studied from 25 ° to 150 °C by applying a nominal heating rate of 2 °C/min and measuring the mass lost with a vacuum microbalance. A maximum rate of desorption was reached at 49 °C and the desorption was completed at about 100 °C. The temperature at which the maximum rate of desorption occurred was independent of the initial coverage of carbon dioxide to within 2 °C. However, the data could not be simply explained by a fit to the first order Wigner–Polanyi desorption equation, in which it is assumed that the frequency factor (ν) and the desorption energy (E) are independent of coverage and temperature. Beyond the maximum, a slow decrease in the experimental rate of desorption, which was found in contrast to the usual sharp cutoff for a first order process, was attributed to desorbing oxygen, readsorption of carbon dioxide, or a variation of E at low coverages. Parallel studies with a residual gas analyzer showed that small q...