Vacuum gage system for radiation environment

Hot-cathode ionization gages used to measure high-vacuum pressures are subject to error when ionizing radiation is present. Because this radiation creates additional ions, a second ion gage is mounted near the pressure-measuring gage to detect and measure the radiation induced error

Estimating sensitivity of vacuum gages

Gage sensitivity for a particular gas is estimated using the known performance of the gage with a reference gas /nitrogen/ and employing several empirical rules which have usable accuracy. Relative gage sensitivities have been estimated for over 100 gases and vapors

NO sub X destruction by CO in NO sub X to NO converters of chemiluminescent NO analyzers

An instrument modification for chemiluminescent NO - NOx analyzers was developed which minimizes the NOx destruction in the NOx to NO converters of NO analyzers due to high concentrations of CO. This mechanism causes the NO analyzers to indicate incorrect NOx concentrations when the analyzers are operated in the NOx analysis mode. The modification is applicable to analyzers in which the detection chamber is evacuated

Empirical Observations on the Sensitivity of Hot Cathode Ionization Type Vacuum Gages

A study of empirical methods of predicting tile relative sensitivities of hot cathode ionization gages is presented. Using previously published gage sensitivities, several rules for predicting relative sensitivity are tested. The relative sensitivity to different gases is shown to be invariant with gage type, in the linear range of gage operation. The total ionization cross section, molecular and molar polarizability, and refractive index are demonstrated to be useful parameters for predicting relative gage sensitivity. Using data from the literature, the probable error of predictions of relative gage sensitivity based on these molecular properties is found to be about 10 percent. A comprehensive table of predicted relative sensitivities, based on empirical methods, is presented

Nonsteady flow-direction measurement

Nonsteady flow probe uses miniature pressure transducers mounted within probe support very close to tube inlets. Response speed depends on internal volume between tube inlet and pressure transducer location

Integrated exhaust gas analysis system for aircraft turbine engine component testing

An integrated exhaust gas analysis system was designed and installed in the hot-section facility at the Lewis Research Center. The system is designed to operate either manually or automatically and also to be operated from a remote station. The system measures oxygen, water vapor, total hydrocarbons, carbon monoxide, carbon dioxide, and oxides of nitrogen. Two microprocessors control the system and the analyzers, collect data and process them into engineering units, and present the data to the facility computers and the system operator. Within the design of this system there are innovative concepts and procedures that are of general interest and application to other gas analysis tasks

An integrated exhaust gas analysis system with self-contained data processing and automatic calibration

An integrated gas analysis system designed to operate in automatic, semiautomatic, and manual modes from a remote control panel is described. The system measures the carbon monoxide, oxygen, water vapor, total hydrocarbons, carbon dioxide, and oxides of nitrogen. A pull through design provides increased reliability and eliminates the need for manual flow rate adjustment and pressure correction. The system contains two microprocessors to range the analyzers, calibrate the system, process the raw data to units of concentration, and provides information to the facility research computer and to the operator through terminal and the control panels. After initial setup, the system operates for several hours without significant operator attention

Apparatus for electrical measurements of thin films from 77 to 1000 K

A novel method of mounting thin samples for electrical measurements is described. A vacuum chuck holds a mounting plate, which, in turn, holds the sample. Contacts on the mounting plate establish electrical connection to the sample. The attachment of wires directly to the samples is unnecessary. Measurements can be made at temperatures from 77 to 1000 K. As an application of the apparatus, resistivity and Hall measurements of a thin silicon carbide sample are presented

Visual detection of point source targets

Visual detection of point source targets in simulated star field backgroun

On the stability of the boundary of the geomagnetic field

Dynamic response determination of geomagnetic field boundary in steady solar wind to small initial disturbance from equilibrium configuratio