A Facility to Produce Uniform Space Charge for Evaluating Ion Measuring Instruments

摘要

A low-speed wind tunnel containing space charge has been constructed and evaluated. The facility is used for testing the performance of ion counters and net space charge measuring devices. Depending on location within the system, space charge densities range from 2 -7 x 10 to the minus 8 power C/cu m. The space charge density is spatially uniform within plus or minus 5% over more than 90% of the cross sectional area of the test volume, but decreases by approximately 20% between two positions separated by 1 m. Ion densities achieved in this system are comparable to those found near high voltage dc transmission lines but are free from the accompanying large electric fields.