Before revision: 16–42, Newnes, 2002 Gas purity The gas in the tube has to be kept pure to maintain the desired properties; even small amount of impurities can dramatically change the tube values ; .
After revision: 16–42, Newnes, 2002 Gas purity The gas in the tube has to be kept pure to maintain the desired properties even small amount of impurities can dramatically change the tube values ; .