For the purposes of this article, the term “working measurement standard” refers to a measuring instrument that is calibrated relative to a reference measurement standard (which is also a measuring instrument). The working and reference measurement standards each consist of an ion chamber and an electrometer that are combined as a single measurement system. | For the purposes of this article, the term “working measurement standard” refers to a measuring instrument that is calibrated relative to a reference measurement standard (which is also a measuring instrument). The working and reference measurement standards each consist of an ion chamber and an electrometer that are combined as a single measurement system. |