Mercury vapor reference

A mercury vapor reference configured to deliver a reference mercury vapor for testing a mercury vapor analyzer, the mercury vapor reference comprising:

• a mercury vapor source configured to produce mercury vapor;
• a variable volume dilution chamber configured to selectively receive and dispense the mercury vapor from the mercury vapor source and a dilution gas, wherein the mercury vapor from the mercury vapor source is diluted with the dilution gas in the variable volume dilution chamber to produce a diluted mercury vapor prior to dispensing;
• a mixing chamber having an airflow path and a mercury vapor inlet port configured to receive the diluted mercury vapor from the variable volume dilution chamber and introduce the received diluted mercury vapor to the mixing chamber;
• and
• a controller coupled to the variable volume dilution chamber, the controller configured to control the variable volume dilution chamber to receive and dispense the mercury vapor and the dilution gas to produce the diluted mercury vapor, wherein the reference mercury vapor is produced in the airflow path when the diluted mercury vapor is introduced to the airflow path via the inlet port.