Apparatus and method for controlling an atomic emission spectrometer

A controller 316 and method for establishing safe operation of an atomic emission spectrometer AES (spark, optical emission spectrometer). At least one test parameter is measured, indicative of the arrangement of a sample on a holder 102, selected from a gas pressure in a chamber 110 housing an electrode 112, and a displacement of part of the sample holder 102. Each test parameter is compared to target values, and the electrode 112 is disabled if parameters are not within a target range, and therefore the sample not correctly arranged or secure. The electrode 112 may be disabled by a switch 322 which regulates a high-voltage current. A lamp may provide a visual indicator when the electrode is energised. The displacement may be an angular displacement of a clamping element 106, which secures the sample to a receiver 104 of holder 102. The method may be repeated at time intervals.