Buse , B . , Kearns , S . , Clapham , C . , & Hawley , D . ( 2016 ) . Decontamination in Electron

4 A prototype Peltier thermoelectric cooling unit has been constructed to cool a cold finger on an 5 electron microprobe. The Peltier unit was tested at 15W and 96W, achieving cold finger 6 temperatures of -10°C and -27°C respectively. The Peltier unit did not adversely affect the analytical 7 stability of the instrument. Heat conduction between the Peltier unit mounted outside the vacuum 8 and the cold finger was found to be very efficient. Under Peltier-cooling, the vacuum improvement 9 associated with water-vapour deposition is not achieved; this has the advantage of avoiding the 10 severe degradation of the vacuum observed when warming up a cold finger from liquid nitrogen 11 temperatures. Carbon contamination rates reduce as cooling commences; by -27°C contamination 12 rates were found to be comparable to liquid nitrogen cooled devices. Peltier cooling therefore 13 provides a viable alternative to liquid nitrogen-cooled cold fingers, with few of their associated 14 disadvantages. 15