A fast-cooling mode for blue series furnaces

Blue series top-loading furnaces are regularly used at neutron facilities to carry out experiments at up to 1700◦C. The sample temperature is controlled using the indirect resistance heating method which consists in placing the sample inside a radiating cylindrical heater made from vanadium or niobium into which a current of up to 180 A circulates. To prevent the oxydation and deterioration of the heated elements, the sample, the heater and the heat shields are in a secondary vacuum which limits very much the cooling rate. We present an automated fast-cooling technique which reduces the cool-down time by a factor of 4 to 5 without impacting the lifetime of the heated elements. This method is now routinely used at the ILL and ISIS facilities and reduces very much beam time losses.