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 degrees 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.