LN2 Thermal cycling of 11T short coil #107 Jan Petrik, Arnaud Foussat - TE/MS-LMF Laetitia Dufay-Chanat, Sebastien Prunet, Johan Bremer - TE/CRG-CI EDMS:2150812

Introduction Goal is to evaluate effect of temperature cycling on Impregnated Quench heater insulation to coil resistance First contact with TE/CRG-CI on 11th December First cycle on 5th February 10 cycles by 15th April 24h cool-down cycle One cycle per week, limited by warm up power Controlled ΔT during magnet cool-down 50K Average 78K Maximum Insulation resistance measurement – 660V, 2mins

Test Setup A 200 mm diameter cryostat with a cartridge heater is connected to 600 l Nitrogen dewar and to the “swimming pool” in which the magnet is placed; During the cool down, the temperature of the gas entering the set-up is regulated to a temperature 100 K lower then the warmest point measured in the magnet set-up; During the warm-up, this gas is regulated to a temperature 100 K colder then the coldest point measured in the magnet set-up;

Temperature Profile

-> humidity build up Results Different temperature (around 0C) Out of LN2, different warm up procedure -> humidity build up Other tests are for quality control. Results noted into individual excel files, checked and then stored in EDMS Jan Petrik, 15/05/2019 5

Results Other tests are for quality control. Results noted into individual excel files, checked and then stored in EDMS Jan Petrik, 15/05/2019 6

Results Other tests are for quality control. Results noted into individual excel files, checked and then stored in EDMS Jan Petrik, 15/05/2019 7

Conclusions Humidity and temperature influenced a lot the QH insulation resistance. Is this influence by humidity developed through insulation cracks? Flush with room temperature nitrogen helps #121R has shown biggest variance during the testing due of humidity. No increase of leakage current observed during the thermal cycle campaign break down voltage was not tested Jan Petrik, 15/05/2019