Leakage tests on the EURATOM LCT coil

The acceptance tests at ambient temperature on the superconducting LCT coil, which was developed and manufactured by Siemens, were successful. The size and complexity of the coil imposed high demands on in-process quality control. The helium leakage tests and integrity of the test procedures were particularly important. Leaks were detected at an early stage by means of inspection and test plans and were repaired at no great expense. Unsuitable components were detected by routine tests on critical parts, such as belows, current feed-throughs and potential separators under simulated operating conditions (cycles up to 4 K and 24 bar). The procedure for checking for helium leaks was selected such that the permissible leak rate could be proved within the minimum possible time. 500 m hollow conductors were tested using a specially developed procedure. Over 500 individual inspections and tests were performed using more than 20 different test set-ups. (orig.)