The yoke of the PANDA Solenoid Magnet was fully assembled at the steel construction company SET in Novosibirsk.The final tests of doors were done on December 25, 2020 - a nice Christmas present for PANDA.
The assembly of the yoke octants is aided by a star shaped installation tool. After its removal the octants stayed in place with minimal deviation. All parts are surveyed with a laser tracker employing fixed fiducial marks even during the assembly process which facilitates the whole operation providing much better precision. No mechanical stoppers are used, as their precision would be too low.
The four doors, two downstream and two upstream, are bolted to the yoke in their closed position. Before opening the doors the bolts are unfastened and the doors are lowered to the sliding rails resting then on heavy weight rollers. The 22t door wings were opened sliding on the rollers with a friction of only about 0.5% - two persons were able to move one wing with a simple manual winch. In the final configuration BINP will equip the doors with hydraulic jacks and actuators, which were not part of the deliverables of SET. Documentation for the completion of the factory acceptance procedure is under way.
The yoke was again disassembled and the parts will be transported to BINP were they will be stored in two halls waiting for the assembly of the complete magnet for testing and field measurements at BINP. The octants and downstream doors will be kept in a climate controlled hall to avoid any unwanted corrosion within the gaps. The outer frame can be stored at simpler conditions.
Currently the cryostat of the superconducting solenoid is in production. At the same time the production of the superconducting wire is in preparation. The assembly of the entire magnet at BINP will take place next year and allow first tests and finally a complete field mapping. For this operation the cryogenic plant of the KEDR magnet at BINP will be employed to provide the necessary supply of liquid Helium for refrigeration.
