CERN LHC - HL-LHC - High Luminosity Large Hadron Collider (2016-2024)
Project coordinators at DAI:
Dariusz Bocian, Jacek Świerblewski
E-mail: Dariusz.Bocian@ifj.edu.pl, Jacek.Swierblewski@ifj.edu.pl
DAI employees involved in the project:
Engineers: Michał Duda, Artur Krawczyk, Waldemar Maciocha, Bogusław Prochal, Adrian Szeliga, Marcin Wartak, Agnieszka Zwoźniak
Technicians:
Description:
The objective of the High Luminosity Large Hadron Collider project is to increase luminosity by a factor of 10 beyond the LHC’s design value. Luminosity is an important indicator of the performance of the accelerator: it is proportional to the number of collisions that occur in a given amount of time. The higher the luminosity, the more data the experiments can gather enabling them to observe rare processes.
The HL-LHC which should be operational by 2025, will allow precise studies of the new particles observed at the LHC, such as the Higgs boson. Superconducting crab cavities will be used to increase the luminosity of the operating collider.
Within the framework of the HiLumi-LHC project engineers from DAI carry out the following tasks:
Participation in the tests of superconducting magnets
To reach increase the luminosity of LHC by factor 10 a lot of its focusing and bending magnets need to be upgraded and redesigned. This task is focused on testing of new models and prototypes of superconducting magnets and planning of testing program for future Inner Triplet String (IT String) installation.
Measurements and analysis of critical currents of Nb3Sn superconductors.
The task let us qualify new superconducting wires and let us confirm correctness of the production process of new magnets.
Participation in the assembly and tests of the crab cavities.
The crab cavities are the main components of the HL-LHC cryomodules. First type is DQW (Double Quarter Wave) crab cavity, Fig.1.
Fig.1 DQW crab cavity.
After manufacturing and degreasing the resonance cavities are cleaned in a special cabinet equipped with a high pressure rinsing system (HPR system), Fig.2. Next they are transferred directly to the clean room to be dried with a flow of clean air, Fig.2. Then the cavities are being equipped with subassemblies e.g. RF antennas inside the clean room of the ISO4 class, Fig.3. The fully equipped and closed cavities are moved from the clean room to the installation area. There they are fixed to the insert and connected to the vacuum line in clean conditions. After pumping down a mass scan analysis is performed by means of the residual gas analyzer (RGA device). It is also necessary to perform leak check using dedicated equipment.
Fig.2 A cavity inside: the cabinet equipped with HPR system (left) and the clean room (right).
Fig.3 Assembly of the RF equipment and the other components inside the clean room.
Previously prepared cavity is installed into a dedicated insert, equipped with temperature and magnetic field sensors, Fig.4. Afterwards the cavity is transported into a cryostat for performing a test, Fig.5.
Fig.4 Cavity installed in the insert.
Fig.5 Transport of the insert with the cavity to the vertical cryostat.
Next stage of the assembly process is installation of the magnetic shield, Fig.6a and the helium tank, Fig.6b.
Fig. 6a Cavity equipped with magnetic shield.
Fig.6b Cavity installed inside a helium tank.
Participation in cryomodule assembly.
After performing of 2K tests, two cavities are transported to the cleanroom for construction of the cavity string, Fig.7.
Fig.7 Two cavities inside the cleanroom during connection of the cavity string.
After leak check of previously created cavity string it is removed from the cleanroom and next stages of the cryomodule assembly process start. After each essential assembly stage the RF tests are performed to check whether the cavity parameters have not changed, Fig.8.
Fig.8 RF measurements during the cryomodule assembly process.
During assembly the cryomodule is being equipped with many components as cryogenic lines, frequency tuning system, Fig.9, thermal shield, MLI (Multi-Layer Insulation) thermal insulation, Fig.10, cavity alignment system, temperature and magnetic field sensors, heaters, He level gauges, RF cables and many more.
Fig.9 Assembly of a frequency tuning system.
Fig.10 MLI insulation and thermal shield.
Next, the whole assembly after precise survey measurements and alignment is installed inside the vacuum vessel equipped with warm magnetic shield. Then the cryomodule is equipped with cryogenic equipment, frequency regulation systems and many others. The last stage is performing of a leak check, survey measurements, RF measurements and connection of all necessary cables and sensors, Fig.11.
Fig.11 The crab cryomodule during the final assembly stage.
The completed cryomodule is transported into the test-stand, Fig.12 for the further cryogenic, vacuum and RF tests before final installation in the SPS (The Super Proton Synchrotron) tunnel.
Fig.12 The crab cryomodule at the test-stand.
Materials
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Last modification date: 18/2/2020