Facility
During LS1 a new irradiation facility, combining a proton irradiation facility and a mixed field facility, has installed in the old DIRAC location of the East-Hall. Such an irradiation facility at CERN is necessary to validate electronics systems to be installed in radiation areas (CERN accelerator chain) as well as to allow for a detailed development of individual electronics components for CERN accelerators (R2E), and to test and validate detectors for the experiments (LHC and others).
In the mixed field facility (CHARM) the beam impinges on a target, which produces a high-radiation field around it. Four mobile shielding plates allow modulating the radiation field in a calibrated way to reproduce the field that objects (e.g. electronics cards, crates of even racks) would receive at specific locations inside the LHC tunnel, adjacent shielded areas or its injector chain. Additional testing stations can be easily configured which are then representative for space, aeronautic and surface applications. Typically a year of exposure in the LHC could be simulated in only a few days in this facility. The size of the available test area is such that also larger objects can be irradiated and ultimately even objects in operation with complex services (power, cooling, etc.) be connected.
The protons that have traversed the upstream proton irradiation area will impinge on a target that generates an intense radiation field. The intensity of the radiation field can be modulated by the choice of target head, e.g. two massive ones (Al or Cu) or one with holes, such that only part of the primary beam interacts in the target. The yield of the massive Al target is about 2.5 times smaller than for the massive Cu target, whereas the Aluminium target with holes gives an additional reduction by a factor of 4 (thus a factor 10 in total). Four mobile shielding plates allow further modulation of the field. The various field configurations are pre-calculated by FLUKA simulations and will be further calibrated by measurement during the commissioning of the facility.
During the on-going facility design and construction, a lot of attention has been paid to the minimisation of the radiation doses to the personnel that has to intervene in this facility. The roof and walls of the facility will be partly covered with marble, thus reducing the induced activity. Before each access the mobile shielding plates will be moved into a shielded position and the target itself moved out of the area into the target storage zone and hidden behind sliding marble doors. After irradiation, activated objects can be stored temporarily for cool-down in a dedicated buffer area.
Two dedicated conveyer systems allow moving samples into or out of the test position. The test position for small samples will be used for in-beam and high-dose measurements. The samples will be mounted in a standardized test box of maximum size 300x300x200 mm3 and maximum weight 10 kg. The conveyor will bring the test box into its location and then returns to its start location. In addition the system allows automatic and manual positioning of an embedded camera for visual observation inside the target chamber. This allows not only remote inspection in case of problems inside the chamber (e.g. blocked target or mobile shielding), but also monitoring of a second conveyor for larger objects.
For larger and/or heavier objects a second conveyer will be installed, which follows a pre-defined path in order to bring equipment to the respective calibrated test locations. Possible tests will use e.g. standardized 19” racks with a reduced height, allowing a common interface with cables coming from the top. The maximum rack dimensions are 1000x1000mm with a height of up to 2m and a maximum weight of 1000 kg. For the cables, a 3D motion cable holder chain will be fixed to a rail on top of the room
