Testing of Low-Density Hexaboards for the CMS HGCAL Detector Upgrade*

In the near future, the CMS Experiment at CERN's Large Hadron Collider will incorporate the High Granularity Endcap Calorimeter (HGCAL) upgrade to its detector system as part of the High-Luminosity Era upgrade. HGCAL will be constructed modularly from many hexagonal-shaped readout boards (hexaboards) attached to silicon sensors.

To perform quality control on the tens of thousands of hexaboads required, the University of Alabama has created an interactive testing suite to streamline the overall process. Using this suite, the University of Alabama has tested 125 low-density full hexaboards (the most-used type) on-site, both under regular conditions and with an applied bias voltage of 1kV. This testing suite has been deployed at CERN to test partial hexaboards, as well as at Fermilab to test assembled modules.

The University of Alabama is also intending to perform testing at-temperature. In addition to creating a dry-air setup to prevent deposition of ice on boards, we have adapted the testing suite mentioned above to work with hardware multiplexers to optimize the number of boards that can be tested in-parallel. This will effectively triple the number of boards that may be tested in any given cold-cycle.