On December 2nd, 2024 at 11.00 am the seminar titled "Estimation of heat load for CERN detectors" will take place at DEIB Conference Room "Emilio Gatti" (Building 20).

In the next upgrade of the CERN Large Hadron Collider detectors (Atlas and CMS) will require cooling capacity of up to 500 kW and accurate, stable temperature control. The cooling system uses CO2 in an evaporative cooling scheme that allows the control to be remote from the experimental chamber: the temperature is controlled by controlling the pressure in the two-phase fluid return from the detector.

The seminar will discuss the problem that the detector heat load is not available to the refrigeration plant control system. Large changes in detector heat load cause changes in the accumulator pressure until they are regulated out. Because of long transfer lines and limited plant dynamic performance, estimating the detector load signal and using this as a disturbance feed-forward will improve the plant performance. The detector load is estimated from the differential pressure in the two-phase return line and this is used as an input into a state estimator built around a simplified model of the detector, the transfer lines and the CO2 accumulator. The goal is to implement the state estimator within the limited capability of the PLC hardware for on-line use in the refrigeration plant control system.

Prof. Boje has undertaken research and consulting work in the field of control systems, quantitative feedback design, system identification, state estimation, and marine and power line robotics. This work has led to publication of around 100 papers in journals and conferences, two book chapters, and four patents. Prof. Boje has industrial experience in the biotechnology, process instrumentation and control, paper and pulp, defence, mining and electrical power (generation and transmission) industries. He has presented seminars and short courses in industry and at universities, both nationally and internationally. He was the international programme committee co-chair of the 2014 International Federation of Automatic Control (IFAC) World Congress and was a member of IFAC’s Technical Board (2014-2017).

Prof. Boje is a registered professional engineer in South Africa, a Fellow of the SA Academy of Engineering and a Member of the IEEE. He has held various positions within the university system including serving as a Deputy Dean and as a Head of Department.