Joris van Heijningen

Research scientist


Centre for Cosmology, Particle Physics and Phenomenology - CP3
Université catholique de Louvain
2, Chemin du Cyclotron - Box L7.01.05
B-1348 Louvain-la-Neuve

+32 10 473215


UCL member card
People responsibilities
Francesca Badaracco
My research focuses on modern control strategies for the Einstein Telescope mirror suspensions and on a cryogenic inertial sensor. I am also interested in the active noise mitigation related to the gravity fluctuations which affect both the current 2nd generation detectors as well as the future 3rd generation detectors (the so-called Newtonian noise).
Research directions:
Cosmology and General Relativity
Data analysis in HEP and GW experiments
Research and development of new detectors

Experiments and collaborations:

Active projects
E-TEST - Cryogenic inertial sensor development
Giacomo Bruno, Krzysztof Piotrzkowski, Joris van Heijningen

On Feb 1, 2020 the R&D EU Interreg project E-TEST officially started. It involves 11 institutes from Belgium, Germany and Netherlands and will carry on crucial detector developments for the Einstein Telescope (ET) - a 3rd generation antenna of gravitational waves, related mostly to cryogenic operations of large mass mirrors and their suspensions, ultra-precise metrology and sensing, as well as to advanced geological studies in the region (the ET is a deep-underground detector). The CP3 group is a partner in this project and is working on work package 1 : "Ultra-cold vibration control" and in particular on a cryogenic superconducting inertial sensor.

Gravitational wave signals below a frequency of about 10 Hz are obscured by thermal noise in current detectors. Because temperature is the vibration of atoms in some respect, making the distance measurement between the mirror surfaces more challenging, the mirrors of future detectors will need to be cooled down to temperatures around 10 K. We need to control the motion of some of the cold objects, for which we develop inertial sensors that can survive this harsh environment.

CP3 members collaborate mostly with RWTH Aachen (they are preparing a cryostat where we will test the sensor), KUL (we are collaborating to develop cryogenic readout electronics for the sensor) and ULiège (we align our sensor efforts).

External collaborators: C. Collette (Liege), S. Hild (Maastricht), A. Bertolini (Nikhef), A. Gatto (KULeuven) and E-TEST collaboration.
ETpathfinder - Bench top suspension design and fabrication
Giacomo Bruno, Nicolas Szilasi, Joris van Heijningen

The ETpathfinder is an R&D infrastructure for testing and prototyping innovative concepts and enabling technologies for the Einstein Telescope, the European concept for a new class of future gravitational wave observatories. ETpathfinder is funded by the interreg program of the EU. The ETpathfinder project broadly consists of six vacuum towers. Four towers are cryogenic and hold suspensions for the mirrors (or test masses) of the experiment. Two towers are operated at room temperature. They hold suspensions for optical tables which hold smaller optics that prepare the beams to be shot into both arms (mode cleaning, frequency stabilisation etc.) and hold the beamsplitters and detection optics.

Many of these optics are suspended individually with small bench top suspensions so they can be steered and additionally seismically isolated. This project concerns the design, prototyping and partial fabrication of >10 suspensions of order 75cm high.

External collaborators: S. Hild (Maastricht), A. Bertolini (Nikhef), Conor Mow-Lowry (Nikhef), Ken Strain (and other LIGO HRTS designers) and ETpathfinder collaboration.
Virgo - instrumentation - mode matching with phase cameras
Joris van Heijningen

A gravitational wave detector consists of many coupled optical cavities, the shortest being centimeter scale with sub-millimeter beams and the longest being several kilometers long with several centimeter size beams. When an input beam’s shape is not matched to the cavity eigenmode (the preferred beam shape of the cavity), we speak of mode mismatch (MM). MM is a source of optical loss from the fundamental mode, shown in the top figure, into cylindrical higher order modes (HOMs) of which an example is shown in the bottom figure. Minimising optical losses in a gravitational wave detector is important if techniques such as squeezed light injection are to be more fruitful. At the moment, no gravitational wave detector has an automated way to control MM. We investigate error signal generation by detection of the cylindrical HOMs. These signals then serve as input for control of MM a coupled cavity set-up.

External collaborators: Nikhef.

Non-active projects
Publications in CP3
All my publications on Inspire