International Summer Research Program in Gravitational-Wave Physics:
Research Experiences for Undergraduates around the world

NIKHEF, Amsterdam
  • Probing neutron star interiors using gravitational waves:
    In 2017, a gravitational wave (GW) signal from the inspiral of two neutron stars was detected by Advanced LIGO and Virgo. This enabled us to make tentative statements about the equation of state (EOS) governing the interiors of neutron stars, which currently is poorly understood. Existing analyses try to constrain the EOS by looking at tidal effects that get imprinted upon the GW signal, telling us how deformable neutron stars are. As the detectors get upgraded, eventually the merger itself will become visible, which contains a great deal more information. An approximate post-merger waveform model is under construction with input from large-scale numerical simulations, which will be implemented in the LIGO Algorithms Library and used to analyze simulated and real binary neutron star mergers.
    Mentor: Chris van den Broeck
    Related Project 2013: "Improvements in Computational Efficiency for CBC Analysis of Advanced Gravitational Wave Detector Data"
  • Phase camera project for Advanced Virgo:
    We have been put in charge of the phase camera project for Advanced Virgo. The purpose of this device is to image the spatial phase and amplitude distribution of an optical beam over a wide range of frequencies and to monitor the evolution of these distributions over time. We have built up a clean room and a laser lab at Nikhef in preparation for this project. The student will work with us to design, construct and test a phase shifting interferometer (and possibly several other setups capable of achieving the stated objectives), and will evaluate the performance relative to a commercial CCD-based imaging device.
    Mentor: Jo van den Brand
    Related Project 2010: "Wave Front Detection for Virgo"
    Related Project 2014: "A Phase Camera for Advanced Virgo"
    Related Project 2015: "Phase camera noise hunting and characterization of AOM"
  • Newtonian noise monitoring for Advanced Virgo and Einstein Telescope:
    Newtonian noise (NN) is expected to be limiting the sensitivity of future third generation gravitational wave detectors such as the Einstein Telescope (ET) in the 2-20 Hz frequency band. Detectors cannot be shielded from such a noise source consisting of gravitational fluctuating forces, originated from seismic and atmospheric induced changes in the mass density around the interferometer, acting directly on the suspended mirrors. Strategies have been elaborated to subtract the NN effect from the interferometer output data stream. All of them are based on the reconstruction of the NN forces acting on the suspended mirrors achieved by mapping accurately the seismic field in the surrounding of the test masses by means of large arrays of seismic sensors. Advanced Virgo, a second generation detector, will not be limited by NN in typical seismic noise conditions; nevertheless it is expected that, in high seismic noise conditions (bad weather), the NN could raise above all other noise sources and be observable in the gravitational wave signal channel. Nikhef is preparing a network of low noise seismic sensors to be deployed around Advanced Virgo test masses to observe, for the first time, the effect of NN on a gravitational wave detector, and then implement and evaluate the mentioned NN subtraction techniques. A first short term explorative network survey of the site was made last summer and the collected data will assist the baseline design of the permanent network to be installed soon at Virgo. The student will work with us analyzing the data from on-field tests and studying the network size and geometrical distribution which is optimal for the Advanced Virgo site. This latter is directly related to the seismic properties of the detector site.
    Towards the Einstein Telescope, Nikhef is also developing advanced ultra-low noise seismic sensors, based on proprietary MEMS technology, that can be batch processed and produced in the large number (thousands) required to realize the NN subtraction in ET. Fully functional MEMS seismic sensors have been processed and they are undergoing extensive testing. Alternatively to the data analysis project, the student can work in our lab in the experimental characterization of the micro mechanical devices.
    Mentor: Alessandro Bertolini
  • NIKHEF Project 2011: "Investigating Control Strategies for the Advanced VIRGO EIB IP using SimMechanics"
  • NIKHEF Project 2012: "ADC Noise Reduction and Characterization of a Compact Michelson Interferometer"

Past IREU Projects
Other Prior Projects