Type of contract
Traineeship contract for a period of 2 months within the EGO Optics laboratory in the Interferometer Technology Department, funded by the EGO Consortium.


The Virgo interferometer is the most sensitive gravitational-wave detector in Europe. It was realized in partnership between the French and Italian institutes CNRS and INFN. Today, there are more than 700 Members in the Virgo Collaboration, representing 129 Institutions in 16 different countries. After the successful observation run of 2019-2020 [1], a deep modification of the interferometer started in order to give birth to a new generation detector called Advanced Virgo Plus (AdV+), In this new version we will use improved mirrors, higher laser power and signal recycling techniques in order to increase the sensitivity by one order of magnitude. The installation is finished and the instrument is now being commissioned to become fully operative by the end of 2022.

The EGO consortium (European Gravitational Observatory), located in Cascina, near Pisa –Italy, hosts the Virgo detector and has been deeply involved in the design and construction of Advanced Virgo. In particular, the EGO optics group is in charge of the injection system (INJ) and is heavily involved in the Auxiliary Lasers System (ALS) for AdV+.

In these subsystems, quadrant photodiodes (QPDs) are used to monitor the position of the beam and being able to implement retroactive loops able to keep the alignment of the beam. Those loops are called Automatic Alignment loop (AA). In fact, the QPDs are made of four photo-sensitive elements, which can detect the asymmetry of the wavefront and give at the same time information as a normal photodiode (by summing the signal of the 4 quadrants). In this way, while a TEM 00 (gaussian) mode will have the same effect on the 4 quadrants, a TEM 01/10 mode, generated by a misalignment of an AA, will be detected from a QPD thanks to the asymmetry of its wavefront.

For the reliability of the automatic alignment control it is important to have a methodology which allows to identify the presence of a stray beam on the QPD. Simulations have already been made and published in an internal Virgo note. From an experimental point of view, it essentially consists of a beam scan on the QPD, acting with the centering actuators, allowing to measure the normalized asymmetry and thanks to a fit, being able to identify the secondary beam.

In this internship we propose to realize the experimental set up and test the procedure to determine the presence of a stray beam and evaluate the beam size.

Applicants should be in their last years of study in optics or physics. The work will be at a level of Bachelor thesis. English required.
Good attitude to experimental work is mandatory, familiarity with control systems and related hardware/software will be an asset.

Place of work
EGO – European Gravitational Observatory – via E. Amaldi n.5 cap 56021 Loc. S. Stefano a Macerata – Cascina (Pisa) ITALY.
Considering the lack of public means of transport to reach the site, it is preferable having a car. EGO also offers a taxi shuttle from Pisa to EGO site at fixed times.

How to apply?
Interested candidates are invited to fill in the Internship Application Form and send it, together with the CV, to internships@ego-gw.it

Further information
For the whole duration of the traineeship, EGO will pay a gross monthly wage of 500,00 euro and offer the lunch service at its canteen during working days to the student.

Privacy and policy
Controller: European Gravitational Observatory – email: ego-gw@pec.it
Responsible for data – email: privacy@ego-gw.it
Under Article 13 of UE Regulation (EU) 2016/79 of the European Parliament and of the Council, required personal data will be exclusively collected and treated for purposes strictly connected to the selection procedure also with the use of computerized procedures, according to current law and regulations concerning the implementation of this kind of activity.
Providing such data to EGO is necessary for the evaluation of participation requirements and of the holding of titles: failure to provide these data may compromise such evaluation.
Data will be kept only for the period required by the selection, evaluation and audit procedures.
EGO guarantees each person the right of access to personal data, as well as the rectification, or erasure or restriction of them, as well as the right to object to their processing; such requests shall be addressed to privacy@ego-gw.it

Closing date for applications
Until position is filled.

Camilla de Rossi, PhD
Optics group
Email: camilla.derossi@ego-gw.it
Phone: +39 050 752544