The workshop will be held in the Institut de Physique Nucleaire d'Orsay (IPN), France, about 30 km south of Paris.
IPN is located in the Faculty of Science of University Paris-Sud, nearby the "Orsay-Ville" station on the RER B line (from Paris, either "Saint-Remy les Chevreuse" or "Orsay-Ville" direction).
Coming from Paris, at the station "Orsay-Ville", take the tunnel under the railway. At the exit of the tunnel, take the first street on the left, rue Georges Clémenceau, and proceed up to the entrance of the campus at the end of the street (note that this entrance is closed for cars). IPN is the first building of the campus on the right. The main entrance is in the building N°100 as indicated on the detailed map below. The workshop will take place in this building, room A015 (same floor as the entrance).
The single ticket from "Paris" to "Orsay-Ville" is 4,35 €. The price of the “Origin-Destination ticket” depends on your trip. You can buy them individually or by packs of 10 (you can save 20% if you buy a pack)
Information on https://www.transilien.com/en/page-editoriale/about-individual-tickets
Information on the different RER lins can be found at: https://parisbytrain.com/wp-content/uploads/2008/05/rer.pdf,
while for metro lins inside Paris: https://en.wikipedia.org/wiki/File:Carte_M%C3%A9tro_de_Paris.svg
A focus on the RER B line can be found at: https://parisbytrain.com/wp-content/uploads/2008/06/b_jo_cdg.pdf
RER B is direct for Charle de Gaulle airport to Orsay. Note however that not all the RER B trains go to Orsay (stops of the next train are indicated at your departure station).
Other useful links: