The dinner on the 25th of May will be held at the Hotel Jakarta (Javakade 766).
From Nikhef it takes about 30 minutes to get there by public transport. An option is to take the train from the station 'Amsterdam Science Park' (6 minute walk from Nikhef) to Amsterdam Centraal. On the North-East Side of the Amsterdam Centraal station you can find tram 26 (going every 10 minutes), which brings you in 5 minutes to 'Kattenburgerstraat'. From this station it is only a 5 minute walk to the Hotel Jakarta.
Individual travel plans can also be checked here.