I did my first postdoc at Brookhaven National Laboratory in Long Island, New York, from 2006 to 2009. I worked as a part of the NSLS-II design team. I started the position with Johan Bentsson as my supervisor. Later, after some disagreements, Sam Krinsky became my supervisor. With Johan, I learned how to use the Tracy particle tracking code and I did dynamic aperture and momentum aperture calculations.