  We present measurements of temperature and magnetic field dependence of the
critical current and excess current in a carbon nanotube Josephson quantum dot
junction. The junction is fabricated in a controlled environment which allows
for extraction of the full critical current. The measurements are performed in
the open quantum dot regime, and fitted to theory with good qualitative
agreement. We also show how to extract level spacing, level broadening, and
charging energy of an open quantum dot from a bias spectroscopy plot.
