Dunning closely followed the work of Ernest Lawrence on the cyclotron. Dunning wanted a more powerful neutron source and the cyclotron appeared as an attractive tool to achieve this end. Government funding was not available for such projects in those days, and university budgets were tight. Nonetheless, during 1935 and 1936 he was able construct a cyclotron using many salvaged parts to reduce costs and funding from industrial and private donations. It was announced in 2007 that Columbia University has decided to junk a 70-year-old atom smasher, which is the nation's oldest artefact of the nuclear era. After being decommissioned in 1965, the machine sat in the basement of Pupin Hall, home of Columbia's physics department. It was scrapped in 2008, although some components are in the Smithsonian Institution in Washington, DC.