MIT Department of Electrical Engineering & Computer Science

MIT's Building 20: The Magical Incubator Story, Anecdote, or Reminiscence

A Dropped Wrench Brought Down the Wall

Dean S. Edmonds, Jr.

I remember when Dick Daley was doing his thesis experiment in molecular beams with one of the long, unwieldy cast brass vacuum systems we had in the lab in those days (1957). All power leads came down from the overhead, and one day Dick was working up there and dropped a wrench. By mischance it stuck and broke an ion gauge plugged into the source chamber at one end of the apparatus, which immediately came up to atmospheric pressure. This took out the partition between the source chamber and the rest of the system , and the shock wave proceeded down the vacuum can taking out magnets, slits, wave guide, and other iron mongery on its way. The combined mass was too much for the flange at the apparatus end, which gave way, turning the vacuum can into a medieval cannon vomiting forth a load of grape shot. The apparatus was pointed at the wall separating it from the B corridor, and I just happened to be walking by when suddenly the wall collapsed and this confused jumble of scrap metal vomited forth into the corridor. It was an amazing sight, but we were all too busy comforting poor Dick, who faced months of rebuilding, to worry about those who by good fortune, were not in the direct line of fire.