NOVA; To the Moon; Interview with Gerald J. Wasserburg, Professor of Geology and Geophysics, Emeritus, on the John D. MacArthur chair at the California Institute of Technology, part 2 of 3

by the moon. What seemed to me the right thing was the name, the whole group of people, the lunatic asylum, the inmates are. Now you must understand there was some problem about that. I submitted the paper, got rave reviews, but they we're going to the lunatic asylum. Call the lunatic asylum because they we have to take our shoes off, be we are focusing on studies of the moon and everybody here is affected by the moon and there's even a Chinese moon maiden inside with a rabbit. What was on here? What went on in here and what went on during the holidays? It was a little bit more frantic than it is now. I think basically the lunar samples were prepared in this room. Here's one of my associates who was in their preparing the samples and Joe Brown and they were meticulously clean and

prepared, the mineral separated and then analyzed in the mass spectrometer. All these rooms are clean, they have epoxy floors in fact very clean. What about these folks who are they up there? This is the meet you popping us as you help invent the mass spectrometer that we're using. This is Lily Ray and handle the computers and this is a gift from the Chinese of the Chinese maiden with the rabbit on the moon, it's not a man on the moon. Some people have said so, yes. What's in here? Here the lunatic one spectrometer. This is the lunatic one spectrometer and design. The story of that is this instrument was designed with a specific purpose of making extremely precise, very sensitive measurements on

moon rocks and this was the instrument on which the rubinium strontium ages of the moon were established. The detail uranium-led ages of the moon established. The neutron exposure of the moons was measured on this by G Price Russ and in fact has one of the most incredible and distinguished histories including the discovery by Typhoon Lee and Dimitri Papanasas, even myself of aluminum 26 in the early solar system, which is a radioactive nuclei. It's the brightest gamma line in the universe. What did it tell us? Tell us the age of the moon. This is a device for converting neutral atoms that you've been prepared chemically into ions. It accelerates them down the flight tube and separates them like a prism. The magnet acts as effectively a prism so the particles go down here and then you can look at different mass numbers of a given element like magnesium 24, 25 and 26 are separated and not together or

strontium 87 is separated from strontium 86. By measuring these you can then calculate what the age is from the decay of rubinium 87 which is making the strontium 87. So in every case you if you say how long we've been in this room carrying out this form of videocie which we you do for a profession and I submit to is you can look at your watch but you need two clocks. You need one clock which is running and one which was synchronized went in the door and stopped and so you have to then find in the rocks these two clocks one of which is stopped and one which is running and subtract them so you measure 87 strontium 86 strontium in a running clock and that in a non-running clock and then you can calculate at the time that the rock has been sitting there. This magnificent machine is 30 years old and still produces some of the finest data in the world. Where's the magnet? Where is it? Yeah that's the magnet. That's the gap in

here. This was all built in the shops here at Caltech and we designed it. Now Dr. Westbrook you've got a little nuts when I started to lean on this machine. How come? Well because the people as you can tell from the notebook are writing in their experiments and they're putting tools down that are supposed to put clean surfaces on there but the dirt in the hallway is not interesting to have in the ion source over here since I'm not interested in analyzing dirt in the hallway I'm interested in analyzing moon rocks or something interesting. Well you try to be very careful also if the high voltage were on you might be killed. Samples are prepared in another room and located and then deposited on this

very teeny filament you see in here and these are then mounted inside of here and then sealed off with this flange and then pumped out and then heated and accelerated down to the from the ion source which this is part of through the lens which is focusing them so that's how the samples are prepared. Do you have any lunar samples in here now? Yes but they're all sealed up right now. We had to find out when the door was open somebody forgot it so in fact there

was we used to play classical music and then we made a discovery and then some airline then put this in the pipe in the sound so we had a copy of that and played that about a loom of 26 but the basic problem was to keep the level of contamination from outside sources to a minimum so that dirt was not put in this room is not been clean for almost 25 years and so the surfaces are kept with a very rigorous control and so dirt doesn't come in on shoes people don't bring in radioactive things which can contaminate things. A lead is not brought in this room and uranium is only brought in in super teeny teeny quantities so the problem is how do you keep clean you keep clean by keeping what you think is dirty and contamination means that you have to be going to contaminate with one thing you have to carry it in some jug but you want to get rid of the rest of stuff and the security thing is we had lunar rocks in here and we still have a very large source of lunar rocks in here and they were not available for

everybody else and having been involved in the case when somebody stole lunar rocks from Bill Libby at a cocktail party why I decided I did not want to be part of parts of the land okay all right okay great that's great you keep going You You

You You