426 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 64 



many electrical pulses which rattle through the electronic equipment 

 each second from other causes, this one pattern can be picked out 

 by the equipment very nicely. 



In addition to going to the electronic analysis equipment, our set of 

 pulses from the top scintillator has also been sent down a long trans- 

 mission line, wrapped back and forth inside the trailer. They take 

 10 microseconds to emerge from the other end. They are then sent to 

 an oscilloscope. The electronic equipment, having sensed the possi- 

 bility of an interesting pattern, signals to the oscilloscope when it 

 sees the second pair of pulses, and the electron beam of the cathode 

 ray tube starts to trace a line of light across the tube face. It will 

 take 20 microseconds to traverse the tube face. 



Thus, 4 microseconds later (10 for the time spent in the transmis- 

 sion line minus 6 while waiting for the neutron signal), the positron 

 pulse from the top scintillator tank emerges from the line and causes 

 the electron beam to deflect upward briefly, then return to its steady 

 sweep across the face of the tube. The amount of deflection of the 

 beam during the pulse is proportional to the energy deposited in the 

 tank, and this is known from our calibration work. Six microseconds 

 later, the neutron pulse arrives from the same top tank. It also 

 deflects the beam briefly, proportional to its amplitude. The beam 

 then completes its track across the remaining part of the tube face, 

 and it is turned off to wait for another interesting event to send it 

 on its brief trip. 



All this has occurred for those signals coming from the top tank. 

 Exactly the same has occurred for those from the center tank of 

 scintillator as well. The pulses from the center tank have passed 

 down their own transmission line and then to the oscilloscope to 

 cause another beam in the same tube to deflect. Its track lies below 

 the first beam so as not to obscure it. The bottom tank is connected 

 as well to a third transmission line and then to a third beam in the 

 tube. But no signals came from this tank in our example described 

 here, so its beam has just swept undeflected across the oscilloscope 

 face. 



During this time a 35 mm. camera loaded with 100 feet of film 

 has been watching the tube face with its shutter permanently open, 

 so that the streaks of light which appeared there are now recorded on 

 one frame of film. After the action has finished, the camera motor 

 advances the film to a fresh frame. 



Thus were the signals from the three tanks sorted out, analyzed, 

 and recorded on film whenever they occurred in a pattern which may 

 have been due to the capture of an antineutrino in the detector. Two 

 triple-beam oscilloscopes were used in parallel, as described above, 

 so that one operating at low gain could look for large pulses while 

 the other operated at higher gain to record the smaller pulses. Each 



