A preliminary run in September 1986was intended only to test the hardware, but it went so well that some of the experiments, particularly the streamer chamber belonging to the "NA35 Collaboration' (59 physicists from 14 institutions in eight countries), were able to take data.
The multiplicity of tracks in theNA35 streamer chamber pictures is quite large by the usual particlephysics standards, and the quality is different from previous nuclear collisions, as Schroeder indicates, comparing an NA35 image with one of a collision at much lower energy in LBL's Bevalac accelerator.
In the streamer chamber pictures, the indication of lambda particles is a "vee,' a vertex from which two tracks curve away in opposite directions.
The scanners sit in a half-darkenedroom over light tables on which the films from the streamer chamber cameras are projected frame by frame.
The blocks give a side view of an event, as the streamer chamber does, but the stacks, which were designed specifically to resolve tracks that are close together, give a head-on view.
Pugh and John Harris of LBL describe the other originally proposed experiment, often referred to as the streamer chamber experiment.
A streamer chamber is a space filled with gas and bounded by electrodes.
Another derivative of the spook business is charge-coupled devices (CCDs), light sensors that Harris is building into a monitoring system to watch the streamer chamber's operation.
The CCDs will give a minute-to-minute check on how well the streamer chamber is doing.
Photo: Streamer chamber shows particle tracks as bright lines like these.