Pictures Pictured here are the etch-pits of the cosmic ray track. Next to each picture is the name of the surface on which it appears. As the analysis below shows, the cosmic ray captured an electron in the glass between 1t and 1b. These same two calibration tracks can be seen in 1b which is the surface immediately adjacent to 2t. These are etch-pits formed by low energy and low charge cosmic rays coming to rest in the glass.
Bowls form some of the background in automated scanning.
Note that they appear in every picture. Because of their circular profile, they are easy to identify. Also note that the interior is nearly as bright as the surrounding surface. This is due to light reflected back to the microscope. The lighter area around the edge of the pictures here is ink used to mark the location of the track.