The scintillators and photomultiplier tubes used in CROP, SALTA, & WALTA were recovered from the CASA experiment. CASA ran during the 1980's, and was the largerst airshower array built at the time. By the late 90's, the project was shut down, its researchers had moved on to other projects (most notably, the Pierre Auger array, under construction in Argentina). The quipment was sitting in the Utah desert, with the Army threatening to bulldoze it into a landfill.
A group of folks went out
to the Dugway proving grounds and collected about 2000 of the
60 cm x 60 cm square scintillator panels. The PMT's were glued
to the center of the panels, and were removed by brute force.
The workers wore protective suits and respirators to protect against
Hanta virus contamination. All the recovered equipment went into
storage for at least 6 months, to render the Hanta virus inactive.
An article from the local ASPEN, Colorado newspaper about the project : summer 2001
Step 1 : Unwrapping and polishing the plastic scintillator panels
Step 2 : Cleaning the PMTs & glueing them to the scintillator panels
Step 3 : Wrapping & sealing the scintillator panels to eliminate light leaks
Step 4 : Testing the finished detectors in a multitude of ways
Text summaries of our method of building a PMT/scintillator coincidence counter
1) testing for light leaks in the sealed scintillator/PMT assembly
2) setting operating voltage thresholds for counted signals
3) determining efficiency of detectors & setting PMT operating voltages
A
one-page text summary of ideas for student activities and experiments
using this equipment