The biggest thing wrong with DR2 was the broken field wires.
There were ~60 broken wires in 10 years, with 30,000 field wires.
The rate is thus 0.0002 per year. This small rate creates a maintenance disaster.
However, the number is so small that it is almost impossible to detect in a test chamber.
The problem was traced to deformation of the aluminum field wires in copper crimp pins.
In this chamber, about 500 wires were strung in aluminum crimp pins.
At the broken wire rate of DR2, we would expect only 0.1 breaks per year.
Wires were driven at the resonance frequency with an audio amplifier to age the crimp and evaluate the strength.
Bushing Breakdown Chamber
The second worst problem with DR2 was the bushing breakdown in sense wires.
There were ~240 "isolated shorts" for 12,000 sense wires, in 10 years, or about 0.002 per year.
Heare, we are subjecting candidate bushings to over-volatge.
Gas Test Chamber
The argon based gas mixture in DR2 had poor efficiency above 1.2 Tesla for the outer 80% of the cell.
This chamber was built to fit inside the CLEO magnet and run during CLEO operation with a cosmic trigger.
Several Helium based gas mixturers were tested with helium-propane (60:40)chosen.
Long Chamber
The long chamber had axial and stereo section for investigating performance of the readout and noise at the stereo angle change interface. This chamber was also used to test the wire tension monitor.
