Three identical sets of chambers have been built (figure 41). Since repair work need the chamber fully opened in clean room. Moisture can be quickly absorbed into G10 boards and epoxy after long time conditioning by gas into super dry condition. On site quick repair is impossible. Thus three chambers in working condition ensure a quick switch if one set develops problems during the experiment.
Currently, one set of chamber is under conditioning by flowing 50/50 premixed Ar/Ethane gas. The voltage is gradually increased during the conditioning. The other two chambers are under dry nitrogen gas to dry out the moisture absorbed during construction.
After conditioning is completed, i.e. the chamber can stably hold HV up to 1900 V, test and calibration will start. These include plateau and efficiency measurements, drift velocity calibration, and calibration of offset parameters. Wire mapping and tracking code are under preparation. These tests will be done in EEL building room 126 where a CODA DAQ is prepared for chamber bench tests.