Handling Considerations

The VDCs are very delicate devices which are absolutely essential to the instrumentation of the Hall A spectrometers. Thus, extreme care must be exercised whenever they are moved or used.

• Before moving a VDC detector package, ensure that the protective plates are in position. Plates include tapped aluminum sheets to be bolted over the entrance and exit aperatures, as well as aluminum sheets which slide in between the two chambers.
• Disconnect and reconnect all TDC cables with extreme care. The conductor pins are relatively fragile, and should one be broken off, repair will be extremely difficult.
• When initiating gas flow, pay strict attention to the feedback parameters. Overpressure may damage the chambers.
• Never attempt to apply HV to the chambers until gas flow conditions have reached steady-state.
• As the amount of heat generated by the pre-amp/discriminator cards it substantial, always make sure adequate cooling is provided before attempting to run. Currently this cooling takes the form of four temporary fans which clamp to the aluminum Faraday cage. Eventually, permanent fans will be installed.
• When ramping the HV, never allow the chambers to draw more than 1 $\mu$A instantaneously. If they do, something is wrong!