checking DC1 current

Hogan Nguyen (
Tue, 29 Jun 1999 11:45:05 -0500


There has been several instances of large current spikes in DC1 during the
high intensity (8e12) running.

The spikes could have been due to chamber voltage ramp-up and ramp-down
currents (we set the voltage 90% lower during offspill). This current is
not a problem. The ramping current occurs at T4 and at the end of T6.
The SLOWDA monitoring, due to finite sampling, cannot distinguish between
T4 and T5, which are <3 sec apart. Theo has now inhibited the SLOWDA
current monitoring during chamber ramping.

To be absolutely sure that the current spikes are due to beam, please look
at the spill scope. Please check the currents measured between T5 and T6.
An explanation is posted on the relay rack.

With good beam at 8e12, the DC1 peak current should be 80-100 uA.
For comparison, DC1 was around 200 uA in 96-97 E832 running.