Log entry time 23:58:14 on January 13, 2011

Entry number 214374

We tried to understand the missing helicity gate issue during the QTOR down period. 

1. Matched the T_Settle & T_Stable of fake MPS to the accelerator MPS settings. The best value to set at the fake MPS to obtain 960Hz accelerator MPS settings is 940us.

2. Checked to see VQWK data read wait time affects the missed helicity gates. We could not find any direct relationship with this factor. SO we ended up with keeping the same values for TS (wait for 60 cycles) and ROC1&2 (wait for 30 cycles)

3. To correct the sync mismatch errors (i.e. ROC4 keep missing/lagging events w.r.t. ROC1&2) we tried to reconfigure the branching settings. We failed due to some unidentified problems with ROC 4 termination. So we reverted to original branching configuration.

4. We had to power cycle the NIM crates that supply fake MPS and supply TS GO signals to correct the GO signal. GO signal was not inhibited when the run has ended due to this crates issues. After power cycling the issues resolved.


5. Still we may need to resolve this missing helicity gates problem. After todays tests upto now we only observed very small no. of missed helicity gates.


We will follow a complete entry with more details later.