| T0/TOF Status Report |
| Frank L. H. Wolfs | |
| PHOBOS Bi-Weekly Meeting | |
| January 30, 2004 |
| Outline |
| Status of T0 detectors: | ||
| T0 OR: review of changes and current status | ||
| T0 OR resolution | ||
| T0 detector response (energy, time, etc.) | ||
| Correlations between T0 and Paddle detectors | ||
| Status of TOF detectors: | ||
| Multiplicity Information | ||
| Energy Information | ||
| T0 Changes |
| Observed poor T0 vertex resolution (> 15 cm) as soon as silicon vertex information was available and that OR signals were late compared to PR03. | |
| Problem due incorrect orientation of cable between discriminator and TEQ. | |
| Change in cabling moved Ors forward by 75 ns. | |
| Discovered problem with TDC 17 (or slot 17). | |
| Moved ORs to TDC 8. Resolution improved to 8 cm. |
| T0 Changes |
| Discovered the FB ORs missing in 30% of the events. | |
| Missing FB ORs were correlated with centrality | |
| Determined that when FB Ors were moved to TDC 8, the prompt signals were to early for the START of the TDC, and the TDC was stopping on the reflection. | |
| Added delay to the FB OR signals. | |
| Vertex resolution improved to 2.5 cm for central events. |
| Setting the TEQ Delays |
| In order to determine the TEQ settings, we select events in which only one T0 counter fires on the array being calibrated (need 100 - 500 sequences to get sufficient statistics). | |
| The vertex difference distributions for each counters on the array are examined, and the required timing shifts to align them are calculated. |
| TEQ Delay Adjustment: Looking at events with a single T0 on either side. |
| Special run to determine TEQ delays (13051, 1/24). | |
| Realized the OR was based on reflection (1/25). | |
| Test run with new TEQ delays (13094, 1/26). | |
| Final TEQ delays (1/27). | |
| T0 Multiplicity (Run 13115) |
| T0 Vertex Centroid (Run 13115) |
| T0 Vertex Resolution (Run 13115) |
| Number of T0P Counters vs Number of T0N Counters (Run 13115, Sequence 0) |
| Number of T0 Counters vs Number of Paddle Counters (Run 13115, Sequence 0) |
| T0 Sum Energy vs Paddle Sum
Energy (Run 13115, Sequence 0) |
| TOF Multiplicity Run 13108 |
| TOF Energy Run 13108 |
| TOF Sum Energy Run 13108 |
| Tasks |
| Adjust and optimize TOF/T0 calibrations. It is our goal to have first order calibrations for all runs in the DB by the end of the run: | ||
| No changes should be required for the TOF software | ||
| Changes are required for T0 software since in PR03 we never used the individual T0 channels. | ||
| We need to make sure that we keep taking daily FB calibrations. | ||
| Once the dust settles, we will focus on PR04 PID with the goal to have first PID information ready at the Collaboration Meeting in March. | ||
| Summary: |
| Ready to go!!!!!! |