Virginia Tech Update for Tracking Group, May 21, 2008

1. CODA and F1TDC setup:
We have a DAQ teststand with CODA and seven F1 TDCs fully operational. We are using the root-based analyzer developed by Paul King and his students to do basic histogramming. The setup is shown in Figure 1 and a hit pattern for the V-plane is shown in Figure 2. The system is currently hooked up to "Hokie 1", the first production chamber. It is currently being used to diagnose a few misbehaving wires. In parallel, we are adapting the HKS analysis code to allow us to do tracking on this data.

Figure 1 - F1TDC crate hooked up to "Hokie 1".	Figure 2 - Hits per wire for v-plane of "Hokie 1".

2. Region 2 Rotator
Paulo and another JLAB designer have nearly complete drawings for a Region 2 rotator. An overview is shown below. A meeting was held last Friday including Paulo, Mark, Roger, the other JLAB designer, and John Leacock. It was the first time Mark had heard about it in detail, but in this first discussion it appears to meet all the requirements. A few points worth noting:
* The rotation is through 180 degrees only.
* Everything is manual on this system. In principle, it could be automated and controlled remotely at some later stage, but for now we are going to go manual. Mark discussed this with both Roger and Greg, and it was determined that it should not be a hindrance.
The drawings didn't quite have the correct final positions of the chambers, so we are iterating on that with Paulo, and then we will review it again when the drawings are complete. Then VT will be responsible for procuring the parts and putting it together. It is of a size that we can probably put it together here at VT, but we are still discussing that internally.

3. Alignment tolerance homework
For the "Would like to" and "Must have" tolerances, I suspect they will be driven by how precisely we need to position our chambers to avoid interfering with the scattered beams from the other octants. I have the simulation ntuple produced that I need to determine this, but I have not had a chance to analyze it yet and generate the relevant numbers.
For "known-to", I'm not quite sure how to determine it just for the Region 2 chambers alone. We should be able to determine relative wire positions (and relative chamber positions) using straight-through tracks in the standard way. But "known-to" presumably says how accurately some reference wire in our chambers (referenced to an observable tooling ball or target) is know with respect to the hall coordinate system. So that is related to our overall tracking algorithm and reconstruction goals.