W&M  report 04-29-2004


1) Visit of Nilanga's Lab (04-19-2004)

Nilanga and Vladimir from UVA showed us their lab where they are building HDC for BigByte.
The UVA HDC layout is almost identical for the HDC build for HKS (Hall C, L. Tang),
the UVA chambers are longer (~2m total).

-> A very fruitful vistit with a lot of information and ideas to be copied:
- technique used to align and fix the wire with a precise angle and spacing (concept.jpg)
- techniques used to strech and glue the HV planes (aluminized mylar foil)
- wire tension unit (DC fan motor maintaining a constant torque)
- precision translation stage with attached camera for wire position meausrement

(Still awaiting Mike Finn's digital camera pictures ...)

Vladimir Nelyubin gave us some drawings as a startup (strecher.pdf , wiring table.pdf , wiring _uv.pdf )

Bottom line: We are saving a lot of R&D time. UVA will inform us when they continue to build their chambers,
                      so we have a chance to see and practice the techniques.


2) Technical drawings

The CAD package SolidWorks arrived last week after all the struggle with getting the $200 student license.
SW is running now on a new computer (3.0 GHz, 2GB RAM, fast grafics card). Solidworks has an interface
to Ansys Finite Element Analysis (FEA), so the exact geometry can be used for stress and deformation studies
with only some mouse klicks (tested).

-> repeating FEA to figure out the optimal frame border size (currently 15cm).
     Simulation: ~2-5 min per border size (before ~2h)

Digging through ~2500 (!) pages of documentation and still on the learing curve ...
Bottom line: The CAD knowledge from AutoCAD are rather hindering than helpful.
A lot of the startup questions were resolved within SolidWorks informal presentation yesterday at JLab (Presentation->Workshop for free =8-) . Seems like the JLab engineers will convert from IDEAS to Solidworks soon. Would ease the cooperation with JLab and the exchange
of drawings.

At present:

- tutorial but exact drawings of the laser table we will setup in ~2 weeks in our detector lab (lasertable.pdf)
- redrawing the VDC parts and a proper assembling of the part with the ability to change dimensions easily. Still in progress.
- upcoming: shielding wall  (wall_cut.pdf) + primitive ferris wheel + VDCs + scintillator + cerenkov
                    including all the degree of freedom (rotation +  translation)

-> goal: SolidWorks has the ability of a collision detection of moving part.
              Very useful for the construction of a sliding/rotation mechanism on the ferris wheel
               in order to insert/retract the VDCs without hitting the detectors.