Region 3 Statuts Report

Small update:

In my previous report I made a link to the Honor Thesis of Graham Giovanetti, who was working on I2C related evaluation boards.
That thesis version was not complete, e.g. it did not contain pictures and graphs.
The official version can be found here:
http://www.wm.edu/physics/SeniorThesis2006/Giovanettithesis.pdf

1) I2C related electronics

The VDC front-end electronics will be controlled using the two-wire I2C bus system. Since the Electronics Group has up to now no experience with I2C related electronics,
Chris Cuevas and Bill Gunning were looking for an evaluation board. The inventor company Philips advised me to get I2C evaluation boards from here:
     http://www.demoboard.com/i2cprod.htm
Chris has ordered a USB-I2C adapter (http://www.demoboard.com/win-i2cUSBDLL.htm) and I was lucky enough to get one of the discontinued evaluation board
(http://www.demoboard.com/I2C_2002-1Akit.htm) . Normally this board is now unavailable but I got one that the company could not sell because one SMD-LED is broken  =8-).

Pic below:  Philips I2C evaluation board (left) and Printerport-I2C adapter board (right)
 
Probably REU student Thomas Ruscher, Bill Gunning  and I will run the first tests with these boards next week .

2)  Front-End Electronics

REU student Thomas Ruscher is getting involved into a 16 channel  Preamplifier/Discriminator board based on the MAD chips that I got from Bill Gunning.
For that we just have gathered enough devices and tools quasi from scatch in order to set up a electronics workbench, that  actually allows us to test the board.

- Digital Oscilloscope (Tektronix TDS 520A)
- Triple Power Supply (JLab Load)
- Low noise laboratory power supply for threshold setting (Instek 3030DD)
- SMD soldering station including a tweezer desoldering iron for removing SMDs (Weller)
- 5 1/2 digit benchtop volt meter (BK Precision 5491A)
- SMD vacuum tweezer (no more 0402 SMDs (0.04"x0.02") snapping off conventional tweezers ... )
- HP 8013B Pulse Generator with ~2ns rise/fall time
- various 50 Ohm attenuators , probes , cables etc
- various magnifying glasses (>= 10x)





Thomas is currently testing and measuring the sensitivity of the MAD inputs by changing the input SMD capacitors, signal height, and threshold. Accordingly to the
MAD specs it should be 3mV/fC which we want to verify.In this context he is checking for channel cross-talk and testing some shieldings.
    
3) Flatness Scanner
Summer student Brian Walsh is modifying the laser and photodiode support. It turned out that for an optimal alignment we need to tilt laser and photodiode very precisely.
In addition the laser diode will be mounted on a XY translation stage. Brian is getting used to SolidWorks and he has finished this design, that allows tilting and XY adjustment.
For the tilting we are using precision screws from Newport (AJS 127-0.5), see  http://dilbert.physics.wm.edu/elog/Construction/289
Currently the W&M machine shop is working on this support.

Pic below: SolidWorks model of the photodiode support for the flatness scanner. This modified support allows tilting and XY translation for optimizing
the alignment. Blue with red circle: Photodiode


4) Wire scanner

Graduate student Brian Hahn is working on the wire scanner. He added a CCD camer viewer GUI under LabView in the WireScanner Controll GUI.
Brian is able to move the camera from wire to wire and extract the intensity profile of the CCD image (~2x3 mm). This profile is fitted with a gaussian
in order to obtain the wire position. At present the position resolution of a wire is ~7-8um given by the sigma of the gaussian fit. Main problem is the high
background intensity with back (but shiny) materials, that lowers the signal to background ratio. The W&M machine shop finished a small board with dowel pins,
that allows to strings wires for a length of 6"  (~mockup wire plane), so Brian can run some tests under semi-realistic conditions.

5) Wire Properties

Graduate student Carissa Capuano is currently stringing a wire on a pully and checks the wire elongation for different weights. We are using a B/W CCD
camera that is hooked up to a 14" monitor or can be read out by a PC video card under Labview (currently occupied by Brian Hahn for the wire scanner).
Carissa is designing a holder for the camera that allows to see a mark on the wire (another 25um wire soldered across the test wire) in front of a steel ruler
with 1/100" scaling (sufficient for this test). Details of the optical system can be found here
http://dilbert.physics.wm.edu/elog/Construction/287

Pic below: 25um wire strung on the laser table. The pulley is at the rear (next to the scale). The area
is "fenched", otherwise the almost invisible wire does not survive for long ...


Pic below: 25um wire seen on a 14" monitor (max resolution; loose wire end, therefore no straight line)


Pic below: camera system , using the same optics like VT

   






.