Just a quick and dirty summary today

Progress Report of Region3

1) Frontend Electronics

Chris Cuevas et al. developed a 16 channel MAD chip card as a replacement for the BigBite drift chambers frontend electronics.
So far Chris and BigBite guys are happy about the first tests with the MAD chip.
After this project has finished Chris promised me to assign one person taking care of our frontend design which is similar but has more features.

Last week W&M ordered 600 MAD chips and a  test board for $20k total from CAEN. Delivery time is about 6-8 weeks.
I suggested to Chris that we should develop a  evaluation board testing the basic function and characteristics
(e.g. channel sensitivity ) of all MAD chips for quality control. So far there is no quality control for the MAD chips used for BigBite ...
(MAD chips are send from CAEN Italy directly to a PCB manufacture for BigBite)


2) Geant4 Simulation

I can not see SolidWorks anymore .... before it makes me dull, I worked a bit on Geant4 for the last ~2 weeks.

Changes and Updates  in v64

- included latest collimator design (credits to Michael Gericke)

- included 2 GEMS (Front + Back). Back GEM is just optional and can be rotated in phi independently from the Front GEM.
 
    One GEM is 15.5x15.5 cm large (arbitrary), consists of 3 GEM foils (50um Kapton+ 2x 5um copper), 1 HV foil
   (50um Kapton + 5um copper), and one Readout plane (300um G10 board, 50um Kapton, 5um copper)
   (The GEM setup was taken from COMPASS design for a triple GEM)

- included dual HDC, each with 6 virtual wire planes, and 10 Mylar foils (HV+gas foils). Dimension based on Norm's drawings.

- included the Shielding Wall with cutouts taken from
   http://www.jlab.org/~yl0094a/Qweak_SCIN/status_report/status_09152005.html

- modified target: alu container filled with liquid H2. Wall thickness + entry/exit window thickness taken from Geant3 definition.

Pic below: Current setup included in QweakSimG4 v64. GEM and HDC frames are not shown.



Pic above: One GEM placed on octant1, another placed on octant3                          Pic above: Dual HDC (frames are not shown).
                  (Frames are not shown)                                                                                           Left corner: part of the MainMagnet upstream "Spider"

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Ran simulation with 100k primary events:


Pic below:  Cross section weighted hit distribution on the Front and Back VDC. Blue: Cerenkov detector hit. Red: all other hits on VDC



Pic below: Drift cell hit distribution of Front VDC.
                 With the new collimator I get a 99.9% instead of 100% theorectical  tracking efficiency. Roughly 1 per 1000 tracks hits less than 4 drift cells (not an issue)


Pic below: GEM hit distribution.                                                                                Pic below: Front  HDC hit distribution
Seems like that my GEM size is still to small (top cut off)




==> At present the QweakSimG4 outputs a Root file which contains a complete set of hit information (e.g. position, angles, momenta, timing, origin of particle, etc ) of all drift chambers.
        The information in the Root file is needed  for developing a global tracking code.

Pic below: Structure of the outputted Root file of QweakSimG4. The hit information is saved in a subdirectory for each ddetector.