Charge Collector Design
The charge collector for the Qweak chambers will use concentric strips aligned with the electron scattering polar angle (: the Z-axis is pointing along the beam direction), shown as the top layer below in read, and radial strips (shown as the bottom layer in blue). The radial strip are not aligned with phi due to the expected phi symmetry. Six, 130 pin output connectors will be used. Two of the pins are ground and 128 carry signals from individual strips.
Latest Design 12/07
The Qweak charge collector has two layers of copper strips. The bottom layer is 400 wide and is in the shape of concentric circles centered around the beam pipe. The strips start at a radius of 7 cm and extend out to 31.4 cm. This should cover the expected angular range of the elastically scattered electrons in the Qweak experiment. The top layer contains copper strips that are 100 wide and correspond to the "y" direction in the monte carlo. The coordinate system is a hybrid between cartesian and spherical.
The output connectors should be mounted on the backside (below the bottom layer) and several theodolite targets are also etched to help with detector alignment.
Files: Gerber files, Text files, PDF files and EPS files
File:Qweak bottomLayer V8.5.pdf
Bottom Copper Layer
Internal radius: 69.7mm
External radius: 313.9mm
Circular lines width: 0.4mm
Top Copper Layer
line width: 0.1mm
PDF file: Media:QweakGEMchargeCollectorTop1.pdf
Gerber file: Media:Qweak_19.8.7.Top.txt
Connector pads view
CERN production
Preliminary design 6/07
The PCboard design software had trouble displaying the entire readout board at once such that you could see enough detail. The two pictures below represent the Top and Bottom halfs of the readout board. A view of the entire board can be seen using a Gerber file viewer. The picture of the top and Bottom layers can be found here ReadoutBoardGerberFiles along with links to the gerber files themselves.
The Top Half of the Charge Collector showing all six output conenctors
This is the bottom half of the charge collector showing only the bottom 2 output connectors
A close up view of the 130 pin pads which will be used to mount connectors for the VFAT cards.
We need to have plated holes which allow the copper lines to pass through to the very last layer where the copper pads for the 130 pin connector are.
The main web page for the connectors is at
[1]
| Point | Coordinates (mm) |
| A | 60.000; 0 |
| B | 26.400; 16.500 |
| C | 3.450; 88.500 |
| D | -17.850; 246.750 |
| E | 60.000; 295.050 |
| F | 138.000; 246.900 |
| G | 116.550; 88.350 |
| H | 93.450; 16.350 |