1. Micromegas for CLAS12 – Preliminary work on integration
Central tracker
Micromegas scheme
Forward Vertex Tracker
F. Sabatié CLAS Collaboration Meeting Feb th 2008

2. Central Tracker scheme
Electronics integration was done using existing aspect ratios (T2K-AFTER). Expect 30% redution in size and power consumption
3 layers of MM (each X,Y)
2 layers of Si
FVT is included (basic MM solution,
3x2 planes)
2 schemes were examined:
Half of the electronics is downstream (shorter paths to electronics, safe)
All the electronics is upstream (obvious advantages but long path to electronics
=> needs testing)
Only basic integration work was done. Need to add the possibility to remove
Si without touching MM. Need to add cryo-target integration.
Half-upstream
All upstream

3. Central Tracker scheme
cooling system for
forward detector
PCB extension cables for FVT
Cables, gas,
cooling, etc
SVT
For now, cylinder divided into 3, all the
dead zones are aligned.
For the FVT, they are also divided into 3
but each is shifted by 60°.
MM FE electronics

4. Integration of the « all upstream » solution inside the magnet
FVT can be integrated at the end of the cylinders
in the case of MM design (PCB extension cable can
make a 90° angle wrt the MM boards).

5. « All upstream » integration solution: some remarks
So far no optimization of dead zones on the detector or the structure was studied (we know how to build all that, needs no R&D).
Structures are in Aluminum, final detector will use lighter material.
Electronics is based on T2K-AFTER, but size/comssumption is pessimistic because not optimized. For the final detector, expect a >30% gain in volume and dissipation + more appropriate connectors.
HV distribution can also be highly optimized
Basic concept to keep: Light cylindrical structure with MM laying on them and forward planes (which can be installed right at the end of MM cyl.), everything laying on a sliding structure for integration by the rear (target then Si and MM). Front End electronics needs to stay close to MM so cylinder has to be longer than the MM themselves. They will also integrate all necessary gas/cables/cooling entries/exits. Glycol distribution system for electronics cooling is mandatory.
Holding of the central tracker is further behind because of TOF.
Integration of Si and MM on the same holding structure has to be seriously studied in if mixed solution is chosen (needs more work before).