1. HERD Tracker Layout Considerations
Franck Cadoux, Xin Wu
University of Geneva
HERD meeting
24 February, 2016

2. Drawing from IHEP Excellent hermeticity
But very difficult to have a tracker layout like this. Main problem is the top tracker
Need space for front end and readout electronics
Need space to route the service (cables and cooling paths) to the bottom
Should avoid routing from the outside of the side trackers to minimize dead material before the first layer of the side trackers
Xin Wu

3. Try Another Approach
Route the service of the top tracker between the calorimeter and the side trackers
Assume readout electronics at the bottom of the detector (long cables ~80 cm)
90° interconnect (Fermi) or 90° connectors
Fermi
Xin Wu
DAMPE

4. Front-end electronics
Can the envelope of the calorimeter be reduced?
Space for service
Xin Wu

5. Top View
Xin Wu

6. Xin Wu

7. Summary The full coverage of a 3D calorimeter is challenging
We need to think about realistic layout options taking into account technical constraints and coverage optimization
A few important (connected) questions affecting the layout choice and science goals
How much tungsten?
Affects weight and mechanical structure.
Tracker for low energy photon?
Affects overall design
Anticoincidence detector or not?
Affects overall design and photon physics
How to do charge measurements?
Tracker is not optimal for measuring high charge because of dynamic range
Should a dedicated charge detector be considered?
Xin Wu