1. SiD Tracker Concepts M. Breidenbach
History
Evolution
6 February 2004
SiD Tracker Concepts M. Breidenbach

2. SiD Tracker Concepts M. Breidenbach
Design Drivers
Excellent momentum measurement
E-Flow calorimetry costs push towards modest(??!!) radius – nominally 1.25 m
E-Flow and momentum measurement both push BR2 – nominally 5 T.
Ergo want tracker with excellent φ measurement- Si Strip Detectors!
Excellent multiparticle resolution
Seems hard to beat Si Strips with ~50 μ pitch.
Jets and backgrounds pretty dense.
6 February 2004
SiD Tracker Concepts M. Breidenbach

3. SiD Tracker Concepts M. Breidenbach
More Design Drivers
Robustness in a linear collider environment.
“This (a linear collider) aint LEP!” John Jaros, circa early 2000’s.
SLC/SLD experience indicates that Si leads directly to peaceful sleep at night. CCD’s were fine, wire and gas detectors were sensitive to beam blasts (that could not happen).
Keep the detector thin.
Experience indicates that endplates of barrel systems ruined forward tracking. (Even SLD!)
Experience indicates that measured stuff (from multiple scattering) much greater than early drawings. Note that cable have to exit some place.
We acknowledge that a profound physics case for thin in the LC context has probably not yet been made – so keep working at it!
6 February 2004
SiD Tracker Concepts M. Breidenbach

4. Tracker Layout Choice Un-simulated and Un-engineered
6 February 2004
SiD Tracker Concepts M. Breidenbach

5. Find tracks from Vertex Detector
Find tracks from 5 layer CCD VXD. SLD was quite successful with 3 layers.
Should extrapolate well into Tracker (Momenter?)
Demo in progress – e.g. Steve Wagner.
6 February 2004
SiD Tracker Concepts M. Breidenbach

6. Make Structure of Long Ladders
Readout half ladders from ends.
Wire bond 10 cm square detectors in daisy chain as in GLAST.
Minimal electronics and power pulsing make gas cooling easy. No liquids, leaks, or associated mass.
6 February 2004
SiD Tracker Concepts M. Breidenbach

7. SiD Tracker Concepts M. Breidenbach
What's Wrong?
We have no support to do anything, except maybe think a little bit.
The outer barrel half length is (nominally) 17 detectors.
This is a lot of capacitance.
S/N is problematic.
Timing tag is hopeless.
Detectors thinner than ~300 μ ~hopeless.
The detectors are wire bonded on a (almost) massless spaceframe. A wirebonding machine for this needs to be invented.
6 February 2004
SiD Tracker Concepts M. Breidenbach

8. SiD Tracker Concepts M. Breidenbach
What else is wrong?
Forward Disks are quite problematic:
Occupancy too high.
Mechanics of making long multi-detector trapezoidal segments ugly.
Timing tag ~necessary.
6 February 2004
SiD Tracker Concepts M. Breidenbach

9. SiD Tracker Concepts M. Breidenbach
Evolve
Ditch (romantic) notion of long ladders and read out each detector.
Detector has signals routed to rectangular grid for bump bonding to detector, analogous to design for Si-W Calorimeter.
Strip Detector
Bypass Caps
Thin Kapton Cable
Readout Chip
6 February 2004
SiD Tracker Concepts M. Breidenbach

10. Space Frame “Sketches”
6 February 2004
SiD Tracker Concepts M. Breidenbach

11. SiD Tracker Concepts M. Breidenbach
Si-W Calorimeter
1024 channels of:
Threshold
Gain
Sense
VCal Cf
Ccal
Range Bit
Cfl
Ref
Reset
End of Conversion
Convert
Integrate
Hold
Discharge
Current Source
Reset (before train)
Si-W Calorimeter Analog Section February 2004
6 February 2004
SiD Tracker Concepts M. Breidenbach

12. Proposed Tracker Electronics
2048 Channels of:
Threshold
VCal Cf
Ccal
Reset
End of Conversion
Convert
Integrate
Hold
Discharge
Current Source
Reset (before train)
SiD Tracker Analog Section February 2004
6 February 2004
SiD Tracker Concepts M. Breidenbach

13. SiD Tracker Concepts M. Breidenbach
Advantages
Higher modularity & improved occupancy
Improved S/N
Easy time tag
No wire bonding
Very modular assembly
Possibility of thinner detectors.
Stereo (even large angle) is easy.
Most of these particularly advantageous for forward disks.
6 February 2004
SiD Tracker Concepts M. Breidenbach

14. SiD Tracker Concepts M. Breidenbach
More
Barrel is ~7000 mW (average, probably generous) per ROC, total power is 280 watts. Endcaps should be less. OK for gas cooling?
Put data concentrator on end of ladder, accept connector (!!) from detector cable. Concentrator output is on optical fiber.
Cable is kapton w copper traces. 20 micron copper 3 mm wide seems ok for chip power; other traces narrower.
6 February 2004
SiD Tracker Concepts M. Breidenbach

15. Thickness Budget (Rough!)
Material
Thickness (Microns)
Thickness
Radiation Lengths (%)
Silicon
300
0.32
Kapton 70
0.02
Copper 20
0.14
Carbon (Structural support)
500 (average)
0.27
Total
0.75
6 February 2004
SiD Tracker Concepts M. Breidenbach

16. (Tentative) Conclusions
Simple is better
Need to evaluate occupancy forward (and lots of other stuff)
6 February 2004
SiD Tracker Concepts M. Breidenbach