1. LHeC “shaking hands” meeting Comments on the Tracker Design I. Tsurin Page 1Liverpool December 16th, 2011 Detector granularity Sensor technology Frontend architecture Data Link Powering and cooling

2. Decisions, Decisions... R&D, infrastructure ? Physics (process driven) (result driven) Page 2 Alternatively, a variety of ROCs is available for which the sensor geometry could be customised. Wire bonding of objects with different pitch is a common practice. The tracker could be built from available frontend and backend modules Example: Liverpool design of a strip module (4 sections of 22mm long strips with 74.5 um pitch) for the Atlas upgrade

3. 6-inch wafers (thicknesses range from150um to 600um) produced by Micron in different processes. Device Specs High spatial resolution is the main requirement for the tracking detector Page 3 Top-down design strategy: Physicists should specify granularity of sensors relying on R&D data and MC studies. Liverpool is now committed to measurements of strip detectors with different implant pitch and width and various intermediate strip options.

4. (IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 58, NO. 3, JUNE 2011, p1308) Sensor Technology is better in terms of achievable resolution Planar Compared to “p-in-n” detectors: Radiation hardness Compared to “n-in-n” detectors: Advantages of the “n-in-p” process Possibility of back-thinning for low material budget Low manufacturing costs (single-side processing) Easy mechanical handling of the backplane Bulk type does not invert - can be operated under- depleted, - relaxed temperature conditions, - simpler data analysis. Page 4

5. because of high resolution requirement Frontend Architecture Analogue ? “Binary” Page 5 Analogue pipeline architecture offers trade-off between data integrity (amplitude information is preserved) and high bandwidth. Limited experience with pixel ROCs (from the lack of available samples :-( Beetle chip is a good platform for strip detectors. It can also operate in the “binary” readout mode.

6. Bandwidths of Micro Twisted-Pair Cables and Fusion Spliced SIMM/GRIN Fibre, K.K. Gan, Department of Physics, The Ohio State University Data Up Link Optics ? “Copper” Page 6

7. Module control has to dial with short circuits dial with line ruptures Frontend Powering Converters ? Serial Single event burnout causes a permanent short Page 7

8. Page 8 Cooling requirements Low voltage: 100mA/chip x 2.5V / 2.5 cm2  1kW/m2 High voltage: 100  A/cm2 x 1000 V  1 kW/m2 (@ -25 deg. C) Convection: ~ 0.5 kW/m2 (@ -25 deg. C) Sensor is cooled through its backplane (suitable for strips) ROC is cooled (current Atlas pixel system) 2.5 kW/m2  3.5 kW (CPT) 20 kW (CST) 4.5 kW (CFT, CBT) 8.5 kW (FST) 5.0 kW (BST) ~ 50 kW in total !

9. What if... Savings in the material budget Improved cooling performance Design uniformity and reliability Slot for services Since there is a big asymmetry in  in the original design,  what are the implications of a narrow gap for ALL highway services brought together ? Page 9