1. Steven Worm – RALOct. 26, 20041 Tracking R&D for the Future Linear Collider Dr. Steven Worm Rutherford Appleton Laboratory

2. Steven Worm – RALOct. 26, 20042 Tracking Features at a Linear Collider UK Tracking R&D: Liverpool, Oxford, Lancaster, Bristol, RAL o At the Linear Collider, Tracking consists of… –Vertex Detector, Central Tracking will be covered –Will not discuss forward tracking systems, segmented EM calorimetry o LC detectors will be precision devices, driven by the physics needs –Need extremely thin, low mass detectors –No need for extreme radiation tolerance –Need extremely high precision vertexing  eg ~20 μm pixels –Can not simply recycle technologies used in LHC or elsewhere o High pixelization and high precision –Very hard to read out 10 9 channels in a few ns –Central Tracker: associate tracks and beam crossings, maintain high precision –Vertex Detector: integrate over many beam crossings but keep occupancy low –Either would be impossible in the LHC; each crossing is far more messy o Accelerator technology strongly influences the detector readout

3. Steven Worm – RALOct. 26, 20043 Linear Collider Accelerator Time Structure o Central Tracking –Large (337 ns) gaps between bunches –Suitable for TPC or all-Silicon readout o Vertex readout –10 9 pixels: must break long bunch trains into small bites (2820/20 = 141) –Read out detector many (ie 20) times during a train  susceptible to pickup –…or store info for each bite and read out during long inter-train spaces Superconducting RF Parameters* Bunches per train2820 Time between bunches337 ns Total time of train950 μs Train frequency5 Hz Time between trains200 ms 337 ns 2820x 0.2 s 0.95 ms Bunch Train Bunch Spacing *Approximate numbers, from TESLA

4. Steven Worm – RALOct. 26, 20044 Central Tracking Detectors o Gaseous Tracking –Most of the activity is in developing a precision TPC o Silicon Strip Tracking –both all-Silicon and partial Silicon options being explored –SiD: Silicon Detector Design Study now underway TPC TrackerSilicon Tracking

5. Steven Worm – RALOct. 26, 20045 Central Tracker R&D – TPC Status o Variety of readout technologies –GEM’s, Micromegas, Silicon readout, resistive pads MPGD’s… o MANY university groups and Labs Carleton U., TRIUMF, Montreal, Orsay, Saclay, Berkeley, NIKHEF, CERN/Medipix, MPI, KEK, MIT, Cornell, Victoria, … o Well evolved research programme –Testbeam Activity at DESY, KEK… –Half-dozen TPC test stands –Magnetic fields to 5.3 T –Study various readouts and gasses with an eye on the resolution o No shortage of interesting ideas, also no clear winner yet.  No UK involvement Micromegas Saclay TPC MediPix2/Micromegas U. Victoria TPC GEM

6. Steven Worm – RALOct. 26, 20046 Central Tracker R&D – Silicon Status o SiD (Silicon Detector Design Study) –Despite simplistic concept drawings, quite a bit of thought to sensor layout –Serious Monte Carlo studies only beginning –Little thought to mechanical or readout details –Not to be underestimated; many interested scientists in the US at SLAC, Fermilab, and elsewhere  Opportunity for involvement in UK

7. Steven Worm – RALOct. 26, 20047 Vertexing Technology Options o Vertex detector needs to be… –Well matched to the physics needs (ie 20μm x 20μm pixels) –Very low mass for entire detector: target is 0.1% X 0 for each ladder in active area (incl. readout, cooling, support) –Read out quickly –Moderately radiation hard o Candidate technologies include… –CCD approach (LCFI) CPCCD (Column-Parallel readout CCD) Oregon/Yale group KEK, Japanese groups… –Active pixels: ISIS (Image Sensor with In-situ Storage) MAPS (Monolithic Active Pixels) DEPFET (Depleted Field-Effect Transistor) APS FAPS (Flexible Active Pixels) SOI (Silicon Over Insulator) APS

8. Steven Worm – RALOct. 26, 20048 CCDs and the Linear Collider: LCFI o Fast Column-Parallel CCD’s (CPCCD) under development –CCD technology proven at SLD, but LC sensors must be faster, more rad-hard –CPCCD’s feature small pixels, can be thinned, large area, and are fast –Next test batch to include some full- scale sensors –Starting to develop detector-sized prototypes (rather than test devices) CPCCD192 mm “Classic CCD” Readout time  N  M/F out N M N Column Parallel CCD Readout time = N/F out CPCCD2

9. Steven Worm – RALOct. 26, 20049 ISIS-based Detectors: LCFI o Long bunch trains and the SLD Experience –Superconducting RF necessitates readout during bunch train –Difficult environment– will be sensitive to noise or RF leakage from train –RF leakage nearly killed external readout electronics at SLD –Investigating storage of signal and readout between trains o Variant of Image Sensor with In-situ Storage (ISIS) being prototyped –Transfer CCD signal to storage channel every ~50μs –Read out in 200 ms quiet period between trains o If successful, will have advantages over CPCCD’s –Very robust against electromagnetic interference –Slower readout (1 MHz) –Very low readout noise –Higher radiation hardness  Promising idea, will be developed

10. Steven Worm – RALOct. 26, 200410 Vertex Detector Technologies o LCFI developments currently in the lead –Readout speed issues should be solved with CPCCD –Resistance to noise, electromagnetic interference (EMI), radiation resistance should be improved with ISIS –We benefit from CCD experience at SLD o Active Pixel Sensors (APS) –Have concentrated on achieving small pixels and 100% active area –Often too much material in sensor or periphery, or have cumbersome readout –All designs sensitive to electromagnetic interference except ISIS –Difficult questions of thin ladders, miniaturized electronics not yet addressed o Which technology will be chosen for the ILC? –All vertex detector technologies are capable of delivering working detector –Decisions made on the basis of thinned ladders and appropriate DAQ in a testbeam in 2010 –Only ISIS or FAPs sensors have potential to solve EMI susceptibility issues

11. Steven Worm – RALOct. 26, 200411 Overall Detector Plans and Status o The plan is for two interaction regions and two experimental groups –LCFI technology can be applied to each detector concept –Likelihood that an LCFI detector technology chosen is currently high o Several design philosophies emerging –Major implications for Central Tracking –Good flexibility for LCFI and vertex community o UK effort on vertex detectors integrates well with LCABD (Advanced Beam Delivery) Detector Concept B Field (Tesla) Main Tracker LCFI Compatible? Silicon (“SiD”)5Silicon stripYes “Large”4TPCYes “Huge”2.5 to 3TPC / JetYes

12. Steven Worm – RALOct. 26, 200412 Timescales for LC Tracking R&D o Accelerator and Detector Timescales Now  Straw proposals for detectors being generated oWill allow rough costing oIs already helping to focus the experimental community oNot an attempt to push detector technology choice 2005  Accelerator Conceptual Design Report (CDR) 2007  Accelerator Technical Design Report (TDR) 2008  Accelerator Site Selection and Site-specific Design 2009  Construction begins, Detector Technical Design Reports (TDR) 2015  First Physics? o Vertex Tracker technology decisions are not imminent 2004–2009  Develop robust vertexing technology for LC environment Circa 2010  Will have prototype modules in test beam for side-by-side comparison (detector and readout on ladders of right size and X 0 ) o Timescales for Central Tracker decisions are earlier 2005-2006  Central Tracker concepts solidify now, since they drive cost 2007  Accelerator Technical Design Report (TDR)

13. Steven Worm – RALOct. 26, 200413 Concluding Remarks Q: How do we ensure that UK groups have a strong showing in LC tracking? A: For Vertex Detectors: –Continue to support LCFI. We have the lead now, but there is enough time to lose this lead before a vertex detector technology choice. Our lead stems from funding that allows development of all necessary components; physics studies, thin ladders, miniaturized readout electronics, and sensors. A: For Central Tracking: –Window of opportunity for UK Silicon Strip community to become a major contributor to the LC via SiD and SiLC, but it is closing. –Little opportunity for gaseous tracking R&D, given activity in the field. A: Continued strong support from PPARC is essential.