Two seemingly incompatible topics: Detector Tracking Review Detector Roadmap

1. Two seemingly incompatible topics: • Detector Tracking Review • Detector Roadmap • From the ILC regional workshop, Beijing, 4-8 Feb LCUK - Detector Report Chris Damerell

2. ILC Detector R&DTracking Review 5-8 February 2007 Chris Damerell RAL On behalf of the ILC Detector R&D Panel (a Panel of the World-Wide Study Organising Committee) (Jean-Claude Brient, Chris Damerell, Ray Frey, Dean Karlen, Wolfgang Lohmann, Hwanbae Park, Yasuhiro Sugimoto, Tohru Takeshita, Harry Weerts) LCUK - Detector Report Chris Damerell

3. Committee membership • Panel members: Chris Damerell, Dean Karlen, Wolfgang Lohmann, Hwanbae Park, Harry Weerts • External consultants: Peter Braun-Munzinger, Ioanis Giomataris, Hideki Hamagaki, Hartmut Sadrozinski, Fabio Sauli, Helmuth Spieler, Mike Tyndel, Yoshinobu Unno • Regional representatives: Jim Brau, Junji Haba, Bing Zhou • RDB chair: Bill Willis • Local tracking experts: Chen Yuanbo, Ouyang Chun • Admin support: Naomi Nagahashi, Maura Barone, Maxine Hronek, Xu Tongzhou LCUK - Detector Report Chris Damerell

4. Overview of these reviews • To be included in every regional workshop from now on: • Beijing (Feb ’07) Tracking • DESY (LCWS June ’07) Calorimetry • Fermilab (Oct ’07) Vertexing • Asia (Feb ‘08) PID, muon trkg, solenoid, beam diagnostics, DAQ • Our responsibility is to work with the R&D collaborations to ensure that the feasibility of the critical goals can be demonstrated by 2010-2012 • This means (for tracking) that the community can be confident that the option they choose will satisfy the challenging physics needs • We are currently far from this position, for all tracking options LCUK - Detector Report Chris Damerell

5. What is at stake It could be that both detector tracking systems will work well, or one well and one badly, or both badly. How to achieve the first outcome? (maybe not by following the easy compromise of ‘one of each technology’) LCUK - Detector Report Chris Damerell

6. Previous history may not be the best guide … • SLC Experiments Workshop 1982 LCUK - Detector Report Chris Damerell

7. Forward tracking: a major challenge e+ e- t tbar, LCWS 1991. At first sight, a confusing spray of particles … LCUK - Detector Report Chris Damerell

8. The miracle of PFA (or equivalent) reveals the flow of energy from the quarks of the primary process But 2 out of 6 jets depend entirely on forward trkg. How good is this? For vertex charge determination, any of the 6 jets may have essential low-Pt tracks curled into the forward silicon system Previously, tracking performance has deteriorated badly in the forward region A chain is as strong as its weakest link LCUK - Detector Report Chris Damerell

9. Structure of this review • Collaboration reports provided an overview of the projects through to ‘completion’ of R&D, meaning ‘ready for design and construction’ • Open session presentations provided summaries of status and plans • Closed session was used to clarify technical and strategic issues • Closeout session: Committee informed collaborations of our draft recommendations, and obtained their verbal agreement • Report (after 5 drafts) was sent to WWS-OC chairs on 23rd March, and published on our Wiki site http://www.linearcollider.org/wiki/doku.php • WWS-OC chairs have suggested a small number of modifications, and collaborations will be invited to contribute appendices covering areas of disagreement • We (the committee) are hoping that our main recommendations will remain intact LCUK - Detector Report Chris Damerell

10. Main recommendations • Building a tracking system with excellent performance for qp >7 degrees will be challenging (John Womersley: ‘It’s very ambitious’) • The committee is convinced of the need to construct large prototypes (~1 m diameter), and operate them in 3-5 T field, under ILC-like beam conditions, to establish the performance for central and forward tracking • We see an opportunity (and a necessity) for enhanced coordination between the groups engaged in tracking R&D, and suggest the formation of a Tracking Coordination Group to achieve this • Among their responsibilities would be to ensure provision of suitable infrastructure, comprising a custom-designed test beam, solenoid, etc, and to coordinate use of these facilities • One tracker with each technology could provide the ‘baseline’ for the two ILC detector designs, with each technology forming an ‘alternative’ in case the other does not reach comparable performance • R&D results could be established by ~2012. Even on the most optimistic ILC schedule, this will be in time for decisions on tracking technologies • One-sentence summary of our Exec Summary: ‘Form a Tracking Coordination Group to coordinate the completion of the R&D programme, so that the community will be able to finalise the choice of tracking technologies for ILC detectors on the basis of these results’ LCUK - Detector Report Chris Damerell

11. Suggested split-coil solenoid Estimated cost ~$800k (Elwyn Baynham industrial contacts) LCUK - Detector Report Chris Damerell

12. Bz along solenoid axis Blue – with iron Red without iron LCUK - Detector Report Chris Damerell

13. Report from Detector Roadmap Group • WWS-OC chairs, 2 physicists per concept, R&D Panel chair, first met 20th March • Jim Brau, Francois Richard, Hitoshi Yamamoto, Ties Behnke, Henri Videau, Yasuhiro Sugimoto, Mark Thomson, Harry Weerts, John Jaros, John Hauptman, Sorina Popescu, Chris Damerell • How to condense from 4 concepts to two contrasting detector designs, to be taken to the point of EDs by 2010? • ILCSC will form an IDAG (MAC-equivalent body) to help • The definitive ILCSC meeting coincided with the Detector R&D Panel closeout meeting on 8th Feb in Beijing. Are there inconsistencies? We think not, by using the accelerator categories of baseline and alternative technologies where justified • We on the Tracking Review Committee wondered if detector R&D should perhaps be made the responsibility of the GDE, since it amounts to ~$30M p.a. against $150M p.a., so it is on the scale of a single RDB topic, but this suggestion was not popular with the WWS-OC chairs • Judging from the tracking review, the ILC detector community needs to be expanded, possibly with LHC physicists and (particularly) engineers now becoming available LCUK - Detector Report Chris Damerell

14. Possible structure for R&D coordination ILCSC * IDAG WWS-OC MAC GDE-EC Det R&D Panel RDB Coordination groups Task forces S0-S5 Accelerator R&D collaborations Detector R&D collaborations XXX not yet formed * an historical anomaly LCUK - Detector Report Chris Damerell

15. Pier Oddone, on the LHC inner triplet quadrupole string failure: • In this case we are dumbfounded that we missed some very simple balance of forces. Not only was it missed in the engineering design but also in the four engineering reviews carried out between 1998 and 2002 before launching the construction of the magnets. Furthermore even though every magnet was thoroughly tested individually, they were never tested with the exact configuration that they would have when installed at CERN—thus missing the opportunity to discover the problem sooner. • To the credit of the RDB, the S2 taskforce (string test of 3 RF cavities in a cryostat) has never been in doubt. What was discussed was whether it was essential to put a beam through the string, and here the conservative decision has also been to do so • Some detector people, who consider it sufficient only to test small prototypes, and rely entirely on simulations of large systems in the 3-5 T field, could perhaps learn from this • RDB priorities through the ED phase are driven mostly by considerations of reducing technical risk. The risk to ILC physics associated with an underperforming tracking system would be a good fraction of the total construction and operating cost of ILC. We cannot afford to get locked in to a technology choice till R&D is completed; would be irresponsible to suggest otherwise. Support for this R&D must be given high priority LCUK - Detector Report Chris Damerell

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