1. Fermilab PMG Jan 20, 2000 Reconsideration of the Installation at D0  Overview  Major constraints  Basics of old, new schemes  Some details on each  Cost/benefit  Proposed plan  Conclusions Jon Kotcher Brookhaven National Laboratory D0 Collaboration Fermilab PMG January 20, 2000

2. Fermilab PMG Jan 20, 2000 Overview  Have worked out two new approaches to detector installation u many options considered u has grown out of detailed discussions among principals and beyond: s Project Management s Sub-Project Managers (esp. Forward Muon, Trackers, Calorimeter) s Project Engineers s Technical Supervisor, Forward Muon survey coordinator,... u a number of details remain that may color how one thinks about each option u none have any significant likelihood of influencing feasibility  Primary goals: u uninterrupted detector commissioning during end game s was very severe - breakdown of LHe ~ Nov 1 for 6 weeks u introduce contingency for the silicon s was none u relieve pressure on end game by doing things early whenever possible

3. Fermilab PMG Jan 20, 2000 Overview  Primary Goals (cont’d) u strive for plan that offers forgiving contingency scheme, fallback possibilities for as many detectors as possible u flexibility  New (any) scheme driven largely by two primary constraints: u Forward Muon installation s huge system that dictates position/movement of major pieces: end irons, trusses u logistics of Silicon and Fiber Tracker installation

4. Fermilab PMG Jan 20, 2000 Major Installation Constraints  South calorimeter must be on platform if platform is to be moved  At some point, north and south sidewalks must be clear to allow assembly of EMC trusses prior to rolling them into Collision Hall u Requires end toroids on platform s For south end, also requires south calorimeter on platform s Must move platform to pick up end irons  In order to install either inner tracker: u both south calorimeter and south end toroid must be on sidewalk to allow access to inner bore  Bringing down either truss from the Hi Bay, with its detectors mounted, requires LHe engines be disconnected u Without detectors, can be avoided

5. Fermilab PMG Jan 20, 2000 Basics  Previously: u No movement of any of the large pieces (N/S truss, end irons, detector platform) until both fiber tracker and silicon are installed and checked out s ~ Nov 1, 2000 u End game paced/driven by movements of these pieces thereafter  Two new schemes: u Both have shield wall coming down to install north truss in Collision Hall immediately after commissioning run s Nov 1, 2000 u Scheme I: s Install south truss in Collision Hall during Aug, 2000 window s platform goes in last u Scheme II (fallback): s platform follows north truss s south truss installed in Collision Hall last u Advantages, disadvantages to each u Both are better than previous version...

6. Fermilab PMG Jan 20, 2000 Old vs. New Installation Scheme  Have learned much in process: u can probably install B-layer MDTs and pixels while detector is in Collision Hall if need be u may be possible to reassemble south truss in pit without breaking helium (remove detectors) u north truss can go onto sidewalk anytime, independent of rest of end game u entire wall does not have to come down to install trusses u various positions of collision wall, surveying, positioning low beta quads, air handler interferences,...  What we’ve learned has greatly facilitated our ability to change course as project evolves

7. Fermilab PMG Jan 20, 2000 Cost/Benefit  Gains derived from new schemes: u Helium interruptions end Sep (Jul) 2000 for early (late) south truss installation s Extended, uninterrupted commissioning of full experiment - including VLPC-based detectors - for at least last 4 months s 6 months in case of late truss s Commissioning of CFT was perilously close to vanishing in old scheme u Went from 0 to ~ 6-8 weeks contingency for silicon in both schemes s can arrive at D0 as late as mid-Nov without delaying roll in (currently mid-Sep) s gained 2 months over next 9 - non-trivial s must be willing to cable south end detectors (CAL, FPS-S, ICD-S, LUM-S) in Collision Hall u Major installation task - south truss installation - done early in Scheme I s a large job we can put behind us - relieve some heat during end game s do they fit? Nice to know this early as possible in case modifications are needed s helps motivate/target completion of major component of Forward Muon system

8. Fermilab PMG Jan 20, 2000 Cost/Benefit  Gains (cont’d): u Early scheme gives 2+ month window (6/22 - 8/23) for B-layer south MDT and pixel installation while south end iron is on platform s very user-friendly configuration s obviates the need for significant amount of engineering, technical work needed otherwise s Forward Muon schedule says this is doable u Survey of south truss in Collision Hall greatly facilitated by Aug roll in (done in November)  Cost: u 1 (early truss) - 2 (late truss) weeks at end s ready for beam was 2/6/01, now 2/13 (2/21) for early (late) truss s can relieve this by rolling in earlier if sensible (partially cable south detectors in CH) u early truss: one additional move of platform (south EF), shield wall (partially) broken down extra time s partially interrupts some installation and hookup –electronics in platform can proceed: a bit hampered, but not seriously s diverts manpower from other DAB work at important time

9. Fermilab PMG Jan 20, 2000 Cost/Benefit  Cost (cont’d) u early truss: significant interruption to CFT hookup (Jul-Sep) - helium, detector access s part of cost for 4 months of full detector commissioning at end u Requires re-shuffling priorities of Forward Muon production s Significant impact to this effort (not always a bad thing!) s Priorities: A-layer installation, C-layer mounted to south truss u Filling calorimeter delayed ~ 2 weeks due to platform movement in Scheme I s CC cosmic running starts ~ Oct 1 (was Sep 20) s early test fill still feasible (Jul-Aug)  Need additional week (3 week window total) in Aug for truss installation u Accelerator Division’s estimates taken into account (roll out low beta quads,...) u believe this should pose no problems, but another week of contingency would probably make sense

10. Fermilab PMG Jan 20, 2000 Relevant Details for Scheme I  Detector back in configuration where it can accept either tracker on 9/8/00 u earliest it can be back in position after truss installation u At present, silicon ready to install 9/19/00 u If accelerator schedule slips, it will cost us to install south truss early  Fiber Tracker must be at D0 by 6/26/00 or its installation will be delayed until 9/8/00 u will delay south truss assembly on south sidewalk - late for Aug roll in u compete with silicon installation/hookup u delays (delicate) hookup of clear waveguides u leaves 3 weeks contingency from current date u decision on whether to pursue early south truss installation must be made before end June; earlier to prepare

11. Fermilab PMG Jan 20, 2000 Our Plan  Are aggressively pursuing early south truss installation (Scheme I) u accomplishing large task early is worth cost in other areas u have shifted priorities in Forward Muon to accomplish this u pushing on Fiber Tracker production  We will move platform ~ late spring under any circumstances u currently mid-June for early truss u right now paced by arrival/installation of Fiber Tracker u installation of A-layer MDTs and pixels should be complete (not necessary, in any case)  Will either pick up north end iron only (late truss), or both end irons (early truss), depending on scheme chosen  Decision on which way to go will be made as late as possible, but early enough to prepare: u by June 1 u earlier if circumstances allow u consistent with Accelerator Division’s needs?

12. Fermilab PMG Jan 20, 2000 Conclusions  Reconsideration of installation sequence has provided significant gains where they matter most  Both preferred scheme (I) and fallback (II) far more flexible than previous version  Decision-making branch point for early south truss installation identified u If scheme is adopted, need at least 1 additional week during August shutdown (2 preferred)  Installation organization in place, implementing collaboration-wide procedures, safety requirements for work in Hall, etc.