DD

Fermilab PMGJan 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 KotcherBrookhaven National Laboratory

D0 Collaboration

Fermilab PMG January 20, 2000

DD

Fermilab PMGJan 20, 2000

Overview

Have worked out two new approaches to detector installation

many options considered has grown out of detailed discussions

among principals and beyond: Project Management Sub-Project Managers (esp. Forward

Muon, Trackers, Calorimeter) Project Engineers Technical Supervisor, Forward Muon

survey coordinator,... a number of details remain that may

color how one thinks about each option none have any significant likelihood of

influencing feasibility Primary goals:

uninterrupted detector commissioning during end game

was very severe - breakdown of LHe ~ Nov 1 for 6 weeks

introduce contingency for the silicon was none

relieve pressure on end game by doing things early whenever possible

DD

Fermilab PMGJan 20, 2000

Overview

Primary Goals (cont’d) strive for plan that offers forgiving

contingency scheme, fallback possibilities for as many detectors as possible

flexibility New (any) scheme driven largely

by two primary constraints: Forward Muon installation

huge system that dictates position/movement of major pieces: end irons, trusses

logistics of Silicon and Fiber Tracker installation

DD

Fermilab PMGJan 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

Requires end toroids on platform For south end, also requires south

calorimeter on platform Must move platform to pick up end

irons

In order to install either inner tracker:

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

Without detectors, can be avoided

DD

Fermilab PMGJan 20, 2000

Basics

Previously: 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

~ Nov 1, 2000 End game paced/driven by movements

of these pieces thereafter

Two new schemes: Both have shield wall coming down to

install north truss in Collision Hall immediately after commissioning run

Nov 1, 2000 Scheme I:

Install south truss in Collision Hall during Aug, 2000 window

platform goes in last Scheme II (fallback):

platform follows north truss south truss installed in Collision Hall last

Advantages, disadvantages to each Both are better than previous version...

DD

Fermilab PMGJan 20, 2000

Old vs. New Installation

Scheme Have learned much in process:

can probably install B-layer MDTs and pixels while detector is in Collision Hall if need be

may be possible to reassemble south truss in pit without breaking helium (remove detectors)

north truss can go onto sidewalk anytime, independent of rest of end game

entire wall does not have to come down to install trusses

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

DD

Fermilab PMGJan 20, 2000

Cost/Benefit Gains derived from new schemes:

Helium interruptions end Sep (Jul) 2000 for early (late) south truss installation

Extended, uninterrupted commissioning of full experiment - including VLPC-based detectors - for at least last 4 months

6 months in case of late truss Commissioning of CFT was perilously

close to vanishing in old scheme Went from 0 to ~ 6-8 weeks contingency for

silicon in both schemes can arrive at D0 as late as mid-Nov

without delaying roll in (currently mid-Sep)

gained 2 months over next 9 - non-trivial must be willing to cable south end

detectors (CAL, FPS-S, ICD-S, LUM-S) in Collision Hall

Major installation task - south truss installation - done early in Scheme I

a large job we can put behind us - relieve some heat during end game

do they fit? Nice to know this early as possible in case modifications are needed

helps motivate/target completion of major component of Forward Muon system

DD

Fermilab PMGJan 20, 2000

Cost/Benefit Gains (cont’d):

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

very user-friendly configuration obviates the need for significant amount of

engineering, technical work needed otherwise

Forward Muon schedule says this is doable Survey of south truss in Collision Hall

greatly facilitated by Aug roll in (done in November)

Cost: 1 (early truss) - 2 (late truss) weeks at end

ready for beam was 2/6/01, now 2/13 (2/21) for early (late) truss

can relieve this by rolling in earlier if sensible (partially cable south detectors in CH)

early truss: one additional move of platform (south EF), shield wall (partially) broken down extra time

partially interrupts some installation and hookup

– electronics in platform can proceed: a bit hampered, but not seriously

diverts manpower from other DAB work at important time

DD

Fermilab PMGJan 20, 2000

Cost/Benefit

Cost (cont’d) early truss: significant interruption to

CFT hookup (Jul-Sep) - helium, detector access

part of cost for 4 months of full detector commissioning at end

Requires re-shuffling priorities of Forward Muon production

Significant impact to this effort (not always a bad thing!)

Priorities: A-layer installation, C-layer mounted to south truss

Filling calorimeter delayed ~ 2 weeks due to platform movement in Scheme I

CC cosmic running starts ~ Oct 1 (was Sep 20)

early test fill still feasible (Jul-Aug) Need additional week (3 week

window total) in Aug for truss installation

Accelerator Division’s estimates taken into account (roll out low beta quads,...)

believe this should pose no problems, but another week of contingency would probably make sense

DD

Fermilab PMGJan 20, 2000

Relevant Details for Scheme I

Detector back in configuration where it can accept either tracker on 9/8/00

earliest it can be back in position after truss installation

At present, silicon ready to install 9/19/00 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

will delay south truss assembly on south sidewalk - late for Aug roll in

compete with silicon installation/hookup delays (delicate) hookup of clear

waveguides leaves 3 weeks contingency from current

date decision on whether to pursue early south

truss installation must be made before end June; earlier to prepare

DD

Fermilab PMGJan 20, 2000

Our Plan

Are aggressively pursuing early south truss installation (Scheme I)

accomplishing large task early is worth cost in other areas

have shifted priorities in Forward Muon to accomplish this

pushing on Fiber Tracker production We will move platform ~ late spring

under any circumstances currently mid-June for early truss right now paced by arrival/installation of

Fiber Tracker 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:

by June 1 earlier if circumstances allow consistent with Accelerator Division’s

needs?

DD

Fermilab PMGJan 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 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.