**D0 RESPONSES TO NOVEMBER 4, 1999 DOE REVIEW RECOMMENDATIONS**

**May 30, 2000**

**Silicon Tracker and Tracking Electronics**

1.  *Improve communication between the D-Zero silicon group; D-Zero
    project management, and SiDet management. Ensure that D-Zero is
    aware of the status of their requests for equipment and personnel.*

> D0 project management communicates with the silicon group through
> weekly project manager\'s meetings. D0 management also regularly
> attends silicon meetings. There are weekly SiDet liaison meetings
> where project needs are communicated to SiDet management.

2.  *The D-Zero silicon group should be provided with adequate technical
    manpower, particularly for post-production testing and rework*.

> The D0 silicon group currently has a staff of 13 technicians on
> detector and component assembly, 3 on barrel/disk assembly, and 7
> shared with CDF on bonding and repair work. This group is producing
> and repairing HDI laminations, ladders and wedges, as well as disk and
> barrel assemblies. All of this work is done in parallel. Manpower is
> adequate, but we expect to be under some stress when barrel, F disk,
> and H disk assembly work is fully ramped up and manpower may have to
> be reassigned to the highest priority subprojects. The laboratory has
> added two temporary physicist positions which have been very important
> to the production and assembly efforts. Much of our technical support
> is through visitors to Fermilab. Those who cannot stay for the
> duration of the project must be replaced.

3.  *Re-evaluate the January 1, 2000, decision date for descoping the
    SMT, in view of the following recommendation.*

> See answer for 5.

4.  *By May 1, 2000, the collaboration should submit a detailed SMT
    installation plan to Fermilab management. The plan should specify
    any descoping that is necessary to meet the laboratory schedule.*

> See answer for 5.

5.  *Develop time contingency in the silicon schedule to allow for
    unforeseen delays.*

> Response to recommendations 3, 4 and 5: The Silicon group has
> re-evaluated plans for installation of the SMT within the D0 detector.
> As a result of this re-evaluation a new plan was developed which
> involves cutting the silicon support cylinder in half and installing
> each half-cylinder independently. This new design allows the detector
> to be installed in the 39\" of space available after the end
> calorimeters are in position on the platform. We now have the
> opportunity to install silicon half-cylinders at any time after the
> fiber tracker installation. This includes installation (and removal)
> of half-cylinders in the collision hall. The new design generates more
> than three months of contingency over the single cylinder design.
> Details of the new installation plan have been presented to the
> Fermilab management in several PMGs.
>
> We have revised our installation schedule based on the half cylinder
> design. The fallback plan presented to the laboratory using the
> revised installation schedule includes fallback decision dates of July
> 1 and September 1 based on the number of detector modules produced.

**Fiber Tracker**

1.  *The D-Zero Collaboration and project management should promptly
    evaluate the impact of looser tolerances for axial ribbon alignment
    or inter-cylinder alignment on the Level 1 trigger*.

> The design tolerances have been met, so this is now a moot point.

2.  *The D-Zero Collaboration and project management should identify two
    to three new post-doc level physicists to be added to the Fiber
    Tracker project in the very near term.*

> Two postdocs were added to this subproject since the last review.

3.  *Resume production of ribbon-mounting on production cylinders as
    soon as possible.*

> Ribbon mounting is complete.

4.  *Complete trial assembly of nested cylinders before the end of
    December 1999*.

> Nesting is on schedule and being done to specification. The final two
> innermost cylinders are in the final stages of assembly.

5.  *Explore the consequences of late delivery of the Fiber Tracker on
    the detector installation schedule.*

> The fiber tracker is nearing completion, and it is presently on
> schedule. We have been optimizing the installation schedule to
> generate sufficient schedule contingency to accommodate any
> foreseeable delays in the fiber tracker and/or silicon tracker
> delivery.

6.  *Prepare a commissioning plan for summer and fall cosmic running,
    including online software and physics goals.*

> We have appointed a commissioning coordinator who is developing
> commissioning plans. Internal commissioning milestones have been
> developed, and the first ones that exercise the DAQ system and the
> muon and calorimeter readout have been met.

**Muon Detectors**

1.  *The D-Zero Collaboration and project management should make timely
    decisions of relaxing technical requirements and tolerances should
    these prove difficult to achieve while still maintaining
    production.*.

> The trigger pixel octants have been assembled to specifications. The
> MDT octant construction is well underway with the smaller A layer
> complete, the B layer octants tubes are fully tested, and the C layer
> octant parts in hand. We have met the required tolerances, and this is
> not an issue for maintaining production rates.

2.  *Find ways to win back lost schedule contingency by increasing
    production rates of forward muon systems octant assembly*.

> This has been done in the case of the trigger pixel octants. They were
> completed ahead of schedule. The MDT octants are presently on schedule
> for production completion. The installation schedule is being
> optimized to generate schedule contingency where possible for the muon
> system.

**Installation and Commissioning**

1.  *Develop a fall-back plan that will assure D-Zero will meet the
    ready for beam milestone (stated as February 2, 2001) by May 1,
    2000.*

> Fallback plans have been developed. A document describing the physics
> impact and the decision dates for fallback plan implementation are
> available.

2.  *Further develop a detailed resource-loaded commissioning plan and
    goals by January 30, 2000*.

> The commissioning coordinator is developing a set of milestones that
> cover the commissioning goals. A more detailed understanding of the
> resource needs is under development.