Installation and Commissioning Task

Overview

The installation and commissioning of the Advanced LIGO detector systems is planned to be as rapid as possible in order to minimize the observatory downtime. It requires the installation of all detector elements in all three LIGO interferometers in a phased approach to best utilize the infrastructure and manpower in the Laboratory and LSC. The subsystem teams are expected to have pre-assembled and pre-tested components available for installation when needed (some assembly and test can take place at the observatory sites in advance).

Functional Requirements

At the end of the installation and commissioning period Advanced LIGO should be running reliably near design sensitivity. The installation and commissioning effort must be done simultaneously with continued observatory site and LIGO Laboratory operations, though much of the staff will be diverted to installation and commissioning tasks.

Concept/Options

The basic conceptual plan for the installation is as follows:

• The installation and commissioning phase is under the direction and responsibility of the LIGO Laboratory. LSC members may contribute and assist. We assume that developers of technology in the LSC will participate in installation and commissioning of their respective components, though our planning assumes much of the labor required will come from the Laboratory staff or contractors.
• Full-scale subsystem testing is performed to prove out the design and fabrication of components, assemblies and subsystems and their interfaces wherever possible.
• System level testing of the full configuration (power and signal recycled Michelson with Fabry-Perot arm cavities) with as much of the full-scale hardware as possible (active seismic system, suspension system, etc.) is performed on the Caltech 40 Meter Interferometer and MIT LASTI testbeds
• Installation exercises will be carried out for the major mechanical subsystems at the MIT LASTI testbed, training the subsystem and observatory staff who will then carry our the installation at the observatories.
• Pre-assembly, pre-alignment and pre-testing (to the extent possible) is carried out for all subsystems prior to installation into the system. For example, the seismic systems will be fully preassembled and sealed for transport from onsite staging buildings into the vacuum equipment areas. Suspensions will be preassembled onsite up to attachment of the final silica fibers and test masses. These will be installed at the time the vacuum system is ready to receive the subsystems.
• In order to minimize observatory downtime, installation will not begin until all required fabrication is complete and all required assembly and unit level testing is complete.
• Two shifts of installation are planned only for labor-intensive activities on the critical path and held in reserve for contingency for non-critical tasks.
• The commissioning teams, as in initial LIGO, require expertise from multiple disciplines and subsystems. Staffing for the design and development phases of the Advanced LIGO effort are planned with the intent of providing this expertise.

One possible option in the overall program, which has significant impact on the installation and commissioning phase, is whether the initial LIGO 2 km interferometer is converted to a 4-km interferometer or operated in the initial LIGO configuration. The baseline for this proposal is that the 2km interferometer will be upgraded and the arm length will be extended to 4 km.

R&D Status/Development Issues

A rapid and predictable installation schedule requires well thought out and tested installation procedures and fixtures. LASTI will provide an opportunity to test these installation procedures in full-scale chambers and to train team leaders. This development is essential for successful installation of the interferometers.

System R&D and testing of the signal and power recycled configuration on the 40 Meter testbed is essential for the commissioning team to gain the experience and expertise that will be required.

Work Plan

In early 2007, the three initial LIGO interferometers will complete their coincident observation run and the Livingston instrument will be turned off. This event will trigger the start of installation activities. For many months prior to this point, the subsystem components will have been pre-positioned at the sites, assembled and tested, and the limiting pace should be set by the available skilled manpower. Near the end of 2007, the initial LIGO Hanford instruments will be turned off. The seismic isolation installation will be completed at Livingston by that time, and that installation team will migrate to Hanford for the commencement of installation there. This staggered pattern will continue with the suspensions, optics, and the other subsystems.

This is the baseline plan. The status of the global observing networks, agreements between projects, and scientific and technical developments may motivate altering the order of upgraded interferometers or the interval between installations of the successive interferometers.

The plan is to perform the physical installation as rapidly as possible to maximize the time for debugging, characterization and commissioning. This is enabled by the pre-deployment of all materials to the sites and by the full-scale testing which minimizes the risk of rework.

The top-down schedule is shown in Figure 1.

click on the image to enlarge

Figure 1 Top-level Advanced LIGO installation schedule

Detail Requirement Sheets

Baseline Plan